Re: [PATCH] nfc: s3fwrn5: fix undefined parameter values in dev_err()

[tangbin]

Hi Nathan:

On 2021/7/28 1:34, Nathan Chancellor wrote:
> On Tue, Jul 27, 2021 at 08:25:06PM +0800, Tang Bin wrote:
> > In the function s3fwrn5_fw_download(), the 'ret' is not assigned,
> > so the correct value should be given in dev_err function.
> >
> > Fixes: a0302ff5906a ("nfc: s3fwrn5: remove unnecessary label")
> > Signed-off-by: Zhang Shengju <zhangshengju@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Tang Bin <tangbin@xxxxxxxxxxxxxxxxxxxx>
> This clears up a clang warning that I see:
>
> drivers/nfc/s3fwrn5/firmware.c:425:41: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
>                          "Cannot allocate shash (code=%d)\n", ret);
>                                                               ^~~
> ./include/linux/dev_printk.h:144:65: note: expanded from macro 'dev_err'
>          dev_printk_index_wrap(_dev_err, KERN_ERR, dev, dev_fmt(fmt), ##__VA_ARGS__)
>                                                                         ^~~~~~~~~~~
> ./include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
>                  _p_func(dev, fmt, ##__VA_ARGS__);                       \
>                                      ^~~~~~~~~~~
> drivers/nfc/s3fwrn5/firmware.c:416:9: note: initialize the variable 'ret' to silence this warning
>          int ret;
>                 ^
>                  = 0
> 1 error generated.
>
> One comment below but regardless:
>
> Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
>
> > ---
> >   drivers/nfc/s3fwrn5/firmware.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/nfc/s3fwrn5/firmware.c b/drivers/nfc/s3fwrn5/firmware.c
> > index 1421ffd46d9a..52c6f76adfb2 100644
> > --- a/drivers/nfc/s3fwrn5/firmware.c
> > +++ b/drivers/nfc/s3fwrn5/firmware.c
> > @@ -422,7 +422,7 @@ int s3fwrn5_fw_download(struct s3fwrn5_fw_info *fw_info)
> >   	tfm = crypto_alloc_shash("sha1", 0, 0);
> >   	if (IS_ERR(tfm)) {
> >   		dev_err(&fw_info->ndev->nfc_dev->dev,
> > -			"Cannot allocate shash (code=%d)\n", ret);
> > +			"Cannot allocate shash (code=%d)\n", PTR_ERR(tfm));
> We know this is going to be an error pointer so this could be changed to
>
> "Cannot allocate shash (code=%pe)\n", tfm);
>
> to make it a little cleaner to understand. See commit 57f5677e535b
> ("printf: add support for printing symbolic error names").

Got it. My patch is looks like a revert, so in the dev_err I used 
'PTR_ERR(tfm)'. After your suggestion,

I will send V2 for you.

Thanks

Tang Bin



> >   		return PTR_ERR(tfm);
> >   	}
> >   
> > --
> > 2.18.2
> Cheers,
> Nathan