[SCSI] scsi_dh: Make alua hardware handler's activate() async

Make the activate function asynchronous by using blk_execute_rq_nowait()

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 73 insertions, 59 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index e8a8928e58bc..4f0d0138f48b 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -60,11 +60,17 @@ struct alua_dh_data {
         int                     bufflen;
         unsigned char           sense[SCSI_SENSE_BUFFERSIZE];
         int                     senselen;
+        struct scsi_device      *sdev;
+        activate_complete       callback_fn;
+        void                    *callback_data;
 };
 
 #define ALUA_POLICY_SWITCH_CURRENT      0
 #define ALUA_POLICY_SWITCH_ALL          1
 
+static char print_alua_state(int);
+static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
+
 static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev)
 {
         struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
@@ -231,18 +237,71 @@ done:
 }
 
 /*
+ * alua_stpg - Evaluate SET TARGET GROUP STATES
+ * @sdev: the device to be evaluated
+ * @state: the new target group state
+ *
+ * Send a SET TARGET GROUP STATES command to the device.
+ * We only have to test here if we should resubmit the command;
+ * any other error is assumed as a failure.
+ */
+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_IO;
+
+        if (error || host_byte(req->errors) != DID_OK ||
+                        msg_byte(req->errors) != COMMAND_COMPLETE)
+                goto done;
+
+        if (err == SCSI_DH_IO && h->senselen > 0) {
+                err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
+                                           &sense_hdr);
+                if (!err) {
+                        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 sense code: %02x/%02x/%02x\n",
+                            ALUA_DH_NAME, sense_hdr.sense_key,
+                            sense_hdr.asc, sense_hdr.ascq);
+                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:
+        blk_put_request(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
- * @sdev: sdev the command should be sent to
  *
  * 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 scsi_device *sdev, struct alua_dh_data *h)
+static unsigned submit_stpg(struct alua_dh_data *h)
 {
         struct request *rq;
         int err = SCSI_DH_RES_TEMP_UNAVAIL;
         int stpg_len = 8;
+        struct scsi_device *sdev = h->sdev;
 
         /* Prepare the data buffer */
         memset(h->buff, 0, stpg_len);
@@ -252,7 +311,7 @@ static unsigned submit_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
 
         rq = get_alua_req(sdev, h->buff, stpg_len, WRITE);
         if (!rq)
-                goto done;
+                return SCSI_DH_RES_TEMP_UNAVAIL;
 
         /* Prepare the command. */
         rq->cmd[0] = MAINTENANCE_OUT;
@@ -266,17 +325,9 @@ static unsigned submit_stpg(struct scsi_device *sdev, struct alua_dh_data *h)
         rq->sense = h->sense;
         memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
         rq->sense_len = h->senselen = 0;
+        rq->end_io_data = h;
 
-        err = blk_execute_rq(rq->q, NULL, rq, 1);
-        if (err == -EIO) {
-                sdev_printk(KERN_INFO, sdev,
-                            "%s: stpg failed with %x\n",
-                            ALUA_DH_NAME, rq->errors);
-                h->senselen = rq->sense_len;
-                err = SCSI_DH_IO;
-        }
-        blk_put_request(rq);
-done:
+        blk_execute_rq_nowait(rq->q, NULL, rq, 1, stpg_endio);
         return err;
 }
 
@@ -477,50 +528,6 @@ static int alua_check_sense(struct scsi_device *sdev,
 }
 
 /*
- * alua_stpg - Evaluate SET TARGET GROUP STATES
- * @sdev: the device to be evaluated
- * @state: the new target group state
- *
- * Send a SET TARGET GROUP STATES command to the device.
- * We only have to test here if we should resubmit the command;
- * any other error is assumed as a failure.
- */
-static int alua_stpg(struct scsi_device *sdev, int state,
-                     struct alua_dh_data *h)
-{
-        struct scsi_sense_hdr sense_hdr;
-        unsigned err;
-        int retry = ALUA_FAILOVER_RETRIES;
-
- retry:
-        err = submit_stpg(sdev, h);
-        if (err == SCSI_DH_IO && h->senselen > 0) {
-                err = scsi_normalize_sense(h->sense, SCSI_SENSE_BUFFERSIZE,
-                                           &sense_hdr);
-                if (!err)
-                        return SCSI_DH_IO;
-                err = alua_check_sense(sdev, &sense_hdr);
-                if (retry > 0 && err == ADD_TO_MLQUEUE) {
-                        retry--;
-                        goto retry;
-                }
-                sdev_printk(KERN_INFO, sdev,
-                            "%s: stpg sense code: %02x/%02x/%02x\n",
-                            ALUA_DH_NAME, sense_hdr.sense_key,
-                            sense_hdr.asc, sense_hdr.ascq);
-                err = SCSI_DH_IO;
-        }
-        if (err == SCSI_DH_OK) {
-                h->state = state;
-                sdev_printk(KERN_INFO, sdev,
-                            "%s: port group %02x switched to state %c\n",
-                            ALUA_DH_NAME, h->group_id,
-                            print_alua_state(h->state) );
-        }
-        return err;
-}
-
-/*
  * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
  * @sdev: the device to be evaluated.
  *
@@ -664,8 +671,14 @@ static int alua_activate(struct scsi_device *sdev,
                         goto out;
         }
 
-        if (h->tpgs & TPGS_MODE_EXPLICIT && h->state != TPGS_STATE_OPTIMIZED)
-                err = alua_stpg(sdev, TPGS_STATE_OPTIMIZED, h);
+        if (h->tpgs & TPGS_MODE_EXPLICIT && h->state != TPGS_STATE_OPTIMIZED) {
+                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;
+        }
 
 out:
         if (fn)
@@ -748,6 +761,7 @@ static int alua_bus_attach(struct scsi_device *sdev)
         h->rel_port = -1;
         h->buff = h->inq;
         h->bufflen = ALUA_INQUIRY_SIZE;
+        h->sdev = sdev;
 
         err = alua_initialize(sdev, h);
         if (err != SCSI_DH_OK)