[PATCH] scsi: Remove usage of struct timeval

[PATCH] scsi: 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>
---
 drivers/scsi/pmcraid.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index 8c27b6a..98af06f 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;
 
-	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] scsi: Remove usage of struct timeval

[Arnd Bergmann]

On Wednesday 04 February 2015 08:39:54 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>

The change you did looks correct, but I see two problems:

- The subject line should mention the name of the driver you
  change, as you are not doing this for the entire scsi subsystem
  at once.

> @@ -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;
>  
> -       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);

It looks like a preexisting bug here, but it makes sense to fix
it at the same time and describe that change in the patch
changelog:

timestamp is declared as an __le64 type but gets set to a cpu-endian
value from tv.tv_sec or ktime_to_ms, which is wrong. The code indeed
gets the endianess right by copying the bytes individually, so I think
you should just use a u64 type here.

	Arnd