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[5.12.227.87]) by smtp.gmail.com with ESMTPSA id bn21sm3746389ejb.47.2021.01.08.09.22.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 Jan 2021 09:22:31 -0800 (PST) Date: Fri, 8 Jan 2021 19:22:29 +0200 From: Vladimir Oltean To: "David S . Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Cong Wang , Stephen Hemminger , Eric Dumazet , George McCollister , Oleksij Rempel , Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , Arnd Bergmann , Taehee Yoo , Jiri Pirko , Florian Westphal , Nikolay Aleksandrov , Pravin B Shelar , Sridhar Samudrala , Saeed Mahameed Subject: Re: [PATCH v5 net-next 11/16] net: propagate errors from dev_get_stats Message-ID: <20210108172229.yxcwp7t2ipacajhs@skbuf> References: <20210108163159.358043-1-olteanv@gmail.com> <20210108163159.358043-12-olteanv@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210108163159.358043-12-olteanv@gmail.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jan 08, 2021 at 06:31:54PM +0200, Vladimir Oltean wrote: > From: Vladimir Oltean > > dev_get_stats can now return error codes. Take the remaining call sites > where those errors can be propagated, which are all trivial, and convert > them to look at that error code and stop processing. > > The effects of simulating a kernel error (returning -ENOMEM) upon > existing programs or kernel interfaces: > > - cat /proc/net/dev prints up until the interface that failed, and there > it returns: > cat: read error: Cannot allocate memory > > - ifstat simply returns this and prints nothing: > Error: Buffer too small for object. > Dump terminated > > - ip -s -s link show behaves the same as ifstat. Note that at first I did not understand why ifstat and "ip -s -s link show" return this message. But in the meantime I figured that it was due to rtnetlink still returning -EMSGSIZE. That is fixed in this patch series, but I forgot to update the commit message to reflect it. The current output from these two commands is: $ ifstat RTNETLINK answers: Cannot allocate memory Dump terminated $ ip -s -s link show RTNETLINK answers: Cannot allocate memory Dump terminated > > - ifconfig prints only the info for the interfaces whose statistics did > not fail. > > Signed-off-by: Vladimir Oltean > --- > Changes in v5: > - Actually propagate errors from bonding and net_failover from within > this patch. > - Properly propagating the dev_get_stats() error code from > rtnl_fill_stats now, and not -EMSGSIZE. > > Changes in v4: > Patch is new (Eric's suggestion).