From c2b0fb9f69987ddec6bf21f95157603ea4c83aff Mon Sep 17 00:00:00 2001 From: "Jiri Slaby (SUSE)" Date: Tue, 19 Sep 2023 10:51:45 +0200 Subject: [PATCH] tty: n_tty: invert the condition in copy_from_read_buf() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Make "no numbers available" a fast quit from the function. And do the 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)" Reviewed-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20230919085156.1578-5-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman --- 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 6a112910c0582..922fb61b587af 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; } /** -- 2.47.2