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"
errors).

Signed-off-by: Malahal Naineni <malahal@us.ibm.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Malahal Naineni 2010-09-24 20:25:49 +02:00 committed by Jens Axboe
parent 4b1977698c
commit c49825facf

View File

@ -214,16 +214,14 @@ 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;
#else
if (b_pfn < blk_max_low_pfn)
dma = 1;
q->limits.bounce_pfn = b_pfn;
#endif
q->limits.bounce_pfn = b_pfn;
if (dma) {
init_emergency_isa_pool();
q->bounce_gfp = GFP_NOIO | GFP_DMA;
q->limits.bounce_pfn = b_pfn;
}
}
EXPORT_SYMBOL(blk_queue_bounce_limit);