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Mon, 10 Apr 2023 23:32:58 -0700 (PDT) Received: from [10.72.12.112] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id x5-20020a634a05000000b0051afa49e07asm1893912pga.50.2023.04.10.23.32.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 10 Apr 2023 23:32:57 -0700 (PDT) Message-ID: <268c8128-d1cf-3103-b990-e92a2e69465f@redhat.com> Date: Tue, 11 Apr 2023 14:32:51 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.1 Subject: Re: [PATCH] tap: fix net_init_tap() return code Content-Language: en-US To: Steven Sistare , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , qemu-devel@nongnu.org References: <1680624004-154390-1-git-send-email-steven.sistare@oracle.com> <9da71dfa-52b7-5b65-3160-6f236440add4@linaro.org> <4be85e27-0990-7ba9-60a1-45d53d63004e@oracle.com> From: Jason Wang In-Reply-To: <4be85e27-0990-7ba9-60a1-45d53d63004e@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=jasowang@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -52 X-Spam_score: -5.3 X-Spam_bar: ----- X-Spam_report: (-5.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-3.246, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, 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 在 2023/4/5 23:38, Steven Sistare 写道: > On 4/4/2023 6:00 PM, Philippe Mathieu-Daudé wrote: >> On 4/4/23 18:00, Steve Sistare wrote: >>> When net_init_tap() succeeds for a multi-queue device, it returns a >>> non-zero ret=1 code to its caller, because of this code where ret becomes >> Indeed g_unix_set_fd_nonblocking() returns TRUE on success. >> >> Reviewed-by: Philippe Mathieu-Daudé >> >>> 1 when g_unix_set_fd_nonblocking succeeds.  Luckily, the only current call >>> site checks for negative, rather than non-zero. >>> >>>      ret = g_unix_set_fd_nonblocking(fd, true, NULL); >>>      if (!ret) { >>>          ... >>>          goto free_fail; >>> >>> Also, if g_unix_set_fd_nonblocking fails (though unlikely), ret=0 is returned, >>> and the caller will use a broken interface. >> We should return -1 from free_fail, not trying to propagate 'ret': > Thanks for the review. I will add your "return -1" changes if Jason agrees. > > - Steve Note that the "free_fail" label is kind of ambiguous. It is used even if we succeed if I was not wrong. Thanks >> -- >8 -- >> diff --git a/net/tap.c b/net/tap.c >> index 1bf085d422..e59238bda0 100644 >> --- a/net/tap.c >> +++ b/net/tap.c >> @@ -821,3 +821,2 @@ int net_init_tap(const Netdev *netdev, const char *name, >>      char ifname[128]; >> -    int ret = 0; >> >> @@ -896,3 +895,2 @@ int net_init_tap(const Netdev *netdev, const char *name, >>                             "the number of vhostfds passed"); >> -                ret = -1; >>                  goto free_fail; >> @@ -904,3 +902,2 @@ int net_init_tap(const Netdev *netdev, const char *name, >>              if (fd == -1) { >> -                ret = -1; >>                  goto free_fail; >> @@ -908,4 +905,3 @@ int net_init_tap(const Netdev *netdev, const char *name, >> >> -            ret = g_unix_set_fd_nonblocking(fd, true, NULL); >> -            if (!ret) { >> +            if (!g_unix_set_fd_nonblocking(fd, true, NULL)) { >>                  error_setg_errno(errp, errno, "%s: Can't use file descriptor %d", >> @@ -918,3 +914,2 @@ int net_init_tap(const Netdev *netdev, const char *name, >>                  if (vnet_hdr < 0) { >> -                    ret = -1; >>                      goto free_fail; >> @@ -924,3 +919,2 @@ int net_init_tap(const Netdev *netdev, const char *name, >>                             "vnet_hdr not consistent across given tap fds"); >> -                ret = -1; >>                  goto free_fail; >> @@ -934,3 +928,2 @@ int net_init_tap(const Netdev *netdev, const char *name, >>                  error_propagate(errp, err); >> -                ret = -1; >>                  goto free_fail; >> @@ -948,3 +941,3 @@ free_fail: >>          g_free(vhost_fds); >> -        return ret; >> +        return -1; >>      } else if (tap->helper) { >> --- >> >>> Fixes: a8208626ba89.. ("net: replace qemu_set_nonblock()") >>> Signed-off-by: Steve Sistare >>> --- >>>   net/tap.c | 4 ++-- >>>   1 file changed, 2 insertions(+), 2 deletions(-)