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Re: [Xen-devel] [PATCH V4 2/3] xen-netback: switch to NAPI + kthread 1:1 model



I sent this patch right before Ian requested more comments in code. Now
I've updated this one. Not going to resend the whole series as this is
only changes in comments.

Sorry for my bad English, I don't know whether I've made them clear
enough. Suggestions are welcomed.


Wei.

---8<---
From bb33027fe4bafeea546352cd3e409466f8bd7aa4 Mon Sep 17 00:00:00 2001
From: Wei Liu <wei.liu2@xxxxxxxxxx>
Date: Tue, 6 Aug 2013 06:59:15 +0100
Subject: [PATCH] xen-netback: switch to NAPI + kthread 1:1 model

This patch implements 1:1 model netback. NAPI and kthread are utilized
to do the weight-lifting job:

- NAPI is used for guest side TX (host side RX)
- kthread is used for guest side RX (host side TX)

Xenvif and xen_netbk are made into one structure to reduce code size.

This model provides better scheduling fairness among vifs. It is also
prerequisite for implementing multiqueue for Xen netback.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 drivers/net/xen-netback/common.h    |  128 +++++---
 drivers/net/xen-netback/interface.c |  119 ++++---
 drivers/net/xen-netback/netback.c   |  607 ++++++++++-------------------------
 3 files changed, 347 insertions(+), 507 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 8a4d77e..184ae0a 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -45,31 +45,105 @@
 #include <xen/grant_table.h>
 #include <xen/xenbus.h>
 
-struct xen_netbk;
+typedef unsigned int pending_ring_idx_t;
+#define INVALID_PENDING_RING_IDX (~0U)
+
+/* For the head field in pending_tx_info: It is used to indicate
+ * whether this tx info is the head of one or more coalesced requests.
+ *
+ * When head != INVALID_PENDING_RING_IDX, it means the start of a new
+ * tx requests queue and the end of previous queue.
+ *
+ * An example sequence of head fields (I = INVALID_PENDING_RING_IDX):
+ *
+ * ... 0 I I I 5 I 9 I I I ...
+ *
+ * After consming the first packet we have:
+ *
+ * ... V V V V 5 I 9 I I I ...
+ *
+ * where V stands for "valid pending ring index", any number other
+ * than INVALID_PENDING_RING_IDX is OK. In practice we use 0.
+ *
+ * The non-INVALID_PENDING_RING_IDX (say 0, 5 and 9 in the above
+ * example) number is the index into pending_tx_info and mmap_pages
+ * arrays.
+ */
+struct pending_tx_info {
+       struct xen_netif_tx_request req; /* coalesced tx request */
+       pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
+                                 * if it is head of one or more tx
+                                 * reqs
+                                 */
+};
+
+#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
+#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
+
+struct xenvif_rx_meta {
+       int id;
+       int size;
+       int gso_size;
+};
+
+/* Discriminate from any valid pending_idx value. */
+#define INVALID_PENDING_IDX 0xFFFF
+
+#define MAX_BUFFER_OFFSET PAGE_SIZE
+
+#define MAX_PENDING_REQS 256
 
 struct xenvif {
        /* Unique identifier for this interface. */
        domid_t          domid;
        unsigned int     handle;
 
-       /* Reference to netback processing backend. */
-       struct xen_netbk *netbk;
+       /* Use NAPI for guest TX */
+       struct napi_struct napi;
+       /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
+       unsigned int tx_irq;
+       /* Only used when feature-split-event-channels = 1 */
+       char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
+       struct xen_netif_tx_back_ring tx;
+       struct sk_buff_head tx_queue;
+       struct page *mmap_pages[MAX_PENDING_REQS];
+       pending_ring_idx_t pending_prod;
+       pending_ring_idx_t pending_cons;
+       u16 pending_ring[MAX_PENDING_REQS];
+       struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
+
+       /* Coalescing tx requests before copying makes number of grant
+        * copy ops greater or equal to number of slots required. In
+        * worst case a tx request consumes 2 gnttab_copy.
+        */
+       struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
 
-       u8               fe_dev_addr[6];
 
+       /* Use kthread for guest RX */
+       struct task_struct *task;
+       wait_queue_head_t wq;
        /* When feature-split-event-channels = 0, tx_irq = rx_irq. */
-       unsigned int tx_irq;
        unsigned int rx_irq;
        /* Only used when feature-split-event-channels = 1 */
-       char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
        char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
+       struct xen_netif_rx_back_ring rx;
+       struct sk_buff_head rx_queue;
 
-       /* List of frontends to notify after a batch of frames sent. */
-       struct list_head notify_list;
+       /* Allow xenvif_start_xmit() to peek ahead in the rx request
+        * ring.  This is a prediction of what rx_req_cons will be
+        * once all queued skbs are put on the ring.
+        */
+       RING_IDX rx_req_cons_peek;
+
+       /* Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
+        * head/fragment page uses 2 copy operations because it
+        * straddles two buffers in the frontend.
+        */
+       struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
+       struct xenvif_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
 
-       /* The shared rings and indexes. */
-       struct xen_netif_tx_back_ring tx;
-       struct xen_netif_rx_back_ring rx;
+
+       u8               fe_dev_addr[6];
 
        /* Frontend feature information. */
        u8 can_sg:1;
@@ -80,13 +154,6 @@ struct xenvif {
        /* Internal feature information. */
        u8 can_queue:1;     /* can queue packets for receiver? */
 
-       /*
-        * Allow xenvif_start_xmit() to peek ahead in the rx request
-        * ring.  This is a prediction of what rx_req_cons will be
-        * once all queued skbs are put on the ring.
-        */
-       RING_IDX rx_req_cons_peek;
-
        /* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
        unsigned long   credit_bytes;
        unsigned long   credit_usec;
@@ -97,11 +164,7 @@ struct xenvif {
        unsigned long rx_gso_checksum_fixup;
 
