[PATCH] net: stmmac: Improve Tx timer arm logic further

[muhammad.nazim.amirul.nazle.asmade at altera.com]

From: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade at altera.com>

Currently hrtimer_start is called even if hrtimer is
active. This is unnecessary and expensive in some targets.
This patch avoids calling hrtimer_start unnecessarily.

Signed-off-by: Rohan G Thomas <rohan.g.thomas at intel.com>
Signed-off-by: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade at altera.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 3591755ea30b..35da51c26248 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3341,12 +3341,14 @@ static void stmmac_tx_timer_arm(struct stmmac_priv *priv, u32 queue)
 	 * Try to cancel any timer if napi is scheduled, timer will be armed
 	 * again in the next scheduled napi.
 	 */
-	if (unlikely(!napi_is_scheduled(napi)))
-		hrtimer_start(&tx_q->txtimer,
-			      STMMAC_COAL_TIMER(tx_coal_timer),
-			      HRTIMER_MODE_REL);
-	else
+	if (unlikely(!napi_is_scheduled(napi))) {
+		if (unlikely(!(hrtimer_active(&tx_q->txtimer))))
+			hrtimer_start(&tx_q->txtimer,
+				      STMMAC_COAL_TIMER(tx_coal_timer),
+				      HRTIMER_MODE_REL);
+	} else {
 		hrtimer_try_to_cancel(&tx_q->txtimer);
+	}
 }
 
 /**
-- 
2.43.7