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From: Ingo Molnar <mingo@kernel.org>
To: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: peterz@infradead.org, mingo@redhat.com, will@kernel.org,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] kernel/locking: make __down_common use flags previously saved
Date: Wed, 12 May 2021 21:09:34 +0200	[thread overview]
Message-ID: <YJwn7qb3/ekFBWDF@gmail.com> (raw)
In-Reply-To: <20210424142823.3896-1-42.hyeyoo@gmail.com>


* Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:

> down, down_interruptible, down_killable, and down_timeout
> call raw_spin_lock_irqsave that saves current status to flags.
> 
> but in __down_common, that is called by functions above, calls
> raw_spin_lock_irq and raw_spin_unlock_irq regardless of flags previously saved.

Yes, this is intentional, because if we get into __down_common() we have to 
schedule, so we have to enable interrupts.

> this mismatch can potentially cause problem.

What problems?

Thanks,

	Ingo

  parent reply	other threads:[~2021-05-12 20:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-24 14:28 [PATCH] kernel/locking: make __down_common use flags previously saved Hyeonggon Yoo
2021-05-11  2:23 ` Hyeonggon Yoo
2021-05-12 19:09 ` Ingo Molnar [this message]
2021-05-17 14:36   ` Hyeonggon Yoo

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