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Commit eb0645a8 authored by Dan Williams's avatar Dan Williams Committed by Linus Torvalds
Browse files

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: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7c6129c6

crypto/async_tx/async_memcpy.c

+4 −15
Original line number Diff line number Diff line
@@ -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;

		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(src_buf, KM_USER1);



		async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);

	}

drivers/md/raid5.c

+2 −2
Original line number Diff line number Diff line
@@ -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 */

include/linux/async_tx.h

+0 −6
Original line number Diff line number Diff line
@@ -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