Weiping Zhang <zwp10758@xxxxxxxxx> 于2018年12月5日周三 下午10:49写道：
>
> Christoph Hellwig <hch@xxxxxxxxxxxxx> 于2018年12月5日周三 下午10:40写道：
> >
> > Can you please also send a patch to not show this attribute for
> > drivers without a timeout handler? Thanks!
> >
Is there a simple way do that ?
Shall we return -ENOTSUPP when user read/write this attribute when
driver has no timeout handler ?
> Do you means checking q->mq_ops->timeout is NULL or not ?
>
> static void blk_mq_rq_timed_out(struct request *req, bool reserved)
> {
> req->rq_flags |= RQF_TIMED_OUT;
> If it's NULL, only re-start a timer for this request in blk_add_timer.
> Is there some defect ? if show this attribute and the driver doesn't
> support timeout handler ？
>
> if (req->q->mq_ops->timeout) {
> enum blk_eh_timer_return ret;
>
> ret = req->q->mq_ops->timeout(req, reserved);
> if (ret == BLK_EH_DONE)
> return;
> WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
> }
>
> blk_add_timer(req);
> }
>
>
> > On Wed, Dec 05, 2018 at 10:17:06PM +0800, Weiping Zhang wrote:
> > > Add documentation for /sys/block/<disk>/queue/io_timeout.
> > >
> > > Signed-off-by: Weiping Zhang <zhangweiping@xxxxxxxxxxxxxx>
> > > ---
> > > Documentation/ABI/testing/sysfs-block | 10 ++++++++++
> > > Documentation/block/queue-sysfs.txt | 7 +++++++
> > > 2 files changed, 17 insertions(+)
> > >
> > > diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
> > > index dea212db9df3..f254a374710a 100644
> > > --- a/Documentation/ABI/testing/sysfs-block
> > > +++ b/Documentation/ABI/testing/sysfs-block
> > > @@ -271,3 +271,13 @@ Description:
> > > size of 512B sectors of the zones of the device, with
> > > the eventual exception of the last zone of the device
> > > which may be smaller.
> > > +
> > > +What: /sys/block/<disk>/queue/io_timeout
> > > +Date: November 2018
> > > +Contact: Weiping Zhang <zhangweiping@xxxxxxxxxxxxxx>
> > > +Description:
> > > + io_timeout is a request’s timeouts at block layer in
> > > + milliseconds. When the underlying driver starts processing
> > > + a request, the generic block layer will start a timer, if
> > > + this request cannot be completed in io_timeout milliseconds,
> > > + a timeout event will occur.
> > > diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt
> > > index 2c1e67058fd3..f0c9bbce73fd 100644
> > > --- a/Documentation/block/queue-sysfs.txt
> > > +++ b/Documentation/block/queue-sysfs.txt
> > > @@ -67,6 +67,13 @@ If set to a value larger than 0, the kernel will put the process issuing
> > > IO to sleep for this amont of microseconds before entering classic
> > > polling.
> > >
> > > +io_timeout (RW)
> > > +---------------
> > > +This is a request’s timeouts at block layer in milliseconds. When the
> > > +underlying driver starts processing a request, the generic block layer
> > > +will start a timer, if this request cannot be completed in io_timeout
> > > +milliseconds, a timeout event will occur.
> > > +
> > > iostats (RW)
> > > -------------
> > > This file is used to control (on/off) the iostats accounting of the
> > > --
> > > 2.14.1
> > >
> > ---end quoted text---
