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Subject[PATCH 4.9 61/86] usb: core: Add a helper function to check the validity of EP type in URB
Date
From: Takashi Iwai <tiwai@suse.de>

commit e901b9873876ca30a09253731bd3a6b00c44b5b0 upstream.

This patch adds a new helper function to perform a sanity check of the
given URB to see whether it contains a valid endpoint. It's a light-
weight version of what usb_submit_urb() does, but without the kernel
warning followed by the stack trace, just returns an error code.

Especially for a driver that doesn't parse the descriptor but fills
the URB with the fixed endpoint (e.g. some quirks for non-compliant
devices), this kind of check is preferable at the probe phase before
actually submitting the urb.

Tested-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/core/urb.c | 30 ++++++++++++++++++++++++++----
include/linux/usb.h | 2 ++
2 files changed, 28 insertions(+), 4 deletions(-)

--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -183,6 +183,31 @@ EXPORT_SYMBOL_GPL(usb_unanchor_urb);

/*-------------------------------------------------------------------*/

+static const int pipetypes[4] = {
+ PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
+};
+
+/**
+ * usb_urb_ep_type_check - sanity check of endpoint in the given urb
+ * @urb: urb to be checked
+ *
+ * This performs a light-weight sanity check for the endpoint in the
+ * given urb. It returns 0 if the urb contains a valid endpoint, otherwise
+ * a negative error code.
+ */
+int usb_urb_ep_type_check(const struct urb *urb)
+{
+ const struct usb_host_endpoint *ep;
+
+ ep = usb_pipe_endpoint(urb->dev, urb->pipe);
+ if (!ep)
+ return -EINVAL;
+ if (usb_pipetype(urb->pipe) != pipetypes[usb_endpoint_type(&ep->desc)])
+ return -EINVAL;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_urb_ep_type_check);
+
/**
* usb_submit_urb - issue an asynchronous transfer request for an endpoint
* @urb: pointer to the urb describing the request
@@ -322,9 +347,6 @@ EXPORT_SYMBOL_GPL(usb_unanchor_urb);
*/
int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
{
- static int pipetypes[4] = {
- PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
- };
int xfertype, max;
struct usb_device *dev;
struct usb_host_endpoint *ep;
@@ -443,7 +465,7 @@ int usb_submit_urb(struct urb *urb, gfp_
*/

/* Check that the pipe's type matches the endpoint's type */
- if (usb_pipetype(urb->pipe) != pipetypes[xfertype])
+ if (usb_urb_ep_type_check(urb))
dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
usb_pipetype(urb->pipe), pipetypes[xfertype]);

--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1655,6 +1655,8 @@ static inline int usb_urb_dir_out(struct
return (urb->transfer_flags & URB_DIR_MASK) == URB_DIR_OUT;
}

+int usb_urb_ep_type_check(const struct urb *urb);
+
void *usb_alloc_coherent(struct usb_device *dev, size_t size,
gfp_t mem_flags, dma_addr_t *dma);
void usb_free_coherent(struct usb_device *dev, size_t size,

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