Commit 7f2bf784 authored Sep 09, 2018 by Nicholas Piggin Committed by Greg Kroah-Hartman Sep 10, 2018

tty: hvc: hvc_write() fix break condition



Commit 550ddadc ("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.

Tested-by: Matteo Croce <mcroce@redhat.com>
Tested-by: Jason Gunthorpe <jgg@mellanox.com>
Tested-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 68b2fc71

drivers/tty/hvc/hvc_console.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -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 = 0;

		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);

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