USB: get rid of urb->lock

Now that urb->status isn't used, urb->lock doesn't protect anything.
This patch (as980) removes it and replaces it with a private mutex in
the one remaining place it was still used: usb_kill_urb.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 6 insertions, 9 deletions

diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index 19f5f66c2733..76db76fdb4ec 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -39,7 +39,6 @@ void usb_init_urb(struct urb *urb)
         if (urb) {
                 memset(urb, 0, sizeof(*urb));
                 kref_init(&urb->kref);
-                spin_lock_init(&urb->lock);
                 INIT_LIST_HEAD(&urb->anchor_list);
         }
 }
@@ -541,19 +540,21 @@ int usb_unlink_urb(struct urb *urb)
  */
 void usb_kill_urb(struct urb *urb)
 {
+        static DEFINE_MUTEX(reject_mutex);
+
         might_sleep();
         if (!(urb && urb->dev && urb->ep))
                 return;
-        spin_lock_irq(&urb->lock);
+        mutex_lock(&reject_mutex);
         ++urb->reject;
-        spin_unlock_irq(&urb->lock);
+        mutex_unlock(&reject_mutex);
 
         usb_hcd_unlink_urb(urb, -ENOENT);
         wait_event(usb_kill_urb_queue, atomic_read(&urb->use_count) == 0);
 
-        spin_lock_irq(&urb->lock);
+        mutex_lock(&reject_mutex);
         --urb->reject;
-        spin_unlock_irq(&urb->lock);
+        mutex_unlock(&reject_mutex);
 }
 
 /**
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 5c7b79088add..5b14b4c81fd6 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1241,7 +1241,6 @@ struct urb
 {
         /* private: usb core and host controller only fields in the urb */
         struct kref kref;               /* reference count of the URB */
-        spinlock_t lock;                /* lock for the URB */
         void *hcpriv;                   /* private data for host controller */
         atomic_t use_count;             /* concurrent submissions counter */
         u8 reject;                      /* submissions will fail */
@@ -1299,7 +1298,6 @@ static inline void usb_fill_control_urb (struct urb *urb,
                                          usb_complete_t complete_fn,
                                          void *context)
 {
-        spin_lock_init(&urb->lock);
         urb->dev = dev;
         urb->pipe = pipe;
         urb->setup_packet = setup_packet;
@@ -1330,7 +1328,6 @@ static inline void usb_fill_bulk_urb (struct urb *urb,
                                       usb_complete_t complete_fn,
                                       void *context)
 {
-        spin_lock_init(&urb->lock);
         urb->dev = dev;
         urb->pipe = pipe;
         urb->transfer_buffer = transfer_buffer;
@@ -1366,7 +1363,6 @@ static inline void usb_fill_int_urb (struct urb *urb,
                                      void *context,
                                      int interval)
 {
-        spin_lock_init(&urb->lock);
         urb->dev = dev;
         urb->pipe = pipe;
         urb->transfer_buffer = transfer_buffer;