[PATCH net-next 00/10] LAN7800 driver improvements

[PATCH net-next 00/10] LAN7800 driver improvements

[John Efstathiades]

This patch set introduces a number of improvements and fixes for
problems found during testing of a modification to add a NAPI-style
approach to packet handling to improve performance.

NOTE: the NAPI changes are not part of this patch set and the issues
      fixed by this patch set are not coupled to the NAPI changes.

Patch 1 fixes white space and style issues.

Patch 2 removes an unused timer.

Patch 3 introduces macros to set the internal packet FIFO flow
control levels, which makes it easier to update the levels in future.

Patch 4 removes an unused queue.

Patch 5 stops the device initiating USB link power management state
transitions that can introduce a packet transmit latency with some
USB 3 hosts and hubs.

Patch 6 updates the LAN7800 MAC reset code to ensure there is no
PHY register access in progress when the MAC is reset. This change
prevents a kernel exception that can otherwise occur.

Patch 7 fixes problems with system suspend and resume handling while
the device is transmitting and receiving data.

Patch 8 fixes problems with auto-suspend and resume handling and
depends on changes introduced by patch 7.

Patch 9 fixes problems with device disconnect handling that can result
in kernel exceptions and/or hang.

Patch 10 limits the rate at which driver warning messages are emitted.

John Efstathiades (10):
  lan78xx: Fix white space and style issues
  lan78xx: Remove unused timer
  lan78xx: Set flow control threshold to prevent packet loss
  lan78xx: Remove unused pause frame queue
  lan78xx: Disable USB3 link power state transitions
  lan78xx: Fix exception on link speed change
  lan78xx: Fix partial packet errors on suspend/resume
  lan78xx: Fix race conditions in suspend/resume handling
  lan78xx: Fix race condition in disconnect handling
  lan78xx: Limit number of driver warning messages

 drivers/net/usb/lan78xx.c | 1074 +++++++++++++++++++++++++++++--------
 1 file changed, 846 insertions(+), 228 deletions(-)

-- 
2.25.1

[PATCH net-next 01/10] lan78xx: Fix white space and style issues

[John Efstathiades]

Fix white space and code style issues identified by checkpatch.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 80 ++++++++++++++++++++-------------------
 1 file changed, 42 insertions(+), 38 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 4e8d3c28f73e..ece044dd0236 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -382,7 +382,7 @@ struct lan78xx_net {
 	struct usb_anchor	deferred;
 
 	struct mutex		phy_mutex; /* for phy access */
-	unsigned		pipe_in, pipe_out, pipe_intr;
+	unsigned int		pipe_in, pipe_out, pipe_intr;
 
 	u32			hard_mtu;	/* count any extra framing */
 	size_t			rx_urb_size;	/* size for rx urbs */
@@ -392,7 +392,7 @@ struct lan78xx_net {
 	wait_queue_head_t	*wait;
 	unsigned char		suspend_count;
 
-	unsigned		maxpacket;
+	unsigned int		maxpacket;
 	struct timer_list	delay;
 	struct timer_list	stat_monitor;
 
@@ -501,7 +501,7 @@ static int lan78xx_read_stats(struct lan78xx_net *dev,
 	if (likely(ret >= 0)) {
 		src = (u32 *)stats;
 		dst = (u32 *)data;
-		for (i = 0; i < sizeof(*stats)/sizeof(u32); i++) {
+		for (i = 0; i < sizeof(*stats) / sizeof(u32); i++) {
 			le32_to_cpus(&src[i]);
 			dst[i] = src[i];
 		}
@@ -515,10 +515,11 @@ static int lan78xx_read_stats(struct lan78xx_net *dev,
 	return ret;
 }
 
-#define check_counter_rollover(struct1, dev_stats, member) {	\
-	if (struct1->member < dev_stats.saved.member)		\
-		dev_stats.rollover_count.member++;		\
-	}
+#define check_counter_rollover(struct1, dev_stats, member)		\
+	do {								\
+		if ((struct1)->member < (dev_stats).saved.member)	\
+			(dev_stats).rollover_count.member++;		\
+	} while (0)
 
 static void lan78xx_check_stat_rollover(struct lan78xx_net *dev,
 					struct lan78xx_statstage *stats)
@@ -844,9 +845,9 @@ static int lan78xx_read_raw_otp(struct lan78xx_net *dev, u32 offset,
 
 	for (i = 0; i < length; i++) {
 		lan78xx_write_reg(dev, OTP_ADDR1,
-					((offset + i) >> 8) & OTP_ADDR1_15_11);
+				  ((offset + i) >> 8) & OTP_ADDR1_15_11);
 		lan78xx_write_reg(dev, OTP_ADDR2,
-					((offset + i) & OTP_ADDR2_10_3));
+				  ((offset + i) & OTP_ADDR2_10_3));
 
 		lan78xx_write_reg(dev, OTP_FUNC_CMD, OTP_FUNC_CMD_READ_);
 		lan78xx_write_reg(dev, OTP_CMD_GO, OTP_CMD_GO_GO_);
@@ -900,9 +901,9 @@ static int lan78xx_write_raw_otp(struct lan78xx_net *dev, u32 offset,
 
 	for (i = 0; i < length; i++) {
 		lan78xx_write_reg(dev, OTP_ADDR1,
-					((offset + i) >> 8) & OTP_ADDR1_15_11);
+				  ((offset + i) >> 8) & OTP_ADDR1_15_11);
 		lan78xx_write_reg(dev, OTP_ADDR2,
-					((offset + i) & OTP_ADDR2_10_3));
+				  ((offset + i) & OTP_ADDR2_10_3));
 		lan78xx_write_reg(dev, OTP_PRGM_DATA, data[i]);
 		lan78xx_write_reg(dev, OTP_TST_CMD, OTP_TST_CMD_PRGVRFY_);
 		lan78xx_write_reg(dev, OTP_CMD_GO, OTP_CMD_GO_GO_);
@@ -959,7 +960,7 @@ static int lan78xx_dataport_wait_not_busy(struct lan78xx_net *dev)
 		usleep_range(40, 100);
 	}
 
-	netdev_warn(dev->net, "lan78xx_dataport_wait_not_busy timed out");
+	netdev_warn(dev->net, "%s timed out", __func__);
 
 	return -EIO;
 }
@@ -972,7 +973,7 @@ static int lan78xx_dataport_write(struct lan78xx_net *dev, u32 ram_select,
 	int i, ret;
 
 	if (usb_autopm_get_interface(dev->intf) < 0)
-			return 0;
+		return 0;
 
 	mutex_lock(&pdata->dataport_mutex);
 
@@ -1045,9 +1046,9 @@ static void lan78xx_deferred_multicast_write(struct work_struct *param)
 	for (i = 1; i < NUM_OF_MAF; i++) {
 		lan78xx_write_reg(dev, MAF_HI(i), 0);
 		lan78xx_write_reg(dev, MAF_LO(i),
-					pdata->pfilter_table[i][1]);
+				  pdata->pfilter_table[i][1]);
 		lan78xx_write_reg(dev, MAF_HI(i),
-					pdata->pfilter_table[i][0]);
+				  pdata->pfilter_table[i][0]);
 	}
 
 	lan78xx_write_reg(dev, RFE_CTL, pdata->rfe_ctl);
@@ -1066,11 +1067,12 @@ static void lan78xx_set_multicast(struct net_device *netdev)
 			    RFE_CTL_DA_PERFECT_ | RFE_CTL_MCAST_HASH_);
 
 	for (i = 0; i < DP_SEL_VHF_HASH_LEN; i++)
-			pdata->mchash_table[i] = 0;
+		pdata->mchash_table[i] = 0;
+
 	/* pfilter_table[0] has own HW address */
 	for (i = 1; i < NUM_OF_MAF; i++) {
-			pdata->pfilter_table[i][0] =
-			pdata->pfilter_table[i][1] = 0;
+		pdata->pfilter_table[i][0] = 0;
+		pdata->pfilter_table[i][1] = 0;
 	}
 
 	pdata->rfe_ctl |= RFE_CTL_BCAST_EN_;
@@ -1264,9 +1266,10 @@ static void lan78xx_status(struct lan78xx_net *dev, struct urb *urb)
 			generic_handle_irq(dev->domain_data.phyirq);
 			local_irq_enable();
 		}
-	} else
+	} else {
 		netdev_warn(dev->net,
 			    "unexpected interrupt: 0x%08x\n", intdata);
+	}
 }
 
 static int lan78xx_ethtool_get_eeprom_len(struct net_device *netdev)
@@ -1355,7 +1358,7 @@ static void lan78xx_get_wol(struct net_device *netdev,
 	struct lan78xx_priv *pdata = (struct lan78xx_priv *)(dev->data[0]);
 
 	if (usb_autopm_get_interface(dev->intf) < 0)
-			return;
+		return;
 
 	ret = lan78xx_read_reg(dev, USB_CFG0, &buf);
 	if (unlikely(ret < 0)) {
@@ -2003,7 +2006,7 @@ static int lan8835_fixup(struct phy_device *phydev)
 
 	/* RGMII MAC TXC Delay Enable */
 	lan78xx_write_reg(dev, MAC_RGMII_ID,
-				MAC_RGMII_ID_TXC_DELAY_EN_);
+			  MAC_RGMII_ID_TXC_DELAY_EN_);
 
 	/* RGMII TX DLL Tune Adjust */
 	lan78xx_write_reg(dev, RGMII_TX_BYP_DLL, 0x3D00);
@@ -3356,9 +3359,10 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev)
 		if (skb)
 			dev_kfree_skb_any(skb);
 		usb_free_urb(urb);
-	} else
+	} else {
 		netif_dbg(dev, tx_queued, dev->net,
 			  "> tx, len %d, type 0x%x\n", length, skb->protocol);
+	}
 }
 
 static void lan78xx_rx_bh(struct lan78xx_net *dev)
@@ -3459,7 +3463,7 @@ static void lan78xx_delayedwork(struct work_struct *work)
 		unlink_urbs(dev, &dev->rxq);
 		status = usb_autopm_get_interface(dev->intf);
 		if (status < 0)
-				goto fail_halt;
+			goto fail_halt;
 		status = usb_clear_halt(dev->udev, dev->pipe_in);
 		usb_autopm_put_interface(dev->intf);
 		if (status < 0 &&
@@ -3632,8 +3636,8 @@ static int lan78xx_probe(struct usb_interface *intf,
 	struct net_device *netdev;
 	struct usb_device *udev;
 	int ret;
-	unsigned maxp;
-	unsigned period;
+	unsigned int maxp;
+	unsigned int period;
 	u8 *buf = NULL;
 
 	udev = interface_to_usbdev(intf);
@@ -3858,10 +3862,10 @@ static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 		/* set WUF_CFG & WUF_MASK for IPv4 Multicast */
 		crc = lan78xx_wakeframe_crc16(ipv4_multicast, 3);
 		lan78xx_write_reg(dev, WUF_CFG(mask_index),
-					WUF_CFGX_EN_ |
-					WUF_CFGX_TYPE_MCAST_ |
-					(0 << WUF_CFGX_OFFSET_SHIFT_) |
-					(crc & WUF_CFGX_CRC16_MASK_));
+				  WUF_CFGX_EN_ |
+				  WUF_CFGX_TYPE_MCAST_ |
+				  (0 << WUF_CFGX_OFFSET_SHIFT_) |
+				  (crc & WUF_CFGX_CRC16_MASK_));
 
 		lan78xx_write_reg(dev, WUF_MASK0(mask_index), 7);
 		lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
@@ -3872,10 +3876,10 @@ static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 		/* for IPv6 Multicast */
 		crc = lan78xx_wakeframe_crc16(ipv6_multicast, 2);
 		lan78xx_write_reg(dev, WUF_CFG(mask_index),
-					WUF_CFGX_EN_ |
-					WUF_CFGX_TYPE_MCAST_ |
-					(0 << WUF_CFGX_OFFSET_SHIFT_) |
-					(crc & WUF_CFGX_CRC16_MASK_));
+				  WUF_CFGX_EN_ |
+				  WUF_CFGX_TYPE_MCAST_ |
+				  (0 << WUF_CFGX_OFFSET_SHIFT_) |
+				  (crc & WUF_CFGX_CRC16_MASK_));
 
 		lan78xx_write_reg(dev, WUF_MASK0(mask_index), 3);
 		lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
@@ -3902,10 +3906,10 @@ static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 		 */
 		crc = lan78xx_wakeframe_crc16(arp_type, 2);
 		lan78xx_write_reg(dev, WUF_CFG(mask_index),
-					WUF_CFGX_EN_ |
-					WUF_CFGX_TYPE_ALL_ |
-					(0 << WUF_CFGX_OFFSET_SHIFT_) |
-					(crc & WUF_CFGX_CRC16_MASK_));
+				  WUF_CFGX_EN_ |
+				  WUF_CFGX_TYPE_ALL_ |
+				  (0 << WUF_CFGX_OFFSET_SHIFT_) |
+				  (crc & WUF_CFGX_CRC16_MASK_));
 
 		lan78xx_write_reg(dev, WUF_MASK0(mask_index), 0x3000);
 		lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
@@ -4050,7 +4054,7 @@ static int lan78xx_resume(struct usb_interface *intf)
 	if (!--dev->suspend_count) {
 		/* resume interrupt URBs */
 		if (dev->urb_intr && test_bit(EVENT_DEV_OPEN, &dev->flags))
-				usb_submit_urb(dev->urb_intr, GFP_NOIO);
+			usb_submit_urb(dev->urb_intr, GFP_NOIO);
 
 		spin_lock_irq(&dev->txq.lock);
 		while ((res = usb_get_from_anchor(&dev->deferred))) {
-- 
2.25.1

