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From: Peter Zijlstra <peterz@infradead.org>
To: NeilBrown <neilb@suse.de>
Cc: Ingo Molnar <mingo@redhat.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jens Axboe <axboe@kernel.dk>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-block@vger.kernel.org
Subject: Re: [PATCH 2/7] sched: change wake_up_bit() and related function to expect unsigned long *
Date: Mon, 16 Sep 2024 13:28:10 +0200	[thread overview]
Message-ID: <20240916112810.GY4723@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20240826063659.15327-3-neilb@suse.de>

On Mon, Aug 26, 2024 at 04:30:59PM +1000, NeilBrown wrote:
> wake_up_bit() currently allows a "void *".  While this isn't strictly a
> problem as the address is never dereferenced, it is inconsistent with
> the corresponding wait_var_event() which requires "unsigned long *" and
> does dereference the pointer.

I'm having trouble parsing this. The way I read it, you're contradicting
yourself. Where does wait_var_event() require 'unsigned long *' ?

> And code that needs to wait for a change in something other than an
> unsigned long would be better served by wake_up_var().

This, afaict the whole var thing is size invariant. It only cares about
the address.

  reply	other threads:[~2024-09-16 11:28 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-26  6:30 [PATCH 0/7 v2 RFC] Make wake_up_{bit,var} less fragile NeilBrown
2024-08-26  6:30 ` [PATCH 1/7] block: change wait on bd_claiming to use a var_waitqueue, not a bit_waitqueue NeilBrown
2024-09-17  3:12   ` Jens Axboe
2024-09-17 21:54     ` NeilBrown
2024-09-17  3:13   ` (subset) " Jens Axboe
2024-08-26  6:30 ` [PATCH 2/7] sched: change wake_up_bit() and related function to expect unsigned long * NeilBrown
2024-09-16 11:28   ` Peter Zijlstra [this message]
2024-09-16 11:48     ` NeilBrown
2024-09-16 18:18       ` Peter Zijlstra
2024-09-16 20:37         ` NeilBrown
2024-08-26  6:31 ` [PATCH 3/7] sched: Improve documentation for wake_up_bit/wait_on_bit family of functions NeilBrown
2024-08-26  6:31 ` [PATCH 4/7] sched: Document wait_var_event() family of functions and wake_up_var() NeilBrown
2024-08-26  6:31 ` [PATCH 5/7] sched: Add test_and_clear_wake_up_bit() and atomic_dec_and_wake_up() NeilBrown
2024-08-26  6:31 ` [PATCH 6/7] sched: Add wait/wake interface for variable updated under a lock NeilBrown
2024-08-26  6:31 ` [PATCH 7/7] Block: switch bd_prepare_to_claim to use wait_var_event_mutex() NeilBrown
2024-09-15 23:52 ` [PATCH 0/7 v2 RFC] Make wake_up_{bit,var} less fragile NeilBrown

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