USB: FHCI: cq_get() should check kfifo_out()'s return value

Since commit 7acd72eb85f1c7a15e8b5eb554994949241737f1 ("kfifo: rename
kfifo_put... into kfifo_in... and kfifo_get... into kfifo_out..."),
kfifo_out() is marked __must_check, and that causes gcc to produce
lots of warnings like this:

  CC      drivers/usb/host/fhci-mem.o
In file included from drivers/usb/host/fhci-hcd.c:34:
drivers/usb/host/fhci.h: In function 'cq_get':
drivers/usb/host/fhci.h:520: warning: ignoring return value of 'kfifo_out', declared with attribute warn_unused_result
...

This patch fixes the issue by properly checking the return value.

Signed-off-by: Anton Vorontsov <avorontsov@mvista.com>
Cc: stable <stable@kernel.org> [.33 and .34]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/usb/host/fhci.h b/drivers/usb/host/fhci.h
index 649ab07308f2..71c3caaea4c1 100644
--- a/drivers/usb/host/fhci.h
+++ b/drivers/usb/host/fhci.h
@@ -20,6 +20,7 @@
 
 #include <linux/kernel.h>
 #include <linux/types.h>
+#include <linux/bug.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/kfifo.h>
@@ -515,9 +516,13 @@ static inline int cq_put(struct kfifo *kfifo, void *p)
 
 static inline void *cq_get(struct kfifo *kfifo)
 {
-        void *p = NULL;
+        unsigned int sz;
+        void *p;
+
+        sz = kfifo_out(kfifo, (void *)&p, sizeof(p));
+        if (sz != sizeof(p))
+                return NULL;
 
-        kfifo_out(kfifo, (void *)&p, sizeof(p));
         return p;
 }