[SCSI] scsi_dh: Make hp 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>

diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
index 0aacafc96f21b5b1a895727b11ee453129664ce0..857fdd6032b25a8df5efee8e70740ea135ae07be 100644 (file)
--- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c
+++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
@@ -39,8 +39,14 @@ struct hp_sw_dh_data {
        unsigned char sense[SCSI_SENSE_BUFFERSIZE];
        int path_state;
        int retries;
+       int retry_cnt;
+       struct scsi_device *sdev;
+       activate_complete       callback_fn;
+       void                    *callback_data;
 };
 
+static int hp_sw_start_stop(struct hp_sw_dh_data *);
+
 static inline struct hp_sw_dh_data *get_hp_sw_data(struct scsi_device *sdev)
 {
        struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
@@ -191,19 +197,53 @@ static int start_done(struct scsi_device *sdev, unsigned char *sense)
        return rc;
 }
 
+static void start_stop_endio(struct request *req, int error)
+{
+       struct hp_sw_dh_data *h = req->end_io_data;
+       unsigned err = SCSI_DH_OK;
+
+       if (error || host_byte(req->errors) != DID_OK ||
+                       msg_byte(req->errors) != COMMAND_COMPLETE) {
+               sdev_printk(KERN_WARNING, h->sdev,
+                           "%s: sending start_stop_unit failed with %x\n",
+                           HP_SW_NAME, req->errors);
+               err = SCSI_DH_IO;
+               goto done;
+       }
+
+       if (req->sense_len > 0) {
+               err = start_done(h->sdev, h->sense);
+               if (err == SCSI_DH_RETRY) {
+                       err = SCSI_DH_IO;
+                       if (--h->retry_cnt) {
+                               blk_put_request(req);
+                               err = hp_sw_start_stop(h);
+                               if (err == SCSI_DH_OK)
+                                       return;
+                       }
+               }
+       }
+done:
+       blk_put_request(req);
+       if (h->callback_fn) {
+               h->callback_fn(h->callback_data, err);
+               h->callback_fn = h->callback_data = NULL;
+       }
+       return;
+
+}
+
 /*
  * hp_sw_start_stop - Send START STOP UNIT command
  * @sdev: sdev command should be sent to
  *
  * Sending START STOP UNIT activates the SP.
  */
-static int hp_sw_start_stop(struct scsi_device *sdev, struct hp_sw_dh_data *h)
+static int hp_sw_start_stop(struct hp_sw_dh_data *h)
 {
        struct request *req;
-       int ret, retry;
 
-retry:
-       req = blk_get_request(sdev->request_queue, WRITE, GFP_NOIO);
+       req = blk_get_request(h->sdev->request_queue, WRITE, GFP_ATOMIC);
        if (!req)
                return SCSI_DH_RES_TEMP_UNAVAIL;
 
@@ -217,32 +257,10 @@ retry:
        req->sense = h->sense;
        memset(req->sense, 0, SCSI_SENSE_BUFFERSIZE);
        req->sense_len = 0;
-       retry = h->retries;
-
-       ret = blk_execute_rq(req->q, NULL, req, 1);
-       if (ret == -EIO) {
-               if (req->sense_len > 0) {
-                       ret = start_done(sdev, h->sense);
-               } else {
-                       sdev_printk(KERN_WARNING, sdev,
-                                   "%s: sending start_stop_unit failed with %x\n",
-                                   HP_SW_NAME, req->errors);
-                       ret = SCSI_DH_IO;
-               }
-       } else
-               ret = SCSI_DH_OK;
-
-       if (ret == SCSI_DH_RETRY) {
-               if (--retry) {
-                       blk_put_request(req);
-                       goto retry;
-               }
-               ret = SCSI_DH_IO;
-       }
-
-       blk_put_request(req);
+       req->end_io_data = h;
 
-       return ret;
+       blk_execute_rq_nowait(req->q, NULL, req, 1, start_stop_endio);
+       return SCSI_DH_OK;
 }
 
 static int hp_sw_prep_fn(struct scsi_device *sdev, struct request *req)
@@ -277,11 +295,13 @@ static int hp_sw_activate(struct scsi_device *sdev,
        ret = hp_sw_tur(sdev, h);
 
        if (ret == SCSI_DH_OK && h->path_state == HP_SW_PATH_PASSIVE) {
-               ret = hp_sw_start_stop(sdev, h);
+               h->retry_cnt = h->retries;
+               h->callback_fn = fn;
+               h->callback_data = data;
+               ret = hp_sw_start_stop(h);
                if (ret == SCSI_DH_OK)
-                       sdev_printk(KERN_INFO, sdev,
-                                   "%s: activated path\n",
-                                   HP_SW_NAME);
+                       return 0;
+               h->callback_fn = h->callback_data = NULL;
        }
 
        if (fn)
@@ -329,6 +349,7 @@ static int hp_sw_bus_attach(struct scsi_device *sdev)
        h = (struct hp_sw_dh_data *) scsi_dh_data->buf;
        h->path_state = HP_SW_PATH_UNINITIALIZED;
        h->retries = HP_SW_RETRIES;
+       h->sdev = sdev;
 
        ret = hp_sw_tur(sdev, h);
        if (ret != SCSI_DH_OK || h->path_state == HP_SW_PATH_UNINITIALIZED)