From 9bd27cba1aeacb6b12d05f4e5ed6361072f08fe0 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Sun, 2 Nov 2008 21:40:07 +0100 Subject: [PATCH] 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 Cc: FUJITA Tomonori Tested-by: Valerio Passini [bart: fixup patch description per comments from Sergei Shtylyov] Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/ide/ide-cd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c index 48b5eda3ab4..42ab6d8715f 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; } -- 2.41.1