From: Sedat Dilek <sedat.dilek@gmail.com>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>,
Karol Herbst <karolherbst@gmail.com>,
Pekka Paalanen <ppaalanen@gmail.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
nouveau@lists.freedesktop.org,
Clang-Built-Linux ML <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH] x86: mmiotrace: Use cpumask_available for cpumask_var_t variables
Date: Wed, 8 Apr 2020 23:36:47 +0200 [thread overview]
Message-ID: <CA+icZUWq=_qjvAf40PqQAj3tQ0WAZ2QAR9hojTuYqZH_=RWd_w@mail.gmail.com> (raw)
In-Reply-To: <CA+icZUUTEEZww3qT0jfFP0ZgUPXoF1_uOHMT4ZecrQxumE1Zmg@mail.gmail.com>
On Wed, Apr 8, 2020 at 11:12 PM Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> On Wed, Apr 8, 2020 at 10:53 PM Nathan Chancellor
> <natechancellor@gmail.com> wrote:
> >
> > When building with Clang + -Wtautological-compare and
> > CONFIG_CPUMASK_OFFSTACK unset:
> >
>
> Hi Nathan,
>
> thanks for the quick patch.
>
> I can confirm I have no CONFIG_CPUMASK_OFFSTACK set.
>
Feel free to add appropriate credits:
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Regards,
- Sedat -
>
> > arch/x86/mm/mmio-mod.c:375:6: warning: comparison of array 'downed_cpus'
> > equal to a null pointer is always false [-Wtautological-pointer-compare]
> > if (downed_cpus == NULL &&
> > ^~~~~~~~~~~ ~~~~
> > arch/x86/mm/mmio-mod.c:405:6: warning: comparison of array 'downed_cpus'
> > equal to a null pointer is always false [-Wtautological-pointer-compare]
> > if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0)
> > ^~~~~~~~~~~ ~~~~
> > 2 warnings generated.
> >
> > Commit f7e30f01a9e2 ("cpumask: Add helper cpumask_available()") added
> > cpumask_available to fix warnings of this nature. Use that here so that
> > clang does not warn regardless of CONFIG_CPUMASK_OFFSTACK's value.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/982
> > Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > ---
> > arch/x86/mm/mmio-mod.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
> > index 109325d77b3e..43fd19b3f118 100644
> > --- a/arch/x86/mm/mmio-mod.c
> > +++ b/arch/x86/mm/mmio-mod.c
> > @@ -372,7 +372,7 @@ static void enter_uniprocessor(void)
> > int cpu;
> > int err;
> >
> > - if (downed_cpus == NULL &&
> > + if (!cpumask_available(downed_cpus) &&
> > !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) {
> > pr_notice("Failed to allocate mask\n");
> > goto out;
> > @@ -402,7 +402,7 @@ static void leave_uniprocessor(void)
> > int cpu;
> > int err;
> >
> > - if (downed_cpus == NULL || cpumask_weight(downed_cpus) == 0)
> > + if (!cpumask_available(downed_cpus) || cpumask_weight(downed_cpus) == 0)
> > return;
> > pr_notice("Re-enabling CPUs...\n");
> > for_each_cpu(cpu, downed_cpus) {
> >
> > base-commit: ae46d2aa6a7fbe8ca0946f24b061b6ccdc6c3f25
> > --
> > 2.26.0
> >
next prev parent reply other threads:[~2020-04-08 21:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-08 20:53 [PATCH] x86: mmiotrace: Use cpumask_available for cpumask_var_t variables Nathan Chancellor
2020-04-08 21:12 ` Sedat Dilek
2020-04-08 21:36 ` Sedat Dilek [this message]
2020-04-15 13:58 ` Sedat Dilek
2020-04-15 13:51 ` Steven Rostedt
2020-05-18 9:31 ` Nathan Chancellor
2020-05-18 18:52 ` Nick Desaulniers
2020-05-18 22:35 ` Steven Rostedt
2020-05-19 0:29 ` Linus Torvalds
2020-05-19 17:52 ` [tip: x86/urgent] x86/mmiotrace: Use cpumask_available() " tip-bot2 for Nathan Chancellor
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