From: Peter Zijlstra <peterz@infradead.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
Ingo Molnar <mingo@redhat.com>,
linux-mm@kvack.org, Shaohua Li <shli@kernel.org>,
linux-raid@vger.kernel.org
Subject: Re: Introduce atomic_dec_and_lock_irqsave()
Date: Fri, 4 May 2018 18:38:26 +0200 [thread overview]
Message-ID: <20180504163826.GR12217@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180504162640.GH30522@ZenIV.linux.org.uk>
On Fri, May 04, 2018 at 05:26:40PM +0100, Al Viro wrote:
> On Fri, May 04, 2018 at 06:21:02PM +0200, Peter Zijlstra wrote:
> > On Fri, May 04, 2018 at 06:07:26PM +0200, Sebastian Andrzej Siewior wrote:
> >
> > > do you intend to kill refcount_dec_and_lock() in the longterm?
> >
> > You meant to say atomic_dec_and_lock() ? Dunno if we ever get there, but
> > typically dec_and_lock is fairly refcounty, but I suppose it is possible
> > to have !refcount users, in which case we're eternally stuck with it.
>
> Yes, there are - consider e.g.
>
> void iput(struct inode *inode)
> {
> if (!inode)
> return;
> BUG_ON(inode->i_state & I_CLEAR);
> retry:
> if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) {
>
> inode->i_count sure as hell isn't refcount_t fodder...
Yeah, I should've remembered, I tried to convert that once ;-) i_count is
a usage count, not a refcount.
next prev parent reply other threads:[~2018-05-04 16:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-04 15:45 Introduce atomic_dec_and_lock_irqsave() Sebastian Andrzej Siewior
2018-05-04 15:45 ` [PATCH 1/5] spinlock: atomic_dec_and_lock: Add an irqsave variant Sebastian Andrzej Siewior
2018-06-04 10:25 ` [PATCH 1/5 v2] " Sebastian Andrzej Siewior
2018-05-04 15:45 ` [PATCH 2/5] mm/backing-dev: Use irqsave variant of atomic_dec_and_lock() Sebastian Andrzej Siewior
2018-05-04 15:45 ` [PATCH 3/5] kernel/user: " Sebastian Andrzej Siewior
2018-05-04 15:45 ` [PATCH 4/5] drivers/md/raid5: " Sebastian Andrzej Siewior
2018-05-04 15:45 ` [PATCH 5/5] drivers/md/raid5: Do not disable irq on release_inactive_stripe_list() call Sebastian Andrzej Siewior
2018-05-04 15:54 ` Introduce atomic_dec_and_lock_irqsave() Peter Zijlstra
2018-05-04 16:07 ` Sebastian Andrzej Siewior
2018-05-04 16:21 ` Peter Zijlstra
2018-05-04 16:26 ` Al Viro
2018-05-04 16:38 ` Peter Zijlstra [this message]
2018-05-23 13:02 ` Peter Zijlstra
2018-05-30 9:26 ` Sebastian Andrzej Siewior
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