[PATCH 08/17] scsi_dh_alua: Make stpg synchronous

Hannes Reinecke
2015-05-04T12:42:39Z

We should be issuing STPG synchronously as we need to
evaluate the return code on failure.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 195 ++++++++++++++---------------
1 file changed, 91 insertions(+), 104 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 1bfc7a4..0b8e111 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -22,6 +22,7 @@
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/module.h>
+#include <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_eh.h>
@@ -179,98 +180,51 @@ done:
}

/*
- * stpg_endio - Evaluate SET TARGET GROUP STATES
- * @sdev: the device to be evaluated
- * @state: the new target group state
- *
- * Evaluate a SET TARGET GROUP STATES command response.
- */
-static void stpg_endio(struct request *req, int error)
-{
- struct alua_dh_data *h = req->end_io_data;
- struct scsi_sense_hdr sense_hdr;
- unsigned err = SCSI_DH_OK;
-
- if (host_byte(req->errors) != DID_OK ||
- msg_byte(req->errors) != COMMAND_COMPLETE) {
- err = SCSI_DH_IO;
- goto done;
- }
-
- if (req->sense_len > 0) {
- if (!scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
- &sense_hdr)) {
- err = SCSI_DH_IO;
- goto done;
- }
- err = alua_check_sense(h->sdev, &sense_hdr);
- if (err == ADD_TO_MLQUEUE) {
- err = SCSI_DH_RETRY;
- goto done;
- }
- sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed\n",
- ALUA_DH_NAME);
- scsi_print_sense_hdr(h->sdev, ALUA_DH_NAME, &sense_hdr);
- err = SCSI_DH_IO;
- } else if (error)
- err = SCSI_DH_IO;
-
- if (err == SCSI_DH_OK) {
- h->state = TPGS_STATE_OPTIMIZED;
- sdev_printk(KERN_INFO, h->sdev,
- "%s: port group %02x switched to state %c\n",
- ALUA_DH_NAME, h->group_id,
- print_alua_state(h->state));
- }
-done:
- req->end_io_data = NULL;
- __blk_put_request(req->q, req);
- if (h->callback_fn) {
- h->callback_fn(h->callback_data, err);
- h->callback_fn = h->callback_data = NULL;
- }
- return;
-}
-
-/*
* submit_stpg - Issue a SET TARGET GROUP STATES command
*
* Currently we're only setting the current target port group state
* to 'active/optimized' and let the array firmware figure out
* the states of the remaining groups.
*/
-static unsigned submit_stpg(struct alua_dh_data *h)
+static unsigned submit_stpg(struct scsi_device *sdev, int group_id,
+ unsigned char *sense)
{
struct request *rq;
+ unsigned char stpg_data[8];
int stpg_len = 8;
- struct scsi_device *sdev = h->sdev;
+ int err;

/* Prepare the data buffer */
- memset(h->buff, 0, stpg_len);
- h->buff[4] = TPGS_STATE_OPTIMIZED & 0x0f;
- h->buff[6] = (h->group_id >> 8) & 0xff;
- h->buff[7] = h->group_id & 0xff;
+ memset(stpg_data, 0, stpg_len);
+ stpg_data[4] = TPGS_STATE_OPTIMIZED & 0x0f;
+ put_unaligned_be16(group_id, &stpg_data[6]);

- rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
+ rq = get_alua_req(sdev, stpg_data, stpg_len, WRITE);
if (!rq)
return SCSI_DH_RES_TEMP_UNAVAIL;

/* Prepare the command. */
rq->cmd[0] = MAINTENANCE_OUT;
rq->cmd[1] = MO_SET_TARGET_PGS;
- rq->cmd[6] = (stpg_len >> 24) & 0xff;
- rq->cmd[7] = (stpg_len >> 16) & 0xff;
- rq->cmd[8] = (stpg_len >> 8) & 0xff;
- rq->cmd[9] = stpg_len & 0xff;
+ put_unaligned_be32(stpg_len, &rq->cmd[6]);
rq->cmd_len = COMMAND_SIZE(MAINTENANCE_OUT);

- rq->sense = h->sense;
+ rq->sense = sense;
memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
- rq->sense_len = h->senselen = 0;
- rq->end_io_data = h;
+ rq->sense_len = 0;
+
+ err = blk_execute_rq(rq->q, NULL, rq, 1);
+ if (err < 0) {
+ if (!rq->errors)
+ err = DID_ERROR << 16;
+ else
+ err = rq->errors;
+ if (rq->sense_len)
+ err |= (DRIVER_SENSE << 24);
+ }
+ blk_put_request(rq);

- blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
- return SCSI_DH_OK;
+ return err;
}

/*
@@ -641,6 +595,70 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h, int wait_
}

/*
+ * alua_stpg - Issue a SET TARGET GROUP STATES command
+ *
+ * Issue a SET TARGET GROUP STATES command and evaluate the
+ * response. Returns SCSI_DH_RETRY per default to trigger
+ * a re-evaluation of the target group state.
+ */
+static unsigned alua_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
+{
+ int retval, err = SCSI_DH_RETRY;
+ unsigned char sense[SCSI_SENSE_BUFFERSIZE];
+ struct scsi_sense_hdr sense_hdr;
+
+ if (!(h->tpgs & TPGS_MODE_EXPLICIT)) {
+ /* Only implicit ALUA supported, retry */
+ return SCSI_DH_RETRY;
+ }
+ switch (h->state) {
+ case TPGS_STATE_OPTIMIZED:
+ return SCSI_DH_OK;
+ case TPGS_STATE_NONOPTIMIZED:
+ if ((h->flags & ALUA_OPTIMIZE_STPG) &&
+ (!h->pref) &&
+ (h->tpgs & TPGS_MODE_IMPLICIT))
+ return SCSI_DH_OK;
+ break;
+ case TPGS_STATE_STANDBY:
+ case TPGS_STATE_UNAVAILABLE:
+ break;
+ case TPGS_STATE_OFFLINE:
+ return SCSI_DH_IO;
+ break;
+ case TPGS_STATE_TRANSITIONING:
+ break;
+ default:
+ sdev_printk(KERN_INFO, sdev,
+ "%s: stpg failed, unhandled TPGS state %d",
+ ALUA_DH_NAME, pg->state);
+ return SCSI_DH_NOSYS;
+ break;
+ }
+ /* Set state to transitioning */
+ h->state = TPGS_STATE_TRANSITIONING;
+ retval = submit_stpg(sdev, h->group_id, sense);
+
+ if (retval) {
+ if (!(driver_byte(retval) & DRIVER_SENSE) ||
+ !scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE,
+ &sense_hdr)) {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: stpg failed, result %d",
+ ALUA_DH_NAME, retval);
+ /* Retry RTPG */
+ return err;
+ }
+ err = alua_check_sense(h->sdev, &sense_hdr);
+ sdev_printk(KERN_INFO, h->sdev, "%s: stpg failed\n",
+ ALUA_DH_NAME);
+ scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
+ err = SCSI_DH_RETRY;
+ }
+ return err;
+}
+
+/*
* alua_initialize - Initialize ALUA state
* @sdev: the device to be initialized
*
@@ -717,7 +735,6 @@ static int alua_activate(struct scsi_device *sdev,
{
struct alua_dh_data *h = sdev->handler_data;
int err = SCSI_DH_OK;
- int stpg = 0;

err = alua_rtpg(sdev, h, 1);
if (err != SCSI_DH_OK)
@@ -726,39 +743,9 @@ static int alua_activate(struct scsi_device *sdev,
if (optimize_stpg)
h->flags |= ALUA_OPTIMIZE_STPG;

- if (h->tpgs & TPGS_MODE_EXPLICIT) {
- switch (h->state) {
- case TPGS_STATE_NONOPTIMIZED:
- stpg = 1;
- if ((h->flags & ALUA_OPTIMIZE_STPG) &&
- (!h->pref) &&
- (h->tpgs & TPGS_MODE_IMPLICIT))
- stpg = 0;
- break;
- case TPGS_STATE_STANDBY:
- case TPGS_STATE_UNAVAILABLE:
- stpg = 1;
- break;
- case TPGS_STATE_OFFLINE:
- err = SCSI_DH_IO;
- break;
- case TPGS_STATE_TRANSITIONING:
- err = SCSI_DH_RETRY;
- break;
- default:
- break;
- }
- }
-
- if (stpg) {
- h->callback_fn = fn;
- h->callback_data = data;
- err = submit_stpg(h);
- if (err == SCSI_DH_OK)
- return 0;
- h->callback_fn = h->callback_data = NULL;
- }
-
+ err = alua_stpg(sdev, h);
+ if (err == SCSI_DH_RETRY)
+ err = alua_rtpg(sdev, h, 1);
out:
if (fn)
fn(data, err);
--
1.8.5.2