dma-debug: add a schedule point in debug_dma_dump_mappings()

debug_dma_dump_mappings() can take a lot of cpu cycles :

lpk43:/# time wc -l /sys/kernel/debug/dma-api/dump
163435 /sys/kernel/debug/dma-api/dump

real	0m0.463s
user	0m0.003s
sys	0m0.459s

Let's add a cond_resched() to avoid holding cpu for too long.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Corentin Labbe <clabbe@baylibre.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 099002d84f466af0a8e421d035ac8eb119e08bd8..4ad74f5987ea9e95f9bb5e2d1592254e367d24fb 100644 (file)
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -420,6 +420,7 @@ void debug_dma_dump_mappings(struct device *dev)
                }
 
                spin_unlock_irqrestore(&bucket->lock, flags);
+               cond_resched();
        }
 }