linux-kernel - [PATCH v4 17/21] serial: omap: make sure to put() on poll_get

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Message-Id: <1346935540-1792-18-git-send-email-balbi@ti.com>
Date:	Thu,  6 Sep 2012 15:45:36 +0300
From:	Felipe Balbi <balbi@...com>
To:	Greg KH <gregkh@...uxfoundation.org>
Cc:	alan@...ux.intel.com, Tony Lindgren <tony@...mide.com>,
	Kevin Hilman <khilman@...com>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	Linux ARM Kernel Mailing List 
	<linux-arm-kernel@...ts.infradead.org>,
	linux-serial@...r.kernel.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	Shubhrajyoti Datta <shubhrajyoti@...com>,
	Sourav Poddar <sourav.poddar@...com>,
	Felipe Balbi <balbi@...com>
Subject: [PATCH v4 17/21] serial: omap: make sure to put() on poll_get_char

if we would reach serial_omap_get_char() while
Data Ready bit isn't set, we would return from
it without kicking our pm timer. This would mean
we would, eventually, have an unbalanced
pm_runtime_get on our device which would prevent
it from ever sleeping again.

Tested-by: Shubhrajyoti D <shubhrajyoti@...com>
Signed-off-by: Felipe Balbi <balbi@...com>
---
 drivers/tty/serial/omap-serial.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 7531147..6a58f4f 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1005,12 +1005,17 @@ static int serial_omap_poll_get_char(struct uart_port *port)
 
 	pm_runtime_get_sync(up->dev);
 	status = serial_in(up, UART_LSR);
-	if (!(status & UART_LSR_DR))
-		return NO_POLL_CHAR;
+	if (!(status & UART_LSR_DR)) {
+		status = NO_POLL_CHAR;
+		goto out;
+	}
 
 	status = serial_in(up, UART_RX);
+
+out:
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
+
 	return status;
 }
 
-- 
1.7.12.rc3

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