[PATCH net-next] r8152: replace tasklet with NAPI

From: Hayes Wang
Date: Tue Jan 13 2015 - 07:11:46 EST

Replace tasklet with NAPI.

Add rx_queue to queue the remaining rx packets if the number of the
rx packets is more than the request from poll().

Signed-off-by: Hayes Wang <hayeswang@xxxxxxxxxxx>
---
drivers/net/usb/r8152.c | 120 ++++++++++++++++++++++++++++++++++--------------
1 file changed, 85 insertions(+), 35 deletions(-)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index b23426e..50387fe 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -27,7 +27,7 @@
#include <linux/usb/cdc.h>

/* Version Information */
-#define DRIVER_VERSION "v1.07.0 (2014/10/09)"
+#define DRIVER_VERSION "v1.08.0 (2015/01/13)"
#define DRIVER_AUTHOR "Realtek linux nic maintainers <nic_swsd@xxxxxxxxxxx>"
#define DRIVER_DESC "Realtek RTL8152/RTL8153 Based USB Ethernet Adapters"
#define MODULENAME "r8152"
@@ -448,6 +448,7 @@ enum rtl_register_content {
#define RTL8152_RMS (VLAN_ETH_FRAME_LEN + VLAN_HLEN)
#define RTL8153_RMS RTL8153_MAX_PACKET
#define RTL8152_TX_TIMEOUT (5 * HZ)
+#define RTL8152_NAPI_WEIGHT 64

/* rtl8152 flags */
enum rtl8152_flags {
@@ -457,7 +458,7 @@ enum rtl8152_flags {
RTL8152_LINK_CHG,
SELECTIVE_SUSPEND,
PHY_RESET,
- SCHEDULE_TASKLET,
+ SCHEDULE_NAPI,
};

/* Define these values to match your device */
@@ -549,14 +550,14 @@ struct tx_agg {
struct r8152 {
unsigned long flags;
struct usb_device *udev;
- struct tasklet_struct tl;
+ struct napi_struct napi;
struct usb_interface *intf;
struct net_device *netdev;
struct urb *intr_urb;
struct tx_agg tx_info[RTL8152_MAX_TX];
struct rx_agg rx_info[RTL8152_MAX_RX];
struct list_head rx_done, tx_free;
- struct sk_buff_head tx_queue;
+ struct sk_buff_head tx_queue, rx_queue;
spinlock_t rx_lock, tx_lock;
struct delayed_work schedule;
struct mii_if_info mii;
@@ -1062,7 +1063,7 @@ static void read_bulk_callback(struct urb *urb)
spin_lock(&tp->rx_lock);
list_add_tail(&agg->list, &tp->rx_done);
spin_unlock(&tp->rx_lock);
- tasklet_schedule(&tp->tl);
+ napi_schedule(&tp->napi);
return;
case -ESHUTDOWN:
set_bit(RTL8152_UNPLUG, &tp->flags);
@@ -1126,7 +1127,7 @@ static void write_bulk_callback(struct urb *urb)
return;

if (!skb_queue_empty(&tp->tx_queue))
- tasklet_schedule(&tp->tl);
+ napi_schedule(&tp->napi);
}

static void intr_callback(struct urb *urb)
@@ -1245,6 +1246,7 @@ static int alloc_all_mem(struct r8152 *tp)
spin_lock_init(&tp->tx_lock);
INIT_LIST_HEAD(&tp->tx_free);
skb_queue_head_init(&tp->tx_queue);
+ skb_queue_head_init(&tp->rx_queue);

for (i = 0; i < RTL8152_MAX_RX; i++) {
buf = kmalloc_node(agg_buf_sz, GFP_KERNEL, node);
@@ -1649,13 +1651,32 @@ return_result:
return checksum;
}

-static void rx_bottom(struct r8152 *tp)
+static int rx_bottom(struct r8152 *tp, int budget)
{
unsigned long flags;
struct list_head *cursor, *next, rx_queue;
+ int work_done = 0;
+
+ if (!skb_queue_empty(&tp->rx_queue)) {
+ while (work_done < budget) {
+ struct sk_buff *skb = __skb_dequeue(&tp->rx_queue);
+ struct net_device *netdev = tp->netdev;
+ struct net_device_stats *stats = &netdev->stats;
+ unsigned int pkt_len;
+
+ if (!skb)
+ break;
+
+ pkt_len = skb->len;
+ napi_gro_receive(&tp->napi, skb);
+ work_done++;
+ stats->rx_packets++;
+ stats->rx_bytes += pkt_len;
+ }
+ }

if (list_empty(&tp->rx_done))
- return;
+ goto out1;

