[media] DVB: dvb_frontend: update locking in dvb_frontend_{add, get_event}

  - fepriv->parameters_out isn't protected by events->mtx, so
    move the call to fe->ops.get_frontend out of the locked area.
  - move the assignment of e->status into the locked area.

  - use direct assignment instead of memcpy.

  - use mutex_lock instead of mutex_lock_interruptible, because
    all code paths protected by this mutex won't block.

Signed-off-by: Andreas Oberritter <obi@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 7 insertions, 17 deletions

diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index 410231112204..d02c32e754f4 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -149,30 +149,25 @@ static void dvb_frontend_add_event(struct dvb_frontend *fe, fe_status_t status)
 
         dprintk ("%s\n", __func__);
 
-        if (mutex_lock_interruptible (&events->mtx))
-                return;
+        if ((status & FE_HAS_LOCK) && fe->ops.get_frontend)
+                fe->ops.get_frontend(fe, &fepriv->parameters_out);
 
-        wp = (events->eventw + 1) % MAX_EVENT;
+        mutex_lock(&events->mtx);
 
+        wp = (events->eventw + 1) % MAX_EVENT;
         if (wp == events->eventr) {
                 events->overflow = 1;
                 events->eventr = (events->eventr + 1) % MAX_EVENT;
         }
 
         e = &events->events[events->eventw];
-
-        if (status & FE_HAS_LOCK)
-                if (fe->ops.get_frontend)
-                        fe->ops.get_frontend(fe, &fepriv->parameters_out);
-
+        e->status = status;
         e->parameters = fepriv->parameters_out;
 
         events->eventw = wp;
 
         mutex_unlock(&events->mtx);
 
-        e->status = status;
-
         wake_up_interruptible (&events->wait_queue);
 }
 
@@ -207,14 +202,9 @@ static int dvb_frontend_get_event(struct dvb_frontend *fe,
                         return ret;
         }
 
-        if (mutex_lock_interruptible (&events->mtx))
-                return -ERESTARTSYS;
-
-        memcpy (event, &events->events[events->eventr],
-                sizeof(struct dvb_frontend_event));
-
+        mutex_lock(&events->mtx);
+        *event = events->events[events->eventr];
         events->eventr = (events->eventr + 1) % MAX_EVENT;
-
         mutex_unlock(&events->mtx);
 
         return 0;