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gobi: Provide netif_wake_queue and netif_stop_queue usage
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This adds use of netif_stop_queue and netif_wake_queue to avoid
that the driver just queues everything in startxmit on an end-
less linked list of urbs.

To test this use:
	iperf -s -u -p 5000 -b
	iperf -c <SERVER> -u -p 5000 -b 20M -i 1 -t 1000

The patch also adds setting txqueuelen and mtu using ifconfig
for easier testing.

To test this use:

	ifconfig wlan0 mtu 1500 txqueuelen 10
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@pvanhoof
pvanhoof committed Apr 10, 2013
1 parent 04c0107 commit b17e13e
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Showing 2 changed files with 96 additions and 1 deletion.
84 changes: 83 additions & 1 deletion drivers/net/usb/gobi/qcusbnet.c
View file
Expand Up @@ -28,6 +28,8 @@
#define DRIVER_AUTHOR "Qualcomm Innovation Center"
#define DRIVER_DESC "gobi"

#define TX_QLEN(dev) (((dev)->udev->speed == USB_SPEED_HIGH) ? ((dev)->usbnet->net->tx_queue_len) : 4)

static LIST_HEAD(qcusbnet_list);
static DEFINE_MUTEX(qcusbnet_lock);

Expand All @@ -52,6 +54,28 @@ void qcusbnet_put(struct qcusbnet *dev)
kobject_put(&dev->kobj);
}

static void
qcusbnet_decurbcnt (struct qcusbnet *dev)
{
if (--dev->urbcnt < TX_QLEN (dev)) {
GOBI_VERBOSE ("qcusbnet_decurbcnt %d (qlen=%lu, mtu=%u)", dev->urbcnt, TX_QLEN(dev), dev->hard_mtu);
if (atomic_sub_return (1, &dev->stopped) == 0) {
GOBI_VERBOSE ("qcusbnet_decurbcnt woke");
netif_wake_queue (dev->usbnet->net);
}
}
}

static void
qcusbnet_incurbcnt (struct qcusbnet *dev)
{
if (++dev->urbcnt > TX_QLEN (dev)) {
GOBI_VERBOSE ("qcusbnet_incurbcnt %d sleep (qlen=%lu, mtu=%u)", dev->urbcnt, TX_QLEN(dev), dev->hard_mtu);
netif_stop_queue (dev->usbnet->net);
atomic_set (&dev->stopped, 1);
}
}

struct qcusbnet *qcusbnet_get(struct qcusbnet *key)
{
/* Given a putative qcusbnet struct, return either the struct itself
Expand Down Expand Up @@ -257,6 +281,9 @@ static void qcnet_bg_complete(struct work_struct *work)
usb_autopm_put_interface(dev->iface);

spin_lock_irqsave(&dev->urbs_lock, listflags);

qcusbnet_decurbcnt (dev);

if (!list_empty(&dev->urbs))
queue_work(dev->workqueue, &dev->startxmit);
spin_unlock_irqrestore(&dev->urbs_lock, listflags);
Expand All @@ -266,21 +293,28 @@ static void qcnet_complete(struct urb *urb)
{
struct qcusbnet *dev = urb->context;

BUG_ON(urb != dev->active);

queue_work(dev->workqueue, &dev->complete);
}

static void qcnet_bg_txtimeout(struct work_struct *work)
{
unsigned long listflags;
struct qcusbnet *dev = container_of(work, struct qcusbnet, txtimeout);
struct list_head *node, *tmp;
struct urb *urb;
if (dev->active)
usb_kill_urb(dev->active);

spin_lock_irqsave(&dev->urbs_lock, listflags);
list_for_each_safe(node, tmp, &dev->urbs) {
urb = list_entry(node, struct urb, urb_list);
list_del(&urb->urb_list);
usb_free_urb(urb);
qcusbnet_decurbcnt (dev);
}
spin_unlock_irqrestore(&dev->urbs_lock, listflags);
}

static void qcnet_txtimeout(struct net_device *netdev)
Expand All @@ -290,6 +324,31 @@ static void qcnet_txtimeout(struct net_device *netdev)
queue_work(dev->workqueue, &dev->txtimeout);
}

static int qcnet_change_mtu (struct net_device *netdev, int new_mtu)
{
struct usbnet *usbnet = netdev_priv(netdev);
struct qcusbnet *dev = (struct qcusbnet *)usbnet->data[0];
int ll_mtu = new_mtu + usbnet->net->hard_header_len;
int old_hard_mtu = dev->hard_mtu;
int old_rx_urb_size = dev->rx_urb_size;

if (new_mtu <= 0)
return -EINVAL;
/* no second zero-length packet read wanted after mtu-sized packets */
if ((ll_mtu % dev->maxpacket) == 0)
return -EDOM;
usbnet->net->mtu = new_mtu;

dev->hard_mtu = usbnet->net->mtu + usbnet->net->hard_header_len;
if (dev->rx_urb_size == old_hard_mtu) {
dev->rx_urb_size = dev->hard_mtu;
if (dev->rx_urb_size > old_rx_urb_size)
usbnet_unlink_rx_urbs(usbnet);
}

return 0;
}

static void qcnet_bg_startxmit(struct work_struct *work)
{
unsigned long listflags;
Expand Down Expand Up @@ -336,10 +395,11 @@ static void qcnet_bg_startxmit(struct work_struct *work)
}

dev->active = urb;

status = usb_submit_urb(urb, GFP_KERNEL);
if (status < 0) {
GOBI_ERROR("failed to submit urb: %d (packet dropped)", status);
usb_free_urb(dev->active);
usb_free_urb(urb);
dev->active = NULL;
usb_autopm_put_interface(dev->iface);
}
Expand Down Expand Up @@ -379,6 +439,7 @@ static int qcnet_startxmit(struct sk_buff *skb, struct net_device *netdev)

