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Tue, 10 Mar 2026 09:18:21 -0700 (PDT) Received: from Cumhall ([70.50.116.180]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-89a57a3a9a2sm22463626d6.15.2026.03.10.09.18.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Mar 2026 09:18:21 -0700 (PDT) Date: Tue, 10 Mar 2026 12:18:09 -0400 (EDT) From: John Kacur To: Crystal Wood cc: Lukas Beckmann , John Kacur , rt-users Subject: Re: [PATCH 2/2] cyclictest: simplify rstat_setup In-Reply-To: <9ff2d632fbbc58fda5509a26f0dee26d6c3aefcd.camel@redhat.com> Message-ID: <85147e31-053f-1b0f-e200-5d49c1b8b123@gmail.com> References: <20260301212407.3146506-1-lbckmnn@mailbox.org> <20260301212407.3146506-3-lbckmnn@mailbox.org> <9ff2d632fbbc58fda5509a26f0dee26d6c3aefcd.camel@redhat.com> Precedence: bulk X-Mailing-List: linux-rt-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Tue, 10 Mar 2026, Crystal Wood wrote: > On Mon, 2026-03-09 at 18:55 -0400, John Kacur wrote: > > > > On Sun, 1 Mar 2026, Lukas Beckmann wrote: > > > +static void rstat_setup(void) > > > +{ > > > + int fd; > > > + pid_t pid; > > > > > > - if (mptr == (void*)-1) > > > - fprintf(stderr, "ERROR: mmap, %s\n", strerror(errno)); > > > + pid = getpid(); > > > > > > - return mptr; > > > -} > > > + snprintf(shm_name, SHM_BUF_SIZE, "%s%d", "/cyclictest", pid); > > > > > > -static int rstat_mlock(void *mptr) > > > -{ > > > - int err; > > > > errno = 0 before the call to shm_unlink for good defensive programming > > other than that the patch looks good, I will do a little more testing > > Defensive against the library returning -1 without setting errno? Seems > a bit paranoid and cluttery... all for the payoff of an "ERROR: > shm_unlink Success" message if it ever does happen *and* the old errno > happened to be ENOENT. > > And the current code uses it even in places that print the message > regardless. > > -Crystal > > Isn't that what defensive programming is? Guarding against something that is unlikely? It's one line of code that I requested in a patch that gets rid of many lines of code, is that really worth arguing over? John Kacur