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From: David Howells <dhowells@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: dhowells@redhat.com, linux-afs@lists.infradead.org,
	linux-fsdevel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return functions
Date: Fri, 01 Sep 2017 22:15:39 +0100	[thread overview]
Message-ID: <3696.1504300539@warthog.procyon.org.uk> (raw)
In-Reply-To: <20170901164233.wu4fdljpivzf5idb@hirez.programming.kicks-ass.net>

Peter Zijlstra <peterz@infradead.org> wrote:

> > 	unsigned int refcount_dec_return(refcount_t *r);
> > 	unsigned int refcount_inc_return(refcount_t *r);
> > 
> 
> I'm not immediately seeing how wanting 1 to mean unused leads to
> requiring these two functions.

Did you read the other other part of the description?

	Further, both functions can be used to accurately trace the refcount
	(refcount_inc() followed by refcount_read() can't be considered
	accurate).

> If you'll remember, I did that for inode_count and only needed
> dec_unless().

I don't remember.  inode_count?  I can't find such a thing - did you mean
i_count?  I don't find anything matching "dec_unless.*i_count" either.

David

  parent reply	other threads:[~2017-09-01 21:15 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-01 15:40 [RFC PATCH 01/11] workqueue: Add a decrement-after-return and wake if 0 facility David Howells
2017-09-01 15:41 ` [RFC PATCH 02/11] refcount: Implement inc/decrement-and-return functions David Howells
2017-09-01 16:42   ` Peter Zijlstra
2017-09-01 21:15   ` David Howells [this message]
2017-09-01 21:50     ` Peter Zijlstra
2017-09-01 22:03       ` Peter Zijlstra
2017-09-01 22:51     ` David Howells
2017-09-04  7:30       ` Peter Zijlstra
2017-09-04 15:36   ` Christoph Hellwig
2017-09-04 16:08   ` David Howells
2017-09-05  6:45     ` Christoph Hellwig
2017-09-01 15:41 ` [RFC PATCH 03/11] Pass mode to wait_on_atomic_t() action funcs and provide default actions David Howells
2017-09-01 15:41 ` [RFC PATCH 04/11] Add a function to start/reduce a timer David Howells
2017-10-20 12:20   ` Thomas Gleixner
2017-11-09  0:33   ` David Howells
2017-09-01 15:41 ` [RFC PATCH 05/11] afs: Lay the groundwork for supporting network namespaces David Howells
2017-09-01 15:41 ` [RFC PATCH 06/11] afs: Add some protocol defs David Howells
2017-09-01 15:41 ` [RFC PATCH 07/11] afs: Update the cache index structure David Howells
2017-09-01 15:41 ` [RFC PATCH 08/11] afs: Keep and pass sockaddr_rxrpc addresses rather than in_addr David Howells
2017-09-01 15:41 ` [RFC PATCH 09/11] afs: Allow IPv6 address specification of VL servers David Howells
2017-09-01 15:42 ` [RFC PATCH 10/11] afs: Overhaul cell database management David Howells
2017-09-01 15:42 ` [RFC PATCH 11/11] afs: Retry rxrpc calls with address rotation on network error David Howells
2017-09-01 15:52 ` [RFC PATCH 00/11] AFS: Namespacing part 1 David Howells
2017-09-05 13:29 ` [RFC PATCH 01/11] workqueue: Add a decrement-after-return and wake if 0 facility Tejun Heo
2017-09-05 14:50 ` David Howells
2017-09-06 14:51   ` Tejun Heo

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