Track attached SCSI devices and update the 'access_state' field
whenever an ALUA state change has been detected.

Signed-off-by: Hannes Reinecke <h...@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c 
b/drivers/scsi/device_handler/scsi_dh_alua.c
index 6c6ff0b..d01c86407 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>
@@ -76,6 +77,7 @@ static struct workqueue_struct *kaluad_wq;
 struct alua_port_group {
        struct kref             kref;
        struct list_head        node;
+       struct list_head        dh_list;
        unsigned char           device_id_str[256];
        int                     device_id_len;
        int                     group_id;
@@ -93,6 +95,7 @@ struct alua_port_group {
 };
 
 struct alua_dh_data {
+       struct list_head        node;
        struct alua_port_group  *pg;
        int                     rel_port;
        spinlock_t              pg_lock;
@@ -243,6 +246,7 @@ struct alua_port_group *alua_get_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);
 
        /* Re-check list again to catch concurrent updates */
@@ -370,13 +374,26 @@ static int alua_check_vpd(struct scsi_device *sdev, 
struct alua_dh_data *h,
                old_pg = pg;
                /* port_group has changed. Update to new port group */
                if (h->pg != pg) {
+                       unsigned long flags;
+
                        old_pg = h->pg;
                        rcu_assign_pointer(h->pg, pg);
+                       spin_lock_irqsave(&old_pg->lock, flags);
+                       list_del_rcu(&h->node);
+                       spin_unlock_irqrestore(&old_pg->lock, flags);
+                       spin_lock_irqsave(&pg->lock, flags);
+                       list_add_rcu(&h->node, &pg->dh_list);
+                       spin_unlock_irqrestore(&pg->lock, flags);
                        h->pg->expiry = 0;
                        pg_found = true;
                }
        } else {
+               unsigned long flags;
+
                rcu_assign_pointer(h->pg, pg);
+               spin_lock_irqsave(&pg->lock, flags);
+               list_add_rcu(&h->node, &pg->dh_list);
+               spin_unlock_irqrestore(&pg->lock, flags);
                pg_found = true;
        }
        alua_rtpg_queue(h->pg, sdev, NULL, true);
@@ -630,6 +647,8 @@ static int alua_rtpg(struct scsi_device *sdev, struct 
alua_port_group *pg)
 
                spin_lock_irqsave(&port_group_lock, flags);
                list_for_each_entry(tmp_pg, &port_group_list, node) {
+                       struct alua_dh_data *h;
+
                        if (tmp_pg->group_id != group_id)
                                continue;
                        if (tmp_pg->device_id_len != pg->device_id_len)
@@ -639,6 +658,12 @@ static int alua_rtpg(struct scsi_device *sdev, struct 
alua_port_group *pg)
                                continue;
                        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) {
+                               if (h->sdev)
+                                       h->sdev->access_state = desc[0];
+                       }
+                       rcu_read_unlock();
                        if (tmp_pg == pg)
                                valid_states = desc[1];
                }
@@ -1056,6 +1081,7 @@ static int alua_bus_attach(struct scsi_device *sdev)
        h->rel_port = -1;
        h->init_error = SCSI_DH_OK;
        h->sdev = sdev;
+       INIT_LIST_HEAD(&h->node);
 
        mutex_init(&h->init_mutex);
        err = alua_initialize(sdev, h);
@@ -1086,6 +1112,9 @@ static void alua_bus_detach(struct scsi_device *sdev)
        h->sdev = NULL;
        spin_unlock(&h->pg_lock);
        if (pg) {
+               spin_lock(&pg->lock);
+               list_del_rcu(&h->node);
+               spin_unlock(&pg->lock);
                synchronize_rcu();
                if (pg->rtpg_sdev)
                        flush_delayed_work(&pg->rtpg_work);
-- 
1.8.5.6

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