[patch] fix warning in drivers/media/dvb/dvb-usb/af9005-fe.c

[Ingo Molnar <mingo@elte.hu>]

* Ingo Molnar <mingo@elte.hu> wrote:

> here's that commit again, standalone, with the crash in 
> af9005_usb_module_init() embedded. Unfortunately i dont have the .config 
> anymore and the crash log is half a year old. I have re-enabled the 
> driver in tip/master so if the crash still triggers i should see it 
> within 1-2 days and i can do a fuller bugreport.

no crashes or build failures so far, so it's looking good!

There's one new compiler warning that i had to fix - but that's all. Find 
the patch attached below.

Btw., there's a handful of warning fixes i carry in tip/warnings/* topic 
branches - you can find them in tip/master via:

  http://people.redhat.com/mingo/tip.git/README

the ones affecting drivers/media/ are:

  f3e67e2: fix warning in drivers/media/video/usbvision/usbvision-i2c.c
  491af31: fix warning in drivers/media/video/cx18/cx18-mailbox.c
  728342a: fix warnings in drivers/media/dvb/ttusb-dec/ttusb_dec.c
  4dda565: fix warning in drivers/media/dvb/frontends/drx397xD.c
  a2e4f4a: fix warning in drivers/media/common/tuners/mxl5007t.c
  8317adf: fix warning in drivers/media/dvb/dvb-usb/anysee.c

this one appears to be GCC warning about a real bug:

  8317adf: fix warning in drivers/media/dvb/dvb-usb/anysee.c

the others are fixes for false positives - i reviewed the affected code 
paths and each commit log includes the analysis about why it is a false 
positive.

You might ask, how did these drivers/media/ commits get into tip/master? 
It is a side-effect of us keeping tip/master continuously -Werror clean 
for 32-bit and 64-bit x86 on allyes/allno/allmod and randconfigs as well, 
Those warning fixes (for the whole kernel - including drivers/media/) go 
into the tip/warnings/* branches.

Please have a look and git-cherry-pick the above commits if they are still 
relevant to your tree and if you agree with them. Thanks,

	Ingo

------------------------->
Subject: fix warning in drivers/media/dvb/dvb-usb/af9005-fe.c
From: Ingo Molnar <mingo@elte.hu>
Date: Sat Dec 27 12:49:36 CET 2008

this warning:

  drivers/media/dvb/dvb-usb/af9005-fe.c: In function ‘af9005_fe_refresh_state’:
  drivers/media/dvb/dvb-usb/af9005-fe.c:223: warning: ‘loc_abort_count’ may be used uninitialized in this function

triggers because GCC does not recognize the (complex but correct) error flow
between:

     - af9005_fe_refresh_state() and af9005_get_post_vit_err_cw_count()

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
---
 drivers/media/dvb/dvb-usb/af9005-fe.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux/drivers/media/dvb/dvb-usb/af9005-fe.c
===================================================================
--- linux.orig/drivers/media/dvb/dvb-usb/af9005-fe.c
+++ linux/drivers/media/dvb/dvb-usb/af9005-fe.c
@@ -220,7 +220,7 @@ static int af9005_get_post_vit_ber(struc
 				   u16 * abort_count)
 {
 	u32 loc_cw_count = 0, loc_err_count;
-	u16 loc_abort_count;
+	u16 uninitialized_var(loc_abort_count);
 	int ret;
 
 	ret =