n_hdlc: honor O_NONBLOCK on write
Make n_hdlc line discipline honor the O_NONBLOCK file flag on write.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/n_hdlc.c b/drivers/char/n_hdlc.c
index ed4e033..69ec639 100644
--- a/drivers/char/n_hdlc.c
+++ b/drivers/char/n_hdlc.c
@@ -677,6 +677,10 @@
/* Allocate transmit buffer */
/* sleep until transmit buffer available */
while (!(tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list))) {
+ if (file->f_flags & O_NONBLOCK) {
+ error = -EAGAIN;
+ break;
+ }
schedule();
n_hdlc = tty2n_hdlc (tty);