Date: Thu, 6 Jun 2013 22:22:23 +0800
From: Wang YanQing <udknight@gmail.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: gregkh@linuxfoundation.org, sfr@canb.auug.org.au,
        linux-next@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] TTY:vt: convert remain take_over_console's users to
 do_take_over_console
Message-ID: <20130606142223.GA4237@udknight>
Mail-Followup-To: Wang YanQing <udknight@gmail.com>,
	Pavel Machek <pavel@ucw.cz>, gregkh@linuxfoundation.org,
	sfr@canb.auug.org.au, linux-next@vger.kernel.org,
	linux-kernel@vger.kernel.org
References: <20130521051511.GA11435@udknight>
 <20130604201317.GA16303@amd.pavel.ucw.cz>
 <20130606012312.GA2001@udknight>
 <20130606114746.GA3659@amd.pavel.ucw.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20130606114746.GA3659@amd.pavel.ucw.cz>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1867
Lines: 49

On Thu, Jun 06, 2013 at 01:47:46PM +0200, Pavel Machek wrote:
> On Thu 2013-06-06 09:23:13, Wang YanQing wrote:
> > On Tue, Jun 04, 2013 at 10:13:18PM +0200, Pavel Machek wrote:
> > > On Tue 2013-05-21 13:15:12, Wang YanQing wrote:
> > > > Impact:
> > > > 1:convert all remain take_over_console to do_take_over_console
> > > 
> > > This is step backwards.
> > 
> > What is step backwards? do_take_over_console appear MUCH MUCH later in kernel
> > than take_over_console, do_take_over_console is the new API, I can't understand
> > what is step backwards.
> 
> "do_*" is internal api, "*" is external api. You sprinkle internal api
> all over the place.
> 

internal vs external? No, they only have one difference, callee vs caller hold
the console lock.

> > > > --- a/arch/alpha/kernel/console.c
> > > > +++ b/arch/alpha/kernel/console.c
> > > > @@ -61,7 +61,9 @@ locate_and_init_vga(void *(*sel_func)(void *, void *))
> > > >  
> > > >  	/* Set the VGA hose and init the new console. */
> > > >  	pci_vga_hose = hose;
> > > > -	take_over_console(&vga_con, 0, MAX_NR_CONSOLES-1, 1);
> > > > +	console_lock();
> > > > +	do_take_over_console(&vga_con, 0, MAX_NR_CONSOLES-1, 1);
> > > > +	console_unlock();
> > > >  }
> > > 
> > > Original was better.
> > 
> > Except reduce some console_lock/unlock scatter scattered in kernel, I 
> > can't see the "BETTER", and it is not a BIG problem for the benefit to
> > unify the API.
> 
> You replaced "calling exported function" with "calling
> internal-sounding function and adding locking too".

do_take_over_console is also exported by:

EXPORT_SYMBOL_GPL(do_take_over_console)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/