linux-kernel - Re: [PATCH v3 4/5] serial: sc16is7xx: split into core and I2C/SPI parts (sc16is7xx

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Date: Tue, 2 Apr 2024 15:51:15 -0400
From: Hugo Villeneuve <hugo@...ovil.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: gregkh@...uxfoundation.org, jirislaby@...nel.org,
 linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org, Hugo Villeneuve
 <hvilleneuve@...onoff.com>
Subject: Re: [PATCH v3 4/5] serial: sc16is7xx: split into core and I2C/SPI
 parts (sc16is7xx_lines)

On Tue, 2 Apr 2024 22:28:25 +0300
Andy Shevchenko <andy.shevchenko@...il.com> wrote:

> On Tue, Apr 2, 2024 at 8:45 PM Hugo Villeneuve <hugo@...ovil.com> wrote:
> >
> > From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> >
> > Before, sc16is7xx_lines was checked for a free (zero) bit first, and then
> > later it was set only if UART port registration succeeded. Now that
> > sc16is7xx_lines is shared for the I2C and SPI drivers, there is a
> > possibility that the two drivers can simultaneously try to reserve the same
> > line bit at the same time.
> >
> > To prevent this, make sure line allocation is reserved atomically, and use
> > a new variable to hold the status of UART port regisration.
> 
> registration

Hi Andy,
will fix for V4.

> 
> > Now that we no longer need to search if a bit is set, it is now possible
> > to simplify sc16is7xx_lines allocation by using the IDA framework.
> 
> ...
> 
> > -static DECLARE_BITMAP(sc16is7xx_lines, SC16IS7XX_MAX_DEVS);
> > +static DEFINE_IDA(sc16is7xx_lines);
> 
> Don't we need to replace bitmap.h with idr.h with this change in place?

Yes, but I will replace bitops.h with idr.h in V4 (bitmap.h was not
included).

While at it, I will include an additional patch to replace inlude of 
<uapi/linux/sched/types.h> with <linux/sched.h>.

Thank you,
Hugo.