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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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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