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| author | Dan Williams <dan.j.williams@intel.com> | 2011-12-19 16:42:34 -0800 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2012-02-19 13:48:51 -0600 |
| commit | b1124cd3ec97406c767b90bf7e93ecd2d2915592 (patch) | |
| tree | d0936775aacff4492177c14a73175738dfb51ee0 /include/scsi | |
| parent | f8daa6e6d83f60a721752cb53433bfdc1503b45f (diff) | |
| download | linux-b1124cd3ec97406c767b90bf7e93ecd2d2915592.tar.gz linux-b1124cd3ec97406c767b90bf7e93ecd2d2915592.tar.bz2 linux-b1124cd3ec97406c767b90bf7e93ecd2d2915592.zip | |
[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 'include/scsi')
| -rw-r--r-- | include/scsi/libsas.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h index 8e402d5a0640..42900fa95a03 100644 --- a/include/scsi/libsas.h +++ b/include/scsi/libsas.h @@ -330,6 +330,7 @@ struct sas_ha_event { enum sas_ha_state { SAS_HA_REGISTERED, + SAS_HA_DRAINING, }; struct sas_ha_struct { @@ -337,6 +338,8 @@ struct sas_ha_struct { struct sas_ha_event ha_events[HA_NUM_EVENTS]; unsigned long pending; + struct list_head defer_q; /* work queued while draining */ + struct mutex drain_mutex; unsigned long state; spinlock_t state_lock; @@ -657,6 +660,7 @@ int sas_eh_bus_reset_handler(struct scsi_cmnd *cmd); extern void sas_target_destroy(struct scsi_target *); extern int sas_slave_alloc(struct scsi_device *); extern int sas_ioctl(struct scsi_device *sdev, int cmd, void __user *arg); +extern int sas_drain_work(struct sas_ha_struct *ha); extern int sas_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, struct request *req); |