scsi: 3ware: fix 32-bit time calculations

twl_aen_queue_event/twa_aen_queue_event, we use do_gettimeofday() to
read the lower 32 bits of the current time in seconds, to pass them to
the TW_IOCTL_GET_NEXT_EVENT ioctl or the 3ware_aen_read sysfs file.

This will overflow on all architectures in year 2106, there is not much
we can do about that without breaking the ABI. User space has 90 years
to learn to deal with it, so it's probably ok.

I'm changing it to use ktime_get_real_seconds() with a comment to
document what happens when.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Adam Radford <aradford@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/3w-9xxx.c

@@ -369,7 +369,6 @@ out:
 static void twa_aen_queue_event(TW_Device_Extension *tw_dev, TW_Command_Apache_Header *header)
 {
 	u32 local_time;
-	struct timeval time;
 	TW_Event *event;
 	unsigned short aen;
 	char host[16];
@@ -392,8 +391,8 @@ static void twa_aen_queue_event(TW_Device_Extension *tw_dev, TW_Command_Apache_H
 	memset(event, 0, sizeof(TW_Event));
 
 	event->severity = TW_SEV_OUT(header->status_block.severity__reserved);
-	do_gettimeofday(&time);
-	local_time = (u32)(time.tv_sec - (sys_tz.tz_minuteswest * 60));
+	/* event->time_stamp_sec overflows in y2106 */
+	local_time = (u32)(ktime_get_real_seconds() - (sys_tz.tz_minuteswest * 60));
 	event->time_stamp_sec = local_time;
 	event->aen_code = aen;
 	event->retrieved = TW_AEN_NOT_RETRIEVED;

drivers/scsi/3w-sas.c

@@ -221,7 +221,6 @@ out:
 static void twl_aen_queue_event(TW_Device_Extension *tw_dev, TW_Command_Apache_Header *header)
 {
 	u32 local_time;
-	struct timeval time;
 	TW_Event *event;
 	unsigned short aen;
 	char host[16];
@@ -240,8 +239,8 @@ static void twl_aen_queue_event(TW_Device_Extension *tw_dev, TW_Command_Apache_H
 	memset(event, 0, sizeof(TW_Event));
 
 	event->severity = TW_SEV_OUT(header->status_block.severity__reserved);
-	do_gettimeofday(&time);
-	local_time = (u32)(time.tv_sec - (sys_tz.tz_minuteswest * 60));
+	/* event->time_stamp_sec overflows in y2106 */
+	local_time = (u32)(ktime_get_real_seconds() - (sys_tz.tz_minuteswest * 60));
 	event->time_stamp_sec = local_time;
 	event->aen_code = aen;
 	event->retrieved = TW_AEN_NOT_RETRIEVED;