[PATCH 4.8 48/49] usb: gadget: f_fs: edit epfile->ep under lock

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michal Nazarewicz <mina86@xxxxxxxxxx>

commit 454915dde06a51133750c6745f0ba57361ba209d upstream.

epfile->ep is protected by ffs->eps_lock (not epfile->mutex) so clear it
while holding the spin lock.

Tested-by: John Stultz <john.stultz@xxxxxxxxxx>
Tested-by: Chen Yu <chenyu56@xxxxxxxxxx>
Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>


---
 drivers/usb/gadget/function/f_fs.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1722,17 +1722,17 @@ static void ffs_func_eps_disable(struct
 	unsigned long flags;
 
 	do {
-		if (epfile)
-			mutex_lock(&epfile->mutex);
 		spin_lock_irqsave(&func->ffs->eps_lock, flags);
 		/* pending requests get nuked */
 		if (likely(ep->ep))
 			usb_ep_disable(ep->ep);
 		++ep;
+		if (epfile)
+			epfile->ep = NULL;
 		spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
 
 		if (epfile) {
-			epfile->ep = NULL;
+			mutex_lock(&epfile->mutex);
 			kfree(epfile->read_buffer);
 			epfile->read_buffer = NULL;
 			mutex_unlock(&epfile->mutex);