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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Johan Hovold <johan@kernel.org>
Subject: [PATCH 4.19 109/118] gnss: serial: fix synchronous write timeout
Date:   Mon, 26 Nov 2018 11:51:43 +0100
Message-Id: <20181126105106.086743620@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@kernel.org>

commit 56a6c7268312cba9436b84cac01b3e502c5c511d upstream.

Passing a timeout of zero to the synchronous serdev_device_write()
helper does currently not imply to wait forever (unlike passing zero to
serdev_device_wait_until_sent()). Instead, if there's insufficient
room in the write buffer, we'd end up with an incomplete write.

Fixes: 37768b054f20 ("gnss: add generic serial driver")
Cc: stable <stable@vger.kernel.org>     # 4.19
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gnss/serial.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gnss/serial.c
+++ b/drivers/gnss/serial.c
@@ -13,6 +13,7 @@
 #include <linux/of.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/sched.h>
 #include <linux/serdev.h>
 #include <linux/slab.h>
 
@@ -63,7 +64,7 @@ static int gnss_serial_write_raw(struct
 	int ret;
 
 	/* write is only buffered synchronously */
-	ret = serdev_device_write(serdev, buf, count, 0);
+	ret = serdev_device_write(serdev, buf, count, MAX_SCHEDULE_TIMEOUT);
 	if (ret < 0)
 		return ret;