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From: Greg KH <gregkh@linuxfoundation.org>
To: tuo cao <91tuocao@gmail.com>
Cc: alcooperx@gmail.com, bcm-kernel-feedback-list@broadcom.com,
	jirislaby@kernel.org, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RESEND] serial: 8250_bcm7271: move spin_lock_irqsave to spin_lock in interrupt handler
Date: Tue, 30 Aug 2022 13:35:07 +0200	[thread overview]
Message-ID: <Yw316/3zuIXvm/Ty@kroah.com> (raw)
In-Reply-To: <CAEVeK2AiYFK9eopn1Uzp+osA-j22e1KbfUohJ+hRVmLNsq0gpQ@mail.gmail.com>

On Sat, Aug 27, 2022 at 05:42:19PM +0800, tuo cao wrote:
> No, whether it's spin_lock_irqsave() or spin_lock(), the security is
> the same. Since this commit:e58aa3d2d0cc01ad8d6f7f640a0670433f794922,
> interrupt nesting is disabled, which means interrupts has disabled in
> the interrupt handlers. So, it is unnecessary to call
> spin_lock_irqsave in a interrupt handler. And it takes less time
> obviously to use spin_lock()，so I think this change is needed.

I have no context at all here, please never top-post :(

And have you measured the time difference?  Is it a real thing?

> Finally, I'm sorry I lacked real hardware to verify it and can't
> provide changelog text.

Try to never do changes for drivers for functionality like this where
you do not have the hardware to test for, until you get a lot more
experience.

good luck!

greg k-h

  reply	other threads:[~2022-08-30 11:38 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-22 14:11 [RESEND] serial: 8250_bcm7271: move spin_lock_irqsave to spin_lock in interrupt handler Tuo Cao
2022-08-22 14:25 ` Greg KH
2022-08-27  9:42   ` tuo cao
2022-08-30 11:35     ` Greg KH [this message]
2022-09-04  8:48       ` tuo cao
2022-09-04 13:10         ` Greg KH

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