Subject: [PATCH] USB: FHCI: cq_get() should check kfifo_out()'s return value

From: Anton Vorontsov <[email-masked]>
Date: Sun, 2 May 2010 21:30:25 +0400

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
...

Fix it with BUG_ON() check. We could just forcibly ignore return
value, but it's better to check if we really got a whole pointer.

Signed-off-by: Anton Vorontsov <[email-masked]>
---
 drivers/usb/host/fhci.h |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/host/fhci.h b/drivers/usb/host/fhci.h
index 72dae1c..a3fd0fd 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 +516,12 @@ static inline int cq_put(struct kfifo *kfifo, void *p)
 
 static inline void *cq_get(struct kfifo *kfifo)
 {
+	unsigned int sz;
 	void *p = NULL;
 
-	kfifo_out(kfifo, (void *)&p, sizeof(p));
+	sz = kfifo_out(kfifo, (void *)&p, sizeof(p));
+	BUG_ON(sz != sizeof(p));
+
 	return p;
 }
 
-- 
1.7.0.5