[PATCH v2] scsi: pmcraid: Remove usage of struct timeval

[PATCH v2] scsi: pmcraid: Remove usage of struct timeval

[Tina Ruchandani]

struct timeval will have its tv_sec field overflow on 32-bit systems
in year 2038 and beyond. This patch removes the usage of struct timeval
and instead uses 64-bit ktime_t to get the current milliseconds
to populate pmcraid_timestamp_data.

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
--
Changes in v2:
 - Change subject line to indicate that change is local to pmcraid driver
   and doesn't cover all of scsi subsystem.
 - Use u64 instead of __l64 for timestamp, as it being set to a cpu-endian
   value.
---
 drivers/scsi/pmcraid.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index 8c27b6a..60ce3c9 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -25,6 +25,7 @@
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/types.h>
+#include <linux/ktime.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/ioport.h>
@@ -5569,11 +5570,9 @@ static void pmcraid_set_timestamp(struct pmcraid_cmd *cmd)
 	__be32 time_stamp_len = cpu_to_be32(PMCRAID_TIMESTAMP_LEN);
 	struct pmcraid_ioadl_desc *ioadl = ioarcb->add_data.u.ioadl;
 
-	struct timeval tv;
-	__le64 timestamp;
+	u64 timestamp;
 
-	do_gettimeofday(&tv);
-	timestamp = tv.tv_sec * 1000;
+	timestamp = ktime_to_ms(ktime_get_real());
 
 	pinstance->timestamp_data->timestamp[0] = (__u8)(timestamp);
 	pinstance->timestamp_data->timestamp[1] = (__u8)((timestamp) >> 8);
-- 
2.2.0.rc0.207.ga3a616c

Re: [PATCH v2] scsi: pmcraid: Remove usage of struct timeval

[Arnd Bergmann]

On Wednesday 25 February 2015 07:49:21 Tina Ruchandani wrote:
> struct timeval will have its tv_sec field overflow on 32-bit systems
> in year 2038 and beyond. This patch removes the usage of struct timeval
> and instead uses 64-bit ktime_t to get the current milliseconds
> to populate pmcraid_timestamp_data.
> 
> Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
> 

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

I notice that this patch also increases the accuracy of the timestamp
from seconds to milliseconds, where the original code ignores the
sub-second portion of the timeval.

Doing this will make the the function a little slower, but I have
verified that it is only called for probe, reset and config-change,
all of which are not timing critical.

	Arnd