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[142.68.26.201]) by smtp.gmail.com with ESMTPSA id e5-20020a05620a12c500b007756c8ce8f5sm2919094qkl.59.2023.10.16.05.11.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Oct 2023 05:11:23 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1qsMRP-001mtq-4i; Mon, 16 Oct 2023 09:11:23 -0300 Date: Mon, 16 Oct 2023 09:11:23 -0300 From: Jason Gunthorpe To: "Zhijian Li (Fujitsu)" Cc: Markus Armbruster , "linux-rdma@vger.kernel.org" , "qemu-devel@nongnu.org" , "quintela@redhat.com" , "peterx@redhat.com" , "leobras@redhat.com" Subject: Re: [PATCH 39/52] migration/rdma: Convert qemu_rdma_write_one() to Error Message-ID: <20231016121123.GD282036@ziepe.ca> References: <20230918144206.560120-1-armbru@redhat.com> <20230918144206.560120-40-armbru@redhat.com> <9e117d0c-cf2b-dd01-7fef-55d1c41d254c@fujitsu.com> <87ttrhgu9e.fsf@pond.sub.org> <87zg17dejj.fsf@pond.sub.org> <9a9ac53b-e409-3b87-ea1b-e133903828a5@fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9a9ac53b-e409-3b87-ea1b-e133903828a5@fujitsu.com> Received-SPF: pass client-ip=2607:f8b0:4864:20::72d; envelope-from=jgg@ziepe.ca; helo=mail-qk1-x72d.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Sat, Oct 07, 2023 at 03:40:50AM +0000, Zhijian Li (Fujitsu) wrote: > +rdma-core > > > Is global variable *errno* reliable when the documentation only states > "returns 0 on success, or the value of errno on failure (which indicates the failure reason)." I think the intention of this language was that an errno constant is returned, the caller should not assume it is stored in errno. errno is difficult, many things overwrite it, you can loose its value during error handling. Jason