Commit efb012b3 authored by Malahal Naineni's avatar Malahal Naineni Committed by Jens Axboe

block: set the bounce_pfn to the actual DMA limit rather than to max memory

The bounce_pfn of the request queue in 64 bit systems is set to the
current max_low_pfn. Adding more memory later makes this incorrect.
Memory allocated beyond this boot time max_low_pfn appear to require
bounce buffers (bounce buffers are actually not allocated but used in
calculating segments that may result in "over max segments limit"
Signed-off-by: default avatarMalahal Naineni <>
Signed-off-by: default avatarJens Axboe <>
parent 260a67a9
......@@ -214,7 +214,7 @@ void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask)
if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
dma = 1;
q->limits.bounce_pfn = max_low_pfn;
q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
if (b_pfn < blk_max_low_pfn)
dma = 1;
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