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authorJames Bottomley <James.Bottomley@HansenPartnership.com>2008-01-01 11:00:10 -0500
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-01-11 19:29:22 -0500
commit465ff3185e0cb76d46137335a4d21d0d9d3ac8a2 (patch)
tree171068cd7d99600cd094c2eb72bac712649fd9eb /drivers/firewire/fw-sbp2.c
parent11c3e689f1c3a73e3af7b0ea767b1b0626da8033 (diff)
[SCSI] relax scsi dma alignment
This patch relaxes the default SCSI DMA alignment from 512 bytes to 4 bytes. I remember from previous discussions that usb and firewire have sector size alignment requirements, so I upped their alignments in the respective slave allocs. The reason for doing this is so that we don't get such a huge amount of copy overhead in bio_copy_user() for udev. (basically all inquiries it issues can now be directly mapped). Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'drivers/firewire/fw-sbp2.c')
-rw-r--r--drivers/firewire/fw-sbp2.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c
index 624ff3e082f6..c2169d215bf7 100644
--- a/drivers/firewire/fw-sbp2.c
+++ b/drivers/firewire/fw-sbp2.c
@@ -1238,6 +1238,12 @@ static int sbp2_scsi_slave_alloc(struct scsi_device *sdev)
1238 1238
1239 sdev->allow_restart = 1; 1239 sdev->allow_restart = 1;
1240 1240
1241 /*
1242 * Update the dma alignment (minimum alignment requirements for
1243 * start and end of DMA transfers) to be a sector
1244 */
1245 blk_queue_update_dma_alignment(sdev->request_queue, 511);
1246
1241 if (lu->tgt->workarounds & SBP2_WORKAROUND_INQUIRY_36) 1247 if (lu->tgt->workarounds & SBP2_WORKAROUND_INQUIRY_36)
1242 sdev->inquiry_len = 36; 1248 sdev->inquiry_len = 36;
1243 1249