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Date: Tue, 7 May 2024 08:54:40 +0100
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Subject: Re: [PATCH] selftests/mqueue: fix 5 warnings about signed/unsigned
 mismatches
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To: John Hubbard <jhubbard@nvidia.com>, Shuah Khan <shuah@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
 David Hildenbrand <david@redhat.com>, SeongJae Park <sj@kernel.org>,
 Valentin Obst <kernel@valentinobst.de>, linux-kselftest@vger.kernel.org,
 LKML <linux-kernel@vger.kernel.org>, llvm@lists.linux.dev
References: <20240505221359.65258-1-jhubbard@nvidia.com>
From: Ryan Roberts <ryan.roberts@arm.com>
In-Reply-To: <20240505221359.65258-1-jhubbard@nvidia.com>
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On 05/05/2024 23:13, John Hubbard wrote:
> When building with clang, via:
> 
>     make LLVM=1 -C tools/testing/selftest
> 
> ...clang warns about several cases of using a signed integer for the
> priority argument to mq_receive(3), which expects an unsigned int.
> 
> Fix this by declaring the type as unsigned int in all cases.
> 
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> ---
>  tools/testing/selftests/mqueue/mq_perf_tests.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/mqueue/mq_perf_tests.c b/tools/testing/selftests/mqueue/mq_perf_tests.c
> index 5c16159d0bcd..fb898850867c 100644
> --- a/tools/testing/selftests/mqueue/mq_perf_tests.c
> +++ b/tools/testing/selftests/mqueue/mq_perf_tests.c
> @@ -323,7 +323,8 @@ void *fake_cont_thread(void *arg)
>  void *cont_thread(void *arg)
>  {
>  	char buff[MSG_SIZE];
> -	int i, priority;
> +	int i;
> +	unsigned int priority;
>  
>  	for (i = 0; i < num_cpus_to_pin; i++)
>  		if (cpu_threads[i] == pthread_self())
> @@ -425,7 +426,8 @@ struct test test2[] = {
>  void *perf_test_thread(void *arg)
>  {
>  	char buff[MSG_SIZE];
> -	int prio_out, prio_in;
> +	int prio_out;

It feels a bit odd for prio_out and prio_in to have different types. I don't
have any prior familiararity with these tests but looks like they are ultimately
the parameters of mq_send() and mq_receive() which both define them as unsigned
ints. Perhaps both should be converted?

> +	unsigned int prio_in;
>  	int i;
>  	clockid_t clock;
>  	pthread_t *t;
> 
> base-commit: f462ae0edd3703edd6f22fe41d336369c38b884b
> prerequisite-patch-id: b901ece2a5b78503e2fb5480f20e304d36a0ea27