media: uvcvideo: Fix allocation for small frame sizes

If a frame has size of less or equal than one packet size
uvc_alloc_urb_buffers() is unable to allocate memory for it due to a
off-by-one error.

Fix the off-by-one-error and now that we are at it, make sure that
stream->urb_size has always a valid value when we return from the
function, even when an error happens.

Fixes: efdc8a9585 ("V4L/DVB (10295): uvcvideo: Retry URB buffers allocation when the system is low on memory.")
Reported-by: Itay Chamiel <itay.chamiel@q.ai>
Closes: https://lore.kernel.org/linux-media/CANiDSCsSoZf2LsCCoWAUbCg6tJT-ypXR1B85aa6rAdMVYr2iBQ@mail.gmail.com/T/#t
Co-developed-by: Itay Chamiel <itay.chamiel@q.ai>
Signed-off-by: Itay Chamiel <itay.chamiel@q.ai>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Itay Chamiel <itay.chamiel@q.ai>
Link: https://patch.msgid.link/20260114-uvc-alloc-urb-v1-1-cedf3fb66711@chromium.org
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
This commit is contained in:
Ricardo Ribalda 2026-01-14 10:32:13 +00:00 committed by Hans Verkuil
parent 4cf3b6fd54
commit 40d3ac25c1

View File

@ -1812,7 +1812,7 @@ static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
npackets = UVC_MAX_PACKETS;
/* Retry allocations until one succeed. */
for (; npackets > 1; npackets /= 2) {
for (; npackets > 0; npackets /= 2) {
stream->urb_size = psize * npackets;
for (i = 0; i < UVC_URBS; ++i) {
@ -1837,6 +1837,7 @@ static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
uvc_dbg(stream->dev, VIDEO,
"Failed to allocate URB buffers (%u bytes per packet)\n",
psize);
stream->urb_size = 0;
return 0;
}