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authorJens Axboe2008-01-29 07:53:40 -0600
committerJens Axboe2008-01-29 14:55:08 -0600
commit86db1e29772372155db08ff48a9ceb76e11a2ad1 (patch)
tree312f38eb3245873c476c50f816b85610fef9615a /block
parent8324aa91d1e11a1fc25f209687a0b2e6c2ed47d0 (diff)
downloadkernel-common-86db1e29772372155db08ff48a9ceb76e11a2ad1.tar.gz
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block: continue ll_rw_blk.c splitup
Adds files for barrier handling, rq execution, io context handling, mapping data to requests, and queue settings. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/Makefile5
-rw-r--r--block/blk-barrier.c319
-rw-r--r--block/blk-core.c1255
-rw-r--r--block/blk-exec.c105
-rw-r--r--block/blk-ioc.c194
-rw-r--r--block/blk-map.c264
-rw-r--r--block/blk-settings.c402
-rw-r--r--block/blk.h17
8 files changed, 1312 insertions, 1249 deletions
diff --git a/block/Makefile b/block/Makefile
index fcaae4ae670..2002046d0a9 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -2,8 +2,9 @@
2# Makefile for the kernel block layer 2# Makefile for the kernel block layer
3# 3#
4 4
5obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o ioctl.o \ 5obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \
6 genhd.o scsi_ioctl.o 6 blk-barrier.o blk-settings.o blk-ioc.o blk-map.o \
7 blk-exec.o ioctl.o genhd.o scsi_ioctl.o
7 8
8obj-$(CONFIG_BLK_DEV_BSG) += bsg.o 9obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
9obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o 10obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
diff --git a/block/blk-barrier.c b/block/blk-barrier.c
new file mode 100644
index 00000000000..5f74fec327d
--- /dev/null
+++ b/block/blk-barrier.c
@@ -0,0 +1,319 @@
1/*
2 * Functions related to barrier IO handling
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
8
9#include "blk.h"
10
11/**
12 * blk_queue_ordered - does this queue support ordered writes
13 * @q: the request queue
14 * @ordered: one of QUEUE_ORDERED_*
15 * @prepare_flush_fn: rq setup helper for cache flush ordered writes
16 *
17 * Description:
18 * For journalled file systems, doing ordered writes on a commit
19 * block instead of explicitly doing wait_on_buffer (which is bad
20 * for performance) can be a big win. Block drivers supporting this
21 * feature should call this function and indicate so.
22 *
23 **/
24int blk_queue_ordered(struct request_queue *q, unsigned ordered,
25 prepare_flush_fn *prepare_flush_fn)
26{
27 if (ordered & (QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH) &&
28 prepare_flush_fn == NULL) {
29 printk(KERN_ERR "blk_queue_ordered: prepare_flush_fn required\n");
30 return -EINVAL;
31 }
32
33 if (ordered != QUEUE_ORDERED_NONE &&
34 ordered != QUEUE_ORDERED_DRAIN &&
35 ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
36 ordered != QUEUE_ORDERED_DRAIN_FUA &&
37 ordered != QUEUE_ORDERED_TAG &&
38 ordered != QUEUE_ORDERED_TAG_FLUSH &&
39 ordered != QUEUE_ORDERED_TAG_FUA) {
40 printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered);
41 return -EINVAL;
42 }
43
44 q->ordered = ordered;
45 q->next_ordered = ordered;
46 q->prepare_flush_fn = prepare_flush_fn;
47
48 return 0;
49}
50
51EXPORT_SYMBOL(blk_queue_ordered);
52
53/*
54 * Cache flushing for ordered writes handling
55 */
56inline unsigned blk_ordered_cur_seq(struct request_queue *q)
57{
58 if (!q->ordseq)
59 return 0;
60 return 1 << ffz(q->ordseq);
61}
62
63unsigned blk_ordered_req_seq(struct request *rq)
64{
65 struct request_queue *q = rq->q;
66
67 BUG_ON(q->ordseq == 0);
68
69 if (rq == &q->pre_flush_rq)
70 return QUEUE_ORDSEQ_PREFLUSH;
71 if (rq == &q->bar_rq)
72 return QUEUE_ORDSEQ_BAR;
73 if (rq == &q->post_flush_rq)
74 return QUEUE_ORDSEQ_POSTFLUSH;
75
76 /*
77 * !fs requests don't need to follow barrier ordering. Always
78 * put them at the front. This fixes the following deadlock.
79 *
80 * http://thread.gmane.org/gmane.linux.kernel/537473
81 */
82 if (!blk_fs_request(rq))
83 return QUEUE_ORDSEQ_DRAIN;
84
85 if ((rq->cmd_flags & REQ_ORDERED_COLOR) ==
86 (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR))
87 return QUEUE_ORDSEQ_DRAIN;
88 else
89 return QUEUE_ORDSEQ_DONE;
90}
91
92void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
93{
94 struct request *rq;
95
96 if (error && !q->orderr)
97 q->orderr = error;
98
99 BUG_ON(q->ordseq & seq);
100 q->ordseq |= seq;
101
102 if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE)
103 return;
104
105 /*
106 * Okay, sequence complete.
107 */
108 q->ordseq = 0;
109 rq = q->orig_bar_rq;
110
111 if (__blk_end_request(rq, q->orderr, blk_rq_bytes(rq)))
112 BUG();
113}
114
115static void pre_flush_end_io(struct request *rq, int error)
116{
117 elv_completed_request(rq->q, rq);
118 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error);
119}
120
121static void bar_end_io(struct request *rq, int error)
122{
123 elv_completed_request(rq->q, rq);
124 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error);
125}
126
127static void post_flush_end_io(struct request *rq, int error)
128{
129 elv_completed_request(rq->q, rq);
130 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error);
131}
132
133static void queue_flush(struct request_queue *q, unsigned which)
134{
135 struct request *rq;
136 rq_end_io_fn *end_io;
137
138 if (which == QUEUE_ORDERED_PREFLUSH) {
139 rq = &q->pre_flush_rq;
140 end_io = pre_flush_end_io;
141 } else {
142 rq = &q->post_flush_rq;
143 end_io = post_flush_end_io;
144 }
145
146 rq->cmd_flags = REQ_HARDBARRIER;
147 rq_init(q, rq);
148 rq->elevator_private = NULL;
149 rq->elevator_private2 = NULL;
150 rq->rq_disk = q->bar_rq.rq_disk;
151 rq->end_io = end_io;
152 q->prepare_flush_fn(q, rq);
153
154 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
155}
156
157static inline struct request *start_ordered(struct request_queue *q,
158 struct request *rq)
159{
160 q->orderr = 0;
161 q->ordered = q->next_ordered;
162 q->ordseq |= QUEUE_ORDSEQ_STARTED;
163
164 /*
165 * Prep proxy barrier request.
166 */
167 blkdev_dequeue_request(rq);
168 q->orig_bar_rq = rq;
169 rq = &q->bar_rq;
170 rq->cmd_flags = 0;
171 rq_init(q, rq);
172 if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
173 rq->cmd_flags |= REQ_RW;
174 if (q->ordered & QUEUE_ORDERED_FUA)
175 rq->cmd_flags |= REQ_FUA;
176 rq->elevator_private = NULL;
177 rq->elevator_private2 = NULL;
178 init_request_from_bio(rq, q->orig_bar_rq->bio);
179 rq->end_io = bar_end_io;
180
181 /*
182 * Queue ordered sequence. As we stack them at the head, we
183 * need to queue in reverse order. Note that we rely on that
184 * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs
185 * request gets inbetween ordered sequence. If this request is
186 * an empty barrier, we don't need to do a postflush ever since
187 * there will be no data written between the pre and post flush.
188 * Hence a single flush will suffice.
189 */
190 if ((q->ordered & QUEUE_ORDERED_POSTFLUSH) && !blk_empty_barrier(rq))
191 queue_flush(q, QUEUE_ORDERED_POSTFLUSH);
192 else
193 q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH;
194
195 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
196
197 if (q->ordered & QUEUE_ORDERED_PREFLUSH) {
198 queue_flush(q, QUEUE_ORDERED_PREFLUSH);
199 rq = &q->pre_flush_rq;
200 } else
201 q->ordseq |= QUEUE_ORDSEQ_PREFLUSH;
202
203 if ((q->ordered & QUEUE_ORDERED_TAG) || q->in_flight == 0)
204 q->ordseq |= QUEUE_ORDSEQ_DRAIN;
205 else
206 rq = NULL;
207
208 return rq;
209}
210
211int blk_do_ordered(struct request_queue *q, struct request **rqp)
212{
213 struct request *rq = *rqp;
214 const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
215
216 if (!q->ordseq) {
217 if (!is_barrier)
218 return 1;
219
220 if (q->next_ordered != QUEUE_ORDERED_NONE) {
221 *rqp = start_ordered(q, rq);
222 return 1;
223 } else {
224 /*
225 * This can happen when the queue switches to
226 * ORDERED_NONE while this request is on it.
227 */
228 blkdev_dequeue_request(rq);
229 if (__blk_end_request(rq, -EOPNOTSUPP,
230 blk_rq_bytes(rq)))
231 BUG();
232 *rqp = NULL;
233 return 0;
234 }
235 }
236
237 /*
238 * Ordered sequence in progress
239 */
240
241 /* Special requests are not subject to ordering rules. */
242 if (!blk_fs_request(rq) &&
243 rq != &q->pre_flush_rq && rq != &q->post_flush_rq)
244 return 1;
245
246 if (q->ordered & QUEUE_ORDERED_TAG) {
247 /* Ordered by tag. Blocking the next barrier is enough. */
248 if (is_barrier && rq != &q->bar_rq)
249 *rqp = NULL;
250 } else {
251 /* Ordered by draining. Wait for turn. */
252 WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));
253 if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))
254 *rqp = NULL;
255 }
256
257 return 1;
258}
259
260static void bio_end_empty_barrier(struct bio *bio, int err)
261{
262 if (err)
263 clear_bit(BIO_UPTODATE, &bio->bi_flags);
264
265 complete(bio->bi_private);
266}
267
268/**
269 * blkdev_issue_flush - queue a flush
270 * @bdev: blockdev to issue flush for
271 * @error_sector: error sector
272 *
273 * Description:
274 * Issue a flush for the block device in question. Caller can supply
275 * room for storing the error offset in case of a flush error, if they
276 * wish to. Caller must run wait_for_completion() on its own.
277 */
278int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
279{
280 DECLARE_COMPLETION_ONSTACK(wait);
281 struct request_queue *q;
282 struct bio *bio;
283 int ret;
284
285 if (bdev->bd_disk == NULL)
286 return -ENXIO;
287
288 q = bdev_get_queue(bdev);
289 if (!q)
290 return -ENXIO;
291
292 bio = bio_alloc(GFP_KERNEL, 0);
293 if (!bio)
294 return -ENOMEM;
295
296 bio->bi_end_io = bio_end_empty_barrier;
297 bio->bi_private = &wait;
298 bio->bi_bdev = bdev;
299 submit_bio(1 << BIO_RW_BARRIER, bio);
300
301 wait_for_completion(&wait);
302
303 /*
304 * The driver must store the error location in ->bi_sector, if
305 * it supports it. For non-stacked drivers, this should be copied
306 * from rq->sector.
