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.
Synchronous STPG can be activated by setting the second module
option to '1'. The corresponding entry in multipath.conf would be:
hardware_handler "3 alua 1 1"
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 41 ++++++++++++++++++++++++------
1 file changed, 33 insertions(+), 8 deletions(-)
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 9d56d6a..eb12074 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -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;
@@ -700,6 +702,7 @@ 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;
@@ -709,6 +712,8 @@ 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) {
spin_unlock_irqrestore(&pg->lock, flags);
@@ -717,7 +722,7 @@ static void alua_rtpg_work(struct work_struct *work)
if (err == SCSI_DH_RETRY) {
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;
}
@@ -735,7 +740,7 @@ 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;
}
@@ -764,6 +769,7 @@ 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;
@@ -781,10 +787,12 @@ 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);
@@ -811,30 +819,36 @@ static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
return err;
}
/*
- * alua_set_params - set/unset the optimize flag
+ * alua_set_params - set/unset the optimize and sync flag
* @sdev: device on the path to be activated
* params - parameters in the following format
* "no_of_params\0param1\0param2\0param3\0...\0"
* For example, to set the flag pass the following parameters
* from multipath.conf
- * hardware_handler "2 alua 1"
+ * hardware_handler "3 alua 1 1"
*/
static int alua_set_params(struct scsi_device *sdev, const char *params)
{
struct alua_dh_data *h = sdev->handler_data;
struct alua_port_group *pg = NULL;
- unsigned int optimize = 0, argc;
+ unsigned int optimize = 0, sync = 0, argc;
const char *p = params;
int result = SCSI_DH_OK;
unsigned long flags;
- if ((sscanf(params, "%u", &argc) != 1) || (argc != 1))
+ if ((sscanf(params, "%u", &argc) != 1) || (argc > 2))
return -EINVAL;
while (*p++)
;
if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1))
return -EINVAL;
+ if (argc == 2) {
+ while (*p++)
+ ;
+ if ((sscanf(p, "%u", &sync) != 1) || (sync > 1))
+ return -EINVAL;
+ }
rcu_read_lock();
pg = rcu_dereference(h->pg);
@@ -846,7 +860,11 @@ static int alua_set_params(struct scsi_device *sdev, const char *params)
if (optimize)
pg->flags |= ALUA_OPTIMIZE_STPG;
else
- pg->flags |= ~ALUA_OPTIMIZE_STPG;
+ pg->flags &= ~ALUA_OPTIMIZE_STPG;
+ if (sync)
+ pg->flags |= ALUA_SYNC_STPG;
+ else
+ pg->flags &= ~ALUA_SYNC_STPG;
spin_unlock_irqrestore(&pg->lock, flags);
rcu_read_unlock();
@@ -1010,10 +1028,16 @@ 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;
@@ -1022,6 +1046,7 @@ 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);
}
--
1.8.5.6
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
