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* Re: [nfsd:nfsd-next 5/23] net/sunrpc/svc_xprt.c:794:20: error: 'current_task' undeclared
       [not found] <53f0db34.mtq2J6NaXWKpR15G%fengguang.wu@intel.com>
@ 2014-08-18 16:18 ` J. Bruce Fields
  2014-08-20 22:33   ` Trond Myklebust
  0 siblings, 1 reply; 3+ messages in thread
From: J. Bruce Fields @ 2014-08-18 16:18 UTC (permalink / raw)
  To: kbuild test robot; +Cc: Trond Myklebust, J. Bruce Fields, kbuild-all, linux-nfs

On Mon, Aug 18, 2014 at 12:41:24AM +0800, kbuild test robot wrote:
> tree:   git://linux-nfs.org/~bfields/linux.git nfsd-next
> head:   da8b8f7602ed3b8105c6247a2844455fec72caaa
> commit: 983c684466e02b21f83c025ea539deee6c0aeac0 [5/23] SUNRPC: get rid of the request wait queue
> config: make ARCH=xtensa allyesconfig
> 
> All error/warnings:
> 
>    net/sunrpc/svc_xprt.c: In function 'svc_recv':
> >> net/sunrpc/svc_xprt.c:794:20: error: 'current_task' undeclared (first use in this function)
>       rqstp->rq_task = current_task;
>                        ^
>    net/sunrpc/svc_xprt.c:794:20: note: each undeclared identifier is reported only once for each function it appears in
> 
> vim +/current_task +794 net/sunrpc/svc_xprt.c
> 
>    788			printk(KERN_ERR
>    789				"svc_recv: service %p, transport not NULL!\n",
>    790				 rqstp);
>    791	
>    792		/* Make sure the task pointer is set! */
>    793		if (WARN_ON_ONCE(!rqstp->rq_task))
>  > 794			rqstp->rq_task = current_task;

I appreciate the effort to fail gracefully here, but maybe this would be
a case for simple BUG_ON()?

I don't think there are normally any important locks held here, and I
can't see any other reason why killing a server thread would bring a box
down.

And the first developer to forget to set rq_task on a newly created
server will get an immediate bug, so this should be obvious enough.
Unless there's fear of a race between starting the thread and setting
rq_task?

--b.

>    795	
>    796		err = svc_alloc_arg(rqstp);
>    797		if (err)
> 
> ---
> 0-DAY kernel build testing backend              Open Source Technology Center
> http://lists.01.org/mailman/listinfo/kbuild                 Intel Corporation

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [nfsd:nfsd-next 5/23] net/sunrpc/svc_xprt.c:794:20: error: 'current_task' undeclared
  2014-08-18 16:18 ` [nfsd:nfsd-next 5/23] net/sunrpc/svc_xprt.c:794:20: error: 'current_task' undeclared J. Bruce Fields
@ 2014-08-20 22:33   ` Trond Myklebust
  2014-08-28 19:52     ` J. Bruce Fields
  0 siblings, 1 reply; 3+ messages in thread
From: Trond Myklebust @ 2014-08-20 22:33 UTC (permalink / raw)
  To: J. Bruce Fields
  Cc: kbuild test robot, J. Bruce Fields, kbuild-all,
	Linux NFS Mailing List

On Mon, Aug 18, 2014 at 12:18 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> On Mon, Aug 18, 2014 at 12:41:24AM +0800, kbuild test robot wrote:
>> tree:   git://linux-nfs.org/~bfields/linux.git nfsd-next
>> head:   da8b8f7602ed3b8105c6247a2844455fec72caaa
>> commit: 983c684466e02b21f83c025ea539deee6c0aeac0 [5/23] SUNRPC: get rid of the request wait queue
>> config: make ARCH=xtensa allyesconfig
>>
>> All error/warnings:
>>
>>    net/sunrpc/svc_xprt.c: In function 'svc_recv':
>> >> net/sunrpc/svc_xprt.c:794:20: error: 'current_task' undeclared (first use in this function)
>>       rqstp->rq_task = current_task;
>>                        ^
>>    net/sunrpc/svc_xprt.c:794:20: note: each undeclared identifier is reported only once for each function it appears in
>>
>> vim +/current_task +794 net/sunrpc/svc_xprt.c
>>
>>    788                        printk(KERN_ERR
>>    789                                "svc_recv: service %p, transport not NULL!\n",
>>    790                                 rqstp);
>>    791
>>    792                /* Make sure the task pointer is set! */
>>    793                if (WARN_ON_ONCE(!rqstp->rq_task))
>>  > 794                        rqstp->rq_task = current_task;
>
> I appreciate the effort to fail gracefully here, but maybe this would be
> a case for simple BUG_ON()?
>
> I don't think there are normally any important locks held here, and I
> can't see any other reason why killing a server thread would bring a box
> down.
>
> And the first developer to forget to set rq_task on a newly created
> server will get an immediate bug, so this should be obvious enough.
> Unless there's fear of a race between starting the thread and setting
> rq_task?
>

No, there is no fear of a race. I'm fine with removing the above check
altogether and just letting code Oops if it turns out that we add new
cases that don't set rq_task.

Ultimately, though, I think we need a better interface for starting
RPC server threads; something that combines svc_prepare_thread() and
kthread_run() into a single function call and that can thus set
rqstp->rq_task correctly.


-- 
Trond Myklebust

Linux NFS client maintainer, PrimaryData

trond.myklebust@primarydata.com

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [nfsd:nfsd-next 5/23] net/sunrpc/svc_xprt.c:794:20: error: 'current_task' undeclared
  2014-08-20 22:33   ` Trond Myklebust
@ 2014-08-28 19:52     ` J. Bruce Fields
  0 siblings, 0 replies; 3+ messages in thread
From: J. Bruce Fields @ 2014-08-28 19:52 UTC (permalink / raw)
  To: Trond Myklebust
  Cc: kbuild test robot, J. Bruce Fields, kbuild-all,
	Linux NFS Mailing List

On Wed, Aug 20, 2014 at 06:33:06PM -0400, Trond Myklebust wrote:
> On Mon, Aug 18, 2014 at 12:18 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> > On Mon, Aug 18, 2014 at 12:41:24AM +0800, kbuild test robot wrote:
> >> tree:   git://linux-nfs.org/~bfields/linux.git nfsd-next
> >> head:   da8b8f7602ed3b8105c6247a2844455fec72caaa
> >> commit: 983c684466e02b21f83c025ea539deee6c0aeac0 [5/23] SUNRPC: get rid of the request wait queue
> >> config: make ARCH=xtensa allyesconfig
> >>
> >> All error/warnings:
> >>
> >>    net/sunrpc/svc_xprt.c: In function 'svc_recv':
> >> >> net/sunrpc/svc_xprt.c:794:20: error: 'current_task' undeclared (first use in this function)
> >>       rqstp->rq_task = current_task;
> >>                        ^
> >>    net/sunrpc/svc_xprt.c:794:20: note: each undeclared identifier is reported only once for each function it appears in
> >>
> >> vim +/current_task +794 net/sunrpc/svc_xprt.c
> >>
> >>    788                        printk(KERN_ERR
> >>    789                                "svc_recv: service %p, transport not NULL!\n",
> >>    790                                 rqstp);
> >>    791
> >>    792                /* Make sure the task pointer is set! */
> >>    793                if (WARN_ON_ONCE(!rqstp->rq_task))
> >>  > 794                        rqstp->rq_task = current_task;
> >
> > I appreciate the effort to fail gracefully here, but maybe this would be
> > a case for simple BUG_ON()?
> >
> > I don't think there are normally any important locks held here, and I
> > can't see any other reason why killing a server thread would bring a box
> > down.
> >
> > And the first developer to forget to set rq_task on a newly created
> > server will get an immediate bug, so this should be obvious enough.
> > Unless there's fear of a race between starting the thread and setting
> > rq_task?
> 
> No, there is no fear of a race. I'm fine with removing the above check
> altogether and just letting code Oops if it turns out that we add new
> cases that don't set rq_task.

OK, I'll remove it entirely.

> Ultimately, though, I think we need a better interface for starting
> RPC server threads; something that combines svc_prepare_thread() and
> kthread_run() into a single function call and that can thus set
> rqstp->rq_task correctly.

Sounds good.

--b.

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2014-08-28 19:52 UTC | newest]

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     [not found] <53f0db34.mtq2J6NaXWKpR15G%fengguang.wu@intel.com>
2014-08-18 16:18 ` [nfsd:nfsd-next 5/23] net/sunrpc/svc_xprt.c:794:20: error: 'current_task' undeclared J. Bruce Fields
2014-08-20 22:33   ` Trond Myklebust
2014-08-28 19:52     ` J. Bruce Fields

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