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authorBorislav Petkov <petkovbb@gmail.com>2008-11-02 21:40:07 +0100
committerBartlomiej Zolnierkiewicz <bzolnier@gmail.com>2008-11-02 21:40:07 +0100
commit9bd27cba1aeacb6b12d05f4e5ed6361072f08fe0 (patch)
tree33917b6981e58ad553a86c44c91f07b1ecb13847
parent721d5dfe7e516954c501d5e9d0dfab379cf4241a (diff)
ide-cd: fix DMA alignment regression
e5318b531b008c79d2a0c0df06a7b8628da38e2f ("ide: use the dma safe check for REQ_TYPE_ATA_PC") introduced a regression which caused some ATAPI drives to turn off DMA for REQ_TYPE_BLOCK_PC commands while burning and thus degrading performance and ultimately causing an excessive amount of underruns. The issue is documented also in: http://bugzilla.kernel.org/show_bug.cgi?id=11742. Signed-off-by: Borislav Petkov <petkovbb@gmail.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Tested-by: Valerio Passini <valerio.passini@unicam.it> [bart: fixup patch description per comments from Sergei Shtylyov] Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
-rw-r--r--drivers/ide/ide-cd.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
index 48b5eda3ab41..42ab6d8715f2 100644
--- a/drivers/ide/ide-cd.c
+++ b/drivers/ide/ide-cd.c
@@ -1250,7 +1250,8 @@ static void cdrom_do_block_pc(ide_drive_t *drive, struct request *rq)
* separate masks.
*/
alignment = queue_dma_alignment(q) | q->dma_pad_mask;
- if ((unsigned long)buf & alignment || rq->data_len & alignment
+ if ((unsigned long)buf & alignment
+ || rq->data_len & q->dma_pad_mask
|| object_is_on_stack(buf))
drive->dma = 0;
}

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