From: "Michael S. Tsirkin" <mst@redhat.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>,
"Enrico Weigelt, metux IT consult" <info@metux.net>,
Viresh Kumar <vireshk@kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
kernel@axis.com, Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
virtualization@lists.linux-foundation.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] gpio: virtio: remove timeout
Date: Mon, 20 Dec 2021 10:35:08 -0500 [thread overview]
Message-ID: <20211220103435-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CAMRc=MeEnSvSxQe-DdLSujSLpzxa-bacJ590BW+tt8awAJq3_w@mail.gmail.com>
On Mon, Dec 20, 2021 at 03:54:56PM +0100, Bartosz Golaszewski wrote:
> On Mon, Dec 20, 2021 at 2:07 PM Vincent Whitchurch
> <vincent.whitchurch@axis.com> wrote:
> >
> > The driver imposes an arbitrary one second timeout on virtio requests,
> > but the specification doesn't prevent the virtio device from taking
> > longer to process requests, so remove this timeout to support all
> > systems and device implementations.
> >
> > Fixes: 3a29355a22c0275fe86 ("gpio: Add virtio-gpio driver")
> > Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
> > ---
> > drivers/gpio/gpio-virtio.c | 6 +-----
> > 1 file changed, 1 insertion(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-virtio.c b/drivers/gpio/gpio-virtio.c
> > index 84f96b78f32a..9f4941bc5760 100644
> > --- a/drivers/gpio/gpio-virtio.c
> > +++ b/drivers/gpio/gpio-virtio.c
> > @@ -100,11 +100,7 @@ static int _virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio,
> > virtqueue_kick(vgpio->request_vq);
> > mutex_unlock(&vgpio->lock);
> >
> > - if (!wait_for_completion_timeout(&line->completion, HZ)) {
> > - dev_err(dev, "GPIO operation timed out\n");
> > - ret = -ETIMEDOUT;
> > - goto out;
> > - }
> > + wait_for_completion(&line->completion);
> >
> > if (unlikely(res->status != VIRTIO_GPIO_STATUS_OK)) {
> > dev_err(dev, "GPIO request failed: %d\n", gpio);
> > --
> > 2.33.1
> >
>
> My knowledge of virtio is limited, I hope this is not a stupid question.
>
> Does this mean the operation can get stuck indefinitely?
>
> Bart
Only if the device is broken. which given it's part of the
hypervisor, is par for the course.
--
MST
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
Viresh Kumar <vireshk@kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Vincent Whitchurch <vincent.whitchurch@axis.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
virtualization@lists.linux-foundation.org,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
kernel@axis.com, Viresh Kumar <viresh.kumar@linaro.org>,
"Enrico Weigelt, metux IT consult" <info@metux.net>
Subject: Re: [PATCH] gpio: virtio: remove timeout
Date: Mon, 20 Dec 2021 10:35:08 -0500 [thread overview]
Message-ID: <20211220103435-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CAMRc=MeEnSvSxQe-DdLSujSLpzxa-bacJ590BW+tt8awAJq3_w@mail.gmail.com>
On Mon, Dec 20, 2021 at 03:54:56PM +0100, Bartosz Golaszewski wrote:
> On Mon, Dec 20, 2021 at 2:07 PM Vincent Whitchurch
> <vincent.whitchurch@axis.com> wrote:
> >
> > The driver imposes an arbitrary one second timeout on virtio requests,
> > but the specification doesn't prevent the virtio device from taking
> > longer to process requests, so remove this timeout to support all
> > systems and device implementations.
> >
> > Fixes: 3a29355a22c0275fe86 ("gpio: Add virtio-gpio driver")
> > Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
> > ---
> > drivers/gpio/gpio-virtio.c | 6 +-----
> > 1 file changed, 1 insertion(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-virtio.c b/drivers/gpio/gpio-virtio.c
> > index 84f96b78f32a..9f4941bc5760 100644
> > --- a/drivers/gpio/gpio-virtio.c
> > +++ b/drivers/gpio/gpio-virtio.c
> > @@ -100,11 +100,7 @@ static int _virtio_gpio_req(struct virtio_gpio *vgpio, u16 type, u16 gpio,
> > virtqueue_kick(vgpio->request_vq);
> > mutex_unlock(&vgpio->lock);
> >
> > - if (!wait_for_completion_timeout(&line->completion, HZ)) {
> > - dev_err(dev, "GPIO operation timed out\n");
> > - ret = -ETIMEDOUT;
> > - goto out;
> > - }
> > + wait_for_completion(&line->completion);
> >
> > if (unlikely(res->status != VIRTIO_GPIO_STATUS_OK)) {
> > dev_err(dev, "GPIO request failed: %d\n", gpio);
> > --
> > 2.33.1
> >
>
> My knowledge of virtio is limited, I hope this is not a stupid question.
>
> Does this mean the operation can get stuck indefinitely?
>
> Bart
Only if the device is broken. which given it's part of the
hypervisor, is par for the course.
--
MST
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Virtualization@lists.linux-foundation.org
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next prev parent reply other threads:[~2021-12-20 15:35 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-20 13:06 [PATCH] gpio: virtio: remove timeout Vincent Whitchurch
2021-12-20 13:06 ` Vincent Whitchurch
2021-12-20 14:54 ` Bartosz Golaszewski
2021-12-20 15:35 ` Michael S. Tsirkin [this message]
2021-12-20 15:35 ` Michael S. Tsirkin
2021-12-20 15:35 ` Michael S. Tsirkin
2021-12-20 15:35 ` Michael S. Tsirkin
2021-12-21 4:26 ` Viresh Kumar
2021-12-21 4:26 ` Viresh Kumar
2021-12-21 15:23 ` Bartosz Golaszewski
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