307 */
308 if (error_sector)
309 *error_sector = bio->bi_sector;
310
311 ret = 0;
312 if (!bio_flagged(bio, BIO_UPTODATE))
313 ret = -EIO;
314
315 bio_put(bio);
316 return ret;
317}
318
319EXPORT_SYMBOL(blkdev_issue_flush);
diff --git a/block/blk-core.c b/block/blk-core.c
index 937f9d0b9bd..2c73ed1a813 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -20,7 +20,6 @@
20#include <linux/kernel_stat.h> 20#include <linux/kernel_stat.h>
21#include <linux/string.h> 21#include <linux/string.h>
22#include <linux/init.h> 22#include <linux/init.h>
23#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
24#include <linux/completion.h> 23#include <linux/completion.h>
25#include <linux/slab.h> 24#include <linux/slab.h>
26#include <linux/swap.h> 25#include <linux/swap.h>
@@ -34,20 +33,9 @@
34 33
35#include "blk.h" 34#include "blk.h"
36 35
37/*
38 * for max sense size
39 */
40#include <scsi/scsi_cmnd.h>
41
42static void blk_unplug_work(struct work_struct *work);
43static void blk_unplug_timeout(unsigned long data);
44static void drive_stat_acct(struct request *rq, int new_io); 36static void drive_stat_acct(struct request *rq, int new_io);
45static void init_request_from_bio(struct request *req, struct bio *bio);
46static int __make_request(struct request_queue *q, struct bio *bio); 37static int __make_request(struct request_queue *q, struct bio *bio);
47static struct io_context *current_io_context(gfp_t gfp_flags, int node);
48static void blk_recalc_rq_segments(struct request *rq); 38static void blk_recalc_rq_segments(struct request *rq);
49static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
50 struct bio *bio);
51 39
52/* 40/*
53 * For the allocated request tables 41 * For the allocated request tables
@@ -60,28 +48,12 @@ struct kmem_cache *request_cachep;
60struct kmem_cache *blk_requestq_cachep = NULL; 48struct kmem_cache *blk_requestq_cachep = NULL;
61 49
62/* 50/*
63 * For io context allocations
64 */
65static struct kmem_cache *iocontext_cachep;
66
67/*
68 * Controlling structure to kblockd 51 * Controlling structure to kblockd
69 */ 52 */
70static struct workqueue_struct *kblockd_workqueue; 53static struct workqueue_struct *kblockd_workqueue;
71 54
72unsigned long blk_max_low_pfn, blk_max_pfn;
73
74EXPORT_SYMBOL(blk_max_low_pfn);
75EXPORT_SYMBOL(blk_max_pfn);
76
77static DEFINE_PER_CPU(struct list_head, blk_cpu_done); 55static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
78 56
79/* Amount of time in which a process may batch requests */
80#define BLK_BATCH_TIME (HZ/50UL)
81
82/* Number of requests a "batching" process may submit */
83#define BLK_BATCH_REQ 32
84
85void blk_queue_congestion_threshold(struct request_queue *q) 57void blk_queue_congestion_threshold(struct request_queue *q)
86{ 58{
87 int nr; 59 int nr;
@@ -117,113 +89,7 @@ struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
117} 89}
118EXPORT_SYMBOL(blk_get_backing_dev_info); 90EXPORT_SYMBOL(blk_get_backing_dev_info);
119 91
120/** 92void rq_init(struct request_queue *q, struct request *rq)
121 * blk_queue_prep_rq - set a prepare_request function for queue
122 * @q: queue
123 * @pfn: prepare_request function
124 *
125 * It's possible for a queue to register a prepare_request callback which
126 * is invoked before the request is handed to the request_fn. The goal of
127 * the function is to prepare a request for I/O, it can be used to build a
128 * cdb from the request data for instance.
129 *
130 */
131void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
132{
133 q->prep_rq_fn = pfn;
134}
135
136EXPORT_SYMBOL(blk_queue_prep_rq);
137
138/**
139 * blk_queue_merge_bvec - set a merge_bvec function for queue
140 * @q: queue
141 * @mbfn: merge_bvec_fn
142 *
143 * Usually queues have static limitations on the max sectors or segments that
144 * we can put in a request. Stacking drivers may have some settings that
145 * are dynamic, and thus we have to query the queue whether it is ok to
146 * add a new bio_vec to a bio at a given offset or not. If the block device
147 * has such limitations, it needs to register a merge_bvec_fn to control
148 * the size of bio's sent to it. Note that a block device *must* allow a
149 * single page to be added to an empty bio. The block device driver may want
150 * to use the bio_split() function to deal with these bio's. By default
151 * no merge_bvec_fn is defined for a queue, and only the fixed limits are
152 * honored.
153 */
154void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
155{
156 q->merge_bvec_fn = mbfn;
157}
158
159EXPORT_SYMBOL(blk_queue_merge_bvec);
160
161void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
162{
163 q->softirq_done_fn = fn;
164}
165
166EXPORT_SYMBOL(blk_queue_softirq_done);
167
168/**
169 * blk_queue_make_request - define an alternate make_request function for a device
170 * @q: the request queue for the device to be affected
171 * @mfn: the alternate make_request function
172 *
173 * Description:
174 * The normal way for &struct bios to be passed to a device
175 * driver is for them to be collected into requests on a request
176 * queue, and then to allow the device driver to select requests
177 * off that queue when it is ready. This works well for many block
178 * devices. However some block devices (typically virtual devices
179 * such as md or lvm) do not benefit from the processing on the
180 * request queue, and are served best by having the requests passed
181 * directly to them. This can be achieved by providing a function
182 * to blk_queue_make_request().
183 *
184 * Caveat:
185 * The driver that does this *must* be able to deal appropriately
186 * with buffers in "highmemory". This can be accomplished by either calling
187 * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
188 * blk_queue_bounce() to create a buffer in normal memory.
189 **/
190void blk_queue_make_request(struct request_queue * q, make_request_fn * mfn)
191{
192 /*
193 * set defaults
194 */
195 q->nr_requests = BLKDEV_MAX_RQ;
196 blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
197 blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
198 q->make_request_fn = mfn;
199 q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
200 q->backing_dev_info.state = 0;
201 q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
202 blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
203 blk_queue_hardsect_size(q, 512);
204 blk_queue_dma_alignment(q, 511);
205 blk_queue_congestion_threshold(q);
206 q->nr_batching = BLK_BATCH_REQ;
207
208 q->unplug_thresh = 4; /* hmm */
209 q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */
210 if (q->unplug_delay == 0)
211 q->unplug_delay = 1;
212
213 INIT_WORK(&q->unplug_work, blk_unplug_work);
214
215 q->unplug_timer.function = blk_unplug_timeout;
216 q->unplug_timer.data = (unsigned long)q;
217
218 /*
219 * by default assume old behaviour and bounce for any highmem page
220 */
221 blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
222}
223
224EXPORT_SYMBOL(blk_queue_make_request);
225
226static void rq_init(struct request_queue *q, struct request *rq)
227{ 93{
228 INIT_LIST_HEAD(&rq->queuelist); 94 INIT_LIST_HEAD(&rq->queuelist);
229 INIT_LIST_HEAD(&rq->donelist); 95 INIT_LIST_HEAD(&rq->donelist);
@@ -247,255 +113,6 @@ static void rq_init(struct request_queue *q, struct request *rq)
247 rq->next_rq = NULL; 113 rq->next_rq = NULL;
248} 114}
249 115
250/**
251 * blk_queue_ordered - does this queue support ordered writes
252 * @q: the request queue
253 * @ordered: one of QUEUE_ORDERED_*
254 * @prepare_flush_fn: rq setup helper for cache flush ordered writes
255 *
256 * Description:
257 * For journalled file systems, doing ordered writes on a commit
258 * block instead of explicitly doing wait_on_buffer (which is bad
259 * for performance) can be a big win. Block drivers supporting this
260 * feature should call this function and indicate so.
261 *
262 **/
263int blk_queue_ordered(struct request_queue *q, unsigned ordered,
264 prepare_flush_fn *prepare_flush_fn)
265{
266 if (ordered & (QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH) &&
267 prepare_flush_fn == NULL) {
268 printk(KERN_ERR "blk_queue_ordered: prepare_flush_fn required\n");
269 return -EINVAL;
270 }
271
272 if (ordered != QUEUE_ORDERED_NONE &&
273 ordered != QUEUE_ORDERED_DRAIN &&
274 ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
275 ordered != QUEUE_ORDERED_DRAIN_FUA &&
276 ordered != QUEUE_ORDERED_TAG &&
277 ordered != QUEUE_ORDERED_TAG_FLUSH &&
278 ordered != QUEUE_ORDERED_TAG_FUA) {
279 printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered);
280 return -EINVAL;
281 }
282
283 q->ordered = ordered;
284 q->next_ordered = ordered;
285 q->prepare_flush_fn = prepare_flush_fn;
286
287 return 0;
288}
289
290EXPORT_SYMBOL(blk_queue_ordered);
291
292/*
293 * Cache flushing for ordered writes handling
294 */
295inline unsigned blk_ordered_cur_seq(struct request_queue *q)
296{
297 if (!q->ordseq)
298 return 0;
299 return 1 << ffz(q->ordseq);
300}
301
302unsigned blk_ordered_req_seq(struct request *rq)
303{
304 struct request_queue *q = rq->q;
305
306 BUG_ON(q->ordseq == 0);
307
308 if (rq == &q->pre_flush_rq)
309 return QUEUE_ORDSEQ_PREFLUSH;
310 if (rq == &q->bar_rq)
311 return QUEUE_ORDSEQ_BAR;
312 if (rq == &q->post_flush_rq)
313 return QUEUE_ORDSEQ_POSTFLUSH;
314
315 /*
316 * !fs requests don't need to follow barrier ordering. Always
317 * put them at the front. This fixes the following deadlock.
318 *
319 * http://thread.gmane.org/gmane.linux.kernel/537473
320 */
321 if (!blk_fs_request(rq))
322 return QUEUE_ORDSEQ_DRAIN;
323
324 if ((rq->cmd_flags & REQ_ORDERED_COLOR) ==
325 (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR))
326 return QUEUE_ORDSEQ_DRAIN;
327 else
328 return QUEUE_ORDSEQ_DONE;
329}
330
331void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
332{
333 struct request *rq;
334
335 if (error && !q->orderr)
336 q->orderr = error;
337
338 BUG_ON(q->ordseq & seq);
339 q->ordseq |= seq;
340
341 if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE)
342 return;
343
344 /*
345 * Okay, sequence complete.
346 */
347 q->ordseq = 0;
348 rq = q->orig_bar_rq;
349
350 if (__blk_end_request(rq, q->orderr, blk_rq_bytes(rq)))
351 BUG();
352}
353
354static void pre_flush_end_io(struct request *rq, int error)
355{
356 elv_completed_request(rq->q, rq);
357 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error);
358}
359
360static void bar_end_io(struct request *rq, int error)
361{
362 elv_completed_request(rq->q, rq);
363 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error);
364}
365
366static void post_flush_end_io(struct request *rq, int error)
367{
368 elv_completed_request(rq->q, rq);
369 blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error);
370}
371
372static void queue_flush(struct request_queue *q, unsigned which)
373{
374 struct request *rq;
375 rq_end_io_fn *end_io;
376
377 if (which == QUEUE_ORDERED_PREFLUSH) {
378 rq = &q->pre_flush_rq;
379 end_io = pre_flush_end_io;
380 } else {
381 rq = &q->post_flush_rq;
382 end_io = post_flush_end_io;
383 }
384
385 rq->cmd_flags = REQ_HARDBARRIER;
386 rq_init(q, rq);
387 rq->elevator_private = NULL;
388 rq->elevator_private2 = NULL;
389 rq->rq_disk = q->bar_rq.rq_disk;
390 rq->end_io = end_io;
391 q->prepare_flush_fn(q, rq);
392
393 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
394}
395
396static inline struct request *start_ordered(struct request_queue *q,
397 struct request *rq)
398{
399 q->orderr = 0;
400 q->ordered = q->next_ordered;
401 q->ordseq |= QUEUE_ORDSEQ_STARTED;
402
403 /*
404 * Prep proxy barrier request.
405 */
406 blkdev_dequeue_request(rq);
407 q->orig_bar_rq = rq;
408 rq = &q->bar_rq;
409 rq->cmd_flags = 0;
410 rq_init(q, rq);
411 if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
412 rq->cmd_flags |= REQ_RW;
413 if (q->ordered & QUEUE_ORDERED_FUA)
414 rq->cmd_flags |= REQ_FUA;
415 rq->elevator_private = NULL;
416 rq->elevator_private2 = NULL;
417 init_request_from_bio(rq, q->orig_bar_rq->bio);
418 rq->end_io = bar_end_io;
419
420 /*
421 * Queue ordered sequence. As we stack them at the head, we
422 * need to queue in reverse order. Note that we rely on that
423 * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs
424 * request gets inbetween ordered sequence. If this request is
425 * an empty barrier, we don't need to do a postflush ever since
426 * there will be no data written between the pre and post flush.
427 * Hence a single flush will suffice.
428 */
429 if ((q->ordered & QUEUE_ORDERED_POSTFLUSH) && !blk_empty_barrier(rq))
430 queue_flush(q, QUEUE_ORDERED_POSTFLUSH);
431 else
432 q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH;
433
434 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
435
436 if (q->ordered & QUEUE_ORDERED_PREFLUSH) {
437 queue_flush(q, QUEUE_ORDERED_PREFLUSH);
438 rq = &q->pre_flush_rq;
439 } else
440 q->ordseq |= QUEUE_ORDSEQ_PREFLUSH;
441
442 if ((q->ordered & QUEUE_ORDERED_TAG) || q->in_flight == 0)
443 q->ordseq |= QUEUE_ORDSEQ_DRAIN;
444 else
445 rq = NULL;
446
447 return rq;
448}
449
450int blk_do_ordered(struct request_queue *q, struct request **rqp)
451{
452 struct request *rq = *rqp;
453 const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
454
455 if (!q->ordseq) {
456 if (!is_barrier)
457 return 1;
458
459 if (q->next_ordered != QUEUE_ORDERED_NONE) {
460 *rqp = start_ordered(q, rq);
461 return 1;
462 } else {
463 /*
464 * This can happen when the queue switches to
465 * ORDERED_NONE while this request is on it.
466 */
467 blkdev_dequeue_request(rq);
468 if (__blk_end_request(rq, -EOPNOTSUPP,
469 blk_rq_bytes(rq)))
470 BUG();
471 *rqp = NULL;
472 return 0;
473 }
474 }
475
476 /*
477 * Ordered sequence in progress
478 */
479
480 /* Special requests are not subject to ordering rules. */
481 if (!blk_fs_request(rq) &&
482 rq != &q->pre_flush_rq && rq != &q->post_flush_rq)
483 return 1;
484
485 if (q->ordered & QUEUE_ORDERED_TAG) {
486 /* Ordered by tag. Blocking the next barrier is enough. */
487 if (is_barrier && rq != &q->bar_rq)
488 *rqp = NULL;
489 } else {
490 /* Ordered by draining. Wait for turn. */
491 WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));
492 if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))
493 *rqp = NULL;
494 }
495
496 return 1;
497}
498
499static void req_bio_endio(struct request *rq, struct bio *bio, 116static void req_bio_endio(struct request *rq, struct bio *bio,
500 unsigned int nbytes, int error) 117 unsigned int nbytes, int error)
501{ 118{
@@ -528,279 +145,6 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
528 } 145 }
529} 146}
530 147
531/**
532 * blk_queue_bounce_limit - set bounce buffer limit for queue
533 * @q: the request queue for the device
534 * @dma_addr: bus address limit
535 *
536 * Description:
537 * Different hardware can have different requirements as to what pages
538 * it can do I/O directly to. A low level driver can call
539 * blk_queue_bounce_limit to have lower memory pages allocated as bounce
540 * buffers for doing I/O to pages residing above @page.
541 **/
542void blk_queue_bounce_limit(struct request_queue *q, u64 dma_addr)
543{
544 unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT;
545 int dma = 0;
546
547 q->bounce_gfp = GFP_NOIO;
548#if BITS_PER_LONG == 64
549 /* Assume anything <= 4GB can be handled by IOMMU.
550 Actually some IOMMUs can handle everything, but I don't
551 know of a way to test this here. */
552 if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
553 dma = 1;
554 q->bounce_pfn = max_low_pfn;
555#else
556 if (bounce_pfn < blk_max_low_pfn)
557 dma = 1;
558 q->bounce_pfn = bounce_pfn;
559#endif
560 if (dma) {
561 init_emergency_isa_pool();
562 q->bounce_gfp = GFP_NOIO | GFP_DMA;
563 q->bounce_pfn = bounce_pfn;
564 }
565}
566
567EXPORT_SYMBOL(blk_queue_bounce_limit);
568
569/**
570 * blk_queue_max_sectors - set max sectors for a request for this queue
571 * @q: the request queue for the device
572 * @max_sectors: max sectors in the usual 512b unit
573 *
574 * Description:
575 * Enables a low level driver to set an upper limit on the size of
576 * received requests.
577 **/
578void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors)
579{
580 if ((max_sectors << 9) < PAGE_CACHE_SIZE) {
581 max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
582 printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
583 }
584
585 if (BLK_DEF_MAX_SECTORS > max_sectors)
586 q->max_hw_sectors = q->max_sectors = max_sectors;
587 else {
588 q->max_sectors = BLK_DEF_MAX_SECTORS;
589 q->max_hw_sectors = max_sectors;
590 }
591}
592
593EXPORT_SYMBOL(blk_queue_max_sectors);
594
595/**
596 * blk_queue_max_phys_segments - set max phys segments for a request for this queue
597 * @q: the request queue for the device
598 * @max_segments: max number of segments
599 *
600 * Description:
601 * Enables a low level driver to set an upper limit on the number of
602 * physical data segments in a request. This would be the largest sized
603 * scatter list the driver could handle.
604 **/
605void blk_queue_max_phys_segments(struct request_queue *q,
606 unsigned short max_segments)
607{
608 if (!max_segments) {
609 max_segments = 1;
610 printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
611 }
612
613 q->max_phys_segments = max_segments;
614}
615
616EXPORT_SYMBOL(blk_queue_max_phys_segments);
617
618/**
619 * blk_queue_max_hw_segments - set max hw segments for a request for this queue
620 * @q: the request queue for the device
621 * @max_segments: max number of segments
622 *
623 * Description:
624 * Enables a low level driver to set an upper limit on the number of
625 * hw data segments in a request. This would be the largest number of
626 * address/length pairs the host adapter can actually give as once
627 * to the device.
628 **/
629void blk_queue_max_hw_segments(struct request_queue *q,
630 unsigned short max_segments)
631{
632 if (!max_segments) {
633 max_segments = 1;
634 printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
635 }
636
637 q->max_hw_segments = max_segments;
638}
639
640EXPORT_SYMBOL(blk_queue_max_hw_segments);
641
642/**
643 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
644 * @q: the request queue for the device
645 * @max_size: max size of segment in bytes
646 *
647 * Description:
648 * Enables a low level driver to set an upper limit on the size of a
649 * coalesced segment
650 **/
651void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
652{
653 if (max_size < PAGE_CACHE_SIZE) {
654 max_size = PAGE_CACHE_SIZE;
655 printk("%s: set to minimum %d\n", __FUNCTION__, max_size);
656 }
657
658 q->max_segment_size = max_size;
659}
660
661EXPORT_SYMBOL(blk_queue_max_segment_size);
662
663/**
664 * blk_queue_hardsect_size - set hardware sector size for the queue
665 * @q: the request queue for the device
666 * @size: the hardware sector size, in bytes
667 *
668 * Description:
669 * This should typically be set to the lowest possible sector size
670 * that the hardware can operate on (possible without reverting to
671 * even internal read-modify-write operations). Usually the default
672 * of 512 covers most hardware.
673 **/
674void blk_queue_hardsect_size(struct request_queue *q, unsigned short size)
675{
676 q->hardsect_size = size;
677}
678
679EXPORT_SYMBOL(blk_queue_hardsect_size);
680
681/*
682 * Returns the minimum that is _not_ zero, unless both are zero.
683 */
684#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
685
686/**
687 * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
688 * @t: the stacking driver (top)
689 * @b: the underlying device (bottom)
690 **/
691void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
692{
693 /* zero is "infinity" */
694 t->max_sectors = min_not_zero(t->max_sectors,b->max_sectors);
695 t->max_hw_sectors = min_not_zero(t->max_hw_sectors,b->max_hw_sectors);
696
697 t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
698 t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
699 t->max_segment_size = min(t->max_segment_size,b->max_segment_size);
700 t->hardsect_size = max(t->hardsect_size,b->hardsect_size);
701 if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))
702 clear_bit(QUEUE_FLAG_CLUSTER, &t->queue_flags);
703}
704
705EXPORT_SYMBOL(blk_queue_stack_limits);
706
707/**
708 * blk_queue_dma_drain - Set up a drain buffer for excess dma.
709 *
710 * @q: the request queue for the device
711 * @buf: physically contiguous buffer
712 * @size: size of the buffer in bytes
713 *
714 * Some devices have excess DMA problems and can't simply discard (or
715 * zero fill) the unwanted piece of the transfer. They have to have a
716 * real area of memory to transfer it into. The use case for this is
717 * ATAPI devices in DMA mode. If the packet command causes a transfer
718 * bigger than the transfer size some HBAs will lock up if there
719 * aren't DMA elements to contain the excess transfer. What this API
720 * does is adjust the queue so that the buf is always appended
721 * silently to the scatterlist.
722 *
723 * Note: This routine adjusts max_hw_segments to make room for
724 * appending the drain buffer. If you call
725 * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after
726 * calling this routine, you must set the limit to one fewer than your
727 * device can support otherwise there won't be room for the drain
728 * buffer.