[PATCH net-next 02/10] lan78xx: Remove unused timer

[John Efstathiades]

Remove kernel timer that is not used by the driver.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index ece044dd0236..2896d31e5573 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -393,7 +393,6 @@ struct lan78xx_net {
 	unsigned char		suspend_count;
 
 	unsigned int		maxpacket;
-	struct timer_list	delay;
 	struct timer_list	stat_monitor;
 
 	unsigned long		data[5];
@@ -3425,8 +3424,7 @@ static void lan78xx_bh(struct tasklet_struct *t)
 		if (!skb_queue_empty(&dev->txq_pend))
 			lan78xx_tx_bh(dev);
 
-		if (!timer_pending(&dev->delay) &&
-		    !test_bit(EVENT_RX_HALT, &dev->flags))
+		if (!test_bit(EVENT_RX_HALT, &dev->flags))
 			lan78xx_rx_bh(dev);
 	}
 }
-- 
2.25.1

[PATCH net-next 03/10] lan78xx: Set flow control threshold to prevent packet loss

[John Efstathiades]

Set threshold at which flow control is triggered to 3/4 full of
the internal Rx packet FIFO to prevent packet drops at high data
rates. The new setting reduces the number of dropped UDP frames
and TCP retransmit requests especially on less capable CPUs.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 2896d31e5573..ccfb2d47932d 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -46,6 +46,19 @@
 
 #define MAX_RX_FIFO_SIZE		(12 * 1024)
 #define MAX_TX_FIFO_SIZE		(12 * 1024)
+
+#define FLOW_THRESHOLD(n)		((((n) + 511) / 512) & 0x7F)
+#define FLOW_CTRL_THRESHOLD(on, off)	((FLOW_THRESHOLD(on)  << 0) | \
+					 (FLOW_THRESHOLD(off) << 8))
+
+/* Flow control turned on when Rx FIFO level rises above this level (bytes) */
+#define FLOW_ON_SS			9216
+#define FLOW_ON_HS			8704
+
+/* Flow control turned off when Rx FIFO level falls below this level (bytes) */
+#define FLOW_OFF_SS			4096
+#define FLOW_OFF_HS			1024
+
 #define DEFAULT_BURST_CAP_SIZE		(MAX_TX_FIFO_SIZE)
 #define DEFAULT_BULK_IN_DELAY		(0x0800)
 #define MAX_SINGLE_PACKET_SIZE		(9000)
@@ -1135,9 +1148,9 @@ static int lan78xx_update_flowcontrol(struct lan78xx_net *dev, u8 duplex,
 		flow |= FLOW_CR_RX_FCEN_;
 
 	if (dev->udev->speed == USB_SPEED_SUPER)
-		fct_flow = 0x817;
+		fct_flow = FLOW_CTRL_THRESHOLD(FLOW_ON_SS, FLOW_OFF_SS);
 	else if (dev->udev->speed == USB_SPEED_HIGH)
-		fct_flow = 0x211;
+		fct_flow = FLOW_CTRL_THRESHOLD(FLOW_ON_HS, FLOW_OFF_HS);
 
 	netif_dbg(dev, link, dev->net, "rx pause %s, tx pause %s",
 		  (cap & FLOW_CTRL_RX ? "enabled" : "disabled"),
-- 
2.25.1

[PATCH net-next 04/10] lan78xx: Remove unused pause frame queue

[John Efstathiades]

Remove the pause frame queue from the driver. It is initialised
but not actually used.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index ccfb2d47932d..746aeeaa9d6e 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -383,7 +383,6 @@ struct lan78xx_net {
 	struct sk_buff_head	rxq;
 	struct sk_buff_head	txq;
 	struct sk_buff_head	done;
-	struct sk_buff_head	rxq_pause;
 	struct sk_buff_head	txq_pend;
 
 	struct tasklet_struct	bh;
@@ -2710,8 +2709,6 @@ static int lan78xx_stop(struct net_device *net)
 
 	usb_kill_urb(dev->urb_intr);
 
-	skb_queue_purge(&dev->rxq_pause);
-
 	/* deferred work (task, timer, softirq) must also stop.
 	 * can't flush_scheduled_work() until we drop rtnl (later),
 	 * else workers could deadlock; so make workers a NOP.
@@ -3003,11 +3000,6 @@ static void lan78xx_skb_return(struct lan78xx_net *dev, struct sk_buff *skb)
 {
 	int status;
 
-	if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
-		skb_queue_tail(&dev->rxq_pause, skb);
-		return;
-	}
-
 	dev->net->stats.rx_packets++;
 	dev->net->stats.rx_bytes += skb->len;
 
@@ -3674,7 +3666,6 @@ static int lan78xx_probe(struct usb_interface *intf,
 	skb_queue_head_init(&dev->rxq);
 	skb_queue_head_init(&dev->txq);
 	skb_queue_head_init(&dev->done);
-	skb_queue_head_init(&dev->rxq_pause);
 	skb_queue_head_init(&dev->txq_pend);
 	mutex_init(&dev->phy_mutex);
 
-- 
2.25.1

[PATCH net-next 05/10] lan78xx: Disable USB3 link power state transitions

[John Efstathiades]

Disable USB3 link power state transitions from U0 (Fully Powered) to
U1 (Standby with Fast Recovery) or U2 (Standby with Slow Recovery).

The device can initiate U1 and U2 state transitions when there is no
activity on the bus which can save power. However, testing with some
USB3 hosts and hubs showed erratic ping response time due to the time
required to transition back to U0 state.

In the following example the outgoing packets were delayed until the
device transitioned from U2 back to U0 giving the misleading
response time.

console:/data/local # ping 192.168.73.1
PING 192.168.73.1 (192.168.73.1) 56(84) bytes of data.
64 bytes from 192.168.73.1: icmp_seq=1 ttl=64 time=466 ms
64 bytes from 192.168.73.1: icmp_seq=2 ttl=64 time=225 ms
64 bytes from 192.168.73.1: icmp_seq=3 ttl=64 time=155 ms
64 bytes from 192.168.73.1: icmp_seq=4 ttl=64 time=7.07 ms
64 bytes from 192.168.73.1: icmp_seq=5 ttl=64 time=141 ms
64 bytes from 192.168.73.1: icmp_seq=6 ttl=64 time=152 ms
64 bytes from 192.168.73.1: icmp_seq=7 ttl=64 time=51.9 ms
64 bytes from 192.168.73.1: icmp_seq=8 ttl=64 time=136 ms

The following shows the behaviour when the U1 and U2 transitions
were disabled.

console:/data/local # ping 192.168.73.1
PING 192.168.73.1 (192.168.73.1) 56(84) bytes of data.
64 bytes from 192.168.73.1: icmp_seq=1 ttl=64 time=6.66 ms
64 bytes from 192.168.73.1: icmp_seq=2 ttl=64 time=2.97 ms
64 bytes from 192.168.73.1: icmp_seq=3 ttl=64 time=2.02 ms
64 bytes from 192.168.73.1: icmp_seq=4 ttl=64 time=2.42 ms
64 bytes from 192.168.73.1: icmp_seq=5 ttl=64 time=2.47 ms
64 bytes from 192.168.73.1: icmp_seq=6 ttl=64 time=2.55 ms
64 bytes from 192.168.73.1: icmp_seq=7 ttl=64 time=2.43 ms
64 bytes from 192.168.73.1: icmp_seq=8 ttl=64 time=2.13 ms

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 44 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 5 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 746aeeaa9d6e..3181753b1621 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -430,6 +430,12 @@ struct lan78xx_net {
 #define	PHY_LAN8835			(0x0007C130)
 #define	PHY_KSZ9031RNX			(0x00221620)
 
+/* Enabling link power state transitions will reduce power consumption
+ * when the link is idle. However, this can cause problems with some
+ * USB3 hubs resulting in erratic packet flow.
+ */
+static bool enable_link_power_states;
+
 /* use ethtool to change the level for any given device */
 static int msg_level = -1;
 module_param(msg_level, int, 0);
@@ -1173,7 +1179,7 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
 	/* clear LAN78xx interrupt status */
 	ret = lan78xx_write_reg(dev, INT_STS, INT_STS_PHY_INT_);
 	if (unlikely(ret < 0))
-		return -EIO;
+		return ret;
 
 	mutex_lock(&phydev->lock);
 	phy_read_status(phydev);
@@ -1186,11 +1192,11 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
 		/* reset MAC */
 		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
 		if (unlikely(ret < 0))
-			return -EIO;
+			return ret;
 		buf |= MAC_CR_RST_;
 		ret = lan78xx_write_reg(dev, MAC_CR, buf);
 		if (unlikely(ret < 0))
-			return -EIO;
+			return ret;
 
 		del_timer(&dev->stat_monitor);
 	} else if (link && !dev->link_on) {
@@ -1198,23 +1204,49 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
 
 		phy_ethtool_ksettings_get(phydev, &ecmd);
 
-		if (dev->udev->speed == USB_SPEED_SUPER) {
+		if (enable_link_power_states &&
+		    dev->udev->speed == USB_SPEED_SUPER) {
 			if (ecmd.base.speed == 1000) {
 				/* disable U2 */
 				ret = lan78xx_read_reg(dev, USB_CFG1, &buf);
+				if (ret < 0)
+					return ret;
 				buf &= ~USB_CFG1_DEV_U2_INIT_EN_;
 				ret = lan78xx_write_reg(dev, USB_CFG1, buf);
+				if (ret < 0)
+					return ret;
 				/* enable U1 */
 				ret = lan78xx_read_reg(dev, USB_CFG1, &buf);
+				if (ret < 0)
+					return ret;
 				buf |= USB_CFG1_DEV_U1_INIT_EN_;
 				ret = lan78xx_write_reg(dev, USB_CFG1, buf);
+				if (ret < 0)
+					return ret;
 			} else {
 				/* enable U1 & U2 */
 				ret = lan78xx_read_reg(dev, USB_CFG1, &buf);
+				if (ret < 0)
+					return ret;
 				buf |= USB_CFG1_DEV_U2_INIT_EN_;
 				buf |= USB_CFG1_DEV_U1_INIT_EN_;
 				ret = lan78xx_write_reg(dev, USB_CFG1, buf);
+				if (ret < 0)
+					return ret;
 			}
+		} else {
+			/* Disabling initiation of U1 and U2 transitions
+			 * prevents erratic ping times when connected to
+			 * some USB3 hubs.
+			 */
+			ret = lan78xx_read_reg(dev, USB_CFG1, &buf);
+			if (ret < 0)
+				return ret;
+			buf &= ~USB_CFG1_DEV_U2_INIT_EN_;
+			buf &= ~USB_CFG1_DEV_U1_INIT_EN_;
+			ret = lan78xx_write_reg(dev, USB_CFG1, buf);
+			if (ret < 0)
+				return ret;
 		}
 
 		ladv = phy_read(phydev, MII_ADVERTISE);
@@ -1231,6 +1263,8 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
 
 		ret = lan78xx_update_flowcontrol(dev, ecmd.base.duplex, ladv,
 						 radv);
+		if (ret < 0)
+			return ret;
 
 		if (!timer_pending(&dev->stat_monitor)) {
 			dev->delta = 1;
@@ -1241,7 +1275,7 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
 		tasklet_schedule(&dev->bh);
 	}
 
-	return ret;
+	return 0;
 }
 
 /* some work can't be done in tasklets, so we use keventd
-- 
2.25.1

[PATCH net-next 06/10] lan78xx: Fix exception on link speed change

[John Efstathiades]

An exception is sometimes seen when the link speed is changed
from auto-negotiation to a fixed speed, or vice versa. The
exception occurs when the MAC is reset (due to the link speed
change) at the same time as the PHY state machine is accessing
a PHY register. The following changes fix this problem.

