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authorJeff Garzik <jeff@garzik.org>2010-11-16 02:10:29 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2010-11-16 13:33:23 -0800
commitf281233d3eba15fb225d21ae2e228fd4553d824a (patch)
tree51134454ba8acb558735f90be5540f7d756483e3 /drivers/message/i2o
parentbdbd01ac444bffb3c9aefed3059d12554059b320 (diff)
SCSI host lock push-down
Move the mid-layer's ->queuecommand() invocation from being locked with the host lock to being unlocked to facilitate speeding up the critical path for drivers who don't need this lock taken anyway. The patch below presents a simple SCSI host lock push-down as an equivalent transformation. No locking or other behavior should change with this patch. All existing bugs and locking orders are preserved. Additionally, add one parameter to queuecommand, struct Scsi_Host * and remove one parameter from queuecommand, void (*done)(struct scsi_cmnd *) Scsi_Host* is a convenient pointer that most host drivers need anyway, and 'done' is redundant to struct scsi_cmnd->scsi_done. Minimal code disturbance was attempted with this change. Most drivers needed only two one-line modifications for their host lock push-down. Signed-off-by: Jeff Garzik <jgarzik@redhat.com> Acked-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/message/i2o')
-rw-r--r--drivers/message/i2o/i2o_scsi.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/message/i2o/i2o_scsi.c b/drivers/message/i2o/i2o_scsi.c
index ea6b2197da8a..97bdf82ec905 100644
--- a/drivers/message/i2o/i2o_scsi.c
+++ b/drivers/message/i2o/i2o_scsi.c
@@ -506,7 +506,7 @@ static struct i2o_driver i2o_scsi_driver = {
* Locks: takes the controller lock on error path only
*/
-static int i2o_scsi_queuecommand(struct scsi_cmnd *SCpnt,
+static int i2o_scsi_queuecommand_lck(struct scsi_cmnd *SCpnt,
void (*done) (struct scsi_cmnd *))
{
struct i2o_controller *c;
@@ -688,7 +688,9 @@ static int i2o_scsi_queuecommand(struct scsi_cmnd *SCpnt,
exit:
return rc;
-};
+}
+
+static DEF_SCSI_QCMD(i2o_scsi_queuecommand)
/**
* i2o_scsi_abort - abort a running command