From 80c716fad82550b6c4ee4b7c6d48bff3fd7dab56 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Fri, 22 Dec 2017 12:52:53 +0100 Subject: [PATCH] scsi: scsi_dh_alua: skip RTPG for devices only supporting active/optimized 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 Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/scsi/device_handler/scsi_dh_alua.c | 37 ++++++++++++++++------ 1 file changed, 28 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index fd22dc6ab5d9..022e421c2185 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -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: -- 2.30.2