729 */
730int blk_queue_dma_drain(struct request_queue *q, void *buf,
731 unsigned int size)
732{
733 if (q->max_hw_segments < 2 || q->max_phys_segments < 2)
734 return -EINVAL;
735 /* make room for appending the drain */
736 --q->max_hw_segments;
737 --q->max_phys_segments;
738 q->dma_drain_buffer = buf;
739 q->dma_drain_size = size;
740
741 return 0;
742}
743
744EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
745
746/**
747 * blk_queue_segment_boundary - set boundary rules for segment merging
748 * @q: the request queue for the device
749 * @mask: the memory boundary mask
750 **/
751void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
752{
753 if (mask < PAGE_CACHE_SIZE - 1) {
754 mask = PAGE_CACHE_SIZE - 1;
755 printk("%s: set to minimum %lx\n", __FUNCTION__, mask);
756 }
757
758 q->seg_boundary_mask = mask;
759}
760
761EXPORT_SYMBOL(blk_queue_segment_boundary);
762
763/**
764 * blk_queue_dma_alignment - set dma length and memory alignment
765 * @q: the request queue for the device
766 * @mask: alignment mask
767 *
768 * description:
769 * set required memory and length aligment for direct dma transactions.
770 * this is used when buiding direct io requests for the queue.
771 *
772 **/
773void blk_queue_dma_alignment(struct request_queue *q, int mask)
774{
775 q->dma_alignment = mask;
776}
777
778EXPORT_SYMBOL(blk_queue_dma_alignment);
779
780/**
781 * blk_queue_update_dma_alignment - update dma length and memory alignment
782 * @q: the request queue for the device
783 * @mask: alignment mask
784 *
785 * description:
786 * update required memory and length aligment for direct dma transactions.
787 * If the requested alignment is larger than the current alignment, then
788 * the current queue alignment is updated to the new value, otherwise it
789 * is left alone. The design of this is to allow multiple objects
790 * (driver, device, transport etc) to set their respective
791 * alignments without having them interfere.
792 *
793 **/
794void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
795{
796 BUG_ON(mask > PAGE_SIZE);
797
798 if (mask > q->dma_alignment)
799 q->dma_alignment = mask;
800}
801
802EXPORT_SYMBOL(blk_queue_update_dma_alignment);
803
804void blk_dump_rq_flags(struct request *rq, char *msg) 148void blk_dump_rq_flags(struct request *rq, char *msg)
805{ 149{
806 int bit; 150 int bit;
@@ -1074,8 +418,8 @@ static inline int ll_new_hw_segment(struct request_queue *q,
1074 return 1; 418 return 1;
1075} 419}
1076 420
1077static int ll_back_merge_fn(struct request_queue *q, struct request *req, 421int ll_back_merge_fn(struct request_queue *q, struct request *req,
1078 struct bio *bio) 422 struct bio *bio)
1079{ 423{
1080 unsigned short max_sectors; 424 unsigned short max_sectors;
1081 int len; 425 int len;
@@ -1285,7 +629,7 @@ static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
1285 blk_unplug(q); 629 blk_unplug(q);
1286} 630}
1287 631
1288static void blk_unplug_work(struct work_struct *work) 632void blk_unplug_work(struct work_struct *work)
1289{ 633{
1290 struct request_queue *q = 634 struct request_queue *q =
1291 container_of(work, struct request_queue, unplug_work); 635 container_of(work, struct request_queue, unplug_work);
@@ -1296,7 +640,7 @@ static void blk_unplug_work(struct work_struct *work)
1296 q->unplug_fn(q); 640 q->unplug_fn(q);
1297} 641}
1298 642
1299static void blk_unplug_timeout(unsigned long data) 643void blk_unplug_timeout(unsigned long data)
1300{ 644{
1301 struct request_queue *q = (struct request_queue *)data; 645 struct request_queue *q = (struct request_queue *)data;
1302 646
@@ -1961,393 +1305,6 @@ void blk_insert_request(struct request_queue *q, struct request *rq,
1961 1305
1962EXPORT_SYMBOL(blk_insert_request); 1306EXPORT_SYMBOL(blk_insert_request);
1963 1307
1964static int __blk_rq_unmap_user(struct bio *bio)
1965{
1966 int ret = 0;
1967
1968 if (bio) {
1969 if (bio_flagged(bio, BIO_USER_MAPPED))
1970 bio_unmap_user(bio);
1971 else
1972 ret = bio_uncopy_user(bio);
1973 }
1974
1975 return ret;
1976}
1977
1978int blk_rq_append_bio(struct request_queue *q, struct request *rq,
1979 struct bio *bio)
1980{
1981 if (!rq->bio)
1982 blk_rq_bio_prep(q, rq, bio);
1983 else if (!ll_back_merge_fn(q, rq, bio))
1984 return -EINVAL;
1985 else {
1986 rq->biotail->bi_next = bio;
1987 rq->biotail = bio;
1988
1989 rq->data_len += bio->bi_size;
1990 }
1991 return 0;
1992}
1993EXPORT_SYMBOL(blk_rq_append_bio);
1994
1995static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
1996 void __user *ubuf, unsigned int len)
1997{
1998 unsigned long uaddr;
1999 struct bio *bio, *orig_bio;
2000 int reading, ret;
2001
2002 reading = rq_data_dir(rq) == READ;
2003
2004 /*
2005 * if alignment requirement is satisfied, map in user pages for
2006 * direct dma. else, set up kernel bounce buffers
2007 */
2008 uaddr = (unsigned long) ubuf;
2009 if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
2010 bio = bio_map_user(q, NULL, uaddr, len, reading);
2011 else
2012 bio = bio_copy_user(q, uaddr, len, reading);
2013
2014 if (IS_ERR(bio))
2015 return PTR_ERR(bio);
2016
2017 orig_bio = bio;
2018 blk_queue_bounce(q, &bio);
2019
2020 /*
2021 * We link the bounce buffer in and could have to traverse it
2022 * later so we have to get a ref to prevent it from being freed
2023 */
2024 bio_get(bio);
2025
2026 ret = blk_rq_append_bio(q, rq, bio);
2027 if (!ret)
2028 return bio->bi_size;
2029
2030 /* if it was boucned we must call the end io function */
2031 bio_endio(bio, 0);
2032 __blk_rq_unmap_user(orig_bio);
2033 bio_put(bio);
2034 return ret;
2035}
2036
2037/**
2038 * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
2039 * @q: request queue where request should be inserted
2040 * @rq: request structure to fill
2041 * @ubuf: the user buffer
2042 * @len: length of user data
2043 *
2044 * Description:
2045 * Data will be mapped directly for zero copy io, if possible. Otherwise
2046 * a kernel bounce buffer is used.
2047 *
2048 * A matching blk_rq_unmap_user() must be issued at the end of io, while
2049 * still in process context.
2050 *
2051 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
2052 * before being submitted to the device, as pages mapped may be out of
2053 * reach. It's the callers responsibility to make sure this happens. The
2054 * original bio must be passed back in to blk_rq_unmap_user() for proper
2055 * unmapping.
2056 */
2057int blk_rq_map_user(struct request_queue *q, struct request *rq,
2058 void __user *ubuf, unsigned long len)
2059{
2060 unsigned long bytes_read = 0;
2061 struct bio *bio = NULL;
2062 int ret;
2063
2064 if (len > (q->max_hw_sectors << 9))
2065 return -EINVAL;
2066 if (!len || !ubuf)
2067 return -EINVAL;
2068
2069 while (bytes_read != len) {
2070 unsigned long map_len, end, start;
2071
2072 map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
2073 end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
2074 >> PAGE_SHIFT;
2075 start = (unsigned long)ubuf >> PAGE_SHIFT;
2076
2077 /*
2078 * A bad offset could cause us to require BIO_MAX_PAGES + 1
2079 * pages. If this happens we just lower the requested
2080 * mapping len by a page so that we can fit
2081 */
2082 if (end - start > BIO_MAX_PAGES)
2083 map_len -= PAGE_SIZE;
2084
2085 ret = __blk_rq_map_user(q, rq, ubuf, map_len);
2086 if (ret < 0)
2087 goto unmap_rq;
2088 if (!bio)
2089 bio = rq->bio;
2090 bytes_read += ret;
2091 ubuf += ret;
2092 }
2093
2094 rq->buffer = rq->data = NULL;
2095 return 0;
2096unmap_rq:
2097 blk_rq_unmap_user(bio);
2098 return ret;
2099}
2100
2101EXPORT_SYMBOL(blk_rq_map_user);
2102
2103/**
2104 * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
2105 * @q: request queue where request should be inserted
2106 * @rq: request to map data to
2107 * @iov: pointer to the iovec
2108 * @iov_count: number of elements in the iovec
2109 * @len: I/O byte count
2110 *
2111 * Description:
2112 * Data will be mapped directly for zero copy io, if possible. Otherwise
2113 * a kernel bounce buffer is used.
2114 *
2115 * A matching blk_rq_unmap_user() must be issued at the end of io, while
2116 * still in process context.
2117 *
2118 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
2119 * before being submitted to the device, as pages mapped may be out of
2120 * reach. It's the callers responsibility to make sure this happens. The
2121 * original bio must be passed back in to blk_rq_unmap_user() for proper
2122 * unmapping.
2123 */
2124int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
2125 struct sg_iovec *iov, int iov_count, unsigned int len)
2126{
2127 struct bio *bio;
2128
2129 if (!iov || iov_count <= 0)
2130 return -EINVAL;
2131
2132 /* we don't allow misaligned data like bio_map_user() does. If the
2133 * user is using sg, they're expected to know the alignment constraints
2134 * and respect them accordingly */
2135 bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ);
2136 if (IS_ERR(bio))
2137 return PTR_ERR(bio);
2138
2139 if (bio->bi_size != len) {
2140 bio_endio(bio, 0);
2141 bio_unmap_user(bio);
2142 return -EINVAL;
2143 }
2144
2145 bio_get(bio);
2146 blk_rq_bio_prep(q, rq, bio);
2147 rq->buffer = rq->data = NULL;
2148 return 0;
2149}
2150
2151EXPORT_SYMBOL(blk_rq_map_user_iov);
2152
2153/**
2154 * blk_rq_unmap_user - unmap a request with user data
2155 * @bio: start of bio list
2156 *
2157 * Description:
2158 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
2159 * supply the original rq->bio from the blk_rq_map_user() return, since
2160 * the io completion may have changed rq->bio.
