Re: How to fix CHECK warning: testing a 'safe expression' ?

[Murali Karicheri]

On 12/17/2014 01:49 PM, Bjorn Helgaas wrote:
> [+cc Christopher, linux-kernel (this doesn't sound like a PCI-specific
> question)]
>
> On Wed, Dec 17, 2014 at 9:18 AM, Murali Karicheri<m-karicheri2@xxxxxx>  wrote:
> > I am trying to address CHECK warnings in my driver and wondering how to
> > resolve 'warning: testing a 'safe expression' which appears when using
> > IS_ERR_OR_NULL(foo)
> >
> > where foo is defined as
> >
> > struct foo_type *foo;
> >
> > The foo get assigned only NULL or ERR_PTR(error code). So I believe the
> > usage is correct. But then how do I make the CHECK happy of its usage?
> >
> > I have tried a grep to check on the current usage of IS_ERR_OR_NULL() and
> > found 276 of them causes this warning in the v3.18 version of the kernel
> > that I am using
> >
> > $ grep -r "warning: testing a 'safe expression" * | wc -l
> > 276
> >
> > Can someone help me undestand what this means and how to fix the same?
> >
> > I run folling for CHECK
> >
> > make C=2 CF="-D__CHECK_ENDIAN__" CHECK=sparse
>
> If you can share your actual code or point to it in the tree, you
> might get more specific help.
>
> Bjorn

For example I get

  CHECK   drivers/pci/host/pci-keystone.c
include/linux/err.h:40:16: warning: testing a 'safe expression'

Actually it is for IS_ERR_OR_NULL() call in the file which is the only
one call in the file.

--
Murali Karicheri
Linux Kernel, Texas Instruments
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