Rework the MAC reset to ensure there is no outstanding MDIO
register transaction before the reset and then wait until the
reset is complete before allowing any further MAC register access.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 54 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 48 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 3181753b1621..9be823616dd7 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -1169,6 +1169,52 @@ static int lan78xx_update_flowcontrol(struct lan78xx_net *dev, u8 duplex,
 	return 0;
 }
 
+static int lan78xx_mac_reset(struct lan78xx_net *dev)
+{
+	unsigned long start_time = jiffies;
+	u32 val;
+	int ret;
+
+	mutex_lock(&dev->phy_mutex);
+
+	/* Resetting the device while there is activity on the MDIO
+	 * bus can result in the MAC interface locking up and not
+	 * completing register access transactions.
+	 */
+	ret = lan78xx_phy_wait_not_busy(dev);
+	if (ret < 0)
+		goto done;
+
+	ret = lan78xx_read_reg(dev, MAC_CR, &val);
+	if (ret < 0)
+		goto done;
+
+	val |= MAC_CR_RST_;
+	ret = lan78xx_write_reg(dev, MAC_CR, val);
+	if (ret < 0)
+		goto done;
+
+	/* Wait for the reset to complete before allowing any further
+	 * MAC register accesses otherwise the MAC may lock up.
+	 */
+	do {
+		ret = lan78xx_read_reg(dev, MAC_CR, &val);
+		if (ret < 0)
+			goto done;
+
+		if (!(val & MAC_CR_RST_)) {
+			ret = 0;
+			goto done;
+		}
+	} while (!time_after(jiffies, start_time + HZ));
+
+	ret = -ETIME;
+done:
+	mutex_unlock(&dev->phy_mutex);
+
+	return ret;
+}
+
 static int lan78xx_link_reset(struct lan78xx_net *dev)
 {
 	struct phy_device *phydev = dev->net->phydev;
@@ -1190,12 +1236,8 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
 		dev->link_on = false;
 
 		/* reset MAC */
-		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
-		if (unlikely(ret < 0))
-			return ret;
-		buf |= MAC_CR_RST_;
-		ret = lan78xx_write_reg(dev, MAC_CR, buf);
-		if (unlikely(ret < 0))
+		ret = lan78xx_mac_reset(dev);
+		if (ret < 0)
 			return ret;
 
 		del_timer(&dev->stat_monitor);
-- 
2.25.1

[PATCH net-next 07/10] lan78xx: Fix partial packet errors on suspend/resume

[John Efstathiades]

The MAC can get out of step with the internal packet FIFOs if the
system goes to sleep when the link is active, especially at high
data rates. This can result in partial frames in the packet FIFOs
that in result in malformed frames being delivered to the host.
This occurs because the driver does not enable/disable the internal
packet FIFOs in step with the corresponding MAC data path. The
following changes fix this problem.

Update code that enables/disables the MAC receiver and transmitter
to the more general Rx and Tx data path, where the data path in each
direction consists of both the MAC function (Tx or Rx) and the
corresponding packet FIFO.

In the receive path the packet FIFO must be enabled before the MAC
receiver but disabled after the MAC receiver.

In the transmit path the opposite is true: the packet FIFO must be
enabled after the MAC transmitter but disabled before the MAC
transmitter.

The packet FIFOs can be flushed safely once the corresponding data
path is stopped.

This patch also adds checks for errors during data path enable and
disable. There is an immediate return from the calling function if
an error is detected. This prevents a cascade of errors that would
otherwise occur.

To maintain consistency with the data path error check and early
exit policy, each register access in lan78xx_suspend() and
lan78xx_resume() is checked for errors. If an error is detected
there is an immediate exit from the calling function.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 546 ++++++++++++++++++++++++++++++--------
 1 file changed, 442 insertions(+), 104 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 9be823616dd7..096304c1b5f4 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -100,6 +100,12 @@
 /* statistic update interval (mSec) */
 #define STAT_UPDATE_TIMER		(1 * 1000)
 
+/* time to wait for MAC or FCT to stop (jiffies) */
+#define HW_DISABLE_TIMEOUT		(HZ / 10)
+
+/* time to wait between polling MAC or FCT state (ms) */
+#define HW_DISABLE_DELAY_MS		1
+
 /* defines interrupts from interrupt EP */
 #define MAX_INT_EP			(32)
 #define INT_EP_INTEP			(31)
@@ -493,6 +499,26 @@ static int lan78xx_write_reg(struct lan78xx_net *dev, u32 index, u32 data)
 	return ret;
 }
 
+static int lan78xx_update_reg(struct lan78xx_net *dev, u32 reg, u32 mask,
+			      u32 data)
+{
+	int ret;
+	u32 buf;
+
+	ret = lan78xx_read_reg(dev, reg, &buf);
+	if (ret < 0)
+		return ret;
+
+	buf &= ~mask;
+	buf |= (mask & data);
+
+	ret = lan78xx_write_reg(dev, reg, buf);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 static int lan78xx_read_stats(struct lan78xx_net *dev,
 			      struct lan78xx_statstage *data)
 {
@@ -2533,26 +2559,186 @@ static void lan78xx_init_ltm(struct lan78xx_net *dev)
 	lan78xx_write_reg(dev, LTM_INACTIVE1, regs[5]);
 }
 
+static int lan78xx_start_hw(struct lan78xx_net *dev, u32 reg, u32 hw_enable)
+{
+	return lan78xx_update_reg(dev, reg, hw_enable, hw_enable);
+}
+
+static int lan78xx_stop_hw(struct lan78xx_net *dev, u32 reg, u32 hw_enabled,
+			   u32 hw_disabled)
+{
+	unsigned long timeout;
+	bool stopped = true;
+	int ret;
+	u32 buf;
+
+	/* Stop the h/w block (if not already stopped) */
+
+	ret = lan78xx_read_reg(dev, reg, &buf);
+	if (ret < 0)
+		return ret;
+
+	if (buf & hw_enabled) {
+		buf &= ~hw_enabled;
+
+		ret = lan78xx_write_reg(dev, reg, buf);
+		if (ret < 0)
+			return ret;
+
+		stopped = false;
+		timeout = jiffies + HW_DISABLE_TIMEOUT;
+		do  {
+			ret = lan78xx_read_reg(dev, reg, &buf);
+			if (ret < 0)
+				return ret;
+
+			if (buf & hw_disabled)
+				stopped = true;
+			else
+				msleep(HW_DISABLE_DELAY_MS);
+		} while (!stopped && !time_after(jiffies, timeout));
+	}
+
+	ret = stopped ? 0 : -ETIME;
+
+	return ret;
+}
+
+static int lan78xx_flush_fifo(struct lan78xx_net *dev, u32 reg, u32 fifo_flush)
+{
+	return lan78xx_update_reg(dev, reg, fifo_flush, fifo_flush);
+}
+
+static int lan78xx_start_tx_path(struct lan78xx_net *dev)
+{
+	int ret;
+
+	netif_dbg(dev, drv, dev->net, "start tx path");
+
+	/* Start the MAC transmitter */
+
+	ret = lan78xx_start_hw(dev, MAC_TX, MAC_TX_TXEN_);
+	if (ret < 0)
+		return ret;
+
+	/* Start the Tx FIFO */
+
+	ret = lan78xx_start_hw(dev, FCT_TX_CTL, FCT_TX_CTL_EN_);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int lan78xx_stop_tx_path(struct lan78xx_net *dev)
+{
+	int ret;
+
+	netif_dbg(dev, drv, dev->net, "stop tx path");
+
+	/* Stop the Tx FIFO */
+
+	ret = lan78xx_stop_hw(dev, FCT_TX_CTL, FCT_TX_CTL_EN_, FCT_TX_CTL_DIS_);
+	if (ret < 0)
+		return ret;
+
+	/* Stop the MAC transmitter */
+
+	ret = lan78xx_stop_hw(dev, MAC_TX, MAC_TX_TXEN_, MAC_TX_TXD_);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+/* The caller must ensure the Tx path is stopped before calling
+ * lan78xx_flush_tx_fifo().
+ */
+static int lan78xx_flush_tx_fifo(struct lan78xx_net *dev)
+{
+	return lan78xx_flush_fifo(dev, FCT_TX_CTL, FCT_TX_CTL_RST_);
+}
+
+static int lan78xx_start_rx_path(struct lan78xx_net *dev)
+{
+	int ret;
+
+	netif_dbg(dev, drv, dev->net, "start rx path");
+
+	/* Start the Rx FIFO */
+
+	ret = lan78xx_start_hw(dev, FCT_RX_CTL, FCT_RX_CTL_EN_);
+	if (ret < 0)
+		return ret;
+
+	/* Start the MAC receiver*/
+
+	ret = lan78xx_start_hw(dev, MAC_RX, MAC_RX_RXEN_);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int lan78xx_stop_rx_path(struct lan78xx_net *dev)
+{
+	int ret;
+
+	netif_dbg(dev, drv, dev->net, "stop rx path");
+
+	/* Stop the MAC receiver */
+
+	ret = lan78xx_stop_hw(dev, MAC_RX, MAC_RX_RXEN_, MAC_RX_RXD_);
+	if (ret < 0)
+		return ret;
+
+	/* Stop the Rx FIFO */
+
+	ret = lan78xx_stop_hw(dev, FCT_RX_CTL, FCT_RX_CTL_EN_, FCT_RX_CTL_DIS_);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+/* The caller must ensure the Rx path is stopped before calling
+ * lan78xx_flush_rx_fifo().
+ */
+static int lan78xx_flush_rx_fifo(struct lan78xx_net *dev)
+{
+	return lan78xx_flush_fifo(dev, FCT_RX_CTL, FCT_RX_CTL_RST_);
+}
+
 static int lan78xx_reset(struct lan78xx_net *dev)
 {
 	struct lan78xx_priv *pdata = (struct lan78xx_priv *)(dev->data[0]);
-	u32 buf;
-	int ret = 0;
 	unsigned long timeout;
+	int ret;
+	u32 buf;
 	u8 sig;
 
 	ret = lan78xx_read_reg(dev, HW_CFG, &buf);
+	if (ret < 0)
+		return ret;
+
 	buf |= HW_CFG_LRST_;
+
 	ret = lan78xx_write_reg(dev, HW_CFG, buf);
+	if (ret < 0)
+		return ret;
 
 	timeout = jiffies + HZ;
 	do {
 		mdelay(1);
 		ret = lan78xx_read_reg(dev, HW_CFG, &buf);
+		if (ret < 0)
+			return ret;
+
 		if (time_after(jiffies, timeout)) {
 			netdev_warn(dev->net,
 				    "timeout on completion of LiteReset");
-			return -EIO;
+			ret = -ETIME;
+			return ret;
 		}
 	} while (buf & HW_CFG_LRST_);
 
@@ -2560,13 +2746,22 @@ static int lan78xx_reset(struct lan78xx_net *dev)
 
 	/* save DEVID for later usage */
 	ret = lan78xx_read_reg(dev, ID_REV, &buf);
+	if (ret < 0)
+		return ret;
+
 	dev->chipid = (buf & ID_REV_CHIP_ID_MASK_) >> 16;
 	dev->chiprev = buf & ID_REV_CHIP_REV_MASK_;
 
 	/* Respond to the IN token with a NAK */
 	ret = lan78xx_read_reg(dev, USB_CFG0, &buf);
+	if (ret < 0)
+		return ret;
+
 	buf |= USB_CFG_BIR_;
+
 	ret = lan78xx_write_reg(dev, USB_CFG0, buf);
+	if (ret < 0)
+		return ret;
 
 	/* Init LTM */
 	lan78xx_init_ltm(dev);
@@ -2589,53 +2784,99 @@ static int lan78xx_reset(struct lan78xx_net *dev)
 	}
 
 	ret = lan78xx_write_reg(dev, BURST_CAP, buf);
+	if (ret < 0)
+		return ret;
 	ret = lan78xx_write_reg(dev, BULK_IN_DLY, DEFAULT_BULK_IN_DELAY);
+	if (ret < 0)
+		return ret;
 
 	ret = lan78xx_read_reg(dev, HW_CFG, &buf);
+	if (ret < 0)
+		return ret;
+
 	buf |= HW_CFG_MEF_;
+
 	ret = lan78xx_write_reg(dev, HW_CFG, buf);
+	if (ret < 0)
+		return ret;
 
 	ret = lan78xx_read_reg(dev, USB_CFG0, &buf);
+	if (ret < 0)
+		return ret;
 	buf |= USB_CFG_BCE_;
+
 	ret = lan78xx_write_reg(dev, USB_CFG0, buf);
+	if (ret < 0)
+		return ret;
 
 	/* set FIFO sizes */
 	buf = (MAX_RX_FIFO_SIZE - 512) / 512;
 	ret = lan78xx_write_reg(dev, FCT_RX_FIFO_END, buf);
+	if (ret < 0)
+		return ret;
 
 	buf = (MAX_TX_FIFO_SIZE - 512) / 512;
 	ret = lan78xx_write_reg(dev, FCT_TX_FIFO_END, buf);
+	if (ret < 0)
+		return ret;
 
 	ret = lan78xx_write_reg(dev, INT_STS, INT_STS_CLEAR_ALL_);
+	if (ret < 0)
+		return ret;
 	ret = lan78xx_write_reg(dev, FLOW, 0);
+	if (ret < 0)
+		return ret;
 	ret = lan78xx_write_reg(dev, FCT_FLOW, 0);
+	if (ret < 0)
+		return ret;
 
 	/* Don't need rfe_ctl_lock during initialisation */
 	ret = lan78xx_read_reg(dev, RFE_CTL, &pdata->rfe_ctl);
+	if (ret < 0)
+		return ret;
+
 	pdata->rfe_ctl |= RFE_CTL_BCAST_EN_ | RFE_CTL_DA_PERFECT_;
+
 	ret = lan78xx_write_reg(dev, RFE_CTL, pdata->rfe_ctl);
+	if (ret < 0)
+		return ret;
 
 	/* Enable or disable checksum offload engines */
-	lan78xx_set_features(dev->net, dev->net->features);
+	ret = lan78xx_set_features(dev->net, dev->net->features);
+	if (ret < 0)
+		return ret;
 
 	lan78xx_set_multicast(dev->net);
 
 	/* reset PHY */
 	ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+	if (ret < 0)
+		return ret;
+
 	buf |= PMT_CTL_PHY_RST_;
+
 	ret = lan78xx_write_reg(dev, PMT_CTL, buf);
+	if (ret < 0)
+		return ret;
 
 	timeout = jiffies + HZ;
 	do {
 		mdelay(1);
 		ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+		if (ret < 0)
+			return ret;
+
 		if (time_after(jiffies, timeout)) {
 			netdev_warn(dev->net, "timeout waiting for PHY Reset");
-			return -EIO;
+			ret = -ETIME;
+			return ret;
 		}
 	} while ((buf & PMT_CTL_PHY_RST_) || !(buf & PMT_CTL_READY_));
 
 	ret = lan78xx_read_reg(dev, MAC_CR, &buf);
+	if (ret < 0)
+		return ret;
+
 	/* LAN7801 only has RGMII mode */
 	if (dev->chipid == ID_REV_CHIP_ID_7801_)
 		buf &= ~MAC_CR_GMII_EN_;
@@ -2649,27 +2890,21 @@ static int lan78xx_reset(struct lan78xx_net *dev)
 		}
 	}
 	ret = lan78xx_write_reg(dev, MAC_CR, buf);
+	if (ret < 0)
+		return ret;
 
-	ret = lan78xx_read_reg(dev, MAC_TX, &buf);
-	buf |= MAC_TX_TXEN_;
-	ret = lan78xx_write_reg(dev, MAC_TX, buf);
-
-	ret = lan78xx_read_reg(dev, FCT_TX_CTL, &buf);
-	buf |= FCT_TX_CTL_EN_;
-	ret = lan78xx_write_reg(dev, FCT_TX_CTL, buf);
+	ret = lan78xx_start_tx_path(dev);
+	if (ret < 0)
+		return ret;
 
 	ret = lan78xx_set_rx_max_frame_length(dev,
 					      dev->net->mtu + VLAN_ETH_HLEN);
+	if (ret < 0)
+		return ret;
 
-	ret = lan78xx_read_reg(dev, MAC_RX, &buf);
-	buf |= MAC_RX_RXEN_;
-	ret = lan78xx_write_reg(dev, MAC_RX, buf);
-
-	ret = lan78xx_read_reg(dev, FCT_RX_CTL, &buf);
-	buf |= FCT_RX_CTL_EN_;
-	ret = lan78xx_write_reg(dev, FCT_RX_CTL, buf);
+	ret = lan78xx_start_rx_path(dev);
 
-	return 0;
+	return ret;
 }
 
 static void lan78xx_init_stats(struct lan78xx_net *dev)
@@ -2705,7 +2940,7 @@ static int lan78xx_open(struct net_device *net)
 
 	ret = usb_autopm_get_interface(dev->intf);
 	if (ret < 0)
-		goto out;
+		return ret;
 
 	phy_start(net->phydev);
 
@@ -2733,7 +2968,6 @@ static int lan78xx_open(struct net_device *net)
 done:
 	usb_autopm_put_interface(dev->intf);
 
-out:
 	return ret;
 }
 
@@ -3882,35 +4116,49 @@ static u16 lan78xx_wakeframe_crc16(const u8 *buf, int len)
 
 static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 {
-	u32 buf;
-	int mask_index;
-	u16 crc;
-	u32 temp_wucsr;
-	u32 temp_pmt_ctl;
 	const u8 ipv4_multicast[3] = { 0x01, 0x00, 0x5E };
 	const u8 ipv6_multicast[3] = { 0x33, 0x33 };
 	const u8 arp_type[2] = { 0x08, 0x06 };
+	u32 temp_pmt_ctl;
+	int mask_index;
+	u32 temp_wucsr;
+	u32 buf;
+	u16 crc;
+	int ret;
 
-	lan78xx_read_reg(dev, MAC_TX, &buf);
-	buf &= ~MAC_TX_TXEN_;
-	lan78xx_write_reg(dev, MAC_TX, buf);
-	lan78xx_read_reg(dev, MAC_RX, &buf);
-	buf &= ~MAC_RX_RXEN_;
-	lan78xx_write_reg(dev, MAC_RX, buf);
+	ret = lan78xx_stop_tx_path(dev);
+	if (ret < 0)
+		return ret;
+	ret = lan78xx_stop_rx_path(dev);
+	if (ret < 0)
+		return ret;
 
-	lan78xx_write_reg(dev, WUCSR, 0);
-	lan78xx_write_reg(dev, WUCSR2, 0);
-	lan78xx_write_reg(dev, WK_SRC, 0xFFF1FF1FUL);
+	ret = lan78xx_write_reg(dev, WUCSR, 0);
+	if (ret < 0)
+		return ret;
+	ret = lan78xx_write_reg(dev, WUCSR2, 0);
+	if (ret < 0)
+		return ret;
+	ret = lan78xx_write_reg(dev, WK_SRC, 0xFFF1FF1FUL);
+	if (ret < 0)
+		return ret;
 
 	temp_wucsr = 0;
 
 	temp_pmt_ctl = 0;
-	lan78xx_read_reg(dev, PMT_CTL, &temp_pmt_ctl);
+
+	ret = lan78xx_read_reg(dev, PMT_CTL, &temp_pmt_ctl);
+	if (ret < 0)
+		return ret;
+
 	temp_pmt_ctl &= ~PMT_CTL_RES_CLR_WKP_EN_;
 	temp_pmt_ctl |= PMT_CTL_RES_CLR_WKP_STS_;
 
-	for (mask_index = 0; mask_index < NUM_OF_WUF_CFG; mask_index++)
-		lan78xx_write_reg(dev, WUF_CFG(mask_index), 0);
+	for (mask_index = 0; mask_index < NUM_OF_WUF_CFG; mask_index++) {
+		ret = lan78xx_write_reg(dev, WUF_CFG(mask_index), 0);
+		if (ret < 0)
+			return ret;
+	}
 
 	mask_index = 0;
 	if (wol & WAKE_PHY) {
@@ -3939,30 +4187,52 @@ static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 
 		/* set WUF_CFG & WUF_MASK for IPv4 Multicast */
 		crc = lan78xx_wakeframe_crc16(ipv4_multicast, 3);
-		lan78xx_write_reg(dev, WUF_CFG(mask_index),
-				  WUF_CFGX_EN_ |
-				  WUF_CFGX_TYPE_MCAST_ |
-				  (0 << WUF_CFGX_OFFSET_SHIFT_) |
-				  (crc & WUF_CFGX_CRC16_MASK_));
-
-		lan78xx_write_reg(dev, WUF_MASK0(mask_index), 7);
-		lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
-		lan78xx_write_reg(dev, WUF_MASK2(mask_index), 0);
-		lan78xx_write_reg(dev, WUF_MASK3(mask_index), 0);
+		ret = lan78xx_write_reg(dev, WUF_CFG(mask_index),
+					WUF_CFGX_EN_ |
+					WUF_CFGX_TYPE_MCAST_ |
+					(0 << WUF_CFGX_OFFSET_SHIFT_) |
+					(crc & WUF_CFGX_CRC16_MASK_));
+		if (ret < 0)
+			return ret;
+
+		ret = lan78xx_write_reg(dev, WUF_MASK0(mask_index), 7);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK2(mask_index), 0);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK3(mask_index), 0);
+		if (ret < 0)
+			return ret;
+
 		mask_index++;
 
 		/* for IPv6 Multicast */
 		crc = lan78xx_wakeframe_crc16(ipv6_multicast, 2);
-		lan78xx_write_reg(dev, WUF_CFG(mask_index),
-				  WUF_CFGX_EN_ |
-				  WUF_CFGX_TYPE_MCAST_ |
-				  (0 << WUF_CFGX_OFFSET_SHIFT_) |
-				  (crc & WUF_CFGX_CRC16_MASK_));
-
-		lan78xx_write_reg(dev, WUF_MASK0(mask_index), 3);
-		lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
-		lan78xx_write_reg(dev, WUF_MASK2(mask_index), 0);
-		lan78xx_write_reg(dev, WUF_MASK3(mask_index), 0);
+		ret = lan78xx_write_reg(dev, WUF_CFG(mask_index),
+					WUF_CFGX_EN_ |
+					WUF_CFGX_TYPE_MCAST_ |
+					(0 << WUF_CFGX_OFFSET_SHIFT_) |
+					(crc & WUF_CFGX_CRC16_MASK_));
+		if (ret < 0)
+			return ret;
+
+		ret = lan78xx_write_reg(dev, WUF_MASK0(mask_index), 3);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK2(mask_index), 0);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK3(mask_index), 0);
+		if (ret < 0)
+			return ret;
+
 		mask_index++;
 
 		temp_pmt_ctl |= PMT_CTL_WOL_EN_;
@@ -3983,16 +4253,27 @@ static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 		 * for packettype (offset 12,13) = ARP (0x0806)
 		 */
 		crc = lan78xx_wakeframe_crc16(arp_type, 2);
-		lan78xx_write_reg(dev, WUF_CFG(mask_index),
-				  WUF_CFGX_EN_ |
-				  WUF_CFGX_TYPE_ALL_ |
-				  (0 << WUF_CFGX_OFFSET_SHIFT_) |
-				  (crc & WUF_CFGX_CRC16_MASK_));
-
-		lan78xx_write_reg(dev, WUF_MASK0(mask_index), 0x3000);
-		lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
-		lan78xx_write_reg(dev, WUF_MASK2(mask_index), 0);
-		lan78xx_write_reg(dev, WUF_MASK3(mask_index), 0);
+		ret = lan78xx_write_reg(dev, WUF_CFG(mask_index),
+					WUF_CFGX_EN_ |
+					WUF_CFGX_TYPE_ALL_ |
+					(0 << WUF_CFGX_OFFSET_SHIFT_) |
+					(crc & WUF_CFGX_CRC16_MASK_));
+		if (ret < 0)
+			return ret;
+
+		ret = lan78xx_write_reg(dev, WUF_MASK0(mask_index), 0x3000);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK1(mask_index), 0);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK2(mask_index), 0);
+		if (ret < 0)
+			return ret;
+		ret = lan78xx_write_reg(dev, WUF_MASK3(mask_index), 0);
+		if (ret < 0)
+			return ret;
+
 		mask_index++;
 
 		temp_pmt_ctl |= PMT_CTL_WOL_EN_;
@@ -4000,7 +4281,9 @@ static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 		temp_pmt_ctl |= PMT_CTL_SUS_MODE_0_;
 	}
 
-	lan78xx_write_reg(dev, WUCSR, temp_wucsr);
+	ret = lan78xx_write_reg(dev, WUCSR, temp_wucsr);
+	if (ret < 0)
+		return ret;
 
 	/* when multiple WOL bits are set */
 	if (hweight_long((unsigned long)wol) > 1) {
@@ -4008,24 +4291,29 @@ static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 		temp_pmt_ctl &= ~PMT_CTL_SUS_MODE_MASK_;
 		temp_pmt_ctl |= PMT_CTL_SUS_MODE_0_;
 	}
-	lan78xx_write_reg(dev, PMT_CTL, temp_pmt_ctl);
+	ret = lan78xx_write_reg(dev, PMT_CTL, temp_pmt_ctl);
+	if (ret < 0)
+		return ret;
 
 	/* clear WUPS */
-	lan78xx_read_reg(dev, PMT_CTL, &buf);
+	ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+	if (ret < 0)
+		return ret;
+
 	buf |= PMT_CTL_WUPS_MASK_;
-	lan78xx_write_reg(dev, PMT_CTL, buf);
 
-	lan78xx_read_reg(dev, MAC_RX, &buf);
-	buf |= MAC_RX_RXEN_;
-	lan78xx_write_reg(dev, MAC_RX, buf);
+	ret = lan78xx_write_reg(dev, PMT_CTL, buf);
+	if (ret < 0)
+		return ret;
 
-	return 0;
+	ret = lan78xx_start_rx_path(dev);
+
+	return ret;
 }
 
 static int lan78xx_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct lan78xx_net *dev = usb_get_intfdata(intf);
-	struct lan78xx_priv *pdata = (struct lan78xx_priv *)(dev->data[0]);
 	u32 buf;
 	int ret;
 
@@ -4043,13 +4331,19 @@ static int lan78xx_suspend(struct usb_interface *intf, pm_message_t message)
 			spin_unlock_irq(&dev->txq.lock);
 		}
 
-		/* stop TX & RX */
-		ret = lan78xx_read_reg(dev, MAC_TX, &buf);
-		buf &= ~MAC_TX_TXEN_;
-		ret = lan78xx_write_reg(dev, MAC_TX, buf);
-		ret = lan78xx_read_reg(dev, MAC_RX, &buf);
-		buf &= ~MAC_RX_RXEN_;
-		ret = lan78xx_write_reg(dev, MAC_RX, buf);
+		/* stop RX */
+		ret = lan78xx_stop_rx_path(dev);
+		if (ret < 0)
+			return ret;
+
+		ret = lan78xx_flush_rx_fifo(dev);
+		if (ret < 0)
+			return ret;
+
+		/* stop Tx */
+		ret = lan78xx_stop_tx_path(dev);
+		if (ret < 0)
+			return ret;
 
