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Subject[PATCH] USB: debugging code shouldn't alter control flow
People have complained that debugging code shouldn't alter the flow of
control; it should restrict itself to printing out warnings and error
messages. Bowing to popular opinion, this patch (as1518) changes the
debugging checks in usb_submit_urb() to follow this guideline.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Keith Packard <keithp@keithp.com>
CC: Pavel Machek <pavel@ucw.cz>

---
drivers/usb/core/urb.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
Index: usb-3.3/drivers/usb/core/urb.c
===================================================================
--- usb-3.3.orig/drivers/usb/core/urb.c
+++ usb-3.3/drivers/usb/core/urb.c
@@ -403,20 +403,17 @@ int usb_submit_urb(struct urb *urb, gfp_
* cause problems in HCDs if they get it wrong.
*/
{
- unsigned int orig_flags = urb->transfer_flags;
unsigned int allowed;
static int pipetypes[4] = {
PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
};

/* Check that the pipe's type matches the endpoint's type */
- if (usb_pipetype(urb->pipe) != pipetypes[xfertype]) {
- dev_err(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
+ if (usb_pipetype(urb->pipe) != pipetypes[xfertype])
+ dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
usb_pipetype(urb->pipe), pipetypes[xfertype]);
- return -EPIPE; /* The most suitable error code :-) */
- }

- /* enforce simple/standard policy */
+ /* Check against a simple/standard policy */
allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK |
URB_FREE_BUFFER);
switch (xfertype) {
@@ -435,14 +432,12 @@ int usb_submit_urb(struct urb *urb, gfp_
allowed |= URB_ISO_ASAP;
break;
}
- urb->transfer_flags &= allowed;
+ allowed &= urb->transfer_flags;

- /* fail if submitter gave bogus flags */
- if (urb->transfer_flags != orig_flags) {
- dev_err(&dev->dev, "BOGUS urb flags, %x --> %x\n",
- orig_flags, urb->transfer_flags);
- return -EINVAL;
- }
+ /* warn if submitter gave bogus flags */
+ if (allowed != urb->transfer_flags)
+ dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n",
+ urb->transfer_flags, allowed);
}
#endif
/*


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