netdev - Re: [PATCH v5] bfin_mac: convert bfin Ethernet driver to NAPI framework

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Message-ID: <20140717222906.GA23125@electric-eye.fr.zoreil.com>
Date:	Fri, 18 Jul 2014 00:29:06 +0200
From:	Francois Romieu <romieu@...zoreil.com>
To:	Sonic Zhang <sonic.adi@...il.com>
Cc:	David Miller <davem@...emloft.net>,
	Eric Dumazet <eric.dumazet@...il.com>,
	netdev <netdev@...r.kernel.org>,
	Varka Bhadram <varkabhadram@...il.com>,
	adi-buildroot-devel@...ts.sourceforge.net,
	"Zhang, Sonic" <sonic.zhang@...log.com>
Subject: Re: [PATCH v5] bfin_mac: convert bfin Ethernet driver to NAPI
 framework

Sonic Zhang <sonic.adi@...il.com> :
> On Thu, Jul 17, 2014 at 5:03 AM, David Miller <davem@...emloft.net> wrote:
[...]
> > Please mimick what other drivers do rather than trying to do things in
> > a special way unique to your driver.
> 
> Driver realtek/8139cp.c does things in the same way as the bfin_mac
> NAPI code.

It wasn't your lucky day.

> In net_poll loop, if napi_complete() is called, the EMAC IRQ is
> enabled more times than the it is disabled. This is not a problem to
> drivers which don't call enable_irq()/disable_irq_nosync(). But, the
> IRQ enabling and disabling operations have to be balanced in the
> bfin_mac driver via __napi_complete() to avoid the kernel warning.

Thanks for the explanation.

In order to use plain napi_complete, may I suggest keeping a mask of
bfin_mac_interrupt disabled irq in the device private area then
enable_irq relevant one - if any - in bfin_mac_poll ?

It should keep things balanced.

-- 
Ueimor
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