        /* Miscellaneous private stuff. */
-       struct list_head schedule_list;
-       atomic_t         refcnt;
        struct net_device *dev;
-
-       wait_queue_head_t waiting_to_free;
 };
 
 static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
@@ -109,9 +172,6 @@ static inline struct xenbus_device 
*xenvif_to_xenbus_device(struct xenvif *vif)
        return to_xenbus_device(vif->dev->dev.parent);
 }
 
-#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
-#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
-
 struct xenvif *xenvif_alloc(struct device *parent,
                            domid_t domid,
                            unsigned int handle);
@@ -121,9 +181,6 @@ int xenvif_connect(struct xenvif *vif, unsigned long 
tx_ring_ref,
                   unsigned int rx_evtchn);
 void xenvif_disconnect(struct xenvif *vif);
 
-void xenvif_get(struct xenvif *vif);
-void xenvif_put(struct xenvif *vif);
-
 int xenvif_xenbus_init(void);
 void xenvif_xenbus_fini(void);
 
@@ -139,18 +196,8 @@ int xen_netbk_map_frontend_rings(struct xenvif *vif,
                                 grant_ref_t tx_ring_ref,
                                 grant_ref_t rx_ring_ref);
 
-/* (De)Register a xenvif with the netback backend. */
-void xen_netbk_add_xenvif(struct xenvif *vif);
-void xen_netbk_remove_xenvif(struct xenvif *vif);
-
-/* (De)Schedule backend processing for a xenvif */
-void xen_netbk_schedule_xenvif(struct xenvif *vif);
-void xen_netbk_deschedule_xenvif(struct xenvif *vif);
-
 /* Check for SKBs from frontend and schedule backend processing */
 void xen_netbk_check_rx_xenvif(struct xenvif *vif);
-/* Receive an SKB from the frontend */
-void xenvif_receive_skb(struct xenvif *vif, struct sk_buff *skb);
 
 /* Queue an SKB for transmission to the frontend */
 void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb);
@@ -163,6 +210,11 @@ void xenvif_carrier_off(struct xenvif *vif);
 /* Returns number of ring slots required to send an skb to the frontend */
 unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff 
*skb);
 
+int xen_netbk_tx_action(struct xenvif *vif, int budget);
+void xen_netbk_rx_action(struct xenvif *vif);
+
+int xen_netbk_kthread(void *data);
+
 extern bool separate_tx_rx_irq;
 
 #endif /* __XEN_NETBACK__COMMON_H__ */
diff --git a/drivers/net/xen-netback/interface.c 
b/drivers/net/xen-netback/interface.c
index 087d2db..44d6b70 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -30,6 +30,7 @@
 
 #include "common.h"
 
+#include <linux/kthread.h>
 #include <linux/ethtool.h>
 #include <linux/rtnetlink.h>
 #include <linux/if_vlan.h>
@@ -38,17 +39,7 @@
 #include <asm/xen/hypercall.h>
 
 #define XENVIF_QUEUE_LENGTH 32
-
-void xenvif_get(struct xenvif *vif)
-{
-       atomic_inc(&vif->refcnt);
-}
-
-void xenvif_put(struct xenvif *vif)
-{
-       if (atomic_dec_and_test(&vif->refcnt))
-               wake_up(&vif->waiting_to_free);
-}
+#define XENVIF_NAPI_WEIGHT  64
 
 int xenvif_schedulable(struct xenvif *vif)
 {
@@ -64,21 +55,55 @@ static irqreturn_t xenvif_tx_interrupt(int irq, void 
*dev_id)
 {
        struct xenvif *vif = dev_id;
 
-       if (vif->netbk == NULL)
-               return IRQ_HANDLED;
-
-       xen_netbk_schedule_xenvif(vif);
+       if (RING_HAS_UNCONSUMED_REQUESTS(&vif->tx))
+               napi_schedule(&vif->napi);
 
        return IRQ_HANDLED;
 }
 
+static int xenvif_poll(struct napi_struct *napi, int budget)
+{
+       struct xenvif *vif = container_of(napi, struct xenvif, napi);
+       int work_done;
+
+       work_done = xen_netbk_tx_action(vif, budget);
+
+       if (work_done < budget) {
+               int more_to_do = 0;
+               unsigned long flags;
+
+               /* It is necessary to disable IRQ before calling
+                * RING_HAS_UNCONSUMED_REQUESTS. Otherwise we might
+                * lose event from the frontend.
+                *
+                * Consider:
+                *   RING_HAS_UNCONSUMED_REQUESTS
+                *   <frontend generates event to trigger napi_schedule>
+                *   __napi_complete
+                *
+                * This handler is still in scheduled state so the
+                * event has no effect at all. After __napi_complete
+                * this handler is descheduled and cannot get
+                * scheduled again. We lose event in this case and the ring
+                * will be completely stalled.
+                */
+
+               local_irq_save(flags);
+
+               RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
+               if (!more_to_do)
+                       __napi_complete(napi);
+
+               local_irq_restore(flags);
+       }
+
+       return work_done;
+}
+
 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
 {
        struct xenvif *vif = dev_id;
 
-       if (vif->netbk == NULL)
-               return IRQ_HANDLED;
-
        if (xenvif_rx_schedulable(vif))
                netif_wake_queue(vif->dev);
 
@@ -99,7 +124,8 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct 
net_device *dev)
 
        BUG_ON(skb->dev != dev);
 
-       if (vif->netbk == NULL)
+       /* Drop the packet if vif is not ready */
+       if (vif->task == NULL)
                goto drop;
 
        /* Drop the packet if the target domain has no receive buffers. */
@@ -108,7 +134,6 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct 
net_device *dev)
 