INIT_LIST_HEAD(&rx_queue);
spin_lock_irqsave(&tp->rx_lock, flags);
@@ -1708,9 +1729,14 @@ static void rx_bottom(struct r8152 *tp)
skb_put(skb, pkt_len);
skb->protocol = eth_type_trans(skb, netdev);
rtl_rx_vlan_tag(rx_desc, skb);
- netif_receive_skb(skb);
- stats->rx_packets++;
- stats->rx_bytes += pkt_len;
+ if (work_done < budget) {
+ napi_gro_receive(&tp->napi, skb);
+ work_done++;
+ stats->rx_packets++;
+ stats->rx_bytes += pkt_len;
+ } else {
+ __skb_queue_tail(&tp->rx_queue, skb);
+ }

find_next_rx:
rx_data = rx_agg_align(rx_data + pkt_len + CRC_SIZE);
@@ -1722,6 +1748,9 @@ find_next_rx:
submit:
r8152_submit_rx(tp, agg, GFP_ATOMIC);
}
+
+out1:
+ return work_done;
}

static void tx_bottom(struct r8152 *tp)
@@ -1761,12 +1790,8 @@ static void tx_bottom(struct r8152 *tp)
} while (res == 0);
}

-static void bottom_half(unsigned long data)
+static void bottom_half(struct r8152 *tp)
{
- struct r8152 *tp;
-
- tp = (struct r8152 *)data;
-
if (test_bit(RTL8152_UNPLUG, &tp->flags))
return;

@@ -1778,12 +1803,28 @@ static void bottom_half(unsigned long data)
if (!netif_carrier_ok(tp->netdev))
return;

- clear_bit(SCHEDULE_TASKLET, &tp->flags);
+ clear_bit(SCHEDULE_NAPI, &tp->flags);

- rx_bottom(tp);
tx_bottom(tp);
}

+static int r8152_poll(struct napi_struct *napi, int budget)
+{
+ struct r8152 *tp = container_of(napi, struct r8152, napi);
+ int work_done;
+
+ work_done = rx_bottom(tp, budget);
+ bottom_half(tp);
+
+ if (work_done < budget) {
+ napi_complete(napi);
+ if (!list_empty(&tp->rx_done))
+ napi_schedule(napi);
+ }
+
+ return work_done;
+}
+
static
int r8152_submit_rx(struct r8152 *tp, struct rx_agg *agg, gfp_t mem_flags)
{
@@ -1810,7 +1851,11 @@ int r8152_submit_rx(struct r8152 *tp, struct rx_agg *agg, gfp_t mem_flags)
spin_lock_irqsave(&tp->rx_lock, flags);
list_add_tail(&agg->list, &tp->rx_done);
spin_unlock_irqrestore(&tp->rx_lock, flags);
- tasklet_schedule(&tp->tl);
+
+ netif_err(tp, rx_err, tp->netdev,
+ "Couldn't submit rx[%p], ret = %d\n", agg, ret);
+
+ napi_schedule(&tp->napi);
}

return ret;
@@ -1929,11 +1974,11 @@ static netdev_tx_t rtl8152_start_xmit(struct sk_buff *skb,

if (!list_empty(&tp->tx_free)) {
if (test_bit(SELECTIVE_SUSPEND, &tp->flags)) {
- set_bit(SCHEDULE_TASKLET, &tp->flags);
+ set_bit(SCHEDULE_NAPI, &tp->flags);
schedule_delayed_work(&tp->schedule, 0);
} else {
usb_mark_last_busy(tp->udev);
- tasklet_schedule(&tp->tl);
+ napi_schedule(&tp->napi);
}
} else if (skb_queue_len(&tp->tx_queue) > tp->tx_qlen) {
netif_stop_queue(netdev);
@@ -2012,6 +2057,7 @@ static int rtl_start_rx(struct r8152 *tp)
{
int i, ret = 0;

+ napi_disable(&tp->napi);
INIT_LIST_HEAD(&tp->rx_done);
for (i = 0; i < RTL8152_MAX_RX; i++) {
INIT_LIST_HEAD(&tp->rx_info[i].list);
@@ -2019,6 +2065,7 @@ static int rtl_start_rx(struct r8152 *tp)
if (ret)
break;
}
+ napi_enable(&tp->napi);

if (ret && ++i < RTL8152_MAX_RX) {
struct list_head rx_queue;
@@ -2049,6 +2096,9 @@ static int rtl_stop_rx(struct r8152 *tp)
for (i = 0; i < RTL8152_MAX_RX; i++)
usb_kill_urb(tp->rx_info[i].urb);

+ while (!skb_queue_empty(&tp->rx_queue))
+ dev_kfree_skb(__skb_dequeue(&tp->rx_queue));
+
return 0;
}

