netdev - [PATCH net 1/2] netdevsim: Ensure policer drop counter always increases

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Message-Id: <20200521114617.1074379-2-idosch@idosch.org>
Date:   Thu, 21 May 2020 14:46:16 +0300
From:   Ido Schimmel <idosch@...sch.org>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org, jiri@...lanox.com,
        mlxsw@...lanox.com, Ido Schimmel <idosch@...lanox.com>
Subject: [PATCH net 1/2] netdevsim: Ensure policer drop counter always increases

From: Ido Schimmel <idosch@...lanox.com>

In case the policer drop counter is retrieved when the jiffies value is
a multiple of 64, the counter will not be incremented.

This randomly breaks a selftest [1] the reads the counter twice and
checks that it was incremented:

```
TEST: Trap policer                                                  [FAIL]
	Policer drop counter was not incremented
```

Fix by always incrementing the counter by 1.

[1] tools/testing/selftests/drivers/net/netdevsim/devlink_trap.sh

Fixes: ad188458d012 ("netdevsim: Add devlink-trap policer support")
Signed-off-by: Ido Schimmel <idosch@...lanox.com>
Reviewed-by: Jiri Pirko <jiri@...lanox.com>
---
 drivers/net/netdevsim/dev.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
index 68668a22b9dd..dc3ff0e20944 100644
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -858,8 +858,7 @@ nsim_dev_devlink_trap_policer_counter_get(struct devlink *devlink,
 		return -EINVAL;
 
 	cnt = &nsim_dev->trap_data->trap_policers_cnt_arr[policer->id - 1];
-	*p_drops = *cnt;
-	*cnt += jiffies % 64;
+	*p_drops = (*cnt)++;
 
 	return 0;
 }
-- 
2.26.2