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tty: Remove baudrate dead code & make ktermios params const

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With the architectures currently in-tree, either:
  1) CBAUDEX is zero
  2) The earlier BOTHER if check covers cbaud < 1 case
  3) All CBAUD bits are covered by the baud_table

Thus, the check for cbaud being out-of-range for CBAUDEX case cannot
ever be true.

The ktermios parameters can now be made const.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220816115739.10928-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ilpo Järvinen 2022-08-16 14:57:32 +03:00 committed by Greg Kroah-Hartman
parent eb9e109d01
commit 87888fb9ac
3 changed files with 10 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/tty/tty.h
View File

@ -73,7 +73,7 @@ void tty_buffer_set_lock_subclass(struct tty_port *port);
bool tty_buffer_restart_work(struct tty_port *port);
bool tty_buffer_cancel_work(struct tty_port *port);
void tty_buffer_flush_work(struct tty_port *port);
speed_t tty_termios_input_baud_rate(struct ktermios *termios);
speed_t tty_termios_input_baud_rate(const struct ktermios *termios);
void tty_ldisc_hangup(struct tty_struct *tty, bool reset);
int tty_ldisc_reinit(struct tty_struct *tty, int disc);
long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);

24
drivers/tty/tty_baudrate.c
View File

@ -49,13 +49,13 @@ static int n_baud_table = ARRAY_SIZE(baud_table);
*
* Convert termios baud rate data into a speed. This should be called
* with the termios lock held if this termios is a terminal termios
* structure. May change the termios data. Device drivers can call this
* function but should use ->c_[io]speed directly as they are updated.
* structure. Device drivers can call this function but should use
* ->c_[io]speed directly as they are updated.
*
* Locking: none
*/
speed_t tty_termios_baud_rate(struct ktermios *termios)
speed_t tty_termios_baud_rate(const struct ktermios *termios)
{
unsigned int cbaud;
@ -67,11 +67,7 @@ speed_t tty_termios_baud_rate(struct ktermios *termios)
if (cbaud & CBAUDEX) {
cbaud &= ~CBAUDEX;
if (cbaud < 1 || cbaud + 15 > n_baud_table)
termios->c_cflag &= ~CBAUDEX;
else
cbaud += 15;
cbaud += 15;
}
return cbaud >= n_baud_table ? 0 : baud_table[cbaud];
}
@ -83,13 +79,13 @@ EXPORT_SYMBOL(tty_termios_baud_rate);
*
* Convert termios baud rate data into a speed. This should be called
* with the termios lock held if this termios is a terminal termios
* structure. May change the termios data. Device drivers can call this
* function but should use ->c_[io]speed directly as they are updated.
* structure. Device drivers can call this function but should use
* ->c_[io]speed directly as they are updated.
*
* Locking: none
*/
speed_t tty_termios_input_baud_rate(struct ktermios *termios)
speed_t tty_termios_input_baud_rate(const struct ktermios *termios)
{
unsigned int cbaud = (termios->c_cflag >> IBSHIFT) & CBAUD;
@ -102,11 +98,7 @@ speed_t tty_termios_input_baud_rate(struct ktermios *termios)
if (cbaud & CBAUDEX) {
cbaud &= ~CBAUDEX;
if (cbaud < 1 || cbaud + 15 > n_baud_table)
termios->c_cflag &= ~(CBAUDEX << IBSHIFT);
else
cbaud += 15;
cbaud += 15;
}
return cbaud >= n_baud_table ? 0 : baud_table[cbaud];
}

2
include/linux/tty.h
View File

@ -434,7 +434,7 @@ int tty_hung_up_p(struct file *filp);
void do_SAK(struct tty_struct *tty);
void __do_SAK(struct tty_struct *tty);
void no_tty(void);
speed_t tty_termios_baud_rate(struct ktermios *termios);
speed_t tty_termios_baud_rate(const struct ktermios *termios);
void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud,
speed_t obaud);
void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud,