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

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Submitter Anton Vorontsov
Date May 2, 2010, 5:30 p.m.
Message ID <20100502173025.GA24086@oksana.dev.rtsoft.ru>
Download mbox | patch
Permalink /patch/51466/
State Not Applicable
Headers show

Comments

Anton Vorontsov - May 2, 2010, 5:30 p.m.
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 <avorontsov@mvista.com>
---
 drivers/usb/host/fhci.h |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
Greg KH - May 4, 2010, 7:17 p.m.
On Sun, May 02, 2010 at 09:30:25PM +0400, Anton Vorontsov wrote:
> 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.

No, you don't want to crash the whole machine for something like this.

Please just handle the error normally and pass it up to the upper levels
if possible.

thanks,

greg k-h

Patch

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;
 }