scsi_dh_alua: update all port states

When we read in the target port group state we should be
updating all affected port groups, otherwise we risk
running out of sync.

Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index ef5d6c3..98d87d9 100644 (file)
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -476,11 +476,13 @@ static int alua_check_sense(struct scsi_device *sdev,
 static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 {
        struct scsi_sense_hdr sense_hdr;
+       struct alua_port_group *tmp_pg;
        int len, k, off, valid_states = 0, bufflen = ALUA_RTPG_SIZE;
-       unsigned char *ucp, *buff;
+       unsigned char *desc, *buff;
        unsigned err, retval;
        unsigned int tpg_desc_tbl_off;
        unsigned char orig_transition_tmo;
+       unsigned long flags;
 
        if (!pg->expiry) {
                unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ;
@@ -582,18 +584,32 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
        else
                tpg_desc_tbl_off = 4;
 
-       for (k = tpg_desc_tbl_off, ucp = buff + tpg_desc_tbl_off;
+       for (k = tpg_desc_tbl_off, desc = buff + tpg_desc_tbl_off;
             k < len;
-            k += off, ucp += off) {
-
-               if (pg->group_id == get_unaligned_be16(&ucp[2])) {
-                       pg->state = ucp[0] & 0x0f;
-                       pg->pref = ucp[0] >> 7;
-                       valid_states = ucp[1];
+            k += off, desc += off) {
+               u16 group_id = get_unaligned_be16(&desc[2]);
+
+               spin_lock_irqsave(&port_group_lock, flags);
+               tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
+                                         group_id);
+               spin_unlock_irqrestore(&port_group_lock, flags);
+               if (tmp_pg) {
+                       if (spin_trylock_irqsave(&tmp_pg->lock, flags)) {
+                               if ((tmp_pg == pg) ||
+                                   !(tmp_pg->flags & ALUA_PG_RUNNING)) {
+                                       tmp_pg->state = desc[0] & 0x0f;
+                                       tmp_pg->pref = desc[0] >> 7;
+                               }
+                               if (tmp_pg == pg)
+                                       valid_states = desc[1];
+                               spin_unlock_irqrestore(&tmp_pg->lock, flags);
+                       }
+                       kref_put(&tmp_pg->kref, release_port_group);
                }
-               off = 8 + (ucp[7] * 4);
+               off = 8 + (desc[7] * 4);
        }
 
+       spin_lock_irqsave(&pg->lock, flags);
        sdev_printk(KERN_INFO, sdev,
                    "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
                    ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state),
@@ -630,6 +646,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
                pg->expiry = 0;
                break;
        }
+       spin_unlock_irqrestore(&pg->lock, flags);
        kfree(buff);
        return err;
 }