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[99.254.144.39]) by smtp.gmail.com with ESMTPSA id ey5-20020a05622a4c0500b003f6bbd7863csm3196694qtb.86.2023.06.05.08.43.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Jun 2023 08:43:57 -0700 (PDT) Date: Mon, 5 Jun 2023 11:43:56 -0400 From: Peter Xu To: John Hubbard Cc: Andrew Morton , David Hildenbrand , Shuah Khan , Nathan Chancellor , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, LKML Subject: Re: [PATCH v2 03/11] selftests/mm: fix "warning: expression which evaluates to zero..." in mlock2-tests.c Message-ID: References: <20230603021558.95299-1-jhubbard@nvidia.com> <20230603021558.95299-4-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230603021558.95299-4-jhubbard@nvidia.com> Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Fri, Jun 02, 2023 at 07:15:50PM -0700, John Hubbard wrote: > The stop variable is a char*, and the code was assigning a char value to > it. This was generating a warning when compiling with clang. > > However, as both David and Peter pointed out, stop is not even used > after the problematic assignment to a char type. So just delete that > line entirely. > > Cc: David Hildenbrand > Cc: Peter Xu > Signed-off-by: John Hubbard > --- > tools/testing/selftests/mm/mlock2-tests.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/tools/testing/selftests/mm/mlock2-tests.c b/tools/testing/selftests/mm/mlock2-tests.c > index 11b2301f3aa3..80cddc0de206 100644 > --- a/tools/testing/selftests/mm/mlock2-tests.c > +++ b/tools/testing/selftests/mm/mlock2-tests.c > @@ -50,7 +50,6 @@ static int get_vm_area(unsigned long addr, struct vm_boundaries *area) > printf("cannot parse /proc/self/maps\n"); > goto out; > } > - stop = '\0'; > > sscanf(line, "%lx", &start); > sscanf(end_addr, "%lx", &end); I'd rather simply make it "*stop = '\0'", or as David suggested dropping stop completely when we're it (assumes that scanf() will always work with number ending with space ' '). No strong opinion here, though. -- Peter Xu