@@ -2884,9 +2934,9 @@ static void set_carrier(struct r8152 *tp)
} else {
if (tp->speed & LINK_STATUS) {
netif_carrier_off(netdev);
- tasklet_disable(&tp->tl);
+ napi_disable(&tp->napi);
tp->rtl_ops.disable(tp);
- tasklet_enable(&tp->tl);
+ napi_enable(&tp->napi);
}
}
tp->speed = speed;
@@ -2919,10 +2969,11 @@ static void rtl_work_func_t(struct work_struct *work)
if (test_bit(RTL8152_SET_RX_MODE, &tp->flags))
_rtl8152_set_rx_mode(tp->netdev);

- if (test_bit(SCHEDULE_TASKLET, &tp->flags) &&
+ /* don't schedule napi before linking */
+ if (test_bit(SCHEDULE_NAPI, &tp->flags) &&
(tp->speed & LINK_STATUS)) {
- clear_bit(SCHEDULE_TASKLET, &tp->flags);
- tasklet_schedule(&tp->tl);
+ clear_bit(SCHEDULE_NAPI, &tp->flags);
+ napi_schedule(&tp->napi);
}

if (test_bit(PHY_RESET, &tp->flags))
@@ -2983,7 +3034,7 @@ static int rtl8152_open(struct net_device *netdev)
res);
free_all_mem(tp);
} else {
- tasklet_enable(&tp->tl);
+ napi_enable(&tp->napi);
}

mutex_unlock(&tp->control);
@@ -2999,7 +3050,7 @@ static int rtl8152_close(struct net_device *netdev)
struct r8152 *tp = netdev_priv(netdev);
int res = 0;

- tasklet_disable(&tp->tl);
+ napi_disable(&tp->napi);
clear_bit(WORK_ENABLE, &tp->flags);
usb_kill_urb(tp->intr_urb);
cancel_delayed_work_sync(&tp->schedule);
@@ -3008,6 +3059,7 @@ static int rtl8152_close(struct net_device *netdev)
res = usb_autopm_get_interface(tp->intf);
if (res < 0) {
rtl_drop_queued_tx(tp);
+ rtl_stop_rx(tp);
} else {
mutex_lock(&tp->control);

@@ -3263,7 +3315,7 @@ static int rtl8152_suspend(struct usb_interface *intf, pm_message_t message)
if (netif_running(netdev) && test_bit(WORK_ENABLE, &tp->flags)) {
clear_bit(WORK_ENABLE, &tp->flags);
usb_kill_urb(tp->intr_urb);
- tasklet_disable(&tp->tl);
+ napi_disable(&tp->napi);
if (test_bit(SELECTIVE_SUSPEND, &tp->flags)) {
rtl_stop_rx(tp);
rtl_runtime_suspend_enable(tp, true);
@@ -3271,7 +3323,7 @@ static int rtl8152_suspend(struct usb_interface *intf, pm_message_t message)
cancel_delayed_work_sync(&tp->schedule);
tp->rtl_ops.down(tp);
}
- tasklet_enable(&tp->tl);
+ napi_enable(&tp->napi);
}
out1:
mutex_unlock(&tp->control);
@@ -3855,7 +3907,6 @@ static int rtl8152_probe(struct usb_interface *intf,
if (ret)
goto out;

- tasklet_init(&tp->tl, bottom_half, (unsigned long)tp);
mutex_init(&tp->control);
INIT_DELAYED_WORK(&tp->schedule, rtl_work_func_t);

@@ -3891,6 +3942,7 @@ static int rtl8152_probe(struct usb_interface *intf,
set_ethernet_addr(tp);

usb_set_intfdata(intf, tp);
+ netif_napi_add(netdev, &tp->napi, r8152_poll, RTL8152_NAPI_WEIGHT);

ret = register_netdev(netdev);
if (ret != 0) {
@@ -3904,15 +3956,13 @@ static int rtl8152_probe(struct usb_interface *intf,
else
device_set_wakeup_enable(&udev->dev, false);

- tasklet_disable(&tp->tl);
-
netif_info(tp, probe, netdev, "%s\n", DRIVER_VERSION);

return 0;

out1:
+ netif_napi_del(&tp->napi);
usb_set_intfdata(intf, NULL);
- tasklet_kill(&tp->tl);
out:
free_netdev(netdev);
return ret;
@@ -3929,7 +3979,7 @@ static void rtl8152_disconnect(struct usb_interface *intf)
if (udev->state == USB_STATE_NOTATTACHED)
set_bit(RTL8152_UNPLUG, &tp->flags);

- tasklet_kill(&tp->tl);
+ netif_napi_del(&tp->napi);
unregister_netdev(tp->netdev);
tp->rtl_ops.unload(tp);
free_netdev(tp->netdev);
--
2.1.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/