Re: [PATCH] missing NULL check in drivers/char/n_tty.c

From: Andrew Morton
Date: Mon Jun 21 2004 - 02:44:22 EST


Dan Aloni <da-x@xxxxxxx> wrote:
>
> On Sun, Jun 20, 2004 at 11:58:24PM -0700, Andrew Morton wrote:
> > Dan Aloni <da-x@xxxxxxx> wrote:
> > >
> > > The rest of the kernel treats tty->driver->chars_in_buffer as a possible
> > > NULL. This patch changes normal_poll() to be consistent with the rest of
> > > the code.
> >
> > It would be better to change the rest of the kernel - remove the tests.
> >
> > If any driver fails to implement ->chars_in_buffer() then we get a nice
> > oops which tells us that driver needs a stub handler.
>
> Are you sure that it won't affect the logic in tty_wait_until_sent()
> drastically? It acts quite differently when ->chars_in_buffer == NULL.

I did a quick grep and it appears that all drivers have set ->chars_in_buffer().

I suspect there are no drivers which fail to set chars_in_buffer.
Otherwise normal_poll() would have been oopsing in 2.4, 2.5 and 2.6?

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