mm: add a might_sleep_if() to dma_pool_alloc()

Buggy drivers (e.g. fsl_udc) could call dma_pool_alloc from atomic context with GFP_KERNEL. In most instances, the first pool_alloc_page call would succeed and the sleeping functions would never be called. This allowed the buggy drivers to slip through the cracks. Add a might_sleep_if() checking for __GFP_WAIT in flags. Signed-off-by: Dima Zavin <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
niw · Oct 26, 2010 · ea05c84 · ea05c84
1 parent d65bfac
commit ea05c84
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/mm/dmapool.c b/mm/dmapool.c
@@ -311,6 +311,8 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags,
 	size_t offset;
 	void *retval;
 
+	might_sleep_if(mem_flags & __GFP_WAIT);
+
 	spin_lock_irqsave(&pool->lock, flags);
  restart:
 	list_for_each_entry(page, &pool->page_list, page_list) {