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From: "J. R. Okajima" <hooanon05g@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jens Axboe <axboe@fb.com>,
	linux-kernel@vger.kernel.org, darrick.wong@oracle.com,
	david@fromorbit.com
Subject: Re: Q: lockdep_assert_held_read() after downgrade_write()
Date: Fri, 03 Feb 2017 01:33:21 +0900	[thread overview]
Message-ID: <9485.1486053201@jrobl> (raw)
In-Reply-To: <20170131163253.GQ6515@twins.programming.kicks-ass.net>

Peter Zijlstra:
> Does something like the below work better? The annotation in
> downgrade_write() would look something like:
>
> +	lock_downgrade(&sem->dep_map, 1, _RET_IP_);
>
> Not even compile tested and lacks the !LOCKDEP build bits.

Thanks for the patch.
It seems working expectedly. I began writing a similar patch locally
with minor consolidations by adding a new function or two. I will send a
patch series. Please review and merge them into v4.10. If you don't like
the patch, especially the new function name, feel free to change it.
I don't know whether !LOCKDEP build bits are necessary or not.


J. R. Okajima

  reply	other threads:[~2017-02-02 16:33 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-30 21:25 Q: lockdep_assert_held_read() after downgrade_write() J. R. Okajima
2017-01-30 21:30 ` Jens Axboe
2017-01-31 10:36   ` Peter Zijlstra
2017-01-31 11:25     ` Peter Zijlstra
2017-01-31 14:23       ` Waiman Long
2017-01-31 14:26         ` Peter Zijlstra
2017-01-31 15:40   ` J. R. Okajima
2017-01-31 16:32     ` Peter Zijlstra
2017-02-02 16:33       ` J. R. Okajima [this message]
2017-02-02 16:38       ` [PATCH 1/3] lockdep: consolidate by new find_held_lock() J. R. Okajima
2017-02-02 16:38         ` [PATCH 2/3] lockdep: consolidate by new validate_held_lock() J. R. Okajima
2017-02-14 12:09           ` Peter Zijlstra
2017-03-16 11:25           ` [tip:locking/core] locking/lockdep: Factor out the validate_held_lock() helper function tip-bot for J. R. Okajima
2017-02-02 16:38         ` [PATCH 3/3] lockdep: new annotation lock_downgrade() J. R. Okajima
2017-02-02 17:59           ` kbuild test robot
2017-02-02 18:45             ` Peter Zijlstra
2017-02-02 21:05               ` J. R. Okajima
2017-02-14 12:11                 ` Peter Zijlstra
2017-03-16 11:25           ` [tip:locking/core] locking/lockdep: Add new check to lock_downgrade() tip-bot for J. R. Okajima
2017-03-16 11:24         ` [tip:locking/core] locking/lockdep: Factor out the find_held_lock() helper function tip-bot for J. R. Okajima

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