uas: Avoid unnecessary unlock / lock calls around unlink_data_urbs
authorHans de Goede <hdegoede@redhat.com>
Thu, 17 Oct 2013 17:19:04 +0000 (19:19 +0200)
committerSarah Sharp <sarah.a.sharp@linux.intel.com>
Tue, 4 Mar 2014 23:38:08 +0000 (15:38 -0800)
All callers of unlink_data_urbs drop devinfo->lock before calling it, and
then immediately take it again after the call. And the first thing
unlink_data_urbs does is take the lock again, and the last thing it does
is drop it. This commit removes all the unnecessary lock dropping and taking.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
drivers/usb/storage/uas.c

index ec1b22d295019f22bb24d6d9d18289452fee3033..dcaf61197032e12bd0a02ac7bf12a9cf6a522d0b 100644 (file)
@@ -93,28 +93,26 @@ static void uas_configure_endpoints(struct uas_dev_info *devinfo);
 static void uas_free_streams(struct uas_dev_info *devinfo);
 static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *caller);
 
+/* Must be called with devinfo->lock held, will temporary unlock the lock */
 static void uas_unlink_data_urbs(struct uas_dev_info *devinfo,
-                                struct uas_cmd_info *cmdinfo)
+                                struct uas_cmd_info *cmdinfo,
+                                unsigned long *lock_flags)
 {
-       unsigned long flags;
-
        /*
         * The UNLINK_DATA_URBS flag makes sure uas_try_complete
         * (called by urb completion) doesn't release cmdinfo
         * underneath us.
         */
-       spin_lock_irqsave(&devinfo->lock, flags);
        cmdinfo->state |= UNLINK_DATA_URBS;
-       spin_unlock_irqrestore(&devinfo->lock, flags);
+       spin_unlock_irqrestore(&devinfo->lock, *lock_flags);
 
        if (cmdinfo->data_in_urb)
                usb_unlink_urb(cmdinfo->data_in_urb);
        if (cmdinfo->data_out_urb)
                usb_unlink_urb(cmdinfo->data_out_urb);
 
-       spin_lock_irqsave(&devinfo->lock, flags);
+       spin_lock_irqsave(&devinfo->lock, *lock_flags);
        cmdinfo->state &= ~UNLINK_DATA_URBS;
-       spin_unlock_irqrestore(&devinfo->lock, flags);
 }
 
 static void uas_do_work(struct work_struct *work)
@@ -361,9 +359,7 @@ static void uas_stat_cmplt(struct urb *urb)
                        uas_sense(urb, cmnd);
                if (cmnd->result != 0) {
                        /* cancel data transfers on error */
-                       spin_unlock_irqrestore(&devinfo->lock, flags);
-                       uas_unlink_data_urbs(devinfo, cmdinfo);
-                       spin_lock_irqsave(&devinfo->lock, flags);
+                       uas_unlink_data_urbs(devinfo, cmdinfo, &flags);
                }
                cmdinfo->state &= ~COMMAND_INFLIGHT;
                uas_try_complete(cmnd, __func__);
@@ -787,9 +783,7 @@ static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
                spin_unlock_irqrestore(&devinfo->lock, flags);
                ret = uas_eh_task_mgmt(cmnd, "ABORT TASK", TMF_ABORT_TASK);
        } else {
-               spin_unlock_irqrestore(&devinfo->lock, flags);
-               uas_unlink_data_urbs(devinfo, cmdinfo);
-               spin_lock_irqsave(&devinfo->lock, flags);
+               uas_unlink_data_urbs(devinfo, cmdinfo, &flags);
                uas_try_complete(cmnd, __func__);
                spin_unlock_irqrestore(&devinfo->lock, flags);
                ret = SUCCESS;