dma-debug: change allocation mode from GFP_NOWAIT to GFP_ATIOMIC

[ Upstream commit 84bc4f1dbbbb5f8aa68706a96711dccb28b518e5 ]

We observed the error "cacheline tracking ENOMEM, dma-debug disabled"
during a light system load (copying some files). The reason for this error
is that the dma_active_cacheline radix tree uses GFP_NOWAIT allocation -
so it can't access the emergency memory reserves and it fails as soon as
anybody reaches the watermark.

This patch changes GFP_NOWAIT to GFP_ATOMIC, so that it can access the
emergency memory reserves.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 61e7240947f5496c60ae43ec0af38c80a554f2b8..163e0e9b357ff246dd3ee7fc5ed0e2b7d798e9c7 100644 (file)
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -465,7 +465,7 @@ EXPORT_SYMBOL(debug_dma_dump_mappings);
  * At any time debug_dma_assert_idle() can be called to trigger a
  * warning if any cachelines in the given page are in the active set.
  */
-static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
+static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC);
 static DEFINE_SPINLOCK(radix_lock);
 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)