linux.git/drivers/tty/n_tty.c, branch v6.9

tty: invert return values of tty_{,un}throttle_safe()

2023-10-03T12:31:15+00:00

If tty_{,un}throttle_safe() returned true on success (similar to
*_trylock()), it would make the conditions in callers more obvious. So
perform the switch to these inverted values (and fix the callers).

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230919085156.1578-8-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: n_tty: use do-while in n_tty_check_{,un}throttle()

2023-10-03T12:31:15+00:00

This change gets rid of the complicated exit from the loops. It can be
done much easier using do-while loops.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230919085156.1578-6-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: n_tty: invert the condition in copy_from_read_buf()

2023-10-03T12:31:15+00:00

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

tty: n_tty: use min3() in copy_from_read_buf()

2023-10-03T12:31:15+00:00

n is a minimum of:
* available chars in the ring buffer
* available chars in the ring buffer till the end of the ring buffer
* requested number (*nr)

We can use min3() for that instead of two min()s.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230919085156.1578-4-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: n_tty: rename and retype 'retval' in n_tty_ioctl()

2023-10-03T12:31:15+00:00

The value stored to the current 'retval' is number of characters. It is
both obtained and put to user as unsigned. So make its type unsigned.
And provided it's not a "return value" per se, rename it to 'num'.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230919085156.1578-3-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: n_tty: use 'retval' instead of 'c'

2023-10-03T12:31:15+00:00

In n_tty_read(), there is a separate int variable 'c' and is used only
to hold an int value returned from job_control(). There is also a
'retval' variable typed ssize_t. So drop this single occurrence of 'c'
and reuse 'retval' which is used on all other places to hold the value
returned from n_tty_read().

Note that 'retval' needs not be initialized now. Drop that.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230919085156.1578-2-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: n_tty: deduplicate copy code in n_tty_receive_buf_real_raw()

2023-08-27T09:46:52+00:00

The code is duplicated to perform the copy twice -- to handle buffer
wrap-around. Instead of the duplication, roll this into the loop.

(And add some blank lines around to have the code a bit more readable.)

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230827074147.2287-15-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: n_tty: extract ECHO_OP processing to a separate function

2023-08-27T09:46:52+00:00

__process_echoes() contains ECHO_OPs processing. It is stuffed in a
while loop and the whole function is barely readable. Separate it to a
new function: n_tty_process_echo_ops().

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230827074147.2287-14-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: n_tty: unify counts to size_t

2023-08-27T09:46:52+00:00

Some count types are already 'size_t' for a long time. Some were
switched to 'size_t' recently. Unify the rest with those now.

This allows for some min_t()s to become min()s. And make one min()
an explicit min_t() as we are comparing signed 'room' to unsigned
'count'.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230827074147.2287-13-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: n_tty: use u8 for chars and flags

2023-08-27T09:46:52+00:00

Unify with the tty layer and use u8 for both chars and flags.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20230827074147.2287-12-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman