Track attached SCSI devices and update the 'access_state' field
whenever an ALUA state change has been detected.
Reviewed-by: Ewan Milne <emilne@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 48 ++++++++++++++++++++++++++++--
1 file changed, 46 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index b429ba3..cbbd957 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -24,6 +24,7 @@
#include <linux/module.h>
#include <asm/unaligned.h>
#include <scsi/scsi.h>
+#include <scsi/scsi_proto.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>
@@ -75,6 +76,7 @@ struct alua_port_group {
struct kref kref;
struct rcu_head rcu;
struct list_head node;
+ struct list_head dh_list;
unsigned char device_id_str[256];
int device_id_len;
int group_id;
@@ -92,6 +94,7 @@ struct alua_port_group {
};
struct alua_dh_data {
+ struct list_head node;
struct alua_port_group *pg;
int group_id;
spinlock_t pg_lock;
@@ -247,6 +250,7 @@ struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
INIT_LIST_HEAD(&pg->rtpg_list);
INIT_LIST_HEAD(&pg->node);
+ INIT_LIST_HEAD(&pg->dh_list);
spin_lock_init(&pg->lock);
spin_lock(&port_group_lock);
@@ -328,6 +332,8 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
{
int rel_port = -1, group_id;
struct alua_port_group *pg, *old_pg = NULL;
+ bool pg_updated;
+ unsigned long flags;
group_id = scsi_vpd_tpg_id(sdev, &rel_port);
if (group_id < 0) {
@@ -357,13 +363,25 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
old_pg = h->pg;
if (old_pg != pg) {
/* port group has changed. Update to new port group */
+ if (h->pg) {
+ spin_lock_irqsave(&old_pg->lock, flags);
+ list_del_rcu(&h->node);
+ spin_unlock_irqrestore(&old_pg->lock, flags);
+ }
rcu_assign_pointer(h->pg, pg);
+ pg_updated = true;
}
if (sdev->synchronous_alua)
pg->flags |= ALUA_SYNC_STPG;
alua_rtpg_queue(h->pg, sdev, NULL, true);
spin_unlock(&h->pg_lock);
+ if (pg_updated) {
+ spin_lock_irqsave(&pg->lock, flags);
+ list_add_rcu(&h->node, &pg->dh_list);
+ spin_unlock_irqrestore(&pg->lock, flags);
+ }
+
if (old_pg)
kref_put(&old_pg->kref, release_port_group);
@@ -613,8 +631,18 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
if (spin_trylock_irqsave(&tmp_pg->lock, flags)) {
if ((tmp_pg == pg) ||
!(tmp_pg->flags & ALUA_PG_RUNNING)) {
+ struct alua_dh_data *h;
+
tmp_pg->state = desc[0] & 0x0f;
tmp_pg->pref = desc[0] >> 7;
+ rcu_read_lock();
+ list_for_each_entry_rcu(h,
+ &tmp_pg->dh_list, node) {
+ /* h->sdev should always be valid */
+ BUG_ON(!h->sdev);
+ h->sdev->access_state = desc[0];
+ }
+ rcu_read_unlock();
}
if (tmp_pg == pg)
valid_states = desc[1];
@@ -645,10 +673,22 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
pg->interval = 2;
err = SCSI_DH_RETRY;
} else {
+ struct alua_dh_data *h;
+
/* Transitioning time exceeded, set port to standby */
err = SCSI_DH_IO;
pg->state = SCSI_ACCESS_STATE_STANDBY;
pg->expiry = 0;
+ rcu_read_lock();
+ list_for_each_entry_rcu(h, &pg->dh_list, node) {
+ BUG_ON(!h->sdev);
+ h->sdev->access_state =
+ (pg->state & SCSI_ACCESS_STATE_MASK);
+ if (pg->pref)
+ h->sdev->access_state |=
+ SCSI_ACCESS_STATE_PREFERRED;
+ }
+ rcu_read_unlock();
}
break;
case SCSI_ACCESS_STATE_OFFLINE:
@@ -1052,6 +1092,7 @@ static int alua_bus_attach(struct scsi_device *sdev)
rcu_assign_pointer(h->pg, NULL);
h->init_error = SCSI_DH_OK;
h->sdev = sdev;
+ INIT_LIST_HEAD(&h->node);
mutex_init(&h->init_mutex);
err = alua_initialize(sdev, h);
@@ -1081,9 +1122,12 @@ static void alua_bus_detach(struct scsi_device *sdev)
rcu_assign_pointer(h->pg, NULL);
h->sdev = NULL;
spin_unlock(&h->pg_lock);
- if (pg)
+ if (pg) {
+ spin_lock(&pg->lock);
+ list_del_rcu(&h->node);
+ spin_unlock(&pg->lock);
kref_put(&pg->kref, release_port_group);
-
+ }
sdev->handler_data = NULL;
kfree(h);
}
--
1.8.5.6
--
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