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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 16:33:23 -0500
commitf281233d3eba15fb225d21ae2e228fd4553d824a (patch)
tree51134454ba8acb558735f90be5540f7d756483e3 /drivers/s390/scsi/zfcp_scsi.c
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/s390/scsi/zfcp_scsi.c')
-rw-r--r--drivers/s390/scsi/zfcp_scsi.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index 50286d8707f3..6bd2dbc4c316 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -76,7 +76,7 @@ static void zfcp_scsi_command_fail(struct scsi_cmnd *scpnt, int result)
76 scpnt->scsi_done(scpnt); 76 scpnt->scsi_done(scpnt);
77} 77}
78 78
79static int zfcp_scsi_queuecommand(struct scsi_cmnd *scpnt, 79static int zfcp_scsi_queuecommand_lck(struct scsi_cmnd *scpnt,
80 void (*done) (struct scsi_cmnd *)) 80 void (*done) (struct scsi_cmnd *))
81{ 81{
82 struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scpnt->device); 82 struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scpnt->device);
@@ -127,6 +127,8 @@ static int zfcp_scsi_queuecommand(struct scsi_cmnd *scpnt,
127 return ret; 127 return ret;
128} 128}
129 129
130static DEF_SCSI_QCMD(zfcp_scsi_queuecommand)
131
130static int zfcp_scsi_slave_alloc(struct scsi_device *sdev) 132static int zfcp_scsi_slave_alloc(struct scsi_device *sdev)
131{ 133{
132 struct fc_rport *rport = starget_to_rport(scsi_target(sdev)); 134 struct fc_rport *rport = starget_to_rport(scsi_target(sdev));