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authorPeter Hurley <peter@hurleysoftware.com>2016-01-09 21:45:14 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-01-28 11:58:02 -0800
commit87108bc9870ae86ca4fcc05115a134af7a0f4e96 (patch)
tree702f4aad21688cc01a3a92d4f2207bf408aa3615
parentffb91a459c6cacb10972f5dff893fb1292bac85d (diff)
tty: n_tty: fix SIGIO for output
According to fcntl(2), "a SIGIO signal is sent whenever input or output becomes possible on that file descriptor", i.e. after the output buffer was full and now has space for new data. But in fact SIGIO is sent after every write. n_tty_write() should set TTY_DO_WRITE_WAKEUP only when not all data could be written to the buffer. [pjh: Also fixes missed SIGIO if amt written just happens to be [ amount still to write Signed-off-by: Johannes Stezenbach <js@sig21.net> [pjh: minor patch edits and re-submit] Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/n_tty.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 5ae661cd236e..fad365aa1f5c 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2361,7 +2361,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
}
break_out:
remove_wait_queue(&tty->write_wait, &wait);
- if (b - buf != nr && tty->fasync)
+ if (nr && tty->fasync)
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
up_read(&tty->termios_rwsem);
return (b - buf) ? b - buf : retval;