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authorArnd Bergmann <arnd@arndb.de>2016-06-17 17:47:25 +0200
committerMartin K. Petersen <martin.petersen@oracle.com>2016-07-12 23:16:31 -0400
commit540eb1eef0aba8bd10b7ebb3dc56cdb9e480164f (patch)
tree7828470058aa0b677333fb23e332f6f75642b349 /drivers
parent0da21c4417ce8fac70bb46dd58c3a63f64bad76c (diff)
scsi: libfc: fix seconds_since_last_reset calculation
The fc_get_host_stats() function contains a complex conversion from jiffies to timespec to seconds. As we try to get rid of uses of struct timespec, we can clean this up and replace it with a simpler computation. Simply dividing the difference in jiffies by HZ is not only much more efficient, it also avoids a problem that causes the seconds_since_last_reset value to be incorrect if jiffies has overrun since the 'boot_time' value was recorded. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/scsi/libfc/fc_lport.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/drivers/scsi/libfc/fc_lport.c b/drivers/scsi/libfc/fc_lport.c
index b9b44daff159..04ce7cfb6d1b 100644
--- a/drivers/scsi/libfc/fc_lport.c
+++ b/drivers/scsi/libfc/fc_lport.c
@@ -301,7 +301,6 @@ struct fc_host_statistics *fc_get_host_stats(struct Scsi_Host *shost)
{
struct fc_host_statistics *fc_stats;
struct fc_lport *lport = shost_priv(shost);
- struct timespec v0, v1;
unsigned int cpu;
u64 fcp_in_bytes = 0;
u64 fcp_out_bytes = 0;
@@ -309,9 +308,7 @@ struct fc_host_statistics *fc_get_host_stats(struct Scsi_Host *shost)
fc_stats = &lport->host_stats;
memset(fc_stats, 0, sizeof(struct fc_host_statistics));
- jiffies_to_timespec(jiffies, &v0);
- jiffies_to_timespec(lport->boot_time, &v1);
- fc_stats->seconds_since_last_reset = (v0.tv_sec - v1.tv_sec);
+ fc_stats->seconds_since_last_reset = (lport->boot_time - jiffies) / HZ;
for_each_possible_cpu(cpu) {
struct fc_stats *stats;