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>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/scsi/a100u2w.c b/drivers/scsi/a100u2w.c
index dbbc601948e5..dc5ac6e528c4 100644
--- a/drivers/scsi/a100u2w.c
+++ b/drivers/scsi/a100u2w.c
@@ -911,7 +911,7 @@ static int inia100_build_scb(struct orc_host * host, struct orc_scb * scb, struc
  *      queue the command down to the controller
  */
 
-static int inia100_queue(struct scsi_cmnd * cmd, void (*done) (struct scsi_cmnd *))
+static int inia100_queue_lck(struct scsi_cmnd * cmd, void (*done) (struct scsi_cmnd *))
 {
         struct orc_scb *scb;
         struct orc_host *host;          /* Point to Host adapter control block */
@@ -930,6 +930,8 @@ static int inia100_queue(struct scsi_cmnd * cmd, void (*done) (struct scsi_cmnd
         return 0;
 }
 
+static DEF_SCSI_QCMD(inia100_queue)
+
 /*****************************************************************************
  Function name  : inia100_abort
  Description    : Abort a queued command.