ide-cd: fix DMA alignment regression
e5318b531b
("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>
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1 changed files with 2 additions and 1 deletions
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@ -1250,7 +1250,8 @@ static void cdrom_do_block_pc(ide_drive_t *drive, struct request *rq)
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* separate masks.
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*/
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alignment = queue_dma_alignment(q) | q->dma_pad_mask;
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if ((unsigned long)buf & alignment || rq->data_len & alignment
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if ((unsigned long)buf & alignment
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|| rq->data_len & q->dma_pad_mask
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|| object_is_on_stack(buf))
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drive->dma = 0;
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}
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