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scsi: scsi_dh_alua: skip RTPG for devices only supporting active/optimized

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For hardware only supporting active/optimized there's no point in ever
re-issuing RTPG as the only new state we can possibly read is
active/optimized.  This avoid spurious errors during path failover on
such arrays.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Hannes Reinecke 2017-12-22 12:52:53 +01:00 committed by Martin K. Petersen
parent bcb872400b
commit 80c716fad8
1 changed files with 28 additions and 9 deletions
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37
drivers/scsi/device_handler/scsi_dh_alua.c
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@ -40,6 +40,7 @@
#define TPGS_SUPPORT_LBA_DEPENDENT 0x10
#define TPGS_SUPPORT_OFFLINE 0x40
#define TPGS_SUPPORT_TRANSITION 0x80
#define TPGS_SUPPORT_ALL 0xdf
#define RTPG_FMT_MASK 0x70
#define RTPG_FMT_EXT_HDR 0x10
@ -81,6 +82,7 @@ struct alua_port_group {
int tpgs;
int state;
int pref;
int valid_states;
unsigned flags; /* used for optimizing STPG */
unsigned char transition_tmo;
unsigned long expiry;
@ -243,6 +245,7 @@ static struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
pg->group_id = group_id;
pg->tpgs = tpgs;
pg->state = SCSI_ACCESS_STATE_OPTIMAL;
pg->valid_states = TPGS_SUPPORT_ALL;
if (optimize_stpg)
pg->flags |= ALUA_OPTIMIZE_STPG;
kref_init(&pg->kref);
@ -516,7 +519,7 @@ 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;
int len, k, off, bufflen = ALUA_RTPG_SIZE;
unsigned char *desc, *buff;
unsigned err, retval;
unsigned int tpg_desc_tbl_off;
@ -541,6 +544,22 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, pg->flags);
if (retval) {
/*
* Some (broken) implementations have a habit of returning
* an error during things like firmware update etc.
* But if the target only supports active/optimized there's
* not much we can do; it's not that we can switch paths
* or anything.
* So ignore any errors to avoid spurious failures during
* path failover.
*/
if ((pg->valid_states & ~TPGS_SUPPORT_OPTIMIZED) == 0) {
sdev_printk(KERN_INFO, sdev,
"%s: ignoring rtpg result %d\n",
ALUA_DH_NAME, retval);
kfree(buff);
return SCSI_DH_OK;
}
if (!scsi_sense_valid(&sense_hdr)) {
sdev_printk(KERN_INFO, sdev,
"%s: rtpg failed, result %d\n",
@ -652,7 +671,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
rcu_read_unlock();
}
if (tmp_pg == pg)
valid_states = desc[1];
tmp_pg->valid_states = desc[1];
spin_unlock_irqrestore(&tmp_pg->lock, flags);
}
kref_put(&tmp_pg->kref, release_port_group);
@ -665,13 +684,13 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
"%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),
pg->pref ? "preferred" : "non-preferred",
valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
pg->valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
pg->valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
pg->valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
pg->valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
pg->valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
pg->valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
pg->valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
switch (pg->state) {
case SCSI_ACCESS_STATE_TRANSITIONING: