netdev - Re: [PATCH] stmmac: call local_irq_save other than disable_irq in poll

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Date:	Tue, 05 May 2015 19:36:33 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	sonic.adi@...il.com
Cc:	peppe.cavallaro@...com, netdev@...r.kernel.org,
	adi-buildroot-devel@...ts.sourceforge.net, sonic.zhang@...log.com
Subject: Re: [PATCH] stmmac: call local_irq_save other than disable_irq in
 poll_controller

From: Sonic Zhang <sonic.adi@...il.com>
Date: Tue, 5 May 2015 15:55:53 +0800

> From: Sonic Zhang <sonic.zhang@...log.com>
> 
> It is possible that poll_controller is called from netpoll.c with irq
> already disabled. Unexpected interrupt may be triggered if always
> enable irq before returning from poll_controller.
> 
> Signed-off-by: Sonic Zhang <sonic.zhang@...log.com>

Nope, this is wrong.

If you don't use disable_irq(), the interrupt handler can run in
parallel on another cpu and you definitely do not want that.

There is nothing wrong with the interrupt triggering on the
enable_irq() here.  If that causes some problem, there is a
bug in this driver.
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