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From: Arnd Bergmann <arnd@arndb.de>
To: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] skd: use ktime_get_real_seconds()
Date: Thu,  2 Nov 2017 12:42:00 +0100	[thread overview]
Message-ID: <20171102114209.1686507-1-arnd@arndb.de> (raw)

Like many storage drivers, skd uses an unsigned 32-bit number for
interchanging the current time with the firmware. This will overflow in
y2106 and is otherwise safe.

However, the get_seconds() function is generally considered deprecated
since the behavior is different between 32-bit and 64-bit architectures,
and using it may indicate a bigger problem.

To annotate that we've thought about this, let's add a comment here
and migrate to the ktime_get_real_seconds() function that consistently
returns a 64-bit number.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/block/skd_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c
index 64d0fc17c174..2819f23e8bf2 100644
--- a/drivers/block/skd_main.c
+++ b/drivers/block/skd_main.c
@@ -1967,7 +1967,8 @@ static void skd_isr_msg_from_dev(struct skd_device *skdev)
 		break;
 
 	case FIT_MTD_CMD_LOG_HOST_ID:
-		skdev->connect_time_stamp = get_seconds();
+		/* hardware interface overflows in y2106 */
+		skdev->connect_time_stamp = (u32)ktime_get_real_seconds();
 		data = skdev->connect_time_stamp & 0xFFFF;
 		mtd = FIT_MXD_CONS(FIT_MTD_CMD_LOG_TIME_STAMP_LO, 0, data);
 		SKD_WRITEL(skdev, mtd, FIT_MSG_TO_DEVICE);
-- 
2.9.0

             reply	other threads:[~2017-11-02 11:42 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-02 11:42 Arnd Bergmann [this message]
2017-11-02 14:27 ` Jens Axboe

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