 		/* empty out the rx and queues */
 		netif_device_detach(dev->net);
@@ -4065,26 +4359,39 @@ static int lan78xx_suspend(struct usb_interface *intf, pm_message_t message)
 
 		if (PMSG_IS_AUTO(message)) {
 			/* auto suspend (selective suspend) */
-			ret = lan78xx_read_reg(dev, MAC_TX, &buf);
-			buf &= ~MAC_TX_TXEN_;
-			ret = lan78xx_write_reg(dev, MAC_TX, buf);
-			ret = lan78xx_read_reg(dev, MAC_RX, &buf);
-			buf &= ~MAC_RX_RXEN_;
-			ret = lan78xx_write_reg(dev, MAC_RX, buf);
+			ret = lan78xx_stop_tx_path(dev);
+			if (ret < 0)
+				return ret;
+
+			ret = lan78xx_stop_rx_path(dev);
+			if (ret < 0)
+				return ret;
 
 			ret = lan78xx_write_reg(dev, WUCSR, 0);
+			if (ret < 0)
+				return ret;
 			ret = lan78xx_write_reg(dev, WUCSR2, 0);
+			if (ret < 0)
+				return ret;
 			ret = lan78xx_write_reg(dev, WK_SRC, 0xFFF1FF1FUL);
+			if (ret < 0)
+				return ret;
 
 			/* set goodframe wakeup */
 			ret = lan78xx_read_reg(dev, WUCSR, &buf);
+			if (ret < 0)
+				return ret;
 
 			buf |= WUCSR_RFE_WAKE_EN_;
 			buf |= WUCSR_STORE_WAKE_;
 
 			ret = lan78xx_write_reg(dev, WUCSR, buf);
+			if (ret < 0)
+				return ret;
 
 			ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+			if (ret < 0)
+				return ret;
 
 			buf &= ~PMT_CTL_RES_CLR_WKP_EN_;
 			buf |= PMT_CTL_RES_CLR_WKP_STS_;
@@ -4095,18 +4402,30 @@ static int lan78xx_suspend(struct usb_interface *intf, pm_message_t message)
 			buf |= PMT_CTL_SUS_MODE_3_;
 
 			ret = lan78xx_write_reg(dev, PMT_CTL, buf);
+			if (ret < 0)
+				return ret;
 
 			ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+			if (ret < 0)
+				return ret;
 
 			buf |= PMT_CTL_WUPS_MASK_;
 
 			ret = lan78xx_write_reg(dev, PMT_CTL, buf);
+			if (ret < 0)
+				return ret;
 
-			ret = lan78xx_read_reg(dev, MAC_RX, &buf);
-			buf |= MAC_RX_RXEN_;
-			ret = lan78xx_write_reg(dev, MAC_RX, buf);
+			ret = lan78xx_start_rx_path(dev);
+			if (ret < 0)
+				return ret;
 		} else {
-			lan78xx_set_suspend(dev, pdata->wol);
+			struct lan78xx_priv *pdata;
+
+			pdata = (struct lan78xx_priv *)(dev->data[0]);
+
+			ret = lan78xx_set_suspend(dev, pdata->wol);
+			if (ret < 0)
+				return ret;
 		}
 	}
 
@@ -4121,7 +4440,6 @@ static int lan78xx_resume(struct usb_interface *intf)
 	struct sk_buff *skb;
 	struct urb *res;
 	int ret;
-	u32 buf;
 
 	if (!timer_pending(&dev->stat_monitor)) {
 		dev->delta = 1;
@@ -4129,10 +4447,17 @@ static int lan78xx_resume(struct usb_interface *intf)
 			  jiffies + STAT_UPDATE_TIMER);
 	}
 
+	ret = lan78xx_flush_tx_fifo(dev);
+	if (ret < 0)
+		return ret;
+
 	if (!--dev->suspend_count) {
 		/* resume interrupt URBs */
-		if (dev->urb_intr && test_bit(EVENT_DEV_OPEN, &dev->flags))
-			usb_submit_urb(dev->urb_intr, GFP_NOIO);
+		if (dev->urb_intr && test_bit(EVENT_DEV_OPEN, &dev->flags)) {
+			ret = usb_submit_urb(dev->urb_intr, GFP_NOIO);
+			if (ret < 0)
+				return ret;
+		}
 
 		spin_lock_irq(&dev->txq.lock);
 		while ((res = usb_get_from_anchor(&dev->deferred))) {
@@ -4159,13 +4484,21 @@ static int lan78xx_resume(struct usb_interface *intf)
 	}
 
 	ret = lan78xx_write_reg(dev, WUCSR2, 0);
+	if (ret < 0)
+		return ret;
 	ret = lan78xx_write_reg(dev, WUCSR, 0);
+	if (ret < 0)
+		return ret;
 	ret = lan78xx_write_reg(dev, WK_SRC, 0xFFF1FF1FUL);
+	if (ret < 0)
+		return ret;
 
 	ret = lan78xx_write_reg(dev, WUCSR2, WUCSR2_NS_RCD_ |
 					     WUCSR2_ARP_RCD_ |
 					     WUCSR2_IPV6_TCPSYN_RCD_ |
 					     WUCSR2_IPV4_TCPSYN_RCD_);
+	if (ret < 0)
+		return ret;
 
 	ret = lan78xx_write_reg(dev, WUCSR, WUCSR_EEE_TX_WAKE_ |
 					    WUCSR_EEE_RX_WAKE_ |
@@ -4174,23 +4507,28 @@ static int lan78xx_resume(struct usb_interface *intf)
 					    WUCSR_WUFR_ |
 					    WUCSR_MPR_ |
 					    WUCSR_BCST_FR_);
+	if (ret < 0)
+		return ret;
 
-	ret = lan78xx_read_reg(dev, MAC_TX, &buf);
-	buf |= MAC_TX_TXEN_;
-	ret = lan78xx_write_reg(dev, MAC_TX, buf);
+	ret = lan78xx_start_tx_path(dev);
 
-	return 0;
+	return ret;
 }
 
 static int lan78xx_reset_resume(struct usb_interface *intf)
 {
 	struct lan78xx_net *dev = usb_get_intfdata(intf);
+	int ret;
 
-	lan78xx_reset(dev);
+	ret = lan78xx_reset(dev);
+	if (ret < 0)
+		return ret;
 
 	phy_start(dev->net->phydev);
 
-	return lan78xx_resume(intf);
+	ret = lan78xx_resume(intf);
+
+	return ret;
 }
 
 static const struct usb_device_id products[] = {
-- 
2.25.1

[PATCH net-next 08/10] lan78xx: Fix race conditions in suspend/resume handling

[John Efstathiades]

If the interface is given an IP address while the device is
suspended (as a result of an auto-suspend event) there is a race
between lan78xx_resume() and lan78xx_open() that can result in an
exception or failure to handle incoming packets. The following
changes fix this problem.

Introduce a mutex to serialise operations in the network interface
open and stop entry points with respect to the USB driver suspend
and resume entry points.

Move Tx and Rx data path start/stop to lan78xx_start() and
lan78xx_stop() respectively and flush the packet FIFOs before
starting the Tx and Rx data paths. This prevents the MAC and FIFOs
getting out of step and delivery of malformed packets to the network
stack.

Stop processing of received packets before disconnecting the
PHY from the MAC to prevent a kernel exception caused by handling
packets after the PHY device has been removed.

Refactor device auto-suspend code to make it consistent with the
the system suspend code and make the suspend handler easier to read.

Add new code to stop wake-on-lan packets or PHY events resuming the
host or device from suspend if the device has not been opened
(typically after an IP address is assigned).

This patch is dependent on changes to lan78xx_suspend() and
lan78xx_resume() introduced in the previous patch of this patch set.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 423 ++++++++++++++++++++++++++------------
 1 file changed, 286 insertions(+), 137 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 096304c1b5f4..feb638d268be 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -399,6 +399,7 @@ struct lan78xx_net {
 	struct urb		*urb_intr;
 	struct usb_anchor	deferred;
 
+	struct mutex		dev_mutex; /* serialise open/stop wrt suspend/resume */
 	struct mutex		phy_mutex; /* for phy access */
 	unsigned int		pipe_in, pipe_out, pipe_intr;
 
@@ -2383,11 +2384,16 @@ static int lan78xx_change_mtu(struct net_device *netdev, int new_mtu)
 	int ll_mtu = new_mtu + netdev->hard_header_len;
 	int old_hard_mtu = dev->hard_mtu;
 	int old_rx_urb_size = dev->rx_urb_size;
+	int ret;
 
 	/* no second zero-length packet read wanted after mtu-sized packets */
 	if ((ll_mtu % dev->maxpacket) == 0)
 		return -EDOM;
 
+	ret = usb_autopm_get_interface(dev->intf);
+	if (ret < 0)
+		return ret;
+
 	lan78xx_set_rx_max_frame_length(dev, new_mtu + VLAN_ETH_HLEN);
 
 	netdev->mtu = new_mtu;
@@ -2403,6 +2409,8 @@ static int lan78xx_change_mtu(struct net_device *netdev, int new_mtu)
 		}
 	}
 
+	usb_autopm_put_interface(dev->intf);
+
 	return 0;
 }
 
@@ -2893,16 +2901,8 @@ static int lan78xx_reset(struct lan78xx_net *dev)
 	if (ret < 0)
 		return ret;
 
-	ret = lan78xx_start_tx_path(dev);
-	if (ret < 0)
-		return ret;
-
 	ret = lan78xx_set_rx_max_frame_length(dev,
 					      dev->net->mtu + VLAN_ETH_HLEN);
-	if (ret < 0)
-		return ret;
-
-	ret = lan78xx_start_rx_path(dev);
 
 	return ret;
 }
@@ -2938,9 +2938,13 @@ static int lan78xx_open(struct net_device *net)
 	struct lan78xx_net *dev = netdev_priv(net);
 	int ret;
 
+	netif_dbg(dev, ifup, dev->net, "open device");
+
 	ret = usb_autopm_get_interface(dev->intf);
 	if (ret < 0)
-		return ret;
+		goto out;
+
+	mutex_lock(&dev->dev_mutex);
 
 	phy_start(net->phydev);
 
@@ -2956,6 +2960,20 @@ static int lan78xx_open(struct net_device *net)
 		}
 	}
 
+	ret = lan78xx_flush_rx_fifo(dev);
+	if (ret < 0)
+		goto done;
+	ret = lan78xx_flush_tx_fifo(dev);
+	if (ret < 0)
+		goto done;
+
+	ret = lan78xx_start_tx_path(dev);
+	if (ret < 0)
+		goto done;
+	ret = lan78xx_start_rx_path(dev);
+	if (ret < 0)
+		goto done;
+
 	lan78xx_init_stats(dev);
 
 	set_bit(EVENT_DEV_OPEN, &dev->flags);
@@ -2966,8 +2984,10 @@ static int lan78xx_open(struct net_device *net)
 
 	lan78xx_defer_kevent(dev, EVENT_LINK_RESET);
 done:
-	usb_autopm_put_interface(dev->intf);
+	mutex_unlock(&dev->dev_mutex);
 
+	usb_autopm_put_interface(dev->intf);
+out:
 	return ret;
 }
 
@@ -2984,38 +3004,56 @@ static void lan78xx_terminate_urbs(struct lan78xx_net *dev)
 	temp = unlink_urbs(dev, &dev->txq) + unlink_urbs(dev, &dev->rxq);
 
 	/* maybe wait for deletions to finish. */
-	while (!skb_queue_empty(&dev->rxq) &&
-	       !skb_queue_empty(&dev->txq) &&
-	       !skb_queue_empty(&dev->done)) {
+	while (!skb_queue_empty(&dev->rxq) ||
+	       !skb_queue_empty(&dev->txq)) {
 		schedule_timeout(msecs_to_jiffies(UNLINK_TIMEOUT_MS));
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		netif_dbg(dev, ifdown, dev->net,
-			  "waited for %d urb completions\n", temp);
+			  "waited for %d urb completions", temp);
 	}
 	set_current_state(TASK_RUNNING);
 	dev->wait = NULL;
 	remove_wait_queue(&unlink_wakeup, &wait);
+
+	while (!skb_queue_empty(&dev->done)) {
+		struct skb_data *entry;
+		struct sk_buff *skb;
+
+		skb = skb_dequeue(&dev->done);
+		entry = (struct skb_data *)(skb->cb);
+		usb_free_urb(entry->urb);
+		dev_kfree_skb(skb);
+	}
 }
 
 static int lan78xx_stop(struct net_device *net)
 {
 	struct lan78xx_net *dev = netdev_priv(net);
 
+	netif_dbg(dev, ifup, dev->net, "stop device");
+
+	mutex_lock(&dev->dev_mutex);
+
 	if (timer_pending(&dev->stat_monitor))
 		del_timer_sync(&dev->stat_monitor);
 
-	if (net->phydev)
-		phy_stop(net->phydev);
-
 	clear_bit(EVENT_DEV_OPEN, &dev->flags);
 	netif_stop_queue(net);
+	tasklet_kill(&dev->bh);
+
+	lan78xx_terminate_urbs(dev);
 
 	netif_info(dev, ifdown, dev->net,
 		   "stop stats: rx/tx %lu/%lu, errs %lu/%lu\n",
 		   net->stats.rx_packets, net->stats.tx_packets,
 		   net->stats.rx_errors, net->stats.tx_errors);
 
