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>

1 files changed, 0 insertions, 6 deletions

diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h
index ff1255079fa1..bdca3f1b3213 100644
--- a/include/linux/async_tx.h
+++ b/include/linux/async_tx.h
@@ -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