        /* Reserve ring slots for the worst-case number of fragments. */
        vif->rx_req_cons_peek += xen_netbk_count_skb_slots(vif, skb);
-       xenvif_get(vif);
 
        if (vif->can_queue && xen_netbk_must_stop_queue(vif))
                netif_stop_queue(dev);
@@ -123,11 +148,6 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct 
net_device *dev)
        return NETDEV_TX_OK;
 }
 
-void xenvif_receive_skb(struct xenvif *vif, struct sk_buff *skb)
-{
-       netif_rx_ni(skb);
-}
-
 void xenvif_notify_tx_completion(struct xenvif *vif)
 {
        if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif))
@@ -142,7 +162,7 @@ static struct net_device_stats *xenvif_get_stats(struct 
net_device *dev)
 
 static void xenvif_up(struct xenvif *vif)
 {
-       xen_netbk_add_xenvif(vif);
+       napi_enable(&vif->napi);
        enable_irq(vif->tx_irq);
        if (vif->tx_irq != vif->rx_irq)
                enable_irq(vif->rx_irq);
@@ -151,12 +171,11 @@ static void xenvif_up(struct xenvif *vif)
 
 static void xenvif_down(struct xenvif *vif)
 {
+       napi_disable(&vif->napi);
        disable_irq(vif->tx_irq);
        if (vif->tx_irq != vif->rx_irq)
                disable_irq(vif->rx_irq);
        del_timer_sync(&vif->credit_timeout);
-       xen_netbk_deschedule_xenvif(vif);
-       xen_netbk_remove_xenvif(vif);
 }
 
 static int xenvif_open(struct net_device *dev)
@@ -272,11 +291,12 @@ struct xenvif *xenvif_alloc(struct device *parent, 
domid_t domid,
        struct net_device *dev;
        struct xenvif *vif;
        char name[IFNAMSIZ] = {};
+       int i;
 
        snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
        dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
        if (dev == NULL) {
-               pr_warn("Could not allocate netdev\n");
+               pr_warn("Could not allocate netdev for %s\n", name);
                return ERR_PTR(-ENOMEM);
        }
 
@@ -285,14 +305,9 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t 
domid,
        vif = netdev_priv(dev);
        vif->domid  = domid;
        vif->handle = handle;
-       vif->netbk  = NULL;
        vif->can_sg = 1;
        vif->csum = 1;
-       atomic_set(&vif->refcnt, 1);
-       init_waitqueue_head(&vif->waiting_to_free);
        vif->dev = dev;
-       INIT_LIST_HEAD(&vif->schedule_list);
-       INIT_LIST_HEAD(&vif->notify_list);
 
        vif->credit_bytes = vif->remaining_credit = ~0UL;
        vif->credit_usec  = 0UL;
@@ -307,6 +322,16 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t 
domid,
 
        dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 
+       skb_queue_head_init(&vif->rx_queue);
+       skb_queue_head_init(&vif->tx_queue);
+
+       vif->pending_cons = 0;
+       vif->pending_prod = MAX_PENDING_REQS;
+       for (i = 0; i < MAX_PENDING_REQS; i++)
+               vif->pending_ring[i] = i;
+       for (i = 0; i < MAX_PENDING_REQS; i++)
+               vif->mmap_pages[i] = NULL;
+
        /*
         * Initialise a dummy MAC address. We choose the numerically
         * largest non-broadcast address to prevent the address getting
@@ -316,6 +341,8 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t 
domid,
        memset(dev->dev_addr, 0xFF, ETH_ALEN);
        dev->dev_addr[0] &= ~0x01;
 
+       netif_napi_add(dev, &vif->napi, xenvif_poll, XENVIF_NAPI_WEIGHT);
+
        netif_carrier_off(dev);
 
        err = register_netdev(dev);
@@ -377,7 +404,14 @@ int xenvif_connect(struct xenvif *vif, unsigned long 
tx_ring_ref,
                disable_irq(vif->rx_irq);
        }
 
-       xenvif_get(vif);
+       init_waitqueue_head(&vif->wq);
+       vif->task = kthread_create(xen_netbk_kthread,
+                                  (void *)vif, vif->dev->name);
+       if (IS_ERR(vif->task)) {
+               pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
+               err = PTR_ERR(vif->task);
+               goto err_rx_unbind;
+       }
 
        rtnl_lock();
        if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
@@ -388,7 +422,13 @@ int xenvif_connect(struct xenvif *vif, unsigned long 
tx_ring_ref,
                xenvif_up(vif);
        rtnl_unlock();
 
+       wake_up_process(vif->task);
+
        return 0;
+
+err_rx_unbind:
+       unbind_from_irqhandler(vif->rx_irq, vif);
+       vif->rx_irq = 0;
 err_tx_unbind:
        unbind_from_irqhandler(vif->tx_irq, vif);
        vif->tx_irq = 0;
@@ -408,7 +448,6 @@ void xenvif_carrier_off(struct xenvif *vif)
        if (netif_running(dev))
                xenvif_down(vif);
        rtnl_unlock();
-       xenvif_put(vif);
 }
 
 void xenvif_disconnect(struct xenvif *vif)
@@ -422,9 +461,6 @@ void xenvif_disconnect(struct xenvif *vif)
        if (netif_carrier_ok(vif->dev))
                xenvif_carrier_off(vif);
 
-       atomic_dec(&vif->refcnt);
-       wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
-
        if (vif->tx_irq) {
                if (vif->tx_irq == vif->rx_irq)
                        unbind_from_irqhandler(vif->tx_irq, vif);
@@ -438,6 +474,11 @@ void xenvif_disconnect(struct xenvif *vif)
                need_module_put = 1;
        }
 