2161 */
2162int blk_rq_unmap_user(struct bio *bio)
2163{
2164 struct bio *mapped_bio;
2165 int ret = 0, ret2;
2166
2167 while (bio) {
2168 mapped_bio = bio;
2169 if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
2170 mapped_bio = bio->bi_private;
2171
2172 ret2 = __blk_rq_unmap_user(mapped_bio);
2173 if (ret2 && !ret)
2174 ret = ret2;
2175
2176 mapped_bio = bio;
2177 bio = bio->bi_next;
2178 bio_put(mapped_bio);
2179 }
2180
2181 return ret;
2182}
2183
2184EXPORT_SYMBOL(blk_rq_unmap_user);
2185
2186/**
2187 * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
2188 * @q: request queue where request should be inserted
2189 * @rq: request to fill
2190 * @kbuf: the kernel buffer
2191 * @len: length of user data
2192 * @gfp_mask: memory allocation flags
2193 */
2194int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
2195 unsigned int len, gfp_t gfp_mask)
2196{
2197 struct bio *bio;
2198
2199 if (len > (q->max_hw_sectors << 9))
2200 return -EINVAL;
2201 if (!len || !kbuf)
2202 return -EINVAL;
2203
2204 bio = bio_map_kern(q, kbuf, len, gfp_mask);
2205 if (IS_ERR(bio))
2206 return PTR_ERR(bio);
2207
2208 if (rq_data_dir(rq) == WRITE)
2209 bio->bi_rw |= (1 << BIO_RW);
2210
2211 blk_rq_bio_prep(q, rq, bio);
2212 blk_queue_bounce(q, &rq->bio);
2213 rq->buffer = rq->data = NULL;
2214 return 0;
2215}
2216
2217EXPORT_SYMBOL(blk_rq_map_kern);
2218
2219/**
2220 * blk_execute_rq_nowait - insert a request into queue for execution
2221 * @q: queue to insert the request in
2222 * @bd_disk: matching gendisk
2223 * @rq: request to insert
2224 * @at_head: insert request at head or tail of queue
2225 * @done: I/O completion handler
2226 *
2227 * Description:
2228 * Insert a fully prepared request at the back of the io scheduler queue
2229 * for execution. Don't wait for completion.
2230 */
2231void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
2232 struct request *rq, int at_head,
2233 rq_end_io_fn *done)
2234{
2235 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
2236
2237 rq->rq_disk = bd_disk;
2238 rq->cmd_flags |= REQ_NOMERGE;
2239 rq->end_io = done;
2240 WARN_ON(irqs_disabled());
2241 spin_lock_irq(q->queue_lock);
2242 __elv_add_request(q, rq, where, 1);
2243 __generic_unplug_device(q);
2244 spin_unlock_irq(q->queue_lock);
2245}
2246EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
2247
2248/**
2249 * blk_execute_rq - insert a request into queue for execution
2250 * @q: queue to insert the request in
2251 * @bd_disk: matching gendisk
2252 * @rq: request to insert
2253 * @at_head: insert request at head or tail of queue
2254 *
2255 * Description:
2256 * Insert a fully prepared request at the back of the io scheduler queue
2257 * for execution and wait for completion.
2258 */
2259int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
2260 struct request *rq, int at_head)
2261{
2262 DECLARE_COMPLETION_ONSTACK(wait);
2263 char sense[SCSI_SENSE_BUFFERSIZE];
2264 int err = 0;
2265
2266 /*
2267 * we need an extra reference to the request, so we can look at
2268 * it after io completion
2269 */
2270 rq->ref_count++;
2271
2272 if (!rq->sense) {
2273 memset(sense, 0, sizeof(sense));
2274 rq->sense = sense;
2275 rq->sense_len = 0;
2276 }
2277
2278 rq->end_io_data = &wait;
2279 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
2280 wait_for_completion(&wait);
2281
2282 if (rq->errors)
2283 err = -EIO;
2284
2285 return err;
2286}
2287
2288EXPORT_SYMBOL(blk_execute_rq);
2289
2290static void bio_end_empty_barrier(struct bio *bio, int err)
2291{
2292 if (err)
2293 clear_bit(BIO_UPTODATE, &bio->bi_flags);
2294
2295 complete(bio->bi_private);
2296}
2297
2298/**
2299 * blkdev_issue_flush - queue a flush
2300 * @bdev: blockdev to issue flush for
2301 * @error_sector: error sector
2302 *
2303 * Description:
2304 * Issue a flush for the block device in question. Caller can supply
2305 * room for storing the error offset in case of a flush error, if they
2306 * wish to. Caller must run wait_for_completion() on its own.
2307 */
2308int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
2309{
2310 DECLARE_COMPLETION_ONSTACK(wait);
2311 struct request_queue *q;
2312 struct bio *bio;
2313 int ret;
2314
2315 if (bdev->bd_disk == NULL)
2316 return -ENXIO;
2317
2318 q = bdev_get_queue(bdev);
2319 if (!q)
2320 return -ENXIO;
2321
2322 bio = bio_alloc(GFP_KERNEL, 0);
2323 if (!bio)
2324 return -ENOMEM;
2325
2326 bio->bi_end_io = bio_end_empty_barrier;
2327 bio->bi_private = &wait;
2328 bio->bi_bdev = bdev;
2329 submit_bio(1 << BIO_RW_BARRIER, bio);
2330
2331 wait_for_completion(&wait);
2332
2333 /*
2334 * The driver must store the error location in ->bi_sector, if
2335 * it supports it. For non-stacked drivers, this should be copied
2336 * from rq->sector.
2337 */
2338 if (error_sector)
2339 *error_sector = bio->bi_sector;
2340
2341 ret = 0;
2342 if (!bio_flagged(bio, BIO_UPTODATE))
2343 ret = -EIO;
2344
2345 bio_put(bio);
2346 return ret;
2347}
2348
2349EXPORT_SYMBOL(blkdev_issue_flush);
2350
2351static void drive_stat_acct(struct request *rq, int new_io) 1308static void drive_stat_acct(struct request *rq, int new_io)
2352{ 1309{
2353 int rw = rq_data_dir(rq); 1310 int rw = rq_data_dir(rq);
@@ -2459,26 +1416,6 @@ void blk_put_request(struct request *req)
2459 1416
2460EXPORT_SYMBOL(blk_put_request); 1417EXPORT_SYMBOL(blk_put_request);
2461 1418
2462/**
2463 * blk_end_sync_rq - executes a completion event on a request
2464 * @rq: request to complete
2465 * @error: end io status of the request
2466 */
2467void blk_end_sync_rq(struct request *rq, int error)
2468{
2469 struct completion *waiting = rq->end_io_data;
2470
2471 rq->end_io_data = NULL;
2472 __blk_put_request(rq->q, rq);
2473
2474 /*
2475 * complete last, if this is a stack request the process (and thus
2476 * the rq pointer) could be invalid right after this complete()
2477 */
2478 complete(waiting);
2479}
2480EXPORT_SYMBOL(blk_end_sync_rq);
2481
2482/* 1419/*
2483 * Has to be called with the request spinlock acquired 1420 * Has to be called with the request spinlock acquired
2484 */ 1421 */
@@ -2557,7 +1494,7 @@ static inline int attempt_front_merge(struct request_queue *q,
2557 return 0; 1494 return 0;
2558} 1495}
2559 1496
2560static void init_request_from_bio(struct request *req, struct bio *bio) 1497void init_request_from_bio(struct request *req, struct bio *bio)
2561{ 1498{
2562 req->cmd_type = REQ_TYPE_FS; 1499 req->cmd_type = REQ_TYPE_FS;
2563 1500
@@ -3524,8 +2461,8 @@ int blk_end_request_callback(struct request *rq, int error, int nr_bytes,
3524} 2461}
3525EXPORT_SYMBOL_GPL(blk_end_request_callback); 2462EXPORT_SYMBOL_GPL(blk_end_request_callback);
3526 2463
3527static void blk_rq_bio_prep(struct request_queue *q, struct request *rq, 2464void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
3528 struct bio *bio) 2465 struct bio *bio)
3529{ 2466{
3530 /* first two bits are identical in rq->cmd_flags and bio->bi_rw */ 2467 /* first two bits are identical in rq->cmd_flags and bio->bi_rw */
3531 rq->cmd_flags |= (bio->bi_rw & 3); 2468 rq->cmd_flags |= (bio->bi_rw & 3);
@@ -3571,188 +2508,12 @@ int __init blk_dev_init(void)
3571 blk_requestq_cachep = kmem_cache_create("blkdev_queue", 2508 blk_requestq_cachep = kmem_cache_create("blkdev_queue",
3572 sizeof(struct request_queue), 0, SLAB_PANIC, NULL); 2509 sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
3573 2510
3574 iocontext_cachep = kmem_cache_create("blkdev_ioc",
3575 sizeof(struct io_context), 0, SLAB_PANIC, NULL);
3576
3577 for_each_possible_cpu(i) 2511 for_each_possible_cpu(i)
3578 INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i)); 2512 INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
3579 2513
3580 open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL); 2514 open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
3581 register_hotcpu_notifier(&blk_cpu_notifier); 2515 register_hotcpu_notifier(&blk_cpu_notifier);
3582 2516
3583 blk_max_low_pfn = max_low_pfn - 1;
3584 blk_max_pfn = max_pfn - 1;
3585
3586 return 0;
3587}
3588
3589static void cfq_dtor(struct io_context *ioc)
3590{
3591 struct cfq_io_context *cic[1];
3592 int r;
3593
3594 /*
3595 * We don't have a specific key to lookup with, so use the gang
3596 * lookup to just retrieve the first item stored. The cfq exit
3597 * function will iterate the full tree, so any member will do.
3598 */
3599 r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1);
3600 if (r > 0)
3601 cic[0]->dtor(ioc);
3602}
3603
3604/*
3605 * IO Context helper functions. put_io_context() returns 1 if there are no
3606 * more users of this io context, 0 otherwise.
3607 */
3608int put_io_context(struct io_context *ioc)
3609{
3610 if (ioc == NULL)
3611 return 1;
3612
3613 BUG_ON(atomic_read(&ioc->refcount) == 0);
3614
3615 if (atomic_dec_and_test(&ioc->refcount)) {
3616 rcu_read_lock();
3617 if (ioc->aic && ioc->aic->dtor)
3618 ioc->aic->dtor(ioc->aic);
3619 rcu_read_unlock();
3620 cfq_dtor(ioc);
3621
3622 kmem_cache_free(iocontext_cachep, ioc);
3623 return 1;
3624 }
3625 return 0; 2517 return 0;
3626} 2518}
3627EXPORT_SYMBOL(put_io_context);
3628
3629static void cfq_exit(struct io_context *ioc)
3630{
3631 struct cfq_io_context *cic[1];
3632 int r;
3633
3634 rcu_read_lock();
3635 /*
3636 * See comment for cfq_dtor()
3637 */
3638 r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1);
3639 rcu_read_unlock();
3640
3641 if (r > 0)
3642 cic[0]->exit(ioc);
3643}
3644
3645/* Called by the exitting task */
3646void exit_io_context(void)
3647{
3648 struct io_context *ioc;
3649
3650 task_lock(current);
3651 ioc = current->io_context;
3652 current->io_context = NULL;
3653 task_unlock(current);
3654
3655 if (atomic_dec_and_test(&ioc->nr_tasks)) {
3656 if (ioc->aic && ioc->aic->exit)
3657 ioc->aic->exit(ioc->aic);
3658 cfq_exit(ioc);
3659
3660 put_io_context(ioc);
3661 }
3662}
3663
3664struct io_context *alloc_io_context(gfp_t gfp_flags, int node)
3665{
3666 struct io_context *ret;
3667
3668 ret = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node);
3669 if (ret) {
3670 atomic_set(&ret->refcount, 1);
3671 atomic_set(&ret->nr_tasks, 1);
3672 spin_lock_init(&ret->lock);
3673 ret->ioprio_changed = 0;
3674 ret->ioprio = 0;
3675 ret->last_waited = jiffies; /* doesn't matter... */
3676 ret->nr_batch_requests = 0; /* because this is 0 */
3677 ret->aic = NULL;
3678 INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH);
3679 ret->ioc_data = NULL;
3680 }
3681
3682 return ret;
3683}
3684
3685/*
3686 * If the current task has no IO context then create one and initialise it.
