[PATCH v2] libfc: fix seconds_since_last_reset miscalculation

[PATCH v2] libfc: fix seconds_since_last_reset miscalculation

[Johannes Thumshirn]

Commit 540eb1eef 'scsi: libfc: fix seconds_since_last_reset calculation'
removed the use of 'struct timespec' from fc_get_host_stats(). This broke the
output of 'fcoeadm -s' after kernel 4.8-rc1.

Fixes: 540eb1eef ('scsi: libfc: fix seconds_since_last_reset calculation')
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/scsi/libfc/fc_lport.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/libfc/fc_lport.c b/drivers/scsi/libfc/fc_lport.c
index 04ce7cf..50c7167 100644
--- a/drivers/scsi/libfc/fc_lport.c
+++ b/drivers/scsi/libfc/fc_lport.c
@@ -308,7 +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));
 
-	fc_stats->seconds_since_last_reset = (lport->boot_time - jiffies) / HZ;
+	fc_stats->seconds_since_last_reset = (jiffies - lport->boot_time) / HZ;
 
 	for_each_possible_cpu(cpu) {
 		struct fc_stats *stats;
-- 
1.8.5.6

Re: [PATCH v2] libfc: fix seconds_since_last_reset miscalculation

[Arnd Bergmann]

On Thursday, November 17, 2016 1:39:27 PM CET Johannes Thumshirn wrote:
> Commit 540eb1eef 'scsi: libfc: fix seconds_since_last_reset calculation'
> removed the use of 'struct timespec' from fc_get_host_stats(). This broke the
> output of 'fcoeadm -s' after kernel 4.8-rc1.
> 
> Fixes: 540eb1eef ('scsi: libfc: fix seconds_since_last_reset calculation')
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> 

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

I actually made the same patch today and was going to send it out
after getting my other patches to build cleanly, but you were faster.

Are we worried about 32-bit systems overflowing here when the elapsed
time since the last reset is over 49 days? If we are, we probably
want another patch on top, though this one is sufficient to fix
the regression, and it has no problems on 64-bit machines.

	Arnd

Re: [PATCH v2] libfc: fix seconds_since_last_reset miscalculation

[Bart Van Assche]

On 11/17/2016 04:39 AM, Johannes Thumshirn wrote:
> Commit 540eb1eef 'scsi: libfc: fix seconds_since_last_reset calculation'
> removed the use of 'struct timespec' from fc_get_host_stats(). This broke the
> output of 'fcoeadm -s' after kernel 4.8-rc1.

Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>

Re: [PATCH v2] libfc: fix seconds_since_last_reset miscalculation

[Martin K. Petersen]

>>>>> "Johannes" == Johannes Thumshirn <jthumshirn@suse.de> writes:

Johannes> Commit 540eb1eef 'scsi: libfc: fix seconds_since_last_reset
Johannes> calculation' removed the use of 'struct timespec' from
Johannes> fc_get_host_stats(). This broke the output of 'fcoeadm -s'
Johannes> after kernel 4.8-rc1.

Applied to 4.9/scsi-fixes.

-- 
Martin K. Petersen	Oracle Linux Engineering