+       if (vif->task)
+               kthread_stop(vif->task);
+
+       netif_napi_del(&vif->napi);
+
        unregister_netdev(vif->dev);
 
        xen_netbk_unmap_frontend_rings(vif);
diff --git a/drivers/net/xen-netback/netback.c 
b/drivers/net/xen-netback/netback.c
index 91f163d..44ccc67 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -70,116 +70,25 @@ module_param(fatal_skb_slots, uint, 0444);
  */
 #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
 
-typedef unsigned int pending_ring_idx_t;
-#define INVALID_PENDING_RING_IDX (~0U)
-
-struct pending_tx_info {
-       struct xen_netif_tx_request req; /* coalesced tx request */
-       struct xenvif *vif;
-       pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
-                                 * if it is head of one or more tx
-                                 * reqs
-                                 */
-};
-
-struct netbk_rx_meta {
-       int id;
-       int size;
-       int gso_size;
-};
-
-#define MAX_PENDING_REQS 256
-
-/* Discriminate from any valid pending_idx value. */
-#define INVALID_PENDING_IDX 0xFFFF
-
-#define MAX_BUFFER_OFFSET PAGE_SIZE
-
-struct xen_netbk {
-       wait_queue_head_t wq;
-       struct task_struct *task;
-
-       struct sk_buff_head rx_queue;
-       struct sk_buff_head tx_queue;
-
-       struct timer_list net_timer;
-
-       struct page *mmap_pages[MAX_PENDING_REQS];
-
-       pending_ring_idx_t pending_prod;
-       pending_ring_idx_t pending_cons;
-       struct list_head net_schedule_list;
-
-       /* Protect the net_schedule_list in netif. */
-       spinlock_t net_schedule_list_lock;
-
-       atomic_t netfront_count;
-
-       struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
-       /* Coalescing tx requests before copying makes number of grant
-        * copy ops greater or equal to number of slots required. In
-        * worst case a tx request consumes 2 gnttab_copy.
-        */
-       struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
-
-       u16 pending_ring[MAX_PENDING_REQS];
-
-       /*
-        * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
-        * head/fragment page uses 2 copy operations because it
-        * straddles two buffers in the frontend.
-        */
-       struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
-       struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
-};
-
-static struct xen_netbk *xen_netbk;
-static int xen_netbk_group_nr;
-
 /*
  * If head != INVALID_PENDING_RING_IDX, it means this tx request is head of
  * one or more merged tx requests, otherwise it is the continuation of
  * previous tx request.
  */
-static inline int pending_tx_is_head(struct xen_netbk *netbk, RING_IDX idx)
-{
-       return netbk->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
-}
-
-void xen_netbk_add_xenvif(struct xenvif *vif)
-{
-       int i;
-       int min_netfront_count;
-       int min_group = 0;
-       struct xen_netbk *netbk;
-
-       min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
-       for (i = 0; i < xen_netbk_group_nr; i++) {
-               int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
-               if (netfront_count < min_netfront_count) {
-                       min_group = i;
-                       min_netfront_count = netfront_count;
-               }
-       }
-
-       netbk = &xen_netbk[min_group];
-
-       vif->netbk = netbk;
-       atomic_inc(&netbk->netfront_count);
-}
-
-void xen_netbk_remove_xenvif(struct xenvif *vif)
+static inline int pending_tx_is_head(struct xenvif *vif, RING_IDX idx)
 {
-       struct xen_netbk *netbk = vif->netbk;
-       vif->netbk = NULL;
-       atomic_dec(&netbk->netfront_count);
+       return vif->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
 }
 
-static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
+static void xen_netbk_idx_release(struct xenvif *vif, u16 pending_idx,
                                  u8 status);
 static void make_tx_response(struct xenvif *vif,
                             struct xen_netif_tx_request *txp,
                             s8       st);
+
+static inline int tx_work_todo(struct xenvif *vif);
+static inline int rx_work_todo(struct xenvif *vif);
+
 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
                                             u16      id,
                                             s8       st,
@@ -187,16 +96,16 @@ static struct xen_netif_rx_response 
*make_rx_response(struct xenvif *vif,
                                             u16      size,
                                             u16      flags);
 
-static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
+static inline unsigned long idx_to_pfn(struct xenvif *vif,
                                       u16 idx)
 {
-       return page_to_pfn(netbk->mmap_pages[idx]);
+       return page_to_pfn(vif->mmap_pages[idx]);
 }
 
-static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
+static inline unsigned long idx_to_kaddr(struct xenvif *vif,
                                         u16 idx)
 {
-       return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
+       return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
 }
 
 /*
@@ -224,15 +133,10 @@ static inline pending_ring_idx_t pending_index(unsigned i)
        return i & (MAX_PENDING_REQS-1);
 }
 
-static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
+static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
 {
        return MAX_PENDING_REQS -
-               netbk->pending_prod + netbk->pending_cons;
-}
-
-static void xen_netbk_kick_thread(struct xen_netbk *netbk)
-{
-       wake_up(&netbk->wq);
+               vif->pending_prod + vif->pending_cons;
 }
 
 static int max_required_rx_slots(struct xenvif *vif)
@@ -364,15 +268,15 @@ struct netrx_pending_operations {
        unsigned copy_prod, copy_cons;
        unsigned meta_prod, meta_cons;
        struct gnttab_copy *copy;
-       struct netbk_rx_meta *meta;
+       struct xenvif_rx_meta *meta;
        int copy_off;
        grant_ref_t copy_gref;
 };
 
-static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
-                                               struct netrx_pending_operations 
*npo)
+static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif,
+                                                struct 
netrx_pending_operations *npo)
 {
-       struct netbk_rx_meta *meta;
+       struct xenvif_rx_meta *meta;
        struct xen_netif_rx_request *req;
 
        req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
@@ -398,7 +302,7 @@ static void netbk_gop_frag_copy(struct xenvif *vif, struct 
sk_buff *skb,
                                unsigned long offset, int *head)
 {
        struct gnttab_copy *copy_gop;
-       struct netbk_rx_meta *meta;
+       struct xenvif_rx_meta *meta;
        unsigned long bytes;
 