3687 * Otherwise, return its existing IO context.
3688 *
3689 * This returned IO context doesn't have a specifically elevated refcount,
3690 * but since the current task itself holds a reference, the context can be
3691 * used in general code, so long as it stays within `current` context.
3692 */
3693static struct io_context *current_io_context(gfp_t gfp_flags, int node)
3694{
3695 struct task_struct *tsk = current;
3696 struct io_context *ret;
3697
3698 ret = tsk->io_context;
3699 if (likely(ret))
3700 return ret;
3701
3702 ret = alloc_io_context(gfp_flags, node);
3703 if (ret) {
3704 /* make sure set_task_ioprio() sees the settings above */
3705 smp_wmb();
3706 tsk->io_context = ret;
3707 }
3708
3709 return ret;
3710}
3711
3712/*
3713 * If the current task has no IO context then create one and initialise it.
3714 * If it does have a context, take a ref on it.
3715 *
3716 * This is always called in the context of the task which submitted the I/O.
3717 */
3718struct io_context *get_io_context(gfp_t gfp_flags, int node)
3719{
3720 struct io_context *ret = NULL;
3721
3722 /*
3723 * Check for unlikely race with exiting task. ioc ref count is
3724 * zero when ioc is being detached.
3725 */
3726 do {
3727 ret = current_io_context(gfp_flags, node);
3728 if (unlikely(!ret))
3729 break;
3730 } while (!atomic_inc_not_zero(&ret->refcount));
3731
3732 return ret;
3733}
3734EXPORT_SYMBOL(get_io_context);
3735
3736void copy_io_context(struct io_context **pdst, struct io_context **psrc)
3737{
3738 struct io_context *src = *psrc;
3739 struct io_context *dst = *pdst;
3740
3741 if (src) {
3742 BUG_ON(atomic_read(&src->refcount) == 0);
3743 atomic_inc(&src->refcount);
3744 put_io_context(dst);
3745 *pdst = src;
3746 }
3747}
3748EXPORT_SYMBOL(copy_io_context);
3749
3750void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
3751{
3752 struct io_context *temp;
3753 temp = *ioc1;
3754 *ioc1 = *ioc2;
3755 *ioc2 = temp;
3756}
3757EXPORT_SYMBOL(swap_io_context);
3758 2519
diff --git a/block/blk-exec.c b/block/blk-exec.c
new file mode 100644
index 00000000000..ebfb44e959a
--- /dev/null
+++ b/block/blk-exec.c
@@ -0,0 +1,105 @@
1/*
2 * Functions related to setting various queue properties from drivers
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
8
9#include "blk.h"
10
11/*
12 * for max sense size
13 */
14#include <scsi/scsi_cmnd.h>
15
16/**
17 * blk_end_sync_rq - executes a completion event on a request
18 * @rq: request to complete
19 * @error: end io status of the request
20 */
21void blk_end_sync_rq(struct request *rq, int error)
22{
23 struct completion *waiting = rq->end_io_data;
24
25 rq->end_io_data = NULL;
26 __blk_put_request(rq->q, rq);
27
28 /*
29 * complete last, if this is a stack request the process (and thus
30 * the rq pointer) could be invalid right after this complete()
31 */
32 complete(waiting);
33}
34EXPORT_SYMBOL(blk_end_sync_rq);
35
36/**
37 * blk_execute_rq_nowait - insert a request into queue for execution
38 * @q: queue to insert the request in
39 * @bd_disk: matching gendisk
40 * @rq: request to insert
41 * @at_head: insert request at head or tail of queue
42 * @done: I/O completion handler
43 *
44 * Description:
45 * Insert a fully prepared request at the back of the io scheduler queue
46 * for execution. Don't wait for completion.
47 */
48void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
49 struct request *rq, int at_head,
50 rq_end_io_fn *done)
51{
52 int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
53
54 rq->rq_disk = bd_disk;
55 rq->cmd_flags |= REQ_NOMERGE;
56 rq->end_io = done;
57 WARN_ON(irqs_disabled());
58 spin_lock_irq(q->queue_lock);
59 __elv_add_request(q, rq, where, 1);
60 __generic_unplug_device(q);
61 spin_unlock_irq(q->queue_lock);
62}
63EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
64
65/**
66 * blk_execute_rq - insert a request into queue for execution
67 * @q: queue to insert the request in
68 * @bd_disk: matching gendisk
69 * @rq: request to insert
70 * @at_head: insert request at head or tail of queue
71 *
72 * Description:
73 * Insert a fully prepared request at the back of the io scheduler queue
74 * for execution and wait for completion.
75 */
76int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
77 struct request *rq, int at_head)
78{
79 DECLARE_COMPLETION_ONSTACK(wait);
80 char sense[SCSI_SENSE_BUFFERSIZE];
81 int err = 0;
82
83 /*
84 * we need an extra reference to the request, so we can look at
85 * it after io completion
86 */
87 rq->ref_count++;
88
89 if (!rq->sense) {
90 memset(sense, 0, sizeof(sense));
91 rq->sense = sense;
92 rq->sense_len = 0;
93 }
94
95 rq->end_io_data = &wait;
96 blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
97 wait_for_completion(&wait);
98
99 if (rq->errors)
100 err = -EIO;
101
102 return err;
103}
104
105EXPORT_SYMBOL(blk_execute_rq);
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
new file mode 100644
index 00000000000..6d1675508eb
--- /dev/null
+++ b/block/blk-ioc.c
@@ -0,0 +1,194 @@
1/*
2 * Functions related to io context handling
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/init.h>
7#include <linux/bio.h>
8#include <linux/blkdev.h>
9#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
10
11#include "blk.h"
12
13/*
14 * For io context allocations
15 */
16static struct kmem_cache *iocontext_cachep;
17
18static void cfq_dtor(struct io_context *ioc)
19{
20 struct cfq_io_context *cic[1];
21 int r;
22
23 /*
24 * We don't have a specific key to lookup with, so use the gang
25 * lookup to just retrieve the first item stored. The cfq exit
26 * function will iterate the full tree, so any member will do.
27 */
28 r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1);
29 if (r > 0)
30 cic[0]->dtor(ioc);
31}
32
33/*
34 * IO Context helper functions. put_io_context() returns 1 if there are no
35 * more users of this io context, 0 otherwise.
36 */
37int put_io_context(struct io_context *ioc)
38{
39 if (ioc == NULL)
40 return 1;
41
42 BUG_ON(atomic_read(&ioc->refcount) == 0);
43
44 if (atomic_dec_and_test(&ioc->refcount)) {
45 rcu_read_lock();
46 if (ioc->aic && ioc->aic->dtor)
47 ioc->aic->dtor(ioc->aic);
48 rcu_read_unlock();
49 cfq_dtor(ioc);
50
51 kmem_cache_free(iocontext_cachep, ioc);
52 return 1;
53 }
54 return 0;
55}
56EXPORT_SYMBOL(put_io_context);
57
58static void cfq_exit(struct io_context *ioc)
59{
60 struct cfq_io_context *cic[1];
61 int r;
62
63 rcu_read_lock();
64 /*
65 * See comment for cfq_dtor()
66 */
67 r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1);
68 rcu_read_unlock();
69
70 if (r > 0)
71 cic[0]->exit(ioc);
72}
73
74/* Called by the exitting task */
75void exit_io_context(void)
76{
77 struct io_context *ioc;
78
79 task_lock(current);
80 ioc = current->io_context;
81 current->io_context = NULL;
82 task_unlock(current);
83
84 if (atomic_dec_and_test(&ioc->nr_tasks)) {
85 if (ioc->aic && ioc->aic->exit)
86 ioc->aic->exit(ioc->aic);
87 cfq_exit(ioc);
88
89 put_io_context(ioc);
90 }
91}
92
93struct io_context *alloc_io_context(gfp_t gfp_flags, int node)
94{
95 struct io_context *ret;
96
97 ret = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node);
98 if (ret) {
99 atomic_set(&ret->refcount, 1);
100 atomic_set(&ret->nr_tasks, 1);
101 spin_lock_init(&ret->lock);
102 ret->ioprio_changed = 0;
103 ret->ioprio = 0;
104 ret->last_waited = jiffies; /* doesn't matter... */
105 ret->nr_batch_requests = 0; /* because this is 0 */
106 ret->aic = NULL;
107 INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH);
108 ret->ioc_data = NULL;
109 }
110
111 return ret;
112}
113
114/*
115 * If the current task has no IO context then create one and initialise it.
116 * Otherwise, return its existing IO context.
117 *
118 * This returned IO context doesn't have a specifically elevated refcount,
119 * but since the current task itself holds a reference, the context can be
120 * used in general code, so long as it stays within `current` context.
121 */
122struct io_context *current_io_context(gfp_t gfp_flags, int node)
123{
124 struct task_struct *tsk = current;
125 struct io_context *ret;
126
127 ret = tsk->io_context;
128 if (likely(ret))
129 return ret;
130
131 ret = alloc_io_context(gfp_flags, node);
132 if (ret) {
133 /* make sure set_task_ioprio() sees the settings above */
134 smp_wmb();
135 tsk->io_context = ret;
136 }
137
138 return ret;
139}
140
141/*
142 * If the current task has no IO context then create one and initialise it.
143 * If it does have a context, take a ref on it.
144 *
145 * This is always called in the context of the task which submitted the I/O.
146 */
147struct io_context *get_io_context(gfp_t gfp_flags, int node)
148{
149 struct io_context *ret = NULL;
150
151 /*
152 * Check for unlikely race with exiting task. ioc ref count is
153 * zero when ioc is being detached.
