Re: [PATCH 1/6] ath6kl: fix sparse warning on init.c

Luis R. Rodriguez
2011-12-20T19:46:27Z

On Tue, Dec 20, 2011 at 09:40:19PM +0200, Kalle Valo wrote:
> On 12/20/2011 08:46 PM, Luis R. Rodriguez wrote:
> > From: Luis R. Rodriguez <mcgrof@qca.qualcomm.com>
> >
> > This fixes this sparse warning:
> >
> > CC [M] drivers/net/wireless/ath/ath6kl/init.o
> > drivers/net/wireless/ath/ath6kl/init.c: In function ‘ath6kl_init_hw_params’:
> > drivers/net/wireless/ath/ath6kl/init.c:1377:26: warning: ‘hw’ may be used uninitialized in this function
>
> That's a compiler warning.
>
> > static int ath6kl_init_hw_params(struct ath6kl *ar)
> > {
> > - const struct ath6kl_hw *hw;
> > + const struct ath6kl_hw *hw = NULL;
> > int i;
> >
> > for (i = 0; i < ARRAY_SIZE(hw_list); i++) {
> > @@ -1390,6 +1390,9 @@ static int ath6kl_init_hw_params(struct ath6kl *ar)
> > return -EINVAL;
> > }
> >
> > + if (!hw)
> > + return -EINVAL;
>
> I can't see how hw can be uninitialised here (looking at the version in
> ath6kl.git). I copy the full code here:
>
> static int ath6kl_init_hw_params(struct ath6kl *ar)
> {
> const struct ath6kl_hw *hw;
> int i;
>
> for (i = 0; i < ARRAY_SIZE(hw_list); i++) {
> hw = &hw_list[i];
>
> if (hw->id == ar->version.target_ver)
> break;
> }
>
> if (i == ARRAY_SIZE(hw_list)) {
> ath6kl_err("Unsupported hardware version: 0x%x\n",
> ar->version.target_ver);
> return -EINVAL;
> }
>
> ar->hw = *hw;
>
> I always check for both compiler and sparse warnings and I have never
> seen this. What version of compiler do you have?
>
> I have:
>
> gcc-4.5.real (Ubuntu/Linaro 4.5.2-8ubuntu4) 4.5.2

Same.

mcgrof@tux ~ $ gcc --version
gcc-4.5.real (Ubuntu/Linaro 4.5.2-8ubuntu4) 4.5.2
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE

Luis