        /* Data must not cross a page boundary. */
@@ -434,15 +338,15 @@ static void netbk_gop_frag_copy(struct xenvif *vif, 
struct sk_buff *skb,
 
                copy_gop = npo->copy + npo->copy_prod++;
                copy_gop->flags = GNTCOPY_dest_gref;
+               copy_gop->len = bytes;
+
                copy_gop->source.domid = DOMID_SELF;
                copy_gop->source.u.gmfn = virt_to_mfn(page_address(page));
-
                copy_gop->source.offset = offset;
-               copy_gop->dest.domid = vif->domid;
 
+               copy_gop->dest.domid = vif->domid;
                copy_gop->dest.offset = npo->copy_off;
                copy_gop->dest.u.ref = npo->copy_gref;
-               copy_gop->len = bytes;
 
                npo->copy_off += bytes;
                meta->size += bytes;
@@ -485,7 +389,7 @@ static int netbk_gop_skb(struct sk_buff *skb,
        int nr_frags = skb_shinfo(skb)->nr_frags;
        int i;
        struct xen_netif_rx_request *req;
-       struct netbk_rx_meta *meta;
+       struct xenvif_rx_meta *meta;
        unsigned char *data;
        int head = 1;
        int old_meta_prod;
@@ -565,7 +469,7 @@ static int netbk_check_gop(struct xenvif *vif, int 
nr_meta_slots,
 }
 
 static void netbk_add_frag_responses(struct xenvif *vif, int status,
-                                    struct netbk_rx_meta *meta,
+                                    struct xenvif_rx_meta *meta,
                                     int nr_meta_slots)
 {
        int i;
@@ -594,9 +498,13 @@ struct skb_cb_overlay {
        int meta_slots_used;
 };
 
-static void xen_netbk_rx_action(struct xen_netbk *netbk)
+static void xen_netbk_kick_thread(struct xenvif *vif)
+{
+       wake_up(&vif->wq);
+}
+
+void xen_netbk_rx_action(struct xenvif *vif)
 {
-       struct xenvif *vif = NULL, *tmp;
        s8 status;
        u16 flags;
        struct xen_netif_rx_response *resp;
@@ -608,17 +516,18 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
        int count;
        unsigned long offset;
        struct skb_cb_overlay *sco;
+       int need_to_notify = 0;
 
        struct netrx_pending_operations npo = {
-               .copy  = netbk->grant_copy_op,
-               .meta  = netbk->meta,
+               .copy  = vif->grant_copy_op,
+               .meta  = vif->meta,
        };
 
        skb_queue_head_init(&rxq);
 
        count = 0;
 
-       while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
+       while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
                vif = netdev_priv(skb->dev);
                nr_frags = skb_shinfo(skb)->nr_frags;
 
@@ -635,27 +544,27 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
                        break;
        }
 
-       BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
+       BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta));
 
        if (!npo.copy_prod)
                return;
 
-       BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
-       gnttab_batch_copy(netbk->grant_copy_op, npo.copy_prod);
+       BUG_ON(npo.copy_prod > ARRAY_SIZE(vif->grant_copy_op));
+       gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod);
 
        while ((skb = __skb_dequeue(&rxq)) != NULL) {
                sco = (struct skb_cb_overlay *)skb->cb;
 
                vif = netdev_priv(skb->dev);
 
-               if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
+               if (vif->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
                        resp = RING_GET_RESPONSE(&vif->rx,
-                                               vif->rx.rsp_prod_pvt++);
+                                                vif->rx.rsp_prod_pvt++);
 
                        resp->flags = XEN_NETRXF_gso_prefix | 
XEN_NETRXF_more_data;
 
-                       resp->offset = netbk->meta[npo.meta_cons].gso_size;
-                       resp->id = netbk->meta[npo.meta_cons].id;
+                       resp->offset = vif->meta[npo.meta_cons].gso_size;
+                       resp->id = vif->meta[npo.meta_cons].id;
                        resp->status = sco->meta_slots_used;
 
                        npo.meta_cons++;
@@ -680,12 +589,12 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
                        flags |= XEN_NETRXF_data_validated;
 
                offset = 0;
-               resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
+               resp = make_rx_response(vif, vif->meta[npo.meta_cons].id,
                                        status, offset,
-                                       netbk->meta[npo.meta_cons].size,
+                                       vif->meta[npo.meta_cons].size,
                                        flags);
 
-               if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
+               if (vif->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
                        struct xen_netif_extra_info *gso =
                                (struct xen_netif_extra_info *)
                                RING_GET_RESPONSE(&vif->rx,
@@ -693,7 +602,7 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
 
                        resp->flags |= XEN_NETRXF_extra_info;
 
-                       gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
+                       gso->u.gso.size = vif->meta[npo.meta_cons].gso_size;
                        gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
                        gso->u.gso.pad = 0;
                        gso->u.gso.features = 0;
@@ -703,112 +612,33 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk)
                }
 
                netbk_add_frag_responses(vif, status,
-                                        netbk->meta + npo.meta_cons + 1,
+                                        vif->meta + npo.meta_cons + 1,
                                         sco->meta_slots_used);
 
                RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
 
+               if (ret)
+                       need_to_notify = 1;
+
                xenvif_notify_tx_completion(vif);
 
-               if (ret && list_empty(&vif->notify_list))
-                       list_add_tail(&vif->notify_list, &notify);
-               else
-                       xenvif_put(vif);
                npo.meta_cons += sco->meta_slots_used;
                dev_kfree_skb(skb);
        }
 
