linux-kernel - [PATCH] staging: speakup: change semaphore to completion

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Date:   Mon, 10 Dec 2018 22:41:50 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     William Hubbs <w.d.hubbs@...il.com>,
        Chris Brannon <chris@...-brannons.com>,
        Kirk Reiser <kirk@...sers.ca>,
        Samuel Thibault <samuel.thibault@...-lyon.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Arnd Bergmann <arnd@...db.de>, speakup@...ux-speakup.org,
        devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org
Subject: [PATCH] staging: speakup: change semaphore to completion

In this driver, both function the same way, but we want to eventually
kill off semaphores, so a completion is the better choice here.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/staging/speakup/spk_ttyio.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/speakup/spk_ttyio.c b/drivers/staging/speakup/spk_ttyio.c
index 979e3ae249c1..c92bbd05516e 100644
--- a/drivers/staging/speakup/spk_ttyio.c
+++ b/drivers/staging/speakup/spk_ttyio.c
@@ -10,7 +10,7 @@
 
 struct spk_ldisc_data {
 	char buf;
-	struct semaphore sem;
+	struct completion completion;
 	bool buf_free;
 };
 
@@ -55,7 +55,7 @@ static int spk_ttyio_ldisc_open(struct tty_struct *tty)
 	if (!ldisc_data)
 		return -ENOMEM;
 
-	sema_init(&ldisc_data->sem, 0);
+	init_completion(&ldisc_data->completion);
 	ldisc_data->buf_free = true;
 	speakup_tty->disc_data = ldisc_data;
 
@@ -95,7 +95,7 @@ static int spk_ttyio_receive_buf2(struct tty_struct *tty,
 
 	ldisc_data->buf = cp[0];
 	ldisc_data->buf_free = false;
-	up(&ldisc_data->sem);
+	complete(&ldisc_data->completion);
 
 	return 1;
 }
@@ -286,7 +286,8 @@ static unsigned char ttyio_in(int timeout)
 	struct spk_ldisc_data *ldisc_data = speakup_tty->disc_data;
 	char rv;
 
-	if (down_timeout(&ldisc_data->sem, usecs_to_jiffies(timeout)) == -ETIME) {
+	if (wait_for_completion_timeout(&ldisc_data->completion,
+					usecs_to_jiffies(timeout)) == 0) {
 		if (timeout)
 			pr_warn("spk_ttyio: timeout (%d)  while waiting for input\n",
 				timeout);
-- 
2.20.0