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async_tx: fix kmap_atomic usage in async_memcpy

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Andrew Morton:
	[async_memcpy] is very wrong if both ASYNC_TX_KMAP_DST and
	ASYNC_TX_KMAP_SRC can ever be set.  We'll end up using the same kmap
	slot for both src add dest and we get either corrupted data or a BUG.

Evgeniy Polyakov:
	Btw, shouldn't it always be kmap_atomic() even if flag is not set.
	That pages are usual one returned by alloc_page().

So fix the usage of kmap_atomic and kill the ASYNC_TX_KMAP_DST and
ASYNC_TX_KMAP_SRC flags.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Williams
2007-07-20 00:31:46 -07:00
committed by Linus Torvalds
parent 7c6129c68f
commit eb0645a8b1
3 changed files with 6 additions and 23 deletions
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4
drivers/md/raid5.c
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@@ -493,12 +493,12 @@ async_copy_data(int frombio, struct bio *bio, struct page *page,
if (frombio)
tx = async_memcpy(page, bio_page, page_offset,
b_offset, clen,
ASYNC_TX_DEP_ACK | ASYNC_TX_KMAP_SRC,
ASYNC_TX_DEP_ACK,
tx, NULL, NULL);
else
tx = async_memcpy(bio_page, page, b_offset,
page_offset, clen,
ASYNC_TX_DEP_ACK | ASYNC_TX_KMAP_DST,
ASYNC_TX_DEP_ACK,
tx, NULL, NULL);
}
if (clen < len) /* hit end of page */