Messages in this thread Patch in this message | | | From | Nicholas Piggin <> | Subject | [PATCH 3/3] tty: hvc: hvc_write() fix break condition | Date | Wed, 5 Sep 2018 22:14:39 +1000 |
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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
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