From: Andi Kleen <ak@suse.de>
Date: Wed, 21 Jun 2006 12:48:09 +0000 (+0200)
Subject: [BLOCK] Fix bounce limit address check
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=8269730b389d4793348d521140f9c76fb1828249;p=linux-beck.git

[BLOCK] Fix bounce limit address check

Do a safer check for when to enable DMA. Currently we enable ISA DMA
for cases that do not need it, resulting in OOM conditions when ZONE_DMA
runs out of space.

Signed-off-by: Jens Axboe <axboe@suse.de>
---

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 2270bb451385..0603ab2f3692 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -638,7 +638,7 @@ void blk_queue_bounce_limit(request_queue_t *q, u64 dma_addr)
 	/* Assume anything <= 4GB can be handled by IOMMU.
 	   Actually some IOMMUs can handle everything, but I don't
 	   know of a way to test this here. */
-	if (bounce_pfn < (0xffffffff>>PAGE_SHIFT))
+	if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
 		dma = 1;
 	q->bounce_pfn = max_low_pfn;
 #else