154 */
155 do {
156 ret = current_io_context(gfp_flags, node);
157 if (unlikely(!ret))
158 break;
159 } while (!atomic_inc_not_zero(&ret->refcount));
160
161 return ret;
162}
163EXPORT_SYMBOL(get_io_context);
164
165void copy_io_context(struct io_context **pdst, struct io_context **psrc)
166{
167 struct io_context *src = *psrc;
168 struct io_context *dst = *pdst;
169
170 if (src) {
171 BUG_ON(atomic_read(&src->refcount) == 0);
172 atomic_inc(&src->refcount);
173 put_io_context(dst);
174 *pdst = src;
175 }
176}
177EXPORT_SYMBOL(copy_io_context);
178
179void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
180{
181 struct io_context *temp;
182 temp = *ioc1;
183 *ioc1 = *ioc2;
184 *ioc2 = temp;
185}
186EXPORT_SYMBOL(swap_io_context);
187
188int __init blk_ioc_init(void)
189{
190 iocontext_cachep = kmem_cache_create("blkdev_ioc",
191 sizeof(struct io_context), 0, SLAB_PANIC, NULL);
192 return 0;
193}
194subsys_initcall(blk_ioc_init);
diff --git a/block/blk-map.c b/block/blk-map.c
new file mode 100644
index 00000000000..916cfc96ffa
--- /dev/null
+++ b/block/blk-map.c
@@ -0,0 +1,264 @@
1/*
2 * Functions related to mapping data to requests
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/bio.h>
7#include <linux/blkdev.h>
8
9#include "blk.h"
10
11int blk_rq_append_bio(struct request_queue *q, struct request *rq,
12 struct bio *bio)
13{
14 if (!rq->bio)
15 blk_rq_bio_prep(q, rq, bio);
16 else if (!ll_back_merge_fn(q, rq, bio))
17 return -EINVAL;
18 else {
19 rq->biotail->bi_next = bio;
20 rq->biotail = bio;
21
22 rq->data_len += bio->bi_size;
23 }
24 return 0;
25}
26EXPORT_SYMBOL(blk_rq_append_bio);
27
28static int __blk_rq_unmap_user(struct bio *bio)
29{
30 int ret = 0;
31
32 if (bio) {
33 if (bio_flagged(bio, BIO_USER_MAPPED))
34 bio_unmap_user(bio);
35 else
36 ret = bio_uncopy_user(bio);
37 }
38
39 return ret;
40}
41
42static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
43 void __user *ubuf, unsigned int len)
44{
45 unsigned long uaddr;
46 struct bio *bio, *orig_bio;
47 int reading, ret;
48
49 reading = rq_data_dir(rq) == READ;
50
51 /*
52 * if alignment requirement is satisfied, map in user pages for
53 * direct dma. else, set up kernel bounce buffers
54 */
55 uaddr = (unsigned long) ubuf;
56 if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
57 bio = bio_map_user(q, NULL, uaddr, len, reading);
58 else
59 bio = bio_copy_user(q, uaddr, len, reading);
60
61 if (IS_ERR(bio))
62 return PTR_ERR(bio);
63
64 orig_bio = bio;
65 blk_queue_bounce(q, &bio);
66
67 /*
68 * We link the bounce buffer in and could have to traverse it
69 * later so we have to get a ref to prevent it from being freed
70 */
71 bio_get(bio);
72
73 ret = blk_rq_append_bio(q, rq, bio);
74 if (!ret)
75 return bio->bi_size;
76
77 /* if it was boucned we must call the end io function */
78 bio_endio(bio, 0);
79 __blk_rq_unmap_user(orig_bio);
80 bio_put(bio);
81 return ret;
82}
83
84/**
85 * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
86 * @q: request queue where request should be inserted
87 * @rq: request structure to fill
88 * @ubuf: the user buffer
89 * @len: length of user data
90 *
91 * Description:
92 * Data will be mapped directly for zero copy io, if possible. Otherwise
93 * a kernel bounce buffer is used.
94 *
95 * A matching blk_rq_unmap_user() must be issued at the end of io, while
96 * still in process context.
97 *
98 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
99 * before being submitted to the device, as pages mapped may be out of
100 * reach. It's the callers responsibility to make sure this happens. The
101 * original bio must be passed back in to blk_rq_unmap_user() for proper
102 * unmapping.
103 */
104int blk_rq_map_user(struct request_queue *q, struct request *rq,
105 void __user *ubuf, unsigned long len)
106{
107 unsigned long bytes_read = 0;
108 struct bio *bio = NULL;
109 int ret;
110
111 if (len > (q->max_hw_sectors << 9))
112 return -EINVAL;
113 if (!len || !ubuf)
114 return -EINVAL;
115
116 while (bytes_read != len) {
117 unsigned long map_len, end, start;
118
119 map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
120 end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
121 >> PAGE_SHIFT;
122 start = (unsigned long)ubuf >> PAGE_SHIFT;
123
124 /*
125 * A bad offset could cause us to require BIO_MAX_PAGES + 1
126 * pages. If this happens we just lower the requested
127 * mapping len by a page so that we can fit
128 */
129 if (end - start > BIO_MAX_PAGES)
130 map_len -= PAGE_SIZE;
131
132 ret = __blk_rq_map_user(q, rq, ubuf, map_len);
133 if (ret < 0)
134 goto unmap_rq;
135 if (!bio)
136 bio = rq->bio;
137 bytes_read += ret;
138 ubuf += ret;
139 }
140
141 rq->buffer = rq->data = NULL;
142 return 0;
143unmap_rq:
144 blk_rq_unmap_user(bio);
145 return ret;
146}
147
148EXPORT_SYMBOL(blk_rq_map_user);
149
150/**
151 * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
152 * @q: request queue where request should be inserted
153 * @rq: request to map data to
154 * @iov: pointer to the iovec
155 * @iov_count: number of elements in the iovec
156 * @len: I/O byte count
157 *
158 * Description:
159 * Data will be mapped directly for zero copy io, if possible. Otherwise
160 * a kernel bounce buffer is used.
161 *
162 * A matching blk_rq_unmap_user() must be issued at the end of io, while
163 * still in process context.
164 *
165 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
166 * before being submitted to the device, as pages mapped may be out of
167 * reach. It's the callers responsibility to make sure this happens. The
168 * original bio must be passed back in to blk_rq_unmap_user() for proper
169 * unmapping.
170 */
171int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
172 struct sg_iovec *iov, int iov_count, unsigned int len)
173{
174 struct bio *bio;
175
176 if (!iov || iov_count <= 0)
177 return -EINVAL;
178
179 /* we don't allow misaligned data like bio_map_user() does. If the
180 * user is using sg, they're expected to know the alignment constraints
181 * and respect them accordingly */
182 bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ);
183 if (IS_ERR(bio))
184 return PTR_ERR(bio);
185
186 if (bio->bi_size != len) {
187 bio_endio(bio, 0);
188 bio_unmap_user(bio);
189 return -EINVAL;
190 }
191
192 bio_get(bio);
193 blk_rq_bio_prep(q, rq, bio);
194 rq->buffer = rq->data = NULL;
195 return 0;
196}
197
198EXPORT_SYMBOL(blk_rq_map_user_iov);
199
200/**
201 * blk_rq_unmap_user - unmap a request with user data
202 * @bio: start of bio list
203 *
204 * Description:
205 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
206 * supply the original rq->bio from the blk_rq_map_user() return, since
207 * the io completion may have changed rq->bio.
208 */
209int blk_rq_unmap_user(struct bio *bio)
210{
211 struct bio *mapped_bio;
212 int ret = 0, ret2;
213
214 while (bio) {
215 mapped_bio = bio;
216 if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
217 mapped_bio = bio->bi_private;
218
219 ret2 = __blk_rq_unmap_user(mapped_bio);
220 if (ret2 && !ret)
221 ret = ret2;
222
223 mapped_bio = bio;
224 bio = bio->bi_next;
225 bio_put(mapped_bio);
226 }
227
228 return ret;
229}
230
231EXPORT_SYMBOL(blk_rq_unmap_user);
232
233/**
234 * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
235 * @q: request queue where request should be inserted
236 * @rq: request to fill
237 * @kbuf: the kernel buffer
238 * @len: length of user data
239 * @gfp_mask: memory allocation flags
240 */
241int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
242 unsigned int len, gfp_t gfp_mask)
243{
244 struct bio *bio;
245
246 if (len > (q->max_hw_sectors << 9))
247 return -EINVAL;
248 if (!len || !kbuf)
249 return -EINVAL;
250
251 bio = bio_map_kern(q, kbuf, len, gfp_mask);
252 if (IS_ERR(bio))
253 return PTR_ERR(bio);
254
255 if (rq_data_dir(rq) == WRITE)
256 bio->bi_rw |= (1 << BIO_RW);
257
258 blk_rq_bio_prep(q, rq, bio);
259 blk_queue_bounce(q, &rq->bio);
260 rq->buffer = rq->data = NULL;
261 return 0;
262}
263
264EXPORT_SYMBOL(blk_rq_map_kern);
diff --git a/block/blk-settings.c b/block/blk-settings.c
new file mode 100644
index 00000000000..4df09a1b8f4
--- /dev/null
+++ b/block/blk-settings.c
@@ -0,0 +1,402 @@
1/*
2 * Functions related to setting various queue properties from drivers
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/init.h>
7#include <linux/bio.h>
8#include <linux/blkdev.h>
9#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
10
11#include "blk.h"
12
13unsigned long blk_max_low_pfn, blk_max_pfn;
14EXPORT_SYMBOL(blk_max_low_pfn);
15EXPORT_SYMBOL(blk_max_pfn);
16
17/**
18 * blk_queue_prep_rq - set a prepare_request function for queue
19 * @q: queue
20 * @pfn: prepare_request function
21 *
22 * It's possible for a queue to register a prepare_request callback which
23 * is invoked before the request is handed to the request_fn. The goal of
24 * the function is to prepare a request for I/O, it can be used to build a
25 * cdb from the request data for instance.
26 *
27 */
28void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
29{
30 q->prep_rq_fn = pfn;
31}
32
33EXPORT_SYMBOL(blk_queue_prep_rq);
34
35/**
36 * blk_queue_merge_bvec - set a merge_bvec function for queue
37 * @q: queue
38 * @mbfn: merge_bvec_fn
39 *
40 * Usually queues have static limitations on the max sectors or segments that
41 * we can put in a request. Stacking drivers may have some settings that
42 * are dynamic, and thus we have to query the queue whether it is ok to
43 * add a new bio_vec to a bio at a given offset or not. If the block device
44 * has such limitations, it needs to register a merge_bvec_fn to control
45 * the size of bio's sent to it. Note that a block device *must* allow a
46 * single page to be added to an empty bio. The block device driver may want
47 * to use the bio_split() function to deal with these bio's. By default
48 * no merge_bvec_fn is defined for a queue, and only the fixed limits are
49 * honored.
50 */
51void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
52{
53 q->merge_bvec_fn = mbfn;
54}
55
56EXPORT_SYMBOL(blk_queue_merge_bvec);
57
58void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
59{
60 q->softirq_done_fn = fn;
61}
62
63EXPORT_SYMBOL(blk_queue_softirq_done);
64
65/**
66 * blk_queue_make_request - define an alternate make_request function for a device
67 * @q: the request queue for the device to be affected
68 * @mfn: the alternate make_request function
69 *
70 * Description:
71 * The normal way for &struct bios to be passed to a device
72 * driver is for them to be collected into requests on a request
73 * queue, and then to allow the device driver to select requests
74 * off that queue when it is ready. This works well for many block
75 * devices. However some block devices (typically virtual devices
76 * such as md or lvm) do not benefit from the processing on the
77 * request queue, and are served best by having the requests passed
78 * directly to them. This can be achieved by providing a function
79 * to blk_queue_make_request().
80 *
81 * Caveat:
82 * The driver that does this *must* be able to deal appropriately
83 * with buffers in "highmemory". This can be accomplished by either calling
84 * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
85 * blk_queue_bounce() to create a buffer in normal memory.