-       list_for_each_entry_safe(vif, tmp, &notify, notify_list) {
+       if (need_to_notify)
                notify_remote_via_irq(vif->rx_irq);
-               list_del_init(&vif->notify_list);
-               xenvif_put(vif);
-       }
 
        /* More work to do? */
-       if (!skb_queue_empty(&netbk->rx_queue) &&
-                       !timer_pending(&netbk->net_timer))
-               xen_netbk_kick_thread(netbk);
+       if (!skb_queue_empty(&vif->rx_queue))
+               xen_netbk_kick_thread(vif);
 }
 
 void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
 {
-       struct xen_netbk *netbk = vif->netbk;
+       skb_queue_tail(&vif->rx_queue, skb);
 
-       skb_queue_tail(&netbk->rx_queue, skb);
-
-       xen_netbk_kick_thread(netbk);
-}
-
-static void xen_netbk_alarm(unsigned long data)
-{
-       struct xen_netbk *netbk = (struct xen_netbk *)data;
-       xen_netbk_kick_thread(netbk);
-}
-
-static int __on_net_schedule_list(struct xenvif *vif)
-{
-       return !list_empty(&vif->schedule_list);
-}
-
-/* Must be called with net_schedule_list_lock held */
-static void remove_from_net_schedule_list(struct xenvif *vif)
-{
-       if (likely(__on_net_schedule_list(vif))) {
-               list_del_init(&vif->schedule_list);
-               xenvif_put(vif);
-       }
-}
-
-static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
-{
-       struct xenvif *vif = NULL;
-
-       spin_lock_irq(&netbk->net_schedule_list_lock);
-       if (list_empty(&netbk->net_schedule_list))
-               goto out;
-
-       vif = list_first_entry(&netbk->net_schedule_list,
-                              struct xenvif, schedule_list);
-       if (!vif)
-               goto out;
-
-       xenvif_get(vif);
-
-       remove_from_net_schedule_list(vif);
-out:
-       spin_unlock_irq(&netbk->net_schedule_list_lock);
-       return vif;
-}
-
-void xen_netbk_schedule_xenvif(struct xenvif *vif)
-{
-       unsigned long flags;
-       struct xen_netbk *netbk = vif->netbk;
-
-       if (__on_net_schedule_list(vif))
-               goto kick;
-
-       spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
-       if (!__on_net_schedule_list(vif) &&
-           likely(xenvif_schedulable(vif))) {
-               list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
-               xenvif_get(vif);
-       }
-       spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
-
-kick:
-       smp_mb();
-       if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
-           !list_empty(&netbk->net_schedule_list))
-               xen_netbk_kick_thread(netbk);
-}
-
-void xen_netbk_deschedule_xenvif(struct xenvif *vif)
-{
-       struct xen_netbk *netbk = vif->netbk;
-       spin_lock_irq(&netbk->net_schedule_list_lock);
-       remove_from_net_schedule_list(vif);
-       spin_unlock_irq(&netbk->net_schedule_list_lock);
+       xen_netbk_kick_thread(vif);
 }
 
 void xen_netbk_check_rx_xenvif(struct xenvif *vif)
@@ -818,7 +648,7 @@ void xen_netbk_check_rx_xenvif(struct xenvif *vif)
        RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
 
        if (more_to_do)
-               xen_netbk_schedule_xenvif(vif);
+               napi_schedule(&vif->napi);
 }
 
 static void tx_add_credit(struct xenvif *vif)
@@ -860,15 +690,12 @@ static void netbk_tx_err(struct xenvif *vif,
                txp = RING_GET_REQUEST(&vif->tx, cons++);
        } while (1);
        vif->tx.req_cons = cons;
-       xen_netbk_check_rx_xenvif(vif);
-       xenvif_put(vif);
 }
 
 static void netbk_fatal_tx_err(struct xenvif *vif)
 {
        netdev_err(vif->dev, "fatal error; disabling device\n");
        xenvif_carrier_off(vif);
-       xenvif_put(vif);
 }
 
 static int netbk_count_requests(struct xenvif *vif,
@@ -969,19 +796,20 @@ static int netbk_count_requests(struct xenvif *vif,
        return slots;
 }
 
-static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
+static struct page *xen_netbk_alloc_page(struct xenvif *vif,
                                         u16 pending_idx)
 {
        struct page *page;
-       page = alloc_page(GFP_KERNEL|__GFP_COLD);
+
+       page = alloc_page(GFP_ATOMIC|__GFP_COLD);
        if (!page)
                return NULL;
-       netbk->mmap_pages[pending_idx] = page;
+       vif->mmap_pages[pending_idx] = page;
+
        return page;
 }
 
-static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
-                                                 struct xenvif *vif,
+static struct gnttab_copy *xen_netbk_get_requests(struct xenvif *vif,
                                                  struct sk_buff *skb,
                                                  struct xen_netif_tx_request 
*txp,
                                                  struct gnttab_copy *gop)
@@ -1012,9 +840,9 @@ static struct gnttab_copy *xen_netbk_get_requests(struct 
xen_netbk *netbk,
        for (shinfo->nr_frags = slot = start; slot < nr_slots;
             shinfo->nr_frags++) {
                struct pending_tx_info *pending_tx_info =
-                       netbk->pending_tx_info;
+                       vif->pending_tx_info;
 
-               page = alloc_page(GFP_KERNEL|__GFP_COLD);
+               page = alloc_page(GFP_ATOMIC|__GFP_COLD);
                if (!page)
                        goto err;
 
@@ -1049,21 +877,18 @@ static struct gnttab_copy *xen_netbk_get_requests(struct 
xen_netbk *netbk,
                                gop->len = txp->size;
                                dst_offset += gop->len;
 
-                               index = pending_index(netbk->pending_cons++);
+                               index = pending_index(vif->pending_cons++);
 
