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From: Andreas Dilger <adilger@dilger.ca>
To: Ingo Molnar <mingo@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Jason Baron <jbaron@akamai.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] epoll: use the waitqueue lock to protect ep->wq
Date: Wed, 6 Dec 2017 19:38:48 -0700	[thread overview]
Message-ID: <7AFB0C38-3D2E-45E8-9092-CA424BFD32B6@dilger.ca> (raw)
In-Reply-To: <20171207004914.lxu2dz6cmxgnrou3@gmail.com>

> On Dec 6, 2017, at 17:49, Ingo Molnar <mingo@kernel.org> wrote:
> 
> This exposes some waitqueue internals, but AFAICS the FUSE code already does a 
> similar trick with fiq->waitq.lock so there's precedent.

What about waitqueue_lock() and waitqueue_unlock() helpers that
lock and unlock, to avoid exposing the internals?  Or would that add
confusion by making users think they need their own waitqueue locking?

Alternately, a helper that returns the pointer to the lock:

#define waitqueue_lockp(wq) &((wq)->lock)

Used like the following:
        spin_lock_irqsave(waitqueue_lockp(&ep->wq), flags);

Cheers, Andreas

  reply	other threads:[~2017-12-07  2:38 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-06 23:52 waitqueue lockdep annotation Christoph Hellwig
2017-12-06 23:52 ` [PATCH 1/2] epoll: use the waitqueue lock to protect ep->wq Christoph Hellwig
2017-12-07  0:49   ` Ingo Molnar
2017-12-07  2:38     ` Andreas Dilger [this message]
2017-12-07  6:12       ` Ingo Molnar
2017-12-14 13:06     ` Christoph Hellwig
2017-12-07 16:09   ` Jason Baron
2017-12-14 13:05     ` Christoph Hellwig
2017-12-06 23:52 ` [PATCH 2/2] sched/wait: assert the wait_queue_head lock is held in __wake_up_common Christoph Hellwig
2017-12-07  0:50   ` Ingo Molnar
2017-12-14 13:08     ` Christoph Hellwig

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