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author | Alison Schofield <amsfield22@gmail.com> | 2015-11-09 11:34:20 -0800 |
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committer | Martin K. Petersen <martin.petersen@oracle.com> | 2015-11-11 20:51:04 -0500 |
commit | 9c9bd593f30fc8a4d6e70d72b49b5651fa492e65 (patch) | |
tree | 3d92a7bd095e43985f94a271105f3e24c68ee8a5 /drivers/scsi | |
parent | 36f8ef7f7684997f1c1efcc775b1d7cdf452ce44 (diff) | |
download | lwn-9c9bd593f30fc8a4d6e70d72b49b5651fa492e65.tar.gz lwn-9c9bd593f30fc8a4d6e70d72b49b5651fa492e65.zip |
scsi: pmcraid: replace struct timeval with ktime_get_real_seconds()
Replace the use of struct timeval and do_gettimeofday() with
64 bit ktime_get_real_seconds. Prevents 32-bit type overflow
in year 2038 on 32-bit systems.
Driver was using the seconds portion of struct timeval (.tv_secs)
to pass a millseconds timestamp to the firmware. This change maintains
that same behavior using ktime_get_real_seconds.
The structure used to pass the timestamp to firmware is 48 bits and
works fine as long as the top 16 bits are zero and they will be zero
for a long time..ie. thousands of years.
Alternative Change: Add sub second granularity to timestamp
As noted above, the driver only used the seconds portion of timeval,
ignores the microseconds portion, and by multiplying by 1000 effectively
does a <<10 and always writes zero into timestamp[0].
The alternative change would pass all the bits to the firmware:
struct timespec64 ts;
ktime_get_real_ts64(&ts);
timestamp = ts.tv_sec * MSEC_PER_SEC + ts.tv_nsec / NSEC_PER_MSEC;
Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r-- | drivers/scsi/pmcraid.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c index ed31d8cc6266..3f64275cfafd 100644 --- a/drivers/scsi/pmcraid.c +++ b/drivers/scsi/pmcraid.c @@ -45,6 +45,7 @@ #include <asm/processor.h> #include <linux/libata.h> #include <linux/mutex.h> +#include <linux/ktime.h> #include <scsi/scsi.h> #include <scsi/scsi_host.h> #include <scsi/scsi_device.h> @@ -5563,11 +5564,9 @@ 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_get_real_seconds() * 1000; pinstance->timestamp_data->timestamp[0] = (__u8)(timestamp); pinstance->timestamp_data->timestamp[1] = (__u8)((timestamp) >> 8); |