Christian Riesch <christian.riesch@xxxxxxxxxx> writes:
> On Tue, Nov 11, 2014 at 2:04 PM, Måns Rullgård <mans@xxxxxxxxx> wrote:
>> Christian Riesch <christian.riesch@xxxxxxxxxx> writes:
> [...]>> diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
>>> index 2e900a9..b09f326 100644
>>> --- a/drivers/tty/n_tty.c
>>> +++ b/drivers/tty/n_tty.c
>>> @@ -321,7 +321,9 @@ static void n_tty_check_unthrottle(struct tty_struct *tty)
>>>
>>> static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
>>> {
>>> - *read_buf_addr(ldata, ldata->read_head++) = c;
>>> + *read_buf_addr(ldata, ldata->read_head) = c;
>>> + /* increment read_head _after_ placing the character in the buffer */
>>> + ldata->read_head++;
>>> }
>>
>> Is that comment really necessary?
>
> No, I am pretty sure that removing the comment would not break the code ;-)
>
> I just thought it would be good to have some kind of reminder here.
> Otherwise someone may think: Hey, it would be a good idea to do the
> increment right in the first line. And submit a patch for it.
The intent all along was to increment after the write. Nobody needs
reminding of that. The problem was a misunderstanding of when the
post-increment takes effect. As much as we'd like for everybody to have
a thorough knowledge of C, a random tty driver doesn't seem the place to
educate them.
--
Måns Rullgård
mans@xxxxxxxxx
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