lkml.org 
[lkml]   [2018]   [Sep]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3/3] tty: hvc: hvc_write() fix break condition
Date
Commit 550ddadcc758 ("tty: hvc: hvc_write() may sleep") broke the
termination condition in case the driver stops accepting characters.
This can result in unnecessary polling of the busy driver.

Restore it by testing the hvc_push return code.

Fixes: 550ddadcc758 ("tty: hvc: hvc_write() may sleep")
Tested-by: Matteo Croce <mcroce@redhat.com>
Tested-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
drivers/tty/hvc/hvc_console.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index bacf9b73ec98..c09a38fb0d66 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -522,6 +522,8 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
return -EIO;

while (count > 0) {
+ int ret;
+
spin_lock_irqsave(&hp->lock, flags);

rsize = hp->outbuf_size - hp->n_outbuf;
@@ -537,10 +539,13 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
}

if (hp->n_outbuf > 0)
- hvc_push(hp);
+ ret = hvc_push(hp);

spin_unlock_irqrestore(&hp->lock, flags);

+ if (!ret)
+ break;
+
if (count) {
if (hp->n_outbuf > 0)
hvc_flush(hp);
--
2.18.0
\
 
 \ /
  Last update: 2018-09-05 14:16    [W:0.058 / U:2.528 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site