-	lan78xx_terminate_urbs(dev);
+	/* ignore errors that occur stopping the Tx and Rx data paths */
+	lan78xx_stop_tx_path(dev);
+	lan78xx_stop_rx_path(dev);
+
+	if (net->phydev)
+		phy_stop(net->phydev);
 
 	usb_kill_urb(dev->urb_intr);
 
@@ -3023,12 +3061,17 @@ static int lan78xx_stop(struct net_device *net)
 	 * can't flush_scheduled_work() until we drop rtnl (later),
 	 * else workers could deadlock; so make workers a NOP.
 	 */
-	dev->flags = 0;
+	clear_bit(EVENT_TX_HALT, &dev->flags);
+	clear_bit(EVENT_RX_HALT, &dev->flags);
+	clear_bit(EVENT_LINK_RESET, &dev->flags);
+	clear_bit(EVENT_STAT_UPDATE, &dev->flags);
+
 	cancel_delayed_work_sync(&dev->wq);
-	tasklet_kill(&dev->bh);
 
 	usb_autopm_put_interface(dev->intf);
 
+	mutex_unlock(&dev->dev_mutex);
+
 	return 0;
 }
 
@@ -3151,6 +3194,9 @@ lan78xx_start_xmit(struct sk_buff *skb, struct net_device *net)
 	struct lan78xx_net *dev = netdev_priv(net);
 	struct sk_buff *skb2 = NULL;
 
+	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags))
+		schedule_delayed_work(&dev->wq, 0);
+
 	if (skb) {
 		skb_tx_timestamp(skb);
 		skb2 = lan78xx_tx_prep(dev, skb, GFP_ATOMIC);
@@ -3751,18 +3797,17 @@ static void lan78xx_delayedwork(struct work_struct *work)
 
 	dev = container_of(work, struct lan78xx_net, wq.work);
 
+	if (usb_autopm_get_interface(dev->intf) < 0)
+		return;
+
 	if (test_bit(EVENT_TX_HALT, &dev->flags)) {
 		unlink_urbs(dev, &dev->txq);
-		status = usb_autopm_get_interface(dev->intf);
-		if (status < 0)
-			goto fail_pipe;
+
 		status = usb_clear_halt(dev->udev, dev->pipe_out);
-		usb_autopm_put_interface(dev->intf);
 		if (status < 0 &&
 		    status != -EPIPE &&
 		    status != -ESHUTDOWN) {
 			if (netif_msg_tx_err(dev))
-fail_pipe:
 				netdev_err(dev->net,
 					   "can't clear tx halt, status %d\n",
 					   status);
@@ -3772,18 +3817,14 @@ static void lan78xx_delayedwork(struct work_struct *work)
 				netif_wake_queue(dev->net);
 		}
 	}
+
 	if (test_bit(EVENT_RX_HALT, &dev->flags)) {
 		unlink_urbs(dev, &dev->rxq);
-		status = usb_autopm_get_interface(dev->intf);
-		if (status < 0)
-			goto fail_halt;
 		status = usb_clear_halt(dev->udev, dev->pipe_in);
-		usb_autopm_put_interface(dev->intf);
 		if (status < 0 &&
 		    status != -EPIPE &&
 		    status != -ESHUTDOWN) {
 			if (netif_msg_rx_err(dev))
-fail_halt:
 				netdev_err(dev->net,
 					   "can't clear rx halt, status %d\n",
 					   status);
@@ -3797,16 +3838,9 @@ static void lan78xx_delayedwork(struct work_struct *work)
 		int ret = 0;
 
 		clear_bit(EVENT_LINK_RESET, &dev->flags);
-		status = usb_autopm_get_interface(dev->intf);
-		if (status < 0)
-			goto skip_reset;
 		if (lan78xx_link_reset(dev) < 0) {
-			usb_autopm_put_interface(dev->intf);
-skip_reset:
 			netdev_info(dev->net, "link reset failed (%d)\n",
 				    ret);
-		} else {
-			usb_autopm_put_interface(dev->intf);
 		}
 	}
 
@@ -3820,6 +3854,8 @@ static void lan78xx_delayedwork(struct work_struct *work)
 
 		dev->delta = min((dev->delta * 2), 50);
 	}
+
+	usb_autopm_put_interface(dev->intf);
 }
 
 static void intr_complete(struct urb *urb)
@@ -3978,6 +4014,7 @@ static int lan78xx_probe(struct usb_interface *intf,
 	skb_queue_head_init(&dev->done);
 	skb_queue_head_init(&dev->txq_pend);
 	mutex_init(&dev->phy_mutex);
+	mutex_init(&dev->dev_mutex);
 
 	tasklet_setup(&dev->bh, lan78xx_bh);
 	INIT_DELAYED_WORK(&dev->wq, lan78xx_delayedwork);
@@ -4114,6 +4151,74 @@ static u16 lan78xx_wakeframe_crc16(const u8 *buf, int len)
 	return crc;
 }
 
+static int lan78xx_set_auto_suspend(struct lan78xx_net *dev)
+{
+	u32 buf;
+	int ret;
+
+	ret = lan78xx_stop_tx_path(dev);
+	if (ret < 0)
+		return ret;
+
+	ret = lan78xx_stop_rx_path(dev);
+	if (ret < 0)
+		return ret;
+
+	/* auto suspend (selective suspend) */
+
+	ret = lan78xx_write_reg(dev, WUCSR, 0);
+	if (ret < 0)
+		return ret;
+	ret = lan78xx_write_reg(dev, WUCSR2, 0);
+	if (ret < 0)
+		return ret;
+	ret = lan78xx_write_reg(dev, WK_SRC, 0xFFF1FF1FUL);
+	if (ret < 0)
+		return ret;
+
+	/* set goodframe wakeup */
+
+	ret = lan78xx_read_reg(dev, WUCSR, &buf);
+	if (ret < 0)
+		return ret;
+
+	buf |= WUCSR_RFE_WAKE_EN_;
+	buf |= WUCSR_STORE_WAKE_;
+
+	ret = lan78xx_write_reg(dev, WUCSR, buf);
+	if (ret < 0)
+		return ret;
+
+	ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+	if (ret < 0)
+		return ret;
+
+	buf &= ~PMT_CTL_RES_CLR_WKP_EN_;
+	buf |= PMT_CTL_RES_CLR_WKP_STS_;
+	buf |= PMT_CTL_PHY_WAKE_EN_;
+	buf |= PMT_CTL_WOL_EN_;
+	buf &= ~PMT_CTL_SUS_MODE_MASK_;
+	buf |= PMT_CTL_SUS_MODE_3_;
+
+	ret = lan78xx_write_reg(dev, PMT_CTL, buf);
+	if (ret < 0)
+		return ret;
+
+	ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+	if (ret < 0)
+		return ret;
+
+	buf |= PMT_CTL_WUPS_MASK_;
+
+	ret = lan78xx_write_reg(dev, PMT_CTL, buf);
+	if (ret < 0)
+		return ret;
+
+	ret = lan78xx_start_rx_path(dev);
+
+	return ret;
+}
+
 static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 {
 	const u8 ipv4_multicast[3] = { 0x01, 0x00, 0x5E };
@@ -4314,15 +4419,22 @@ static int lan78xx_set_suspend(struct lan78xx_net *dev, u32 wol)
 static int lan78xx_suspend(struct usb_interface *intf, pm_message_t message)
 {
 	struct lan78xx_net *dev = usb_get_intfdata(intf);
-	u32 buf;
+	bool dev_open;
 	int ret;
 
-	if (!dev->suspend_count++) {
+	mutex_lock(&dev->dev_mutex);
+
+	netif_dbg(dev, ifdown, dev->net,
+		  "suspending: pm event %#x", message.event);
+
+	dev_open = test_bit(EVENT_DEV_OPEN, &dev->flags);
+
+	if (dev_open) {
 		spin_lock_irq(&dev->txq.lock);
 		/* don't autosuspend while transmitting */
 		if ((skb_queue_len(&dev->txq) ||
 		     skb_queue_len(&dev->txq_pend)) &&
-			PMSG_IS_AUTO(message)) {
+		    PMSG_IS_AUTO(message)) {
 			spin_unlock_irq(&dev->txq.lock);
 			ret = -EBUSY;
 			goto out;
@@ -4334,171 +4446,204 @@ static int lan78xx_suspend(struct usb_interface *intf, pm_message_t message)
 		/* stop RX */
 		ret = lan78xx_stop_rx_path(dev);
 		if (ret < 0)
-			return ret;
+			goto out;
 
 		ret = lan78xx_flush_rx_fifo(dev);
 		if (ret < 0)
-			return ret;
+			goto out;
 
 		/* stop Tx */
 		ret = lan78xx_stop_tx_path(dev);
 		if (ret < 0)
-			return ret;
+			goto out;
 
-		/* empty out the rx and queues */
+		/* empty out the Rx and Tx queues */
 		netif_device_detach(dev->net);
 		lan78xx_terminate_urbs(dev);
 		usb_kill_urb(dev->urb_intr);
 
 		/* reattach */
 		netif_device_attach(dev->net);
-	}
 
-	if (test_bit(EVENT_DEV_ASLEEP, &dev->flags)) {
 		del_timer(&dev->stat_monitor);
 
 		if (PMSG_IS_AUTO(message)) {
-			/* auto suspend (selective suspend) */
-			ret = lan78xx_stop_tx_path(dev);
+			ret = lan78xx_set_auto_suspend(dev);
 			if (ret < 0)
-				return ret;
+				goto out;
+		} else {
+			struct lan78xx_priv *pdata;
 
-			ret = lan78xx_stop_rx_path(dev);
+			pdata = (struct lan78xx_priv *)(dev->data[0]);
+			netif_carrier_off(dev->net);
+			ret = lan78xx_set_suspend(dev, pdata->wol);
 			if (ret < 0)
-				return ret;
+				goto out;
+		}
+	} else {
+		/* Interface is down; don't allow WOL and PHY
+		 * events to wake up the host
+		 */
+		u32 buf;
 
-			ret = lan78xx_write_reg(dev, WUCSR, 0);
-			if (ret < 0)
-				return ret;
-			ret = lan78xx_write_reg(dev, WUCSR2, 0);
-			if (ret < 0)
-				return ret;
-			ret = lan78xx_write_reg(dev, WK_SRC, 0xFFF1FF1FUL);
-			if (ret < 0)
-				return ret;
+		set_bit(EVENT_DEV_ASLEEP, &dev->flags);
 
-			/* set goodframe wakeup */
-			ret = lan78xx_read_reg(dev, WUCSR, &buf);
-			if (ret < 0)
-				return ret;
+		ret = lan78xx_write_reg(dev, WUCSR, 0);
+		if (ret < 0)
+			goto out;
+		ret = lan78xx_write_reg(dev, WUCSR2, 0);
+		if (ret < 0)
+			goto out;
 
-			buf |= WUCSR_RFE_WAKE_EN_;
-			buf |= WUCSR_STORE_WAKE_;
+		ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+		if (ret < 0)
+			goto out;
 
-			ret = lan78xx_write_reg(dev, WUCSR, buf);
-			if (ret < 0)
-				return ret;
+		buf &= ~PMT_CTL_RES_CLR_WKP_EN_;
+		buf |= PMT_CTL_RES_CLR_WKP_STS_;
+		buf &= ~PMT_CTL_SUS_MODE_MASK_;
+		buf |= PMT_CTL_SUS_MODE_3_;
 
-			ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
-			if (ret < 0)
-				return ret;
+		ret = lan78xx_write_reg(dev, PMT_CTL, buf);
+		if (ret < 0)
+			goto out;
 
-			buf &= ~PMT_CTL_RES_CLR_WKP_EN_;
-			buf |= PMT_CTL_RES_CLR_WKP_STS_;
+		ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
+		if (ret < 0)
+			goto out;
 
-			buf |= PMT_CTL_PHY_WAKE_EN_;
-			buf |= PMT_CTL_WOL_EN_;
-			buf &= ~PMT_CTL_SUS_MODE_MASK_;
-			buf |= PMT_CTL_SUS_MODE_3_;
+		buf |= PMT_CTL_WUPS_MASK_;
 
-			ret = lan78xx_write_reg(dev, PMT_CTL, buf);
-			if (ret < 0)
-				return ret;
+		ret = lan78xx_write_reg(dev, PMT_CTL, buf);
+		if (ret < 0)
+			goto out;
+	}
 
-			ret = lan78xx_read_reg(dev, PMT_CTL, &buf);
-			if (ret < 0)
-				return ret;
+	ret = 0;
+out:
+	mutex_unlock(&dev->dev_mutex);
 
-			buf |= PMT_CTL_WUPS_MASK_;
+	return ret;
+}
 
-			ret = lan78xx_write_reg(dev, PMT_CTL, buf);
-			if (ret < 0)
-				return ret;
+static bool lan78xx_submit_deferred_urbs(struct lan78xx_net *dev)
+{
+	bool pipe_halted = false;
+	struct urb *urb;
 
-			ret = lan78xx_start_rx_path(dev);
-			if (ret < 0)
-				return ret;
-		} else {
-			struct lan78xx_priv *pdata;
+	while ((urb = usb_get_from_anchor(&dev->deferred))) {
+		struct sk_buff *skb = urb->context;
+		int ret;
 
-			pdata = (struct lan78xx_priv *)(dev->data[0]);
+		if (!netif_device_present(dev->net) ||
+		    !netif_carrier_ok(dev->net) ||
+		    pipe_halted) {
+			usb_free_urb(urb);
+			dev_kfree_skb(skb);
+			continue;
+		}
 
-			ret = lan78xx_set_suspend(dev, pdata->wol);
-			if (ret < 0)
-				return ret;
+		ret = usb_submit_urb(urb, GFP_ATOMIC);
+
+		if (ret == 0) {
+			netif_trans_update(dev->net);
+			lan78xx_queue_skb(&dev->txq, skb, tx_start);
+		} else {
+			usb_free_urb(urb);
+			dev_kfree_skb(skb);
+
+			if (ret == -EPIPE) {
+				netif_stop_queue(dev->net);
+				pipe_halted = true;
+			} else if (ret == -ENODEV) {
+				netif_device_detach(dev->net);
+			}
 		}
 	}
 
-	ret = 0;
-out:
-	return ret;
+	return pipe_halted;
 }
 
 static int lan78xx_resume(struct usb_interface *intf)
 {
 	struct lan78xx_net *dev = usb_get_intfdata(intf);
-	struct sk_buff *skb;
-	struct urb *res;
+	bool dev_open;
 	int ret;
 
-	if (!timer_pending(&dev->stat_monitor)) {
-		dev->delta = 1;
-		mod_timer(&dev->stat_monitor,
-			  jiffies + STAT_UPDATE_TIMER);
-	}
+	mutex_lock(&dev->dev_mutex);
 
-	ret = lan78xx_flush_tx_fifo(dev);
-	if (ret < 0)
-		return ret;
+	netif_dbg(dev, ifup, dev->net, "resuming device");
 
-	if (!--dev->suspend_count) {
-		/* resume interrupt URBs */
-		if (dev->urb_intr && test_bit(EVENT_DEV_OPEN, &dev->flags)) {
-			ret = usb_submit_urb(dev->urb_intr, GFP_NOIO);
-			if (ret < 0)
-				return ret;
-		}
+	dev_open = test_bit(EVENT_DEV_OPEN, &dev->flags);
+
+	if (dev_open) {
+		bool pipe_halted = false;
+
+		ret = lan78xx_flush_tx_fifo(dev);
+		if (ret < 0)
+			goto out;
+
+		if (dev->urb_intr) {
+			int ret = usb_submit_urb(dev->urb_intr, GFP_KERNEL);
 
-		spin_lock_irq(&dev->txq.lock);
-		while ((res = usb_get_from_anchor(&dev->deferred))) {
-			skb = (struct sk_buff *)res->context;
-			ret = usb_submit_urb(res, GFP_ATOMIC);
 			if (ret < 0) {
-				dev_kfree_skb_any(skb);
-				usb_free_urb(res);
-				usb_autopm_put_interface_async(dev->intf);
-			} else {
-				netif_trans_update(dev->net);
-				lan78xx_queue_skb(&dev->txq, skb, tx_start);
+				if (ret == -ENODEV)
+					netif_device_detach(dev->net);
+
+			netdev_warn(dev->net, "Failed to submit intr URB");
 			}
 		}
 
+		spin_lock_irq(&dev->txq.lock);
+
+		if (netif_device_present(dev->net)) {
+			pipe_halted = lan78xx_submit_deferred_urbs(dev);
+
+			if (pipe_halted)
+				lan78xx_defer_kevent(dev, EVENT_TX_HALT);
+		}
+
 		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
+
 		spin_unlock_irq(&dev->txq.lock);
 
-		if (test_bit(EVENT_DEV_OPEN, &dev->flags)) {
-			if (!(skb_queue_len(&dev->txq) >= dev->tx_qlen))
-				netif_start_queue(dev->net);
-			tasklet_schedule(&dev->bh);
+		if (!pipe_halted &&
+		    netif_device_present(dev->net) &&
+		    (skb_queue_len(&dev->txq) < dev->tx_qlen))
+			netif_start_queue(dev->net);
+
+		ret = lan78xx_start_tx_path(dev);
+		if (ret < 0)
+			goto out;
+
+		tasklet_schedule(&dev->bh);
+
+		if (!timer_pending(&dev->stat_monitor)) {
+			dev->delta = 1;
+			mod_timer(&dev->stat_monitor,
+				  jiffies + STAT_UPDATE_TIMER);
 		}
+
+	} else {
+		clear_bit(EVENT_DEV_ASLEEP, &dev->flags);
 	}
 
 	ret = lan78xx_write_reg(dev, WUCSR2, 0);
 	if (ret < 0)
-		return ret;
+		goto out;
 	ret = lan78xx_write_reg(dev, WUCSR, 0);
 	if (ret < 0)
-		return ret;
+		goto out;
 	ret = lan78xx_write_reg(dev, WK_SRC, 0xFFF1FF1FUL);
 	if (ret < 0)
-		return ret;
+		goto out;
 
 	ret = lan78xx_write_reg(dev, WUCSR2, WUCSR2_NS_RCD_ |
 					     WUCSR2_ARP_RCD_ |
 					     WUCSR2_IPV6_TCPSYN_RCD_ |
 					     WUCSR2_IPV4_TCPSYN_RCD_);
 	if (ret < 0)
-		return ret;
+		goto out;
 
 	ret = lan78xx_write_reg(dev, WUCSR, WUCSR_EEE_TX_WAKE_ |
 					    WUCSR_EEE_RX_WAKE_ |
@@ -4508,9 +4653,11 @@ static int lan78xx_resume(struct usb_interface *intf)
 					    WUCSR_MPR_ |
 					    WUCSR_BCST_FR_);
 	if (ret < 0)
-		return ret;
+		goto out;
 
-	ret = lan78xx_start_tx_path(dev);
+	ret = 0;
+out:
+	mutex_unlock(&dev->dev_mutex);
 
 	return ret;
 }
@@ -4520,6 +4667,8 @@ static int lan78xx_reset_resume(struct usb_interface *intf)
 	struct lan78xx_net *dev = usb_get_intfdata(intf);
 	int ret;
 
+	netif_dbg(dev, ifup, dev->net, "(reset) resuming device");
+
 	ret = lan78xx_reset(dev);
 	if (ret < 0)
 		return ret;
-- 
2.25.1

[PATCH net-next 09/10] lan78xx: Fix race condition in disconnect handling

[John Efstathiades]

If there is a device disconnect at roughly the same time as a
deferred PHY link reset there is a race condition that can result
in a kernel lock up due to a null pointer dereference in the
driver's deferred work handling routine lan78xx_delayedwork().
The following changes fix this problem.

Add new status flag EVENT_DEV_DISCONNECT to indicate when the
device has been removed and use it to prevent operations, such as
register access, that will fail once the device is removed.

Stop processing of deferred work items when the driver's USB
disconnect handler is invoked.

Disconnect the PHY only after the network device has been
unregistered and all delayed work has been cancelled.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 66 +++++++++++++++++++++++++++++++++------
 1 file changed, 57 insertions(+), 9 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index feb638d268be..c4e5b643b809 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -360,6 +360,7 @@ struct usb_context {
 #define EVENT_DEV_ASLEEP		7
 #define EVENT_DEV_OPEN			8
 #define EVENT_STAT_UPDATE		9
+#define EVENT_DEV_DISCONNECT		10
 
 struct statstage {
 	struct mutex			access_lock;	/* for stats access */
@@ -450,9 +451,13 @@ MODULE_PARM_DESC(msg_level, "Override default message level");
 
 static int lan78xx_read_reg(struct lan78xx_net *dev, u32 index, u32 *data)
 {
-	u32 *buf = kmalloc(sizeof(u32), GFP_KERNEL);
+	u32 *buf;
 	int ret;
 
+	if (test_bit(EVENT_DEV_DISCONNECT, &dev->flags))
+		return -ENODEV;
+
+	buf = kmalloc(sizeof(u32), GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
@@ -476,9 +481,13 @@ static int lan78xx_read_reg(struct lan78xx_net *dev, u32 index, u32 *data)
 
 static int lan78xx_write_reg(struct lan78xx_net *dev, u32 index, u32 data)
 {
-	u32 *buf = kmalloc(sizeof(u32), GFP_KERNEL);
+	u32 *buf;
 	int ret;
 
+	if (test_bit(EVENT_DEV_DISCONNECT, &dev->flags))
+		return -ENODEV;
+
+	buf = kmalloc(sizeof(u32), GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
@@ -3160,16 +3169,23 @@ static void tx_complete(struct urb *urb)
 		/* software-driven interface shutdown */
 		case -ECONNRESET:
 		case -ESHUTDOWN:
+			netif_dbg(dev, tx_err, dev->net,
+				  "tx err interface gone %d\n",
+				  entry->urb->status);
 			break;
 
 		case -EPROTO:
 		case -ETIME:
 		case -EILSEQ:
 			netif_stop_queue(dev->net);
+			netif_dbg(dev, tx_err, dev->net,
+				  "tx err queue stopped %d\n",
+				  entry->urb->status);
 			break;
 		default:
 			netif_dbg(dev, tx_err, dev->net,
-				  "tx err %d\n", entry->urb->status);
+				  "unknown tx err %d\n",
+				  entry->urb->status);
 			break;
 		}
 	}
@@ -3503,6 +3519,7 @@ static int rx_submit(struct lan78xx_net *dev, struct urb *urb, gfp_t flags)
 			lan78xx_defer_kevent(dev, EVENT_RX_HALT);
 			break;
 		case -ENODEV:
+		case -ENOENT:
 			netif_dbg(dev, ifdown, dev->net, "device gone\n");
 			netif_device_detach(dev->net);
 			break;
@@ -3703,6 +3720,12 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev)
 		lan78xx_defer_kevent(dev, EVENT_TX_HALT);
 		usb_autopm_put_interface_async(dev->intf);
 		break;
+	case -ENODEV:
+	case -ENOENT:
+		netif_dbg(dev, tx_err, dev->net,
+			  "tx: submit urb err %d (disconnected?)", ret);
+		netif_device_detach(dev->net);
+		break;
 	default:
 		usb_autopm_put_interface_async(dev->intf);
 		netif_dbg(dev, tx_err, dev->net,
@@ -3797,6 +3820,9 @@ static void lan78xx_delayedwork(struct work_struct *work)
 
 	dev = container_of(work, struct lan78xx_net, wq.work);
 
+	if (test_bit(EVENT_DEV_DISCONNECT, &dev->flags))
+		return;
+
 	if (usb_autopm_get_interface(dev->intf) < 0)
 		return;
 
@@ -3871,6 +3897,7 @@ static void intr_complete(struct urb *urb)
 
 	/* software-driven interface shutdown */
 	case -ENOENT:			/* urb killed */
+	case -ENODEV:			/* hardware gone */
 	case -ESHUTDOWN:		/* hardware gone */
 		netif_dbg(dev, ifdown, dev->net,
 			  "intr shutdown, code %d\n", status);
@@ -3884,14 +3911,29 @@ static void intr_complete(struct urb *urb)
 		break;
 	}
 
-	if (!netif_running(dev->net))
+	if (!netif_device_present(dev->net) ||
+	    !netif_running(dev->net)) {
+		netdev_warn(dev->net, "not submitting new status URB");
 		return;
+	}
 
 	memset(urb->transfer_buffer, 0, urb->transfer_buffer_length);
 	status = usb_submit_urb(urb, GFP_ATOMIC);
-	if (status != 0)
+
+	switch (status) {
+	case  0:
+		break;
+	case -ENODEV:
+	case -ENOENT:
+		netif_dbg(dev, timer, dev->net,
+			  "intr resubmit %d (disconnect?)", status);
+		netif_device_detach(dev->net);
+		break;
+	default:
 		netif_err(dev, timer, dev->net,
 			  "intr resubmit --> %d\n", status);
+		break;
+	}
 }
 
 static void lan78xx_disconnect(struct usb_interface *intf)
@@ -3906,8 +3948,15 @@ static void lan78xx_disconnect(struct usb_interface *intf)
 	if (!dev)
 		return;
 
+	set_bit(EVENT_DEV_DISCONNECT, &dev->flags);
+
 	udev = interface_to_usbdev(intf);
 	net = dev->net;
+
+	unregister_netdev(net);
+
+	cancel_delayed_work_sync(&dev->wq);
+
 	phydev = net->phydev;
 
 	phy_unregister_fixup_for_uid(PHY_KSZ9031RNX, 0xfffffff0);
@@ -3918,12 +3967,11 @@ static void lan78xx_disconnect(struct usb_interface *intf)
 	if (phy_is_pseudo_fixed_link(phydev))
 		fixed_phy_unregister(phydev);
 
-	unregister_netdev(net);
-
-	cancel_delayed_work_sync(&dev->wq);
-
 	usb_scuttle_anchored_urbs(&dev->deferred);
 
+	if (timer_pending(&dev->stat_monitor))
+		del_timer_sync(&dev->stat_monitor);
+
 	lan78xx_unbind(dev, intf);
 
 	usb_kill_urb(dev->urb_intr);
-- 
2.25.1

[PATCH net-next 10/10] lan78xx: Limit number of driver warning messages

[John Efstathiades]

Device removal can result in a large burst of driver warning messages
(20 - 30) sent to the kernel log. Most of these are register read/write
failures.

