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authorSebastian Ott <sebott@linux.vnet.ibm.com>2014-06-04 16:07:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-04 16:53:58 -0700
commit8bf8fcb07653fbaea74f96bba1e4ed0f851675ab (patch)
tree6412234c0fea986db2c88874221c42bf56c7acff /mm/mempool.c
parent02a8efeda894d3541c7143ed818b25b299504190 (diff)
downloadlinux-8bf8fcb07653fbaea74f96bba1e4ed0f851675ab.tar.gz
mm/mempool: warn about __GFP_ZERO usage
Memory obtained via mempool_alloc is not always zeroed even when called with __GFP_ZERO. Add a note and VM_BUG_ON statement to make that clear. [akpm@linux-foundation.org: use VM_WARN_ON_ONCE] Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mempool.c')
-rw-r--r--mm/mempool.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/mempool.c b/mm/mempool.c
index 905434f18c97..455d468c3a5d 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -192,6 +192,7 @@ EXPORT_SYMBOL(mempool_resize);
* returns NULL. Note that due to preallocation, this function
* *never* fails when called from process contexts. (it might
* fail if called from an IRQ context.)
+ * Note: using __GFP_ZERO is not supported.
*/
void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
{
@@ -200,6 +201,7 @@ void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
wait_queue_t wait;
gfp_t gfp_temp;
+ VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO);
might_sleep_if(gfp_mask & __GFP_WAIT);
gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */