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| author | Jeff Garzik <jeff@garzik.org> | 2010-11-16 02:10:29 -0500 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-11-16 13:33:23 -0800 |
| commit | f281233d3eba15fb225d21ae2e228fd4553d824a (patch) | |
| tree | 51134454ba8acb558735f90be5540f7d756483e3 /drivers/scsi/libsas/sas_scsi_host.c | |
| parent | bdbd01ac444bffb3c9aefed3059d12554059b320 (diff) | |
| download | linux-f281233d3eba15fb225d21ae2e228fd4553d824a.tar.gz linux-f281233d3eba15fb225d21ae2e228fd4553d824a.tar.bz2 linux-f281233d3eba15fb225d21ae2e228fd4553d824a.zip | |
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/scsi/libsas/sas_scsi_host.c')
| -rw-r--r-- | drivers/scsi/libsas/sas_scsi_host.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c index 55f09e92ab59..29251fabecc6 100644 --- a/drivers/scsi/libsas/sas_scsi_host.c +++ b/drivers/scsi/libsas/sas_scsi_host.c @@ -189,7 +189,7 @@ int sas_queue_up(struct sas_task *task) * Note: XXX: Remove the host unlock/lock pair when SCSI Core can * call us without holding an IRQ spinlock... */ -int sas_queuecommand(struct scsi_cmnd *cmd, +static int sas_queuecommand_lck(struct scsi_cmnd *cmd, void (*scsi_done)(struct scsi_cmnd *)) __releases(host->host_lock) __acquires(dev->sata_dev.ap->lock) @@ -254,6 +254,8 @@ out: return res; } +DEF_SCSI_QCMD(sas_queuecommand) + static void sas_eh_finish_cmd(struct scsi_cmnd *cmd) { struct sas_task *task = TO_SAS_TASK(cmd); |