On Tue, 19 Sep 2023, Jiri Slaby (SUSE) wrote:
> Make "no numbers available" a fast quit from the function. And do the
Did you really intend to write "numbers" and not e.g. characters?
The change itself looks good,
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
--
i.
> heavy work outside the 'if'. This makes the code more understandable and
> conforming to the common kernel coding style.
>
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx>
> ---
> drivers/tty/n_tty.c | 38 ++++++++++++++++++++------------------
> 1 file changed, 20 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
> index 6a112910c058..922fb61b587a 100644
> --- a/drivers/tty/n_tty.c
> +++ b/drivers/tty/n_tty.c
> @@ -1966,24 +1966,26 @@ static bool copy_from_read_buf(const struct tty_struct *tty, u8 **kbp,
> size_t tail = MASK(ldata->read_tail);
>
> n = min3(head - ldata->read_tail, N_TTY_BUF_SIZE - tail, *nr);
> - if (n) {
> - u8 *from = read_buf_addr(ldata, tail);
> - memcpy(*kbp, from, n);
> - is_eof = n == 1 && *from == EOF_CHAR(tty);
> - tty_audit_add_data(tty, from, n);
> - zero_buffer(tty, from, n);
> - smp_store_release(&ldata->read_tail, ldata->read_tail + n);
> - /* Turn single EOF into zero-length read */
> - if (L_EXTPROC(tty) && ldata->icanon && is_eof &&
> - (head == ldata->read_tail))
> - return false;
> - *kbp += n;
> - *nr -= n;
> -
> - /* If we have more to copy, let the caller know */
> - return head != ldata->read_tail;
> - }
> - return false;
> + if (!n)
> + return false;
> +
> + u8 *from = read_buf_addr(ldata, tail);
> + memcpy(*kbp, from, n);
> + is_eof = n == 1 && *from == EOF_CHAR(tty);
> + tty_audit_add_data(tty, from, n);
> + zero_buffer(tty, from, n);
> + smp_store_release(&ldata->read_tail, ldata->read_tail + n);
> +
> + /* Turn single EOF into zero-length read */
> + if (L_EXTPROC(tty) && ldata->icanon && is_eof &&
> + head == ldata->read_tail)
> + return false;
> +
> + *kbp += n;
> + *nr -= n;
> +
> + /* If we have more to copy, let the caller know */
> + return head != ldata->read_tail;
> }
>
> /**
>
