Commit 00642a1b authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Martin K. Petersen

scsi_dh_alua: Allow workqueue to run synchronously

Some arrays may only capable of handling one STPG at a time,
so this patch adds a singlethreaded workqueue for STPGs to be
submitted synchronously.
Reviewed-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 03197b61
......@@ -64,6 +64,7 @@
/* device handler flags */
#define ALUA_OPTIMIZE_STPG 0x01
#define ALUA_RTPG_EXT_HDR_UNSUPP 0x02
#define ALUA_SYNC_STPG 0x04
/* State machine flags */
#define ALUA_PG_RUN_RTPG 0x10
#define ALUA_PG_RUN_STPG 0x20
......@@ -76,6 +77,7 @@ MODULE_PARM_DESC(optimize_stpg, "Allow use of a non-optimized path, rather than
static LIST_HEAD(port_group_list);
static DEFINE_SPINLOCK(port_group_lock);
static struct workqueue_struct *kaluad_wq;
static struct workqueue_struct *kaluad_sync_wq;
struct alua_port_group {
struct kref kref;
......@@ -686,6 +688,7 @@ static void alua_rtpg_work(struct work_struct *work)
int err = SCSI_DH_OK;
struct alua_queue_data *qdata, *tmp;
unsigned long flags;
struct workqueue_struct *alua_wq = kaluad_wq;
spin_lock_irqsave(&pg->lock, flags);
sdev = pg->rtpg_sdev;
......@@ -695,6 +698,8 @@ static void alua_rtpg_work(struct work_struct *work)
spin_unlock_irqrestore(&pg->lock, flags);
return;
}
if (pg->flags & ALUA_SYNC_STPG)
alua_wq = kaluad_sync_wq;
pg->flags |= ALUA_PG_RUNNING;
if (pg->flags & ALUA_PG_RUN_RTPG) {
pg->flags &= ~ALUA_PG_RUN_RTPG;
......@@ -705,7 +710,7 @@ static void alua_rtpg_work(struct work_struct *work)
pg->flags &= ~ALUA_PG_RUNNING;
pg->flags |= ALUA_PG_RUN_RTPG;
spin_unlock_irqrestore(&pg->lock, flags);
queue_delayed_work(kaluad_wq, &pg->rtpg_work,
queue_delayed_work(alua_wq, &pg->rtpg_work,
pg->interval * HZ);
return;
}
......@@ -722,7 +727,7 @@ static void alua_rtpg_work(struct work_struct *work)
pg->interval = 0;
pg->flags &= ~ALUA_PG_RUNNING;
spin_unlock_irqrestore(&pg->lock, flags);
queue_delayed_work(kaluad_wq, &pg->rtpg_work,
queue_delayed_work(alua_wq, &pg->rtpg_work,
pg->interval * HZ);
return;
}
......@@ -751,6 +756,7 @@ static void alua_rtpg_queue(struct alua_port_group *pg,
{
int start_queue = 0;
unsigned long flags;
struct workqueue_struct *alua_wq = kaluad_wq;
if (!pg)
return;
......@@ -768,10 +774,12 @@ static void alua_rtpg_queue(struct alua_port_group *pg,
scsi_device_get(sdev);
start_queue = 1;
}
if (pg->flags & ALUA_SYNC_STPG)
alua_wq = kaluad_sync_wq;
spin_unlock_irqrestore(&pg->lock, flags);
if (start_queue &&
!queue_delayed_work(kaluad_wq, &pg->rtpg_work,
!queue_delayed_work(alua_wq, &pg->rtpg_work,
msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS))) {
scsi_device_put(sdev);
kref_put(&pg->kref, release_port_group);
......@@ -990,10 +998,16 @@ static int __init alua_init(void)
/* Temporary failure, bypass */
return SCSI_DH_DEV_TEMP_BUSY;
}
kaluad_sync_wq = create_workqueue("kaluad_sync");
if (!kaluad_sync_wq) {
destroy_workqueue(kaluad_wq);
return SCSI_DH_DEV_TEMP_BUSY;
}
r = scsi_register_device_handler(&alua_dh);
if (r != 0) {
printk(KERN_ERR "%s: Failed to register scsi device handler",
ALUA_DH_NAME);
destroy_workqueue(kaluad_sync_wq);
destroy_workqueue(kaluad_wq);
}
return r;
......@@ -1002,6 +1016,7 @@ static int __init alua_init(void)
static void __exit alua_exit(void)
{
scsi_unregister_device_handler(&alua_dh);
destroy_workqueue(kaluad_sync_wq);
destroy_workqueue(kaluad_wq);
}
......
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