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@xxxxxxxxxx)
diff -r 09daf852c1c5 -r c9516154fabc block/blk-settings.c
--- a/block/blk-settings.c Thu Sep 09 12:10:43 2010 -0700
+++ b/block/blk-settings.c Mon Sep 13 10:15:24 2010 -0700
@@ -214,16 +214,14 @@ void blk_queue_bounce_limit(struct reque
*/
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;
+#endif
q->limits.bounce_pfn = b_pfn;
-#endif
if (dma) {
init_emergency_isa_pool();
q->limits.bounce_gfp = GFP_NOIO | GFP_DMA;
- q->limits.bounce_pfn = b_pfn;
}
}
EXPORT_SYMBOL(blk_queue_bounce_limit);
--
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