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| author |  James Bottomley <James.Bottomley@HansenPartnership.com>
| 2008-01-01 10:00:10 -0600 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@HansenPartnership.com>
| 2008-01-11 18:29:22 -0600 |
| commit | 465ff3185e0cb76d46137335a4d21d0d9d3ac8a2 (patch) | |
| tree | 171068cd7d99600cd094c2eb72bac712649fd9eb /drivers/firewire | |
| parent | [SCSI] block: Introduce new blk_queue_update_dma_alignment interface (diff) | |
| download | linux-465ff3185e0cb76d46137335a4d21d0d9d3ac8a2.tar.gz linux-465ff3185e0cb76d46137335a4d21d0d9d3ac8a2.tar.bz2 linux-465ff3185e0cb76d46137335a4d21d0d9d3ac8a2.zip | |
[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')
| -rw-r--r-- | drivers/firewire/fw-sbp2.c | 6 |
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) sdev->allow_restart = 1; + /* + * Update the dma alignment (minimum alignment requirements for + * start and end of DMA transfers) to be a sector + */ + blk_queue_update_dma_alignment(sdev->request_queue, 511); + if (lu->tgt->workarounds & SBP2_WORKAROUND_INQUIRY_36) sdev->inquiry_len = 36; |