Re: [PATCH 1/2] Input: i8042 - Prevent intermixing i8042 commands

From: Raul Rangel
Date: Mon Aug 31 2020 - 09:40:09 EST


On Sat, Aug 29, 2020 at 1:48 AM Pavel Machek <pavel@xxxxxx> wrote:
>
> On Thu 2020-08-27 13:52:22, Raul E Rangel wrote:
> > The i8042_mutex must be held by writers of the AUX and KBD ports, as
> > well as users of i8042_command. There were a lot of users of
> > i8042_command that were not calling i8042_lock_chip/i8042_unlock_chip.
> > This resulted in i8042_commands being issues in between PS/2
> > transactions.
> >
> > This change moves the mutex lock into i8042_command and removes the
> > burden of locking the mutex from the callers.
> >
> > It is expected that the i8042_mutex is locked before calling
> > i8042_aux_write or i8042_kbd_write. This is currently done by the PS/2
> > layer via ps2_begin_command and ps2_end_command. Other modules
> > (serio_raw) do not currently lock the mutex, so there is still a
> > possibility for intermixed commands.
>
>
> > @@ -343,10 +330,14 @@ int i8042_command(unsigned char *param, int command)
> > unsigned long flags;
> > int retval;
> >
> > + mutex_lock(&i8042_mutex);
> > +
> > spin_lock_irqsave(&i8042_lock, flags);
> > retval = __i8042_command(param, command);
> > spin_unlock_irqrestore(&i8042_lock, flags);
> >
> > + mutex_unlock(&i8042_mutex);
> > +
> > return retval;
>
> There's something wrong with whitespace here. Checkpatch?
> Pavel
It's fixed in the v2 patch: https://patchwork.kernel.org/patch/11741855/

Thanks