iscsi: reorganize iscsi_readcapacity_sync

Avoid the goto, and use the same retry logic for the 10- and 16-
byte versions.

Cc: qemu-stable@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 1288844e)
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

block/iscsi.c

@@ -931,60 +931,58 @@ static int iscsi_readcapacity_sync(IscsiLun *iscsilun)
     int ret = 0;
     int retries = ISCSI_CMD_RETRIES; 
 
-try_again:
-    switch (iscsilun->type) {
-    case TYPE_DISK:
-        task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun);
-        if (task == NULL || task->status != SCSI_STATUS_GOOD) {
-            if (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION
-                    && task->sense.key == SCSI_SENSE_UNIT_ATTENTION
-                    && retries-- > 0) {
-                scsi_free_scsi_task(task);
-                goto try_again;
-            }
-            error_report("iSCSI: failed to send readcapacity16 command.");
-            ret = -EINVAL;
-            goto out;
-        }
-        rc16 = scsi_datain_unmarshall(task);
-        if (rc16 == NULL) {
-            error_report("iSCSI: Failed to unmarshall readcapacity16 data.");
-            ret = -EINVAL;
-            goto out;
-        }
-        iscsilun->block_size = rc16->block_length;
-        iscsilun->num_blocks = rc16->returned_lba + 1;
-        break;
-    case TYPE_ROM:
-        task = iscsi_readcapacity10_sync(iscsilun->iscsi, iscsilun->lun, 0, 0);
-        if (task == NULL || task->status != SCSI_STATUS_GOOD) {
-            error_report("iSCSI: failed to send readcapacity10 command.");
-            ret = -EINVAL;
-            goto out;
-        }
-        rc10 = scsi_datain_unmarshall(task);
-        if (rc10 == NULL) {
-            error_report("iSCSI: Failed to unmarshall readcapacity10 data.");
-            ret = -EINVAL;
-            goto out;
+    do {
+        if (task != NULL) {
+            scsi_free_scsi_task(task);
+            task = NULL;
         }
-        iscsilun->block_size = rc10->block_size;
-        if (rc10->lba == 0) {
-            /* blank disk loaded */
-            iscsilun->num_blocks = 0;
-        } else {
-            iscsilun->num_blocks = rc10->lba + 1;
+
+        switch (iscsilun->type) {
+        case TYPE_DISK:
+            task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun);
+            if (task != NULL && task->status == SCSI_STATUS_GOOD) {
+                rc16 = scsi_datain_unmarshall(task);
+                if (rc16 == NULL) {
+                    error_report("iSCSI: Failed to unmarshall readcapacity16 data.");
+                    ret = -EINVAL;
+                } else {
+                    iscsilun->block_size = rc16->block_length;
+                    iscsilun->num_blocks = rc16->returned_lba + 1;
+                }
+            }
+            break;
+        case TYPE_ROM:
+            task = iscsi_readcapacity10_sync(iscsilun->iscsi, iscsilun->lun, 0, 0);
+            if (task != NULL && task->status == SCSI_STATUS_GOOD) {
+                rc10 = scsi_datain_unmarshall(task);
+                if (rc10 == NULL) {
+                    error_report("iSCSI: Failed to unmarshall readcapacity10 data.");
+                    ret = -EINVAL;
+                } else {
+                    iscsilun->block_size = rc10->block_size;
+                    if (rc10->lba == 0) {
+                        /* blank disk loaded */
+                        iscsilun->num_blocks = 0;
+                    } else {
+                        iscsilun->num_blocks = rc10->lba + 1;
+                    }
+                }
+            }
+            break;
+        default:
+            return 0;
         }
-        break;
-    default:
-        break;
-    }
+    } while (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION
+             && task->sense.key == SCSI_SENSE_UNIT_ATTENTION
+             && retries-- > 0);
 
-out:
+    if (task == NULL || task->status != SCSI_STATUS_GOOD) {
+        error_report("iSCSI: failed to send readcapacity10 command.");
+        ret = -EINVAL;
+    }
     if (task) {
         scsi_free_scsi_task(task);
     }
-
     return ret;
 }