-                               pending_idx = netbk->pending_ring[index];
+                               pending_idx = vif->pending_ring[index];
 
                                memcpy(&pending_tx_info[pending_idx].req, txp,
                                       sizeof(*txp));
-                               xenvif_get(vif);
-
-                               pending_tx_info[pending_idx].vif = vif;
 
                                /* Poison these fields, corresponding
                                 * fields for head tx req will be set
                                 * to correct values after the loop.
                                 */
-                               netbk->mmap_pages[pending_idx] = (void *)(~0UL);
+                               vif->mmap_pages[pending_idx] = (void *)(~0UL);
                                pending_tx_info[pending_idx].head =
                                        INVALID_PENDING_RING_IDX;
 
@@ -1083,7 +908,7 @@ static struct gnttab_copy *xen_netbk_get_requests(struct 
xen_netbk *netbk,
                first->req.offset = 0;
                first->req.size = dst_offset;
                first->head = start_idx;
-               netbk->mmap_pages[head_idx] = page;
+               vif->mmap_pages[head_idx] = page;
                frag_set_pending_idx(&frags[shinfo->nr_frags], head_idx);
        }
 
@@ -1093,18 +918,18 @@ static struct gnttab_copy *xen_netbk_get_requests(struct 
xen_netbk *netbk,
 err:
        /* Unwind, freeing all pages and sending error responses. */
        while (shinfo->nr_frags-- > start) {
-               xen_netbk_idx_release(netbk,
+               xen_netbk_idx_release(vif,
                                frag_get_pending_idx(&frags[shinfo->nr_frags]),
                                XEN_NETIF_RSP_ERROR);
        }
        /* The head too, if necessary. */
        if (start)
-               xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+               xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
 
        return NULL;
 }
 
-static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
+static int xen_netbk_tx_check_gop(struct xenvif *vif,
                                  struct sk_buff *skb,
                                  struct gnttab_copy **gopp)
 {
@@ -1119,7 +944,7 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
        /* Check status of header. */
        err = gop->status;
        if (unlikely(err))
-               xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+               xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
 
        /* Skip first skb fragment if it is on same page as header fragment. */
        start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
@@ -1129,7 +954,7 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
                pending_ring_idx_t head;
 
                pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
-               tx_info = &netbk->pending_tx_info[pending_idx];
+               tx_info = &vif->pending_tx_info[pending_idx];
                head = tx_info->head;
 
                /* Check error status: if okay then remember grant handle. */
@@ -1137,18 +962,19 @@ static int xen_netbk_tx_check_gop(struct xen_netbk 
*netbk,
                        newerr = (++gop)->status;
                        if (newerr)
                                break;
-                       peek = netbk->pending_ring[pending_index(++head)];
-               } while (!pending_tx_is_head(netbk, peek));
+                       peek = vif->pending_ring[pending_index(++head)];
+               } while (!pending_tx_is_head(vif, peek));
 
                if (likely(!newerr)) {
                        /* Had a previous error? Invalidate this fragment. */
                        if (unlikely(err))
-                               xen_netbk_idx_release(netbk, pending_idx, 
XEN_NETIF_RSP_OKAY);
+                               xen_netbk_idx_release(vif, pending_idx,
+                                                     XEN_NETIF_RSP_OKAY);
                        continue;
                }
 
                /* Error on this fragment: respond to client with an error. */
-               xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+               xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
 
                /* Not the first error? Preceding frags already invalidated. */
                if (err)
@@ -1156,10 +982,11 @@ static int xen_netbk_tx_check_gop(struct xen_netbk 
*netbk,
 
                /* First error: invalidate header and preceding fragments. */
                pending_idx = *((u16 *)skb->data);
-               xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+               xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
                for (j = start; j < i; j++) {
                        pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
-                       xen_netbk_idx_release(netbk, pending_idx, 
XEN_NETIF_RSP_OKAY);
+                       xen_netbk_idx_release(vif, pending_idx,
+                                             XEN_NETIF_RSP_OKAY);
                }
 
                /* Remember the error: invalidate all subsequent fragments. */
@@ -1170,7 +997,7 @@ static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
        return err;
 }
 
-static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
+static void xen_netbk_fill_frags(struct xenvif *vif, struct sk_buff *skb)
 {
        struct skb_shared_info *shinfo = skb_shinfo(skb);
        int nr_frags = shinfo->nr_frags;
@@ -1184,16 +1011,16 @@ static void xen_netbk_fill_frags(struct xen_netbk 
*netbk, struct sk_buff *skb)
 
                pending_idx = frag_get_pending_idx(frag);
 
-               txp = &netbk->pending_tx_info[pending_idx].req;
-               page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
+               txp = &vif->pending_tx_info[pending_idx].req;
+               page = virt_to_page(idx_to_kaddr(vif, pending_idx));
                __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
                skb->len += txp->size;
                skb->data_len += txp->size;
                skb->truesize += txp->size;
 
                /* Take an extra reference to offset xen_netbk_idx_release */
-               get_page(netbk->mmap_pages[pending_idx]);
-               xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+               get_page(vif->mmap_pages[pending_idx]);
+               xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
        }
 }
 
@@ -1353,16 +1180,14 @@ static bool tx_credit_exceeded(struct xenvif *vif, 
unsigned size)
        return false;
 }
 
-static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
+static unsigned xen_netbk_tx_build_gops(struct xenvif *vif)
 {
-       struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
+       struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop;
        struct sk_buff *skb;
        int ret;
 
-       while ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX
-               < MAX_PENDING_REQS) &&
-               !list_empty(&netbk->net_schedule_list)) {
-               struct xenvif *vif;
+       while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
+               < MAX_PENDING_REQS)) {
                struct xen_netif_tx_request txreq;
                struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
                struct page *page;
@@ -1373,16 +1198,6 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk 
*netbk)
                unsigned int data_len;
                pending_ring_idx_t index;
 
