From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH] vdpa: bypass waking up vhost_woker for vdpa vq kick Date: Tue, 2 Jun 2020 19:10:38 +0800 Message-ID: References: <20200602094203.GU30374@kadam> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Dan Carpenter , kbuild@lists.01.org, Zhu Lingshan , mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: lkp@intel.com, kbuild-all@lists.01.org, lulu@redhat.com, dan.daly@intel.com, cunming.liang@intel.com List-Id: virtualization@lists.linuxfoundation.org On 2020/6/2 下午6:16, Jason Wang wrote: > > On 2020/6/2 下午5:42, Dan Carpenter wrote: >> Hi Zhu, >> >> url: >> https://github.com/0day-ci/linux/commits/Zhu-Lingshan/vdpa-bypass-waking-up-vhost_woker-for-vdpa-vq-kick/20200526-133819 >> >> base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git >> linux-next >> config: x86_64-randconfig-m001-20200529 (attached as .config) >> compiler: gcc-9 (Debian 9.3.0-13) 9.3.0 >> >> If you fix the issue, kindly add following tag as appropriate >> Reported-by: kbuild test robot >> Reported-by: Dan Carpenter >> >> smatch warnings: >> drivers/vhost/vdpa.c:348 vhost_vdpa_set_vring_kick() error: >> uninitialized symbol 'r'. >> >> # >> https://github.com/0day-ci/linux/commit/a84ddbf1ef29f18aafb2bb8a93bcedd4a29a967d >> >> git remote add linux-review https://github.com/0day-ci/linux >> git remote update linux-review >> git checkout a84ddbf1ef29f18aafb2bb8a93bcedd4a29a967d >> vim +/r +348 drivers/vhost/vdpa.c >> >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  316  static long >> vhost_vdpa_set_vring_kick(struct vhost_virtqueue *vq, >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26 317                        >> void __user *argp) >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  318  { >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  319      bool pollstart = >> false, pollstop = false; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  320      struct file >> *eventfp, *filep = NULL; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  321      struct >> vhost_vring_file f; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  322      long r; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  323 >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  324      if >> (copy_from_user(&f, argp, sizeof(f))) >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  325          return -EFAULT; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  326 >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  327      eventfp = f.fd == -1 >> ? NULL : eventfd_fget(f.fd); >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  328      if (IS_ERR(eventfp)) { >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  329          r = >> PTR_ERR(eventfp); >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  330          return r; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  331      } >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  332 >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  333      if (eventfp != >> vq->kick) { >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  334          pollstop = >> (filep = vq->kick) != NULL; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  335          pollstart = >> (vq->kick = eventfp) != NULL; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  336      } else >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  337          filep = eventfp; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  338 >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  339      if (pollstop && >> vq->handle_kick) >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  340 vhost_vdpa_poll_stop(vq); >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  341 >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  342      if (filep) >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  343 fput(filep); >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  344 >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  345      if (pollstart && >> vq->handle_kick) >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  346          r = >> vhost_vdpa_poll_start(vq); >> >> "r" not initialized on else path. >> >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  347 >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26 @348      return r; >> a84ddbf1ef29f1 Zhu Lingshan 2020-05-26  349  } > > > Will fix. > > Thanks Lingshan reminds me that we've posted V2 which reuses the vhost.c implementation for polling. So there's no need for the fix. Thanks