The patch titled
USB: fix a bug in usb_start_wait_urb
has been added to the -mm tree. Its filename is
usb-fix-a-bug-in-usb_start_wait_urb.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: USB: fix a bug in usb_start_wait_urb
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
This patch (as941) fixes a bug recently added to the USB synchronous API.
The status of a completed URB must be preserved separately across a
completion callback. Also, the actual_length value isn't available until
after the URB has fully completed.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/usb/core/message.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
diff -puN drivers/usb/core/message.c~usb-fix-a-bug-in-usb_start_wait_urb drivers/usb/core/message.c
--- a/drivers/usb/core/message.c~usb-fix-a-bug-in-usb_start_wait_urb
+++ a/drivers/usb/core/message.c
@@ -18,9 +18,17 @@
#include "hcd.h" /* for usbcore internals */
#include "usb.h"
+struct api_context {
+ struct completion done;
+ int status;
+};
+
static void usb_api_blocking_completion(struct urb *urb)
{
- complete((struct completion *)urb->context);
+ struct api_context *ctx = urb->context;
+
+ ctx->status = urb->status;
+ complete(&ctx->done);
}
@@ -32,20 +40,21 @@ static void usb_api_blocking_completion(
*/
static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
{
- struct completion done;
+ struct api_context ctx;
unsigned long expire;
int retval;
- int status = urb->status;
- init_completion(&done);
- urb->context = &done;
+ init_completion(&ctx.done);
+ urb->context = &ctx;
urb->actual_length = 0;
retval = usb_submit_urb(urb, GFP_NOIO);
if (unlikely(retval))
goto out;
expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
- if (!wait_for_completion_timeout(&done, expire)) {
+ if (!wait_for_completion_timeout(&ctx.done, expire)) {
+ usb_kill_urb(urb);
+ retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);
dev_dbg(&urb->dev->dev,
"%s timed out on ep%d%s len=%d/%d\n",
@@ -54,11 +63,8 @@ static int usb_start_wait_urb(struct urb
usb_pipein(urb->pipe) ? "in" : "out",
urb->actual_length,
urb->transfer_buffer_length);
-
- usb_kill_urb(urb);
- retval = status == -ENOENT ? -ETIMEDOUT : status;
} else
- retval = status;
+ retval = ctx.status;
out:
if (actual_length)
*actual_length = urb->actual_length;
_
Patches currently in -mm which might be from stern@xxxxxxxxxxxxxxxxxxx are
nikon-d50-is-an-unusual-device.patch
usb-fix-a-bug-in-usb_start_wait_urb.patch
-
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