r8169: remove unneeded mmiowb barriers

hkallweit · davem330 · commit eb160971af7a · 2019-02-18T16:38:25.000-08:00
writex() has implicit barriers, that's what makes it different from
writex_relaxed(). Therefore these calls to mmiowb() can be removed.

This patch was recently reverted due to a dependency with another
problematic patch. But because it didn't contribute to the problem
it was rebased and can be resubmitted.

Signed-off-by: Heiner Kallweit &lt;hkallweit1@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
@@ -1288,13 +1288,11 @@ static u8 rtl8168d_efuse_read(struct rtl8169_private *tp, int reg_addr)
 static void rtl_ack_events(struct rtl8169_private *tp, u16 bits)
 {
 	RTL_W16(tp, IntrStatus, bits);
-	mmiowb();
 }
 
 static void rtl_irq_disable(struct rtl8169_private *tp)
 {
 	RTL_W16(tp, IntrMask, 0);
-	mmiowb();
 }
 
 #define RTL_EVENT_NAPI_RX	(RxOK | RxErr)
@@ -6251,8 +6249,6 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 
 	RTL_W8(tp, TxPoll, NPQ);
 
-	mmiowb();
-
 	if (!rtl_tx_slots_avail(tp, MAX_SKB_FRAGS)) {
 		/* Avoid wrongly optimistic queue wake-up: rtl_tx thread must
 		 * not miss a ring update when it notices a stopped queue.
@@ -6597,9 +6593,7 @@ static int rtl8169_poll(struct napi_struct *napi, int budget)
 
 	if (work_done < budget) {
 		napi_complete_done(napi, work_done);
-
 		rtl_irq_enable(tp);
-		mmiowb();
 	}
 
 	return work_done;

Original file line number	Diff line number	Diff line change
`@@ -1288,13 +1288,11 @@ static u8 rtl8168d_efuse_read(struct rtl8169_private *tp, int reg_addr)`
`1288`	`1288`	`static void rtl_ack_events(struct rtl8169_private *tp, u16 bits)`
`1289`	`1289`	`{`
`1290`	`1290`	`RTL_W16(tp, IntrStatus, bits);`
`1291`		`- mmiowb();`
`1292`	`1291`	`}`
`1293`	`1292`
`1294`	`1293`	`static void rtl_irq_disable(struct rtl8169_private *tp)`
`1295`	`1294`	`{`
`1296`	`1295`	`RTL_W16(tp, IntrMask, 0);`
`1297`		`- mmiowb();`
`1298`	`1296`	`}`
`1299`	`1297`
`1300`	`1298`	`#define RTL_EVENT_NAPI_RX (RxOK \| RxErr)`
`@@ -6251,8 +6249,6 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,`
`6251`	`6249`
`6252`	`6250`	`RTL_W8(tp, TxPoll, NPQ);`
`6253`	`6251`
`6254`		`- mmiowb();`
`6255`		`-`
`6256`	`6252`	`if (!rtl_tx_slots_avail(tp, MAX_SKB_FRAGS)) {`
`6257`	`6253`	`/* Avoid wrongly optimistic queue wake-up: rtl_tx thread must`
`6258`	`6254`	`* not miss a ring update when it notices a stopped queue.`
`@@ -6597,9 +6593,7 @@ static int rtl8169_poll(struct napi_struct *napi, int budget)`
`6597`	`6593`
`6598`	`6594`	`if (work_done < budget) {`
`6599`	`6595`	`napi_complete_done(napi, work_done);`
`6600`		`-`
`6601`	`6596`	`rtl_irq_enable(tp);`
`6602`		`- mmiowb();`
`6603`	`6597`	`}`
`6604`	`6598`
`6605`	`6599`	`return work_done;`