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async_tx: fix kmap_atomic usage in async_memcpy 

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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
crypto/async_tx/async_memcpy.c
View File

@ -36,7 +36,6 @@
* @offset: offset in pages to start transaction
* @len: length in bytes
* @flags: ASYNC_TX_ASSUME_COHERENT, ASYNC_TX_ACK, ASYNC_TX_DEP_ACK,
* ASYNC_TX_KMAP_SRC, ASYNC_TX_KMAP_DST
* @depend_tx: memcpy depends on the result of this transaction
* @cb_fn: function to call when the memcpy completes
* @cb_param: parameter to pass to the callback routine
@ -88,23 +87,13 @@ async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
__FUNCTION__);
}
if (flags & ASYNC_TX_KMAP_DST)
dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset;
else
dest_buf = page_address(dest) + dest_offset;
if (flags & ASYNC_TX_KMAP_SRC)
src_buf = kmap_atomic(src, KM_USER0) + src_offset;
else
src_buf = page_address(src) + src_offset;
dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset;
src_buf = kmap_atomic(src, KM_USER1) + src_offset;
memcpy(dest_buf, src_buf, len);
if (flags & ASYNC_TX_KMAP_DST)
kunmap_atomic(dest_buf, KM_USER0);
if (flags & ASYNC_TX_KMAP_SRC)
kunmap_atomic(src_buf, KM_USER0);
kunmap_atomic(dest_buf, KM_USER0);
kunmap_atomic(src_buf, KM_USER1);
async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
}

4
drivers/md/raid5.c
View File

@ -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 */

6
include/linux/async_tx.h
View File

@ -51,10 +51,6 @@ struct dma_chan_ref {
* @ASYNC_TX_ACK: immediately ack the descriptor, precludes setting up a
* dependency chain
* @ASYNC_TX_DEP_ACK: ack the dependency descriptor. Useful for chaining.
* @ASYNC_TX_KMAP_SRC: if the transaction is to be performed synchronously
* take an atomic mapping (KM_USER0) on the source page(s)
* @ASYNC_TX_KMAP_DST: if the transaction is to be performed synchronously
* take an atomic mapping (KM_USER0) on the dest page(s)
*/
enum async_tx_flags {
ASYNC_TX_XOR_ZERO_DST = (1 << 0),
@ -62,8 +58,6 @@ enum async_tx_flags {
ASYNC_TX_ASSUME_COHERENT = (1 << 2),
ASYNC_TX_ACK = (1 << 3),
ASYNC_TX_DEP_ACK = (1 << 4),
ASYNC_TX_KMAP_SRC = (1 << 5),
ASYNC_TX_KMAP_DST = (1 << 6),
};
#ifdef CONFIG_DMA_ENGINE