Re: [PATCHv7 17/23] scsi_dh_alua: update all port states

[Bart Van Assche]

On 02/15/2016 12:24 AM, Hannes Reinecke wrote:

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 
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[PATCHv7 17/23] scsi_dh_alua: update all port states

[Hannes Reinecke]

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: Christoph Hellwig 
Signed-off-by: Hannes Reinecke 
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 35 ++
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c 
b/drivers/scsi/device_handler/scsi_dh_alua.c
index c09a523..6de9261 100644
--- 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([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([2]);
+
+   spin_lock_irqsave(_group_lock, flags);
+   tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
+ group_id);
+   spin_unlock_irqrestore(_group_lock, flags);
+   if (tmp_pg) {
+   if (spin_trylock_irqsave(_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(_pg->lock, flags);
+   }
+   kref_put(_pg->kref, release_port_group);
}
-   off = 8 + (ucp[7] * 4);
+   off = 8 + (desc[7] * 4);
}
 
+   spin_lock_irqsave(>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(>lock, flags);
kfree(buff);
return err;
 }
-- 
1.8.5.6

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