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, 1 insertions, 1 deletions

diff --git a/drivers/scsi/dtc.h b/drivers/scsi/dtc.h
index 0b205f8c7326..cdc621204b66 100644
--- a/drivers/scsi/dtc.h
+++ b/drivers/scsi/dtc.h
@@ -36,7 +36,7 @@ static int dtc_abort(Scsi_Cmnd *);
 static int dtc_biosparam(struct scsi_device *, struct block_device *,
                          sector_t, int*);
 static int dtc_detect(struct scsi_host_template *);
-static int dtc_queue_command(Scsi_Cmnd *, void (*done)(Scsi_Cmnd *));
+static int dtc_queue_command(struct Scsi_Host *, struct scsi_cmnd *);
 static int dtc_bus_reset(Scsi_Cmnd *);
 
 #ifndef CMD_PER_LUN