-               /* Get a netif from the list with work to do. */
-               vif = poll_net_schedule_list(netbk);
-               /* This can sometimes happen because the test of
-                * list_empty(net_schedule_list) at the top of the
-                * loop is unlocked.  Just go back and have another
-                * look.
-                */
-               if (!vif)
-                       continue;
-
                if (vif->tx.sring->req_prod - vif->tx.req_cons >
                    XEN_NETIF_TX_RING_SIZE) {
                        netdev_err(vif->dev,
@@ -1395,10 +1210,8 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk 
*netbk)
                }
 
                RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
-               if (!work_to_do) {
-                       xenvif_put(vif);
-                       continue;
-               }
+               if (!work_to_do)
+                       break;
 
                idx = vif->tx.req_cons;
                rmb(); /* Ensure that we see the request before we copy it. */
@@ -1406,10 +1219,8 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk 
*netbk)
 
                /* Credit-based scheduling. */
                if (txreq.size > vif->remaining_credit &&
-                   tx_credit_exceeded(vif, txreq.size)) {
-                       xenvif_put(vif);
-                       continue;
-               }
+                   tx_credit_exceeded(vif, txreq.size))
+                       break;
 
                vif->remaining_credit -= txreq.size;
 
@@ -1422,12 +1233,12 @@ static unsigned xen_netbk_tx_build_gops(struct 
xen_netbk *netbk)
                                                          work_to_do);
                        idx = vif->tx.req_cons;
                        if (unlikely(work_to_do < 0))
-                               continue;
+                               break;
                }
 
                ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
                if (unlikely(ret < 0))
-                       continue;
+                       break;
 
                idx += ret;
 
@@ -1435,7 +1246,7 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk 
*netbk)
                        netdev_dbg(vif->dev,
                                   "Bad packet size: %d\n", txreq.size);
                        netbk_tx_err(vif, &txreq, idx);
-                       continue;
+                       break;
                }
 
                /* No crossing a page as the payload mustn't fragment. */
@@ -1445,11 +1256,11 @@ static unsigned xen_netbk_tx_build_gops(struct 
xen_netbk *netbk)
                                   txreq.offset, txreq.size,
                                   (txreq.offset&~PAGE_MASK) + txreq.size);
                        netbk_fatal_tx_err(vif);
-                       continue;
+                       break;
                }
 
-               index = pending_index(netbk->pending_cons);
-               pending_idx = netbk->pending_ring[index];
+               index = pending_index(vif->pending_cons);
+               pending_idx = vif->pending_ring[index];
 
                data_len = (txreq.size > PKT_PROT_LEN &&
                            ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
@@ -1474,16 +1285,16 @@ static unsigned xen_netbk_tx_build_gops(struct 
xen_netbk *netbk)
                        if (netbk_set_skb_gso(vif, skb, gso)) {
                                /* Failure in netbk_set_skb_gso is fatal. */
                                kfree_skb(skb);
-                               continue;
+                               break;
                        }
                }
 
                /* XXX could copy straight to head */
-               page = xen_netbk_alloc_page(netbk, pending_idx);
+               page = xen_netbk_alloc_page(vif, pending_idx);
                if (!page) {
                        kfree_skb(skb);
                        netbk_tx_err(vif, &txreq, idx);
-                       continue;
+                       break;
                }
 
                gop->source.u.ref = txreq.gref;
@@ -1499,10 +1310,9 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk 
*netbk)
 
                gop++;
 
-               memcpy(&netbk->pending_tx_info[pending_idx].req,
+               memcpy(&vif->pending_tx_info[pending_idx].req,
                       &txreq, sizeof(txreq));
-               netbk->pending_tx_info[pending_idx].vif = vif;
-               netbk->pending_tx_info[pending_idx].head = index;
+               vif->pending_tx_info[pending_idx].head = index;
                *((u16 *)skb->data) = pending_idx;
 
                __skb_put(skb, data_len);
@@ -1517,46 +1327,45 @@ static unsigned xen_netbk_tx_build_gops(struct 
xen_netbk *netbk)
                                             INVALID_PENDING_IDX);
                }
 
-               netbk->pending_cons++;
+               vif->pending_cons++;
 
-               request_gop = xen_netbk_get_requests(netbk, vif,
-                                                    skb, txfrags, gop);
+               request_gop = xen_netbk_get_requests(vif, skb, txfrags, gop);
                if (request_gop == NULL) {
                        kfree_skb(skb);
                        netbk_tx_err(vif, &txreq, idx);
-                       continue;
+                       break;
                }
                gop = request_gop;
 
-               __skb_queue_tail(&netbk->tx_queue, skb);
+               __skb_queue_tail(&vif->tx_queue, skb);
 
                vif->tx.req_cons = idx;
-               xen_netbk_check_rx_xenvif(vif);
 
-               if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
+               if ((gop-vif->tx_copy_ops) >= ARRAY_SIZE(vif->tx_copy_ops))
                        break;
        }
 
-       return gop - netbk->tx_copy_ops;
+       return gop - vif->tx_copy_ops;
 }
 
-static void xen_netbk_tx_submit(struct xen_netbk *netbk)
+
+static int xen_netbk_tx_submit(struct xenvif *vif, int budget)
 {
-       struct gnttab_copy *gop = netbk->tx_copy_ops;
+       struct gnttab_copy *gop = vif->tx_copy_ops;
        struct sk_buff *skb;
+       int work_done = 0;
 
-       while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
+       while (work_done < budget &&
+              (skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
                struct xen_netif_tx_request *txp;
-               struct xenvif *vif;
                u16 pending_idx;
                unsigned data_len;
 
                pending_idx = *((u16 *)skb->data);
-               vif = netbk->pending_tx_info[pