Thread (66 messages) 66 messages, 5 authors, 2012-09-16
STALE5013d REVIEWED: 1 (0M)
Revisions (2)
  1. v3 [diff vs current]
  2. v4 current

[PATCH v4 17/21] serial: omap: make sure to put() on poll_get_char

From: Felipe Balbi <hidden>
Date: 2012-09-06 12:52:37
Also in: linux-omap, linux-serial, lkml
Subsystem: the rest, tty layer and serial drivers · Maintainers: Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby

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 <redacted>
Signed-off-by: Felipe Balbi <redacted>
---
 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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