diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2011-12-20 00:42:34 (GMT) |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2012-02-19 19:48:51 (GMT) |
| commit | b1124cd3ec97406c767b90bf7e93ecd2d2915592 (patch) | |
| tree | d0936775aacff4492177c14a73175738dfb51ee0 /drivers/scsi/libsas/sas_init.c | |
| parent | f8daa6e6d83f60a721752cb53433bfdc1503b45f (diff) | |
| download | linux-b1124cd3ec97406c767b90bf7e93ecd2d2915592.tar.xz | |
[SCSI] libsas: introduce sas_drain_work()
When an lldd invokes ->notify_port_event() it can trigger a chain of libsas
events to:
1/ form the port and find the direct attached device
2/ if the attached device is an expander perform domain discovery
A call to flush_workqueue() will only flush the initial port formation work.
Currently libsas users need to call scsi_flush_work() up to the max depth of
chain (which will grow from 2 to 3 when ata discovery is moved to its own
discovery event). Instead of open coding multiple calls switch to use
drain_workqueue() to flush sas work.
drain_workqueue() does not handle new work submitted during the drain so
libsas needs a bit of infrastructure to hold off unchained work submissions
while a drain is in flight. A lldd ->notify() event is considered 'unchained'
while a sas_discover_event() is 'chained'. As Tejun notes:
"For now, I think it would be best to add private wrapper in libsas to
support deferring unchained work items while draining."
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi/libsas/sas_init.c')
| -rw-r--r-- | drivers/scsi/libsas/sas_init.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c index da244e6..572b943 100644 --- a/drivers/scsi/libsas/sas_init.c +++ b/drivers/scsi/libsas/sas_init.c @@ -114,6 +114,8 @@ int sas_register_ha(struct sas_ha_struct *sas_ha) set_bit(SAS_HA_REGISTERED, &sas_ha->state); spin_lock_init(&sas_ha->state_lock); + mutex_init(&sas_ha->drain_mutex); + INIT_LIST_HEAD(&sas_ha->defer_q); error = sas_register_phys(sas_ha); if (error) { @@ -157,12 +159,13 @@ int sas_unregister_ha(struct sas_ha_struct *sas_ha) { unsigned long flags; - /* Set the state to unregistered to avoid further - * events to be queued */ + /* Set the state to unregistered to avoid further unchained + * events to be queued + */ spin_lock_irqsave(&sas_ha->state_lock, flags); clear_bit(SAS_HA_REGISTERED, &sas_ha->state); spin_unlock_irqrestore(&sas_ha->state_lock, flags); - scsi_flush_work(sas_ha->core.shost); + sas_drain_work(sas_ha); sas_unregister_ports(sas_ha); |