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/dpt_i2o.c b/drivers/scsi/dpt_i2o.c
index 23dec0063385..cffcb108ac96 100644
--- a/drivers/scsi/dpt_i2o.c
+++ b/drivers/scsi/dpt_i2o.c
@@ -423,7 +423,7 @@ static int adpt_slave_configure(struct scsi_device * device)
         return 0;
 }
 
-static int adpt_queue(struct scsi_cmnd * cmd, void (*done) (struct scsi_cmnd *))
+static int adpt_queue_lck(struct scsi_cmnd * cmd, void (*done) (struct scsi_cmnd *))
 {
         adpt_hba* pHba = NULL;
         struct adpt_device* pDev = NULL;        /* dpt per device information */
@@ -491,6 +491,8 @@ static int adpt_queue(struct scsi_cmnd * cmd, void (*done) (struct scsi_cmnd *))
         return adpt_scsi_to_i2o(pHba, cmd, pDev);
 }
 
+static DEF_SCSI_QCMD(adpt_queue)
+
 static int adpt_bios_param(struct scsi_device *sdev, struct block_device *dev,
                 sector_t capacity, int geom[])
 {