[PATCH 5.17 130/772] dma-debug: change allocation mode from GFP_NOWAIT to GFP_ATIOMIC

Greg Kroah-Hartman
2022-06-07T20:43:10Z

From: Mikulas Patocka <mpatocka@redhat.com>

[ 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>
---
kernel/dma/debug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index f8ff598596b8..ac740630c79c 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -448,7 +448,7 @@ void debug_dma_dump_mappings(struct device *dev)
* other hand, consumes a single dma_debug_entry, but inserts 'nents'
* entries into the tree.
*/
-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)
--
2.35.1