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[73.238.82.198]) by smtp.gmail.com with ESMTPSA id p15sm4676553qta.81.2019.03.04.11.25.33 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 04 Mar 2019 11:25:34 -0800 (PST) Date: Mon, 4 Mar 2019 14:25:31 -0500 From: "Michael S. Tsirkin" To: Pankaj Gupta Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, amit@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org, xiaohli@redhat.com Subject: Re: [PATCH] virtio_console: free unused buffers with virtio port Message-ID: <20190304142506-mutt-send-email-mst@kernel.org> References: <20190304130511.14450-1-pagupta@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190304130511.14450-1-pagupta@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 04, 2019 at 06:35:11PM +0530, Pankaj Gupta wrote: > The commit a7a69ec0d8e4 ("virtio_console: free buffers after reset") > deffered detaching of unused buffer to virtio device unplug time. > > This causes unplug/replug of single port in virtio device with an > error "Error allocating inbufs\n". As we don't free the unused buffers > attached with the port. Re-plug the same port tries to allocate new > buffers in virtqueue and results in this error if queue is full. > > This patch removes the unused buffers in vq's when we unplug the port. > This is the best we can do as we cannot call device_reset because virtio > device is still active. This was the working behaviour before the change > introduced in commit b3258ff1d6. > > Reported-by: Xiaohui Li > Fixes: b3258ff1d6 ("virtio_console: free buffers after reset") > Signed-off-by: Pankaj Gupta I think if you do this you need to add support in the packed ring. > --- > drivers/char/virtio_console.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index fbeb71953526..5fbf2ac73111 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -1506,15 +1506,25 @@ static void remove_port(struct kref *kref) > kfree(port); > } > > +static void remove_unused_bufs(struct virtqueue *vq) > +{ > + struct port_buffer *buf; > + > + while ((buf = virtqueue_detach_unused_buf(vq))) > + free_buf(buf, true); > +} > + > static void remove_port_data(struct port *port) > { > spin_lock_irq(&port->inbuf_lock); > /* Remove unused data this port might have received. */ > discard_port_data(port); > + remove_unused_bufs(port->in_vq); > spin_unlock_irq(&port->inbuf_lock); > > spin_lock_irq(&port->outvq_lock); > reclaim_consumed_buffers(port); > + remove_unused_bufs(port->out_vq); > spin_unlock_irq(&port->outvq_lock); > } > > @@ -1950,11 +1960,9 @@ static void remove_vqs(struct ports_device *portdev) > struct virtqueue *vq; > > virtio_device_for_each_vq(portdev->vdev, vq) { > - struct port_buffer *buf; > > flush_bufs(vq, true); > - while ((buf = virtqueue_detach_unused_buf(vq))) > - free_buf(buf, true); > + remove_unused_bufs(vq); > } > portdev->vdev->config->del_vqs(portdev->vdev); > kfree(portdev->in_vqs); > -- > 2.20.1