diff options
| author | Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> | 2023-03-09 10:20:32 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-03-17 15:01:08 +0100 |
| commit | 7e26c84d02d17e7412e6f2471916fd415654a1ba (patch) | |
| tree | 45dad8770275398807603351ced02b55b6383e20 /drivers/tty/n_tty.c | |
| parent | 9db1be84054b7445f911b9efe9bc3c924ffdb543 (diff) | |
n_tty: Use DIV_ROUND_UP() in room calculation
When PARMRK is set, a character can result in up to 3 chars in the read
buffer. Receive code calculates for how many characters there (at
least) is room. Convert an opencoded rounding in the calculation to use
DIV_ROUND_UP().
Note: the room variable is decremented afterwards by one which ensures
the characters will fit into the buffer for real so the code is okay
despite rounding upwards.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230309082035.14880-6-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/n_tty.c')
| -rw-r--r-- | drivers/tty/n_tty.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 2cf263de1366..6d754fc35dce 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -36,6 +36,7 @@ #include <linux/file.h> #include <linux/interrupt.h> #include <linux/major.h> +#include <linux/math.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/poll.h> @@ -1692,7 +1693,7 @@ n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp, room = N_TTY_BUF_SIZE - (ldata->read_head - tail); if (I_PARMRK(tty)) - room = (room + 2) / 3; + room = DIV_ROUND_UP(room, 3); room--; if (room <= 0) { overflow = ldata->icanon && ldata->canon_head == tail; |