usb: gadget: f_fs: Ensure ep0req is dequeued before free_request

[ Upstream commit ce405d561b020e5a46340eb5146805a625dcacee ]

As per the documentation, function usb_ep_free_request guarantees
the request will not be queued or no longer be re-queued (or
otherwise used). However, with the current implementation it
doesn't make sure that the request in ep0 isn't reused.

Fix this by dequeuing the ep0req on functionfs_unbind before
freeing the request to align with the definition.

Fixes: ddf8abd25994 ("USB: f_fs: the FunctionFS driver")
Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com>
Tested-by: Krishna Kurapati <quic_kriskura@quicinc.com>
Link: https://lore.kernel.org/r/20221215052906.8993-3-quic_ugoswami@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index bb6fe1f..523a961 100644 (file)
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1895,6 +1895,8 @@ static void functionfs_unbind(struct ffs_data *ffs)
        ENTER();
 
        if (!WARN_ON(!ffs->gadget)) {
+               /* dequeue before freeing ep0req */
+               usb_ep_dequeue(ffs->gadget->ep0, ffs->ep0req);
                mutex_lock(&ffs->mutex);
                usb_ep_free_request(ffs->gadget->ep0, ffs->ep0req);
                ffs->ep0req = NULL;