[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 <min...@mina86.com>

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.stu...@linaro.org>
Tested-by: Chen Yu <cheny...@huawei.com>
Signed-off-by: Michal Nazarewicz <min...@mina86.com>
Signed-off-by: Felipe Balbi <felipe.ba...@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>


---
 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);