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 <dima@android.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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 <dima@android.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dima Zavin · Linus Torvalds
1 parent d65bfacb04
Showing 1 changed file with 2 additions and 0 deletions Side-by-side Diff
mm/dmapool.c
@@ -311,6 +311,8 @@
 	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) {
...	...	@@ -311,6 +311,8 @@
311	311	size_t offset;
312	312	void *retval;
313	313
	314	+ might_sleep_if(mem_flags & __GFP_WAIT);
	315	+
314	316	spin_lock_irqsave(&pool->lock, flags);
315	317	restart:
316	318	list_for_each_entry(page, &pool->page_list, page_list) {