linux-kernel - Re: [PATCH v1 1/1] tty: Drop duplicate NULL check in TTY port functions

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Message-ID: <YfuxANmSQDfIQZO4@smile.fi.intel.com>
Date:   Thu, 3 Feb 2022 12:40:00 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Jiri Slaby <jirislaby@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/1] tty: Drop duplicate NULL check in TTY port
 functions

On Thu, Feb 03, 2022 at 09:36:55AM +0100, Jiri Slaby wrote:
> On 02. 02. 22, 17:57, Andy Shevchenko wrote:
> > The free_page(addr), which becomes free_pages(addr, 0) checks addr against 0.
> > No need to repeat this check in the callers, i.e.  tty_port_free_xmit_buf()
> > and tty_port_destructor().
> > 
> > Note, INIT_KFIFO() is safe without that check, because it's aware of kfifo PTR
> > versus embedded kfifo.
> 
> Not sure what you mean here ^^^? But it might be one of the morning brain
> parser errors.

Or maybe my evening weren't working...

Actually INIT_KFIFO() can be outside of that check from day 1 because it
operates on a separate member and does not rely on the FIFO itself to be
allocated.

I tried to explain that, while kfifo allocation goes together with buffer,
there is no dependency to any of those allocations.

-- 
With Best Regards,
Andy Shevchenko