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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 13:33:23 -0800
commitf281233d3eba15fb225d21ae2e228fd4553d824a (patch)
tree51134454ba8acb558735f90be5540f7d756483e3 /arch/ia64
parentbdbd01ac444bffb3c9aefed3059d12554059b320 (diff)
downloadlinux-2.6.38-lt-ux500-f281233d3eba15fb225d21ae2e228fd4553d824a.tar.gz
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 'arch/ia64')
-rw-r--r--arch/ia64/hp/sim/simscsi.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/ia64/hp/sim/simscsi.c b/arch/ia64/hp/sim/simscsi.c
index 3a078ad3aa4..331de723c67 100644
--- a/arch/ia64/hp/sim/simscsi.c
+++ b/arch/ia64/hp/sim/simscsi.c
@@ -202,7 +202,7 @@ simscsi_readwrite10 (struct scsi_cmnd *sc, int mode)
}
static int
-simscsi_queuecommand (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
+simscsi_queuecommand_lck (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
{
unsigned int target_id = sc->device->id;
char fname[MAX_ROOT_LEN+16];
@@ -326,6 +326,8 @@ simscsi_queuecommand (struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
return 0;
}
+static DEF_SCSI_QCMD(simscsi_queuecommand)
+
static int
simscsi_host_reset (struct scsi_cmnd *sc)
{