diff options
| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-04-08 14:51:30 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-04-15 10:26:58 +0200 |
| commit | 6c80c0b94b94192d9a34b400f8237703c6475f4d (patch) | |
| tree | 2e4cdf5a94b5923315d00abe771f91314902d133 /drivers/tty | |
| parent | da5d669e00d2c437b3f508d60add417fc74f4bb6 (diff) | |
tty: move some internal tty lock enums and functions out of tty.h
Move the TTY_LOCK_* enums and tty_ldisc lock functions out of the global
tty.h into the local header file to clean things up.
Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20210408125134.3016837-10-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/tty.h | 26 | ||||
| -rw-r--r-- | drivers/tty/tty_buffer.c | 2 | ||||
| -rw-r--r-- | drivers/tty/tty_mutex.c | 1 |
3 files changed, 28 insertions, 1 deletions
diff --git a/drivers/tty/tty.h b/drivers/tty/tty.h index 55003840cd68..af997a4174c5 100644 --- a/drivers/tty/tty.h +++ b/drivers/tty/tty.h @@ -17,6 +17,32 @@ #define tty_info_ratelimited(tty, f, ...) \ tty_msg(pr_info_ratelimited, tty, f, ##__VA_ARGS__) +/* + * Lock subclasses for tty locks + * + * TTY_LOCK_NORMAL is for normal ttys and master ptys. + * TTY_LOCK_SLAVE is for slave ptys only. + * + * Lock subclasses are necessary for handling nested locking with pty pairs. + * tty locks which use nested locking: + * + * legacy_mutex - Nested tty locks are necessary for releasing pty pairs. + * The stable lock order is master pty first, then slave pty. + * termios_rwsem - The stable lock order is tty_buffer lock->termios_rwsem. + * Subclassing this lock enables the slave pty to hold its + * termios_rwsem when claiming the master tty_buffer lock. + * tty_buffer lock - slave ptys can claim nested buffer lock when handling + * signal chars. The stable lock order is slave pty, then + * master. + */ +enum { + TTY_LOCK_NORMAL = 0, + TTY_LOCK_SLAVE, +}; + +int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout); +void tty_ldisc_unlock(struct tty_struct *tty); + /* tty_audit.c */ #ifdef CONFIG_AUDIT void tty_audit_add_data(struct tty_struct *tty, const void *data, size_t size); diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 6d4995a5f318..9733469a14b2 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -17,7 +17,7 @@ #include <linux/delay.h> #include <linux/module.h> #include <linux/ratelimit.h> - +#include "tty.h" #define MIN_TTYB_SIZE 256 #define TTYB_ALIGN_MASK 255 diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c index 2640635ee177..393518a24cfe 100644 --- a/drivers/tty/tty_mutex.c +++ b/drivers/tty/tty_mutex.c @@ -4,6 +4,7 @@ #include <linux/kallsyms.h> #include <linux/semaphore.h> #include <linux/sched.h> +#include "tty.h" /* Legacy tty mutex glue */ |