This change limits the rate at which these messages are emitted.

Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
---
 drivers/net/usb/lan78xx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index c4e5b643b809..9a51ab881047 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -468,7 +468,7 @@ static int lan78xx_read_reg(struct lan78xx_net *dev, u32 index, u32 *data)
 	if (likely(ret >= 0)) {
 		le32_to_cpus(buf);
 		*data = *buf;
-	} else {
+	} else if (net_ratelimit()) {
 		netdev_warn(dev->net,
 			    "Failed to read register index 0x%08x. ret = %d",
 			    index, ret);
@@ -498,7 +498,8 @@ static int lan78xx_write_reg(struct lan78xx_net *dev, u32 index, u32 data)
 			      USB_VENDOR_REQUEST_WRITE_REGISTER,
 			      USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 			      0, index, buf, 4, USB_CTRL_SET_TIMEOUT);
-	if (unlikely(ret < 0)) {
+	if (unlikely(ret < 0) &&
+	    net_ratelimit()) {
 		netdev_warn(dev->net,
 			    "Failed to write register index 0x%08x. ret = %d",
 			    index, ret);
-- 
2.25.1

Re: [PATCH net-next 05/10] lan78xx: Disable USB3 link power state transitions

[Jakub Kicinski]

On Mon, 23 Aug 2021 14:52:24 +0100 John Efstathiades wrote:
> Disable USB3 link power state transitions from U0 (Fully Powered) to
> U1 (Standby with Fast Recovery) or U2 (Standby with Slow Recovery).
> 
> The device can initiate U1 and U2 state transitions when there is no
> activity on the bus which can save power. However, testing with some
> USB3 hosts and hubs showed erratic ping response time due to the time
> required to transition back to U0 state.
> 
> In the following example the outgoing packets were delayed until the
> device transitioned from U2 back to U0 giving the misleading
> response time.
> 
> console:/data/local # ping 192.168.73.1
> PING 192.168.73.1 (192.168.73.1) 56(84) bytes of data.
> 64 bytes from 192.168.73.1: icmp_seq=1 ttl=64 time=466 ms
> 64 bytes from 192.168.73.1: icmp_seq=2 ttl=64 time=225 ms
> 64 bytes from 192.168.73.1: icmp_seq=3 ttl=64 time=155 ms
> 64 bytes from 192.168.73.1: icmp_seq=4 ttl=64 time=7.07 ms
> 64 bytes from 192.168.73.1: icmp_seq=5 ttl=64 time=141 ms
> 64 bytes from 192.168.73.1: icmp_seq=6 ttl=64 time=152 ms
> 64 bytes from 192.168.73.1: icmp_seq=7 ttl=64 time=51.9 ms
> 64 bytes from 192.168.73.1: icmp_seq=8 ttl=64 time=136 ms
> 
> The following shows the behaviour when the U1 and U2 transitions
> were disabled.
> 
> console:/data/local # ping 192.168.73.1
> PING 192.168.73.1 (192.168.73.1) 56(84) bytes of data.
> 64 bytes from 192.168.73.1: icmp_seq=1 ttl=64 time=6.66 ms
> 64 bytes from 192.168.73.1: icmp_seq=2 ttl=64 time=2.97 ms
> 64 bytes from 192.168.73.1: icmp_seq=3 ttl=64 time=2.02 ms
> 64 bytes from 192.168.73.1: icmp_seq=4 ttl=64 time=2.42 ms
> 64 bytes from 192.168.73.1: icmp_seq=5 ttl=64 time=2.47 ms
> 64 bytes from 192.168.73.1: icmp_seq=6 ttl=64 time=2.55 ms
> 64 bytes from 192.168.73.1: icmp_seq=7 ttl=64 time=2.43 ms
> 64 bytes from 192.168.73.1: icmp_seq=8 ttl=64 time=2.13 ms
> 
> Signed-off-by: John Efstathiades <john.efstathiades@pebblebay.com>
> ---
>  drivers/net/usb/lan78xx.c | 44 ++++++++++++++++++++++++++++++++++-----
>  1 file changed, 39 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
> index 746aeeaa9d6e..3181753b1621 100644
> --- a/drivers/net/usb/lan78xx.c
> +++ b/drivers/net/usb/lan78xx.c
> @@ -430,6 +430,12 @@ struct lan78xx_net {
>  #define	PHY_LAN8835			(0x0007C130)
>  #define	PHY_KSZ9031RNX			(0x00221620)
>  
> +/* Enabling link power state transitions will reduce power consumption
> + * when the link is idle. However, this can cause problems with some
> + * USB3 hubs resulting in erratic packet flow.
> + */
> +static bool enable_link_power_states;

How is the user supposed to control this? Are similar issues not
addressed at the USB layer? There used to be a "no autosuspend"
flag that all netdev drivers set.. 

Was linux-usb consulted? Adding the list to Cc.

>  /* use ethtool to change the level for any given device */
>  static int msg_level = -1;
>  module_param(msg_level, int, 0);
> @@ -1173,7 +1179,7 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
>  	/* clear LAN78xx interrupt status */
>  	ret = lan78xx_write_reg(dev, INT_STS, INT_STS_PHY_INT_);
>  	if (unlikely(ret < 0))
> -		return -EIO;
> +		return ret;
>  
>  	mutex_lock(&phydev->lock);
>  	phy_read_status(phydev);
> @@ -1186,11 +1192,11 @@ static int lan78xx_link_reset(struct lan78xx_net *dev)
>  		/* reset MAC */
>  		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
>  		if (unlikely(ret < 0))
> -			return -EIO;
> +			return ret;
>  		buf |= MAC_CR_RST_;
>  		ret = lan78xx_write_reg(dev, MAC_CR, buf);
>  		if (unlikely(ret < 0))
> -			return -EIO;
> +			return ret;

Please split the ret code changes to a separate, earlier patch.

>  		del_timer(&dev->stat_monitor);
>  	} else if (link && !dev->link_on) {

Re: [PATCH net-next 06/10] lan78xx: Fix exception on link speed change

[Jakub Kicinski]

On Mon, 23 Aug 2021 14:52:25 +0100 John Efstathiades wrote:
> +	ret = -ETIME;

ETIMEDOUT

RE: [PATCH net-next 05/10] lan78xx: Disable USB3 link power state transitions

[John Efstathiades]

> > +/* Enabling link power state transitions will reduce power consumption
> > + * when the link is idle. However, this can cause problems with some
> > + * USB3 hubs resulting in erratic packet flow.
> > + */
> > +static bool enable_link_power_states;
> 
> How is the user supposed to control this? Are similar issues not
> addressed at the USB layer? There used to be a "no autosuspend"
> flag that all netdev drivers set..

The change is specific to U1 and U2 transitions initiated by the device
itself and does not affect ability of the device to respond to
host-initiated U1 and U2 transitions.

There is no user access to this. The driver would have to be recompiled to
change the default. 

> 
> Was linux-usb consulted? Adding the list to Cc.
> 
No, they weren't, but the change was discussed with the driver maintainer at
Microchip.

> >  		/* reset MAC */
> >  		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
> >  		if (unlikely(ret < 0))
> > -			return -EIO;
> > +			return ret;
> >  		buf |= MAC_CR_RST_;
> >  		ret = lan78xx_write_reg(dev, MAC_CR, buf);
> >  		if (unlikely(ret < 0))
> > -			return -EIO;
> > +			return ret;
> 
> Please split the ret code changes to a separate, earlier patch.

There are ret code changes in later patches in this set. As a general, rule
should ret code changes be put into their own patch?

Re: [PATCH net-next 05/10] lan78xx: Disable USB3 link power state transitions

[Jakub Kicinski]

On Tue, 24 Aug 2021 09:59:12 +0100 John Efstathiades wrote:
> > > +/* Enabling link power state transitions will reduce power consumption
> > > + * when the link is idle. However, this can cause problems with some
> > > + * USB3 hubs resulting in erratic packet flow.
> > > + */
> > > +static bool enable_link_power_states;  
> > 
> > How is the user supposed to control this? Are similar issues not
> > addressed at the USB layer? There used to be a "no autosuspend"
> > flag that all netdev drivers set..  
> 
> The change is specific to U1 and U2 transitions initiated by the device
> itself and does not affect ability of the device to respond to
> host-initiated U1 and U2 transitions.
> 
> There is no user access to this. The driver would have to be recompiled to
> change the default. 

Do you expect the device-initiated transitions to always be causing
trouble or are there scenarios where they are useful?

Having to recompile the driver is a middle ground rarely chosen
upstream. If the code has very low chance of being useful - let's
remove it (git will hold it forever if needed); if there are reasonable
chances someone will find it useful it should be configurable from user
space, or preferably automatically enabled based on some device match
list.

> > Was linux-usb consulted? Adding the list to Cc.
>  
> No, they weren't, but the change was discussed with the driver maintainer at
> Microchip.

Good to hear manufacturer is advising but the Linux USB community 
may have it's own preferences / experience.

> > >  		/* reset MAC */
> > >  		ret = lan78xx_read_reg(dev, MAC_CR, &buf);
> > >  		if (unlikely(ret < 0))
> > > -			return -EIO;
> > > +			return ret;
> > >  		buf |= MAC_CR_RST_;
> > >  		ret = lan78xx_write_reg(dev, MAC_CR, buf);
> > >  		if (unlikely(ret < 0))
> > > -			return -EIO;
> > > +			return ret;  
> > 
> > Please split the ret code changes to a separate, earlier patch.  
> 
> There are ret code changes in later patches in this set. As a general, rule
> should ret code changes be put into their own patch?

It's case by case, in this patch the ret code changes and error
propagation does not seem to be inherently related to the main 
change the patch is making. I think you're referring to patch 7 -
similar comment indeed applies there. I'd recommend taking the 
error propagation changes into a separate patch (can be a single 
one for code extracted from both patches).

RE: [PATCH net-next 05/10] lan78xx: Disable USB3 link power state transitions

[John Efstathiades]

> Do you expect the device-initiated transitions to always be causing
> trouble or are there scenarios where they are useful?

It's a particular problem on Android devices.

> Having to recompile the driver is a middle ground rarely chosen
> upstream. If the code has very low chance of being useful - let's
> remove it (git will hold it forever if needed); if there are reasonable
> chances someone will find it useful it should be configurable from user
> space, or preferably automatically enabled based on some device match
> list.

I like the sound of the device match list but I don't know what you mean.
Is there a driver or other reference you could point me at that provides
additional info?

> > > Was linux-usb consulted? Adding the list to Cc.
> >
> > No, they weren't, but the change was discussed with the driver
> maintainer at
> > Microchip.
> 
> Good to hear manufacturer is advising but the Linux USB community
> may have it's own preferences / experience.

Understood.

> > > Please split the ret code changes to a separate, earlier patch.
> >
> > There are ret code changes in later patches in this set. As a general,
> rule
> > should ret code changes be put into their own patch?
> 
> It's case by case, in this patch the ret code changes and error
> propagation does not seem to be inherently related to the main
> change the patch is making. I think you're referring to patch 7 -
> similar comment indeed applies there. I'd recommend taking the
> error propagation changes into a separate patch (can be a single
> one for code extracted from both patches).

Thanks, I am working on this and have incorporated the error propagation
changes from patch 7.

Re: [PATCH net-next 05/10] lan78xx: Disable USB3 link power state transitions

[Jakub Kicinski]

On Tue, 24 Aug 2021 15:33:13 +0100 John Efstathiades wrote:
> > Do you expect the device-initiated transitions to always be causing
> > trouble or are there scenarios where they are useful?  
> 
> It's a particular problem on Android devices.
> 
> > Having to recompile the driver is a middle ground rarely chosen
> > upstream. If the code has very low chance of being useful - let's
> > remove it (git will hold it forever if needed); if there are reasonable
> > chances someone will find it useful it should be configurable from user
> > space, or preferably automatically enabled based on some device match
> > list.  
> 
> I like the sound of the device match list but I don't know what you mean.
> Is there a driver or other reference you could point me at that provides
> additional info?

Depends on what the discriminator is. If problems happen with 
a particular ASIC revisions driver needs to read the revision
out and make a match. If it's product by product you can use
struct usb_device_id :: driver_info to attach metadata per 
device ID. If it's related to the platform things like DMI
matching are sometimes used. I have very limited experience 
with Android / embedded ARM so not sure what would work there.

RE: [PATCH net-next 05/10] lan78xx: Disable USB3 link power state transitions

[John Efstathiades]

> > I like the sound of the device match list but I don't know what you
> mean.
> > Is there a driver or other reference you could point me at that provides
> > additional info?
> 
> Depends on what the discriminator is. If problems happen with
> a particular ASIC revisions driver needs to read the revision
> out and make a match. If it's product by product you can use
> struct usb_device_id :: driver_info to attach metadata per
> device ID. If it's related to the platform things like DMI
> matching are sometimes used. I have very limited experience
> with Android / embedded ARM so not sure what would work there.

Thanks. Based on that I will remove this change from the patch set and
discuss again with the driver maintainer.