USB: usbcore get rid of the timer in usb_start_wait_urb()

This patch uses completion timeout instead of a timer to implement
a timeout when submitting an URB in usb_start_wait_urb().

It also fixes a small issue. With the previous code, if no timeout
happened and the URB's status was set to ECONNRESET value, the code
assumed wrongly that a timeout had occured.

Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 29 insertions, 44 deletions

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 4cc8d3e67db7..49cfd7928a1c 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -23,59 +23,44 @@ static void usb_api_blocking_completion(struct urb *urb, struct pt_regs *regs)
 }
 
 
-static void timeout_kill(unsigned long data)
-{
-        struct urb      *urb = (struct urb *) data;
-
-        usb_unlink_urb(urb);
-}
-
-// Starts urb and waits for completion or timeout
-// note that this call is NOT interruptible, while
-// many device driver i/o requests should be interruptible
-static int usb_start_wait_urb(struct urb *urb, int timeout, int* actual_length)
+/*
+ * Starts urb and waits for completion or timeout. Note that this call
+ * is NOT interruptible. Many device driver i/o requests should be
+ * interruptible and therefore these drivers should implement their
+ * own interruptible routines.
+ */
+static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
 { 
-        struct completion       done;
-        struct timer_list       timer;
-        int                     status;
+        struct completion done;
+        unsigned long expire;
+        int status;
 
         init_completion(&done);         
         urb->context = &done;
         urb->actual_length = 0;
         status = usb_submit_urb(urb, GFP_NOIO);
-
-        if (status == 0) {
-                if (timeout > 0) {
-                        init_timer(&timer);
-                        timer.expires = jiffies + msecs_to_jiffies(timeout);
-                        timer.data = (unsigned long)urb;
-                        timer.function = timeout_kill;
-                        /* grr.  timeout _should_ include submit delays. */
-                        add_timer(&timer);
-                }
-                wait_for_completion(&done);
+        if (unlikely(status))
+                goto out;
+
+        expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
+        if (!wait_for_completion_timeout(&done, expire)) {
+
+                dev_dbg(&urb->dev->dev,
+                        "%s timed out on ep%d%s len=%d/%d\n",
+                        current->comm,
+                        usb_pipeendpoint(urb->pipe),
+                        usb_pipein(urb->pipe) ? "in" : "out",
+                        urb->actual_length,
+                        urb->transfer_buffer_length);
+
+                usb_kill_urb(urb);
+                status = urb->status == -ENOENT ? -ETIMEDOUT : urb->status;
+        } else
                 status = urb->status;
-                /* note:  HCDs return ETIMEDOUT for other reasons too */
-                if (status == -ECONNRESET) {
-                        dev_dbg(&urb->dev->dev,
-                                "%s timed out on ep%d%s len=%d/%d\n",
-                                current->comm,
-                                usb_pipeendpoint(urb->pipe),
-                                usb_pipein(urb->pipe) ? "in" : "out",
-                                urb->actual_length,
-                                urb->transfer_buffer_length
-                                );
-                        if (urb->actual_length > 0)
-                                status = 0;
-                        else
-                                status = -ETIMEDOUT;
-                }
-                if (timeout > 0)
-                        del_timer_sync(&timer);
-        }
-
+out:
         if (actual_length)
                 *actual_length = urb->actual_length;
+
         usb_free_urb(urb);
         return status;
 }