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authorJeff Garzik <jgarzik@pobox.com>2005-10-05 07:13:30 -0400
committerJeff Garzik <jgarzik@pobox.com>2005-10-05 07:13:30 -0400
commitcedc9a478d8c6265879dc3839ef3d4849a709184 (patch)
tree0c8e0fbffdb6081381c01b8cfd93c95b168acb44 /drivers/scsi/libata-scsi.c
parented39f731ab2e77e58122232f6e27333331d7793d (diff)
libata: fix ATAPI DMA alignment issues
ATAPI needs to be padded to next 4 byte boundary, if misaligned. Original work by me, many fixes from Tejun Heo.
Diffstat (limited to 'drivers/scsi/libata-scsi.c')
-rw-r--r--drivers/scsi/libata-scsi.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 104fd9a63e73..ee3f1050fb5f 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -150,10 +150,10 @@ struct ata_queued_cmd *ata_scsi_qc_new(struct ata_port *ap,
qc->scsidone = done;
if (cmd->use_sg) {
- qc->sg = (struct scatterlist *) cmd->request_buffer;
+ qc->__sg = (struct scatterlist *) cmd->request_buffer;
qc->n_elem = cmd->use_sg;
} else {
- qc->sg = &qc->sgent;
+ qc->__sg = &qc->sgent;
qc->n_elem = 1;
}
} else {
@@ -364,6 +364,16 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
*/
blk_queue_max_sectors(sdev->request_queue, 2048);
}
+
+ /*
+ * SATA DMA transfers must be multiples of 4 byte, so
+ * we need to pad ATAPI transfers using an extra sg.
+ * Decrement max hw segments accordingly.
+ */
+ if (dev->class == ATA_DEV_ATAPI) {
+ request_queue_t *q = sdev->request_queue;
+ blk_queue_max_hw_segments(q, q->max_hw_segments - 1);
+ }
}
return 0; /* scsi layer doesn't check return value, sigh */