Bart Van Assche <bvanassche@xxxxxxx> 于2018年12月7日周五 上午12:22写道： > > On Wed, 2018-12-05 at 22:17 +0800, Weiping Zhang wrote: > > +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. > > Sorry but I think this description is still somewhat confusing. How about > changing that description into the following? > > io_timeout is the request timeout in milliseconds. If a request does not > complete in this time then the block driver timeout handler is invoked. > That timeout handler can decide to retry the request, to fail it or to > start a device recovery strategy. > Sorry for late reply, thanks for your suggestion I'll post it in V4. > Bart. >> > Is there a simple way do that ? >> >> How about checking the timeout member of struct blk_mq_ops for blk-mq and >> checking the rq_timed_out_fn member in struct request_queue for the legacy >> block layer? > >Just the former given that the legacy code is gone in for-next. > >> > Shall we return -ENOTSUPP when user read/write this attribute when > >> driver has no timeout handler ? > > > >A much more elegant solution is to introduce a sysfs attribute group for the > >io_timeout attribute and to make that group visible only if a timeout handler > >has been defined. See e.g. disk_attr_group in block/genhd.c for an example. > >Agreed, that is the way to go. OK, I'll do that. Thanks Weiping