86 **/
87void blk_queue_make_request(struct request_queue * q, make_request_fn * mfn)
88{
89 /*
90 * set defaults
91 */
92 q->nr_requests = BLKDEV_MAX_RQ;
93 blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
94 blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
95 q->make_request_fn = mfn;
96 q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
97 q->backing_dev_info.state = 0;
98 q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
99 blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
100 blk_queue_hardsect_size(q, 512);
101 blk_queue_dma_alignment(q, 511);
102 blk_queue_congestion_threshold(q);
103 q->nr_batching = BLK_BATCH_REQ;
104
105 q->unplug_thresh = 4; /* hmm */
106 q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */
107 if (q->unplug_delay == 0)
108 q->unplug_delay = 1;
109
110 INIT_WORK(&q->unplug_work, blk_unplug_work);
111
112 q->unplug_timer.function = blk_unplug_timeout;
113 q->unplug_timer.data = (unsigned long)q;
114
115 /*
116 * by default assume old behaviour and bounce for any highmem page
117 */
118 blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
119}
120
121EXPORT_SYMBOL(blk_queue_make_request);
122
123/**
124 * blk_queue_bounce_limit - set bounce buffer limit for queue
125 * @q: the request queue for the device
126 * @dma_addr: bus address limit
127 *
128 * Description:
129 * Different hardware can have different requirements as to what pages
130 * it can do I/O directly to. A low level driver can call
131 * blk_queue_bounce_limit to have lower memory pages allocated as bounce
132 * buffers for doing I/O to pages residing above @page.
133 **/
134void blk_queue_bounce_limit(struct request_queue *q, u64 dma_addr)
135{
136 unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT;
137 int dma = 0;
138
139 q->bounce_gfp = GFP_NOIO;
140#if BITS_PER_LONG == 64
141 /* Assume anything <= 4GB can be handled by IOMMU.
142 Actually some IOMMUs can handle everything, but I don't
143 know of a way to test this here. */
144 if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
145 dma = 1;
146 q->bounce_pfn = max_low_pfn;
147#else
148 if (bounce_pfn < blk_max_low_pfn)
149 dma = 1;
150 q->bounce_pfn = bounce_pfn;
151#endif
152 if (dma) {
153 init_emergency_isa_pool();
154 q->bounce_gfp = GFP_NOIO | GFP_DMA;
155 q->bounce_pfn = bounce_pfn;
156 }
157}
158
159EXPORT_SYMBOL(blk_queue_bounce_limit);
160
161/**
162 * blk_queue_max_sectors - set max sectors for a request for this queue
163 * @q: the request queue for the device
164 * @max_sectors: max sectors in the usual 512b unit
165 *
166 * Description:
167 * Enables a low level driver to set an upper limit on the size of
168 * received requests.
169 **/
170void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors)
171{
172 if ((max_sectors << 9) < PAGE_CACHE_SIZE) {
173 max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
174 printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
175 }
176
177 if (BLK_DEF_MAX_SECTORS > max_sectors)
178 q->max_hw_sectors = q->max_sectors = max_sectors;
179 else {
180 q->max_sectors = BLK_DEF_MAX_SECTORS;
181 q->max_hw_sectors = max_sectors;
182 }
183}
184
185EXPORT_SYMBOL(blk_queue_max_sectors);
186
187/**
188 * blk_queue_max_phys_segments - set max phys segments for a request for this queue
189 * @q: the request queue for the device
190 * @max_segments: max number of segments
191 *
192 * Description:
193 * Enables a low level driver to set an upper limit on the number of
194 * physical data segments in a request. This would be the largest sized
195 * scatter list the driver could handle.
196 **/
197void blk_queue_max_phys_segments(struct request_queue *q,
198 unsigned short max_segments)
199{
200 if (!max_segments) {
201 max_segments = 1;
202 printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
203 }
204
205 q->max_phys_segments = max_segments;
206}
207
208EXPORT_SYMBOL(blk_queue_max_phys_segments);
209
210/**
211 * blk_queue_max_hw_segments - set max hw segments for a request for this queue
212 * @q: the request queue for the device
213 * @max_segments: max number of segments
214 *
215 * Description:
216 * Enables a low level driver to set an upper limit on the number of
217 * hw data segments in a request. This would be the largest number of
218 * address/length pairs the host adapter can actually give as once
219 * to the device.
220 **/
221void blk_queue_max_hw_segments(struct request_queue *q,
222 unsigned short max_segments)
223{
224 if (!max_segments) {
225 max_segments = 1;
226 printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
227 }
228
229 q->max_hw_segments = max_segments;
230}
231
232EXPORT_SYMBOL(blk_queue_max_hw_segments);
233
234/**
235 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
236 * @q: the request queue for the device
237 * @max_size: max size of segment in bytes
238 *
239 * Description:
240 * Enables a low level driver to set an upper limit on the size of a
241 * coalesced segment
242 **/
243void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
244{
245 if (max_size < PAGE_CACHE_SIZE) {
246 max_size = PAGE_CACHE_SIZE;
247 printk("%s: set to minimum %d\n", __FUNCTION__, max_size);
248 }
249
250 q->max_segment_size = max_size;
251}
252
253EXPORT_SYMBOL(blk_queue_max_segment_size);
254
255/**
256 * blk_queue_hardsect_size - set hardware sector size for the queue
257 * @q: the request queue for the device
258 * @size: the hardware sector size, in bytes
259 *
260 * Description:
261 * This should typically be set to the lowest possible sector size
262 * that the hardware can operate on (possible without reverting to
263 * even internal read-modify-write operations). Usually the default
264 * of 512 covers most hardware.
265 **/
266void blk_queue_hardsect_size(struct request_queue *q, unsigned short size)
267{
268 q->hardsect_size = size;
269}
270
271EXPORT_SYMBOL(blk_queue_hardsect_size);
272
273/*
274 * Returns the minimum that is _not_ zero, unless both are zero.
275 */
276#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
277
278/**
279 * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
280 * @t: the stacking driver (top)
281 * @b: the underlying device (bottom)
282 **/
283void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
284{
285 /* zero is "infinity" */
286 t->max_sectors = min_not_zero(t->max_sectors,b->max_sectors);
287 t->max_hw_sectors = min_not_zero(t->max_hw_sectors,b->max_hw_sectors);
288
289 t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
290 t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
291 t->max_segment_size = min(t->max_segment_size,b->max_segment_size);
292 t->hardsect_size = max(t->hardsect_size,b->hardsect_size);
293 if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))
294 clear_bit(QUEUE_FLAG_CLUSTER, &t->queue_flags);
295}
296
297EXPORT_SYMBOL(blk_queue_stack_limits);
298
299/**
300 * blk_queue_dma_drain - Set up a drain buffer for excess dma.
301 *
302 * @q: the request queue for the device
303 * @buf: physically contiguous buffer
304 * @size: size of the buffer in bytes
305 *
306 * Some devices have excess DMA problems and can't simply discard (or
307 * zero fill) the unwanted piece of the transfer. They have to have a
308 * real area of memory to transfer it into. The use case for this is
309 * ATAPI devices in DMA mode. If the packet command causes a transfer
310 * bigger than the transfer size some HBAs will lock up if there
311 * aren't DMA elements to contain the excess transfer. What this API
312 * does is adjust the queue so that the buf is always appended
313 * silently to the scatterlist.
314 *
315 * Note: This routine adjusts max_hw_segments to make room for
316 * appending the drain buffer. If you call
317 * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after
318 * calling this routine, you must set the limit to one fewer than your
319 * device can support otherwise there won't be room for the drain
320 * buffer.
321 */
322int blk_queue_dma_drain(struct request_queue *q, void *buf,
323 unsigned int size)
324{
325 if (q->max_hw_segments < 2 || q->max_phys_segments < 2)
326 return -EINVAL;
327 /* make room for appending the drain */
328 --q->max_hw_segments;
329 --q->max_phys_segments;
330 q->dma_drain_buffer = buf;
331 q->dma_drain_size = size;
332
333 return 0;
334}
335
336EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
337
338/**
339 * blk_queue_segment_boundary - set boundary rules for segment merging
340 * @q: the request queue for the device
341 * @mask: the memory boundary mask
342 **/
343void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
344{
345 if (mask < PAGE_CACHE_SIZE - 1) {
346 mask = PAGE_CACHE_SIZE - 1;
347 printk("%s: set to minimum %lx\n", __FUNCTION__, mask);
348 }
349
350 q->seg_boundary_mask = mask;
351}
352
353EXPORT_SYMBOL(blk_queue_segment_boundary);
354
355/**
356 * blk_queue_dma_alignment - set dma length and memory alignment
357 * @q: the request queue for the device
358 * @mask: alignment mask
359 *
360 * description:
361 * set required memory and length aligment for direct dma transactions.
362 * this is used when buiding direct io requests for the queue.
363 *
364 **/
365void blk_queue_dma_alignment(struct request_queue *q, int mask)
366{
367 q->dma_alignment = mask;
368}
369
370EXPORT_SYMBOL(blk_queue_dma_alignment);
371
372/**
373 * blk_queue_update_dma_alignment - update dma length and memory alignment
374 * @q: the request queue for the device
375 * @mask: alignment mask
376 *
377 * description:
378 * update required memory and length aligment for direct dma transactions.
379 * If the requested alignment is larger than the current alignment, then
380 * the current queue alignment is updated to the new value, otherwise it
381 * is left alone. The design of this is to allow multiple objects
382 * (driver, device, transport etc) to set their respective
383 * alignments without having them interfere.
384 *
385 **/
386void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
387{
388 BUG_ON(mask > PAGE_SIZE);
389
390 if (mask > q->dma_alignment)
391 q->dma_alignment = mask;
392}
393
394EXPORT_SYMBOL(blk_queue_update_dma_alignment);
395
396int __init blk_settings_init(void)
397{
398 blk_max_low_pfn = max_low_pfn - 1;
399 blk_max_pfn = max_pfn - 1;
400 return 0;
401}
402subsys_initcall(blk_settings_init);
diff --git a/block/blk.h b/block/blk.h
index d88549df1b0..08339400719 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -1,11 +1,28 @@
1#ifndef BLK_INTERNAL_H 1#ifndef BLK_INTERNAL_H
2#define BLK_INTERNAL_H 2#define BLK_INTERNAL_H
3 3
4/* Amount of time in which a process may batch requests */
5#define BLK_BATCH_TIME (HZ/50UL)
6
7/* Number of requests a "batching" process may submit */
8#define BLK_BATCH_REQ 32
9
4extern struct kmem_cache *blk_requestq_cachep; 10extern struct kmem_cache *blk_requestq_cachep;
5extern struct kobj_type blk_queue_ktype; 11extern struct kobj_type blk_queue_ktype;
6 12
13void rq_init(struct request_queue *q, struct request *rq);
14void init_request_from_bio(struct request *req, struct bio *bio);
15void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
16 struct bio *bio);
17int ll_back_merge_fn(struct request_queue *q, struct request *req,
18 struct bio *bio);
7void __blk_queue_free_tags(struct request_queue *q); 19void __blk_queue_free_tags(struct request_queue *q);
8 20
21void blk_unplug_work(struct work_struct *work);
22void blk_unplug_timeout(unsigned long data);
23
24struct io_context *current_io_context(gfp_t gfp_flags, int node);
25
9void blk_queue_congestion_threshold(struct request_queue *q); 26void blk_queue_congestion_threshold(struct request_queue *q);
10 27
11/* 28/*
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