• Jeff Garzik's avatar
    SCSI host lock push-down · f281233d
    Jeff Garzik authored
    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: default avatarJeff Garzik <jgarzik@redhat.com>
    Acked-by: default avatarJames Bottomley <James.Bottomley@suse.de>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    f281233d