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| author | James Bottomley <James.Bottomley@HansenPartnership.com> | 2008-01-01 19:00:10 +0300 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@HansenPartnership.com> | 2008-01-12 03:29:22 +0300 |
| commit | 465ff3185e0cb76d46137335a4d21d0d9d3ac8a2 (patch) | |
| tree | 171068cd7d99600cd094c2eb72bac712649fd9eb /drivers/ata/libata-scsi.c | |
| parent | 11c3e689f1c3a73e3af7b0ea767b1b0626da8033 (diff) | |
| download | linux-465ff3185e0cb76d46137335a4d21d0d9d3ac8a2.tar.xz | |
[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/ata/libata-scsi.c')
| -rw-r--r-- | drivers/ata/libata-scsi.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 264ae60e3fd8..4bb268b9aaeb 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -824,6 +824,9 @@ static void ata_scsi_sdev_config(struct scsi_device *sdev) * requests. */ sdev->max_device_blocked = 1; + + /* set the min alignment */ + blk_queue_update_dma_alignment(sdev->request_queue, ATA_DMA_PAD_SZ - 1); } static void ata_scsi_dev_config(struct scsi_device *sdev, @@ -878,7 +881,7 @@ int ata_scsi_slave_config(struct scsi_device *sdev) if (dev) ata_scsi_dev_config(sdev, dev); - return 0; /* scsi layer doesn't check return value, sigh */ + return 0; } /** |