spin_lock_irqsave(&dev->urbs_lock, listflags);
list_add_tail(&urb->urb_list, &dev->urbs);
qcusbnet_incurbcnt (dev);
spin_unlock_irqrestore(&dev->urbs_lock, listflags);

queue_work(dev->workqueue, &dev->startxmit);
Expand Down Expand Up @@ -582,6 +643,7 @@ static int discover_endpoints(struct qcusbnet *dev)

int qcnet_probe(struct usb_interface *iface, const struct usb_device_id *vidpids)
{
struct usb_device *xdev;
int status;
struct usbnet *usbnet;
struct qcusbnet *dev;
Expand All @@ -591,6 +653,9 @@ int qcnet_probe(struct usb_interface *iface, const struct usb_device_id *vidpids
u8 *addr;
const char *id;

xdev = interface_to_usbdev (iface);
usb_get_dev (xdev);

status = usbnet_probe(iface, vidpids);
if (status < 0) {
GOBI_WARN("usbnet_probe failed: %d", status);
Expand Down Expand Up @@ -618,6 +683,7 @@ int qcnet_probe(struct usb_interface *iface, const struct usb_device_id *vidpids
goto fail_disconnect;
}

dev->udev = xdev;
dev->dying = false;
dev->iface = iface;

Expand Down Expand Up @@ -646,6 +712,7 @@ int qcnet_probe(struct usb_interface *iface, const struct usb_device_id *vidpids
netdevops->ndo_stop = qcnet_stop;
netdevops->ndo_start_xmit = qcnet_startxmit;
netdevops->ndo_tx_timeout = qcnet_txtimeout;
netdevops->ndo_change_mtu = qcnet_change_mtu;

usbnet->net->netdev_ops = netdevops;

Expand All @@ -667,6 +734,8 @@ int qcnet_probe(struct usb_interface *iface, const struct usb_device_id *vidpids

spin_lock_init(&dev->urbs_lock);
INIT_LIST_HEAD(&dev->urbs);
atomic_set (&dev->stopped, 0);
dev->urbcnt = 0;
dev->active = NULL;
INIT_WORK(&dev->startxmit, qcnet_bg_startxmit);
INIT_WORK(&dev->txtimeout, qcnet_bg_txtimeout);
Expand All @@ -678,6 +747,13 @@ int qcnet_probe(struct usb_interface *iface, const struct usb_device_id *vidpids
qc_setdown(dev, DOWN_NO_NDIS_CONNECTION);
qc_setdown(dev, DOWN_NET_IFACE_STOPPED);

dev->usbnet->net->tx_queue_len = 4;
dev->hard_mtu = usbnet->net->mtu + usbnet->net->hard_header_len;

if (!dev->rx_urb_size)
dev->rx_urb_size = dev->hard_mtu;
dev->maxpacket = usb_maxpacket (dev->udev, usbnet->out, 1);

status = qc_register(dev);
if (status) {
GOBI_ERROR("qc_register failed: %d", status);
Expand Down Expand Up @@ -719,6 +795,7 @@ EXPORT_SYMBOL_GPL(qcnet_probe);

static void qcnet_disconnect(struct usb_interface *intf)
{
unsigned long listflags;
struct usbnet *usbnet = usb_get_intfdata(intf);
struct qcusbnet *dev = (struct qcusbnet *)usbnet->data[0];
struct list_head *node, *tmp;
Expand All @@ -730,11 +807,16 @@ static void qcnet_disconnect(struct usb_interface *intf)
qc_deregister(dev);

destroy_workqueue(dev->workqueue);

spin_lock_irqsave(&dev->urbs_lock, listflags);
list_for_each_safe(node, tmp, &dev->urbs) {
urb = list_entry(node, struct urb, urb_list);
list_del(&urb->urb_list);
usb_free_urb(urb);
qcusbnet_decurbcnt (dev);
}
spin_unlock_irqrestore(&dev->urbs_lock, listflags);

usbnet_disconnect(intf);
qcusbnet_put(dev);
}
Expand Down
13 changes: 13 additions & 0 deletions drivers/net/usb/gobi/structs.h
View file
Expand Up @@ -45,6 +45,12 @@ do { \
#define GOBI_WARN(fmt, arg...) GOBI_LOG(1, fmt, ##arg)
#define GOBI_DEBUG(fmt, arg...) GOBI_LOG(2, fmt, ##arg)

#ifdef VERBOSE_GOBI_DEBUG
#define GOBI_VERBOSE(fmt, arg...) GOBI_LOG(0, fmt, ##arg)
#else
#define GOBI_VERBOSE(fmt, arg...)
#endif

struct qcusbnet;

struct urbreq {
Expand Down Expand Up @@ -84,6 +90,7 @@ struct qcusbnet {
struct kobject kobj;
struct usbnet *usbnet;
struct usb_interface *iface;
struct usb_device *udev;
int (*open)(struct net_device *);
int (*stop)(struct net_device *);
unsigned long down;
Expand All @@ -97,6 +104,8 @@ struct qcusbnet {
spinlock_t urbs_lock;
struct list_head urbs;
struct urb *active;
unsigned int urbcnt;
atomic_t stopped;

struct work_struct startxmit;
struct work_struct txtimeout;
Expand All @@ -106,6 +115,10 @@ struct qcusbnet {
unsigned int int_in_endp;
unsigned int bulk_in_endp;
unsigned int bulk_out_endp;

u32 hard_mtu;
size_t rx_urb_size;
unsigned maxpacket;
};

#endif /* !QCUSBNET_STRUCTS_H */

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