Fix emergency allocation accounting.

1 files changed, 23 insertions, 19 deletions

diff --git a/linux-core/drm_memory.c b/linux-core/drm_memory.c
index 12e01414..75f5b521 100644
--- a/linux-core/drm_memory.c
+++ b/linux-core/drm_memory.c
@@ -61,35 +61,39 @@ static inline size_t drm_size_align(size_t size)
 
 int drm_alloc_memctl(size_t size)
 {
-        int ret = 0;
+        int ret = 0;
         unsigned long a_size = drm_size_align(size);
-        unsigned long new_used = drm_memctl.cur_used + a_size;
+        unsigned long new_used;
 
         spin_lock(&drm_memctl.lock);
-        if (unlikely(new_used > drm_memctl.high_threshold)) {
-                if (!DRM_SUSER(DRM_CURPROC) ||
-                    (new_used + drm_memctl.emer_used > drm_memctl.emer_threshold) ||
-                    (a_size > 2*PAGE_SIZE)) {
-                        ret = -ENOMEM;
-                        goto out;
-                }
-
-                /*
-                 * Allow small root-only allocations, even if the
-                 * high threshold is exceeded.
-                 */
-
-                new_used -= drm_memctl.high_threshold;
-                drm_memctl.emer_used += new_used;
-                a_size -= new_used;
+        new_used = drm_memctl.cur_used + a_size;
+        if (likely(new_used < drm_memctl.high_threshold)) {
+                drm_memctl.cur_used = new_used;
+                goto out;
         }
-        drm_memctl.cur_used += a_size;
+
+        /*
+         * Allow small allocations from root-only processes to
+         * succeed until the emergency threshold is reached.
+         */
+
+        new_used += drm_memctl.emer_used;
+        if (unlikely(!DRM_SUSER(DRM_CURPROC) ||
+                     (a_size > 16*PAGE_SIZE) ||
+                     (new_used > drm_memctl.emer_threshold))) {
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        drm_memctl.cur_used = drm_memctl.high_threshold;
+        drm_memctl.emer_used = new_used - drm_memctl.high_threshold;
 out:
         spin_unlock(&drm_memctl.lock);
         return ret;
 }
 EXPORT_SYMBOL(drm_alloc_memctl);
 
+
 void drm_free_memctl(size_t size)
 {
         unsigned long a_size = drm_size_align(size);