aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorChristoph Hellwig2010-06-18 09:59:42 -0500
committerJens Axboe2010-08-07 11:23:08 -0500
commit66ac0280197981f88774e74b60c8e5f9f07c1dba (patch)
treed093ce493146779926df88b5831805c6f9ee14e1 /block/blk-core.c
parent082439004b31adc146e96e5f1c574dd2b57dcd93 (diff)
downloadkernel-common-66ac0280197981f88774e74b60c8e5f9f07c1dba.tar.gz
kernel-common-66ac0280197981f88774e74b60c8e5f9f07c1dba.tar.xz
kernel-common-66ac0280197981f88774e74b60c8e5f9f07c1dba.zip
block: don't allocate a payload for discard request
Allocating a fixed payload for discard requests always was a horrible hack, and it's not coming to byte us when adding support for discard in DM/MD. So change the code to leave the allocation of a payload to the lowlevel driver. Unfortunately that means we'll need another hack, which allows us to update the various block layer length fields indicating that we have a payload. Instead of hiding this in sd.c, which we already partially do for UNMAP support add a documented helper in the core block layer for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block/blk-core.c')
-rw-r--r--block/blk-core.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 66c3cfe94d0..3531d8e1da0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1135,6 +1135,38 @@ void blk_put_request(struct request *req)
1135} 1135}
1136EXPORT_SYMBOL(blk_put_request); 1136EXPORT_SYMBOL(blk_put_request);
1137 1137
1138/**
1139 * blk_add_request_payload - add a payload to a request
1140 * @rq: request to update
1141 * @page: page backing the payload
1142 * @len: length of the payload.
1143 *
1144 * This allows to later add a payload to an already submitted request by
1145 * a block driver. The driver needs to take care of freeing the payload
1146 * itself.
1147 *
1148 * Note that this is a quite horrible hack and nothing but handling of
1149 * discard requests should ever use it.
1150 */
1151void blk_add_request_payload(struct request *rq, struct page *page,
1152 unsigned int len)
1153{
1154 struct bio *bio = rq->bio;
1155
1156 bio->bi_io_vec->bv_page = page;
1157 bio->bi_io_vec->bv_offset = 0;
1158 bio->bi_io_vec->bv_len = len;
1159
1160 bio->bi_size = len;
1161 bio->bi_vcnt = 1;
1162 bio->bi_phys_segments = 1;
1163
1164 rq->__data_len = rq->resid_len = len;
1165 rq->nr_phys_segments = 1;
1166 rq->buffer = bio_data(bio);
1167}
1168EXPORT_SYMBOL_GPL(blk_add_request_payload);
1169
1138void init_request_from_bio(struct request *req, struct bio *bio) 1170void init_request_from_bio(struct request *req, struct bio *bio)
1139{ 1171{
1140 req->cpu = bio->bi_comp_cpu; 1172 req->cpu = bio->bi_comp_cpu;