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authorAlan Cox <alan@redhat.com>2007-07-15 23:39:43 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-16 09:05:41 -0700
commit9c1729db3e6d738f872bcb090212af00473bf666 (patch)
treebe68b99784607953fb50d9330d34c2728215be57 /include
parentc9c64155f5a81b4b41e98f9fb9c464a565c1bf72 (diff)
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')
-rw-r--r--include/linux/tty.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h
index bb457608520..deaba9ec500 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;