[PATCH 5.15 140/570] USB: usbcore: Introduce usb_bulk_msg_killable()

Greg Kroah-Hartman
2026-04-13T16:24:08Z

From: Alan Stern <stern@rowland.harvard.edu>

commit 416909962e7cdf29fd01ac523c953f37708df93d upstream.

The synchronous message API in usbcore (usb_control_msg(),
usb_bulk_msg(), and so on) uses uninterruptible waits. However,
drivers may call these routines in the context of a user thread, which
means it ought to be possible to at least kill them.

For this reason, introduce a new usb_bulk_msg_killable() function
which behaves the same as usb_bulk_msg() except for using
wait_for_completion_killable_timeout() instead of
wait_for_completion_timeout(). The same can be done later for
usb_control_msg() later on, if it turns out to be needed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Suggested-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/linux-usb/3acfe838-6334-4f6d-be7c-4bb01704b33d@rowland.harvard.edu/
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
CC: stable@vger.kernel.org
Link: https://patch.msgid.link/248628b4-cc83-4e81-a620-3ce4e0376d41@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/core/message.c | 79 +++++++++++++++++++++++++++++++++++++++------
include/linux/usb.h | 5 +-
2 files changed, 72 insertions(+), 12 deletions(-)

--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -41,16 +41,17 @@ static void usb_api_blocking_completion(

/*
- * 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.
+ * Starts urb and waits for completion or timeout.
+ * Whether or not the wait is killable depends on the flag passed in.
+ * For example, compare usb_bulk_msg() and usb_bulk_msg_killable().
*/
-static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)
+static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length,
+ bool killable)
{
struct api_context ctx;
unsigned long expire;
int retval;
+ long rc;

init_completion(&ctx.done);
urb->context = &ctx;
@@ -60,12 +61,21 @@ static int usb_start_wait_urb(struct urb
goto out;

expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;
- if (!wait_for_completion_timeout(&ctx.done, expire)) {
+ if (killable)
+ rc = wait_for_completion_killable_timeout(&ctx.done, expire);
+ else
+ rc = wait_for_completion_timeout(&ctx.done, expire);
+ if (rc <= 0) {
usb_kill_urb(urb);
- retval = (ctx.status == -ENOENT ? -ETIMEDOUT : ctx.status);
+ if (ctx.status != -ENOENT)
+ retval = ctx.status;
+ else if (rc == 0)
+ retval = -ETIMEDOUT;
+ else
+ retval = rc;

dev_dbg(&urb->dev->dev,
- "%s timed out on ep%d%s len=%u/%u\n",
+ "%s timed out or killed on ep%d%s len=%u/%u\n",
current->comm,
usb_endpoint_num(&urb->ep->desc),
usb_urb_dir_in(urb) ? "in" : "out",
@@ -99,7 +109,7 @@ static int usb_internal_control_msg(stru
usb_fill_control_urb(urb, usb_dev, pipe, (unsigned char *)cmd, data,
len, usb_api_blocking_completion, NULL);

- retv = usb_start_wait_urb(urb, timeout, &length);
+ retv = usb_start_wait_urb(urb, timeout, &length, false);
if (retv < 0)
return retv;
else
@@ -384,10 +394,59 @@ int usb_bulk_msg(struct usb_device *usb_
usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,
usb_api_blocking_completion, NULL);

- return usb_start_wait_urb(urb, timeout, actual_length);
+ return usb_start_wait_urb(urb, timeout, actual_length, false);
}
EXPORT_SYMBOL_GPL(usb_bulk_msg);

+/**
+ * usb_bulk_msg_killable - Builds a bulk urb, sends it off and waits for completion in a killable state
+ * @usb_dev: pointer to the usb device to send the message to
+ * @pipe: endpoint "pipe" to send the message to
+ * @data: pointer to the data to send
+ * @len: length in bytes of the data to send
+ * @actual_length: pointer to a location to put the actual length transferred
+ * in bytes
+ * @timeout: time in msecs to wait for the message to complete before
+ * timing out (if 0 the wait is forever)
+ *
+ * Context: task context, might sleep.
+ *
+ * This function is just like usb_blk_msg() except that it waits in a
+ * killable state.
+ *
+ * Return:
+ * If successful, 0. Otherwise a negative error number. The number of actual
+ * bytes transferred will be stored in the @actual_length parameter.
+ *
+ */
+int usb_bulk_msg_killable(struct usb_device *usb_dev, unsigned int pipe,
+ void *data, int len, int *actual_length, int timeout)
+{
+ struct urb *urb;
+ struct usb_host_endpoint *ep;
+
+ ep = usb_pipe_endpoint(usb_dev, pipe);
+ if (!ep || len < 0)
+ return -EINVAL;
+
+ urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!urb)
+ return -ENOMEM;
+
+ if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
+ USB_ENDPOINT_XFER_INT) {
+ pipe = (pipe & ~(3 << 30)) | (PIPE_INTERRUPT << 30);
+ usb_fill_int_urb(urb, usb_dev, pipe, data, len,
+ usb_api_blocking_completion, NULL,
+ ep->desc.bInterval);
+ } else
+ usb_fill_bulk_urb(urb, usb_dev, pipe, data, len,
+ usb_api_blocking_completion, NULL);
+
+ return usb_start_wait_urb(urb, timeout, actual_length, true);
+}
+EXPORT_SYMBOL_GPL(usb_bulk_msg_killable);
+
/*-------------------------------------------------------------------*/

static void sg_clean(struct usb_sg_request *io)
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1811,8 +1811,9 @@ extern int usb_control_msg(struct usb_de
extern int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe,
void *data, int len, int *actual_length, int timeout);
extern int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe,
- void *data, int len, int *actual_length,
- int timeout);
+ void *data, int len, int *actual_length, int timeout);
+extern int usb_bulk_msg_killable(struct usb_device *usb_dev, unsigned int pipe,
+ void *data, int len, int *actual_length, int timeout);

/* wrappers around usb_control_msg() for the most common standard requests */
int usb_control_msg_send(struct usb_device *dev, __u8 endpoint, __u8 request,