On Wed, 5 Sep 2018 22:14:39 +1000
Nicholas Piggin <npig...@gmail.com> wrote:
> 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 <mcr...@redhat.com>
> Tested-by: Leon Romanovsky <leo...@mellanox.com>
> Signed-off-by: Nicholas Piggin <npig...@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;
That needs to be 'int ret = 0;' to avoid used uninitialized.
Let me know if I should resend the patches.
Thanks,
Nick
