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| author | Alan Cox <alan@redhat.com> | 2007-07-15 23:39:43 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-16 09:05:41 -0700 |
| commit | 9c1729db3e6d738f872bcb090212af00473bf666 (patch) | |
| tree | be68b99784607953fb50d9330d34c2728215be57 /include/linux/tty.h | |
| parent | c9c64155f5a81b4b41e98f9fb9c464a565c1bf72 (diff) | |
| download | linux-9c1729db3e6d738f872bcb090212af00473bf666.tar.gz linux-9c1729db3e6d738f872bcb090212af00473bf666.tar.bz2 linux-9c1729db3e6d738f872bcb090212af00473bf666.zip | |
Prevent an O_NDELAY writer from blocking when a tty write is blocked by the tty atomic writer mutex
Without this a tty write could block if a previous blocking tty write was
in progress on the same tty and blocked by a line discipline or hardware
event. Originally found and reported by Dave Johnson.
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Dave Johnson <djohnson+linux-kernel@sw.starentnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/tty.h')
| -rw-r--r-- | include/linux/tty.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h index bb4576085203..deaba9ec5004 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -338,6 +338,12 @@ extern struct tty_struct *get_current_tty(void); extern struct mutex tty_mutex; +extern void tty_write_unlock(struct tty_struct *tty); +extern int tty_write_lock(struct tty_struct *tty, int ndelay); +#define tty_is_writelocked(tty) (mutex_is_locked(&tty->atomic_write_lock)) + + + /* n_tty.c */ extern struct tty_ldisc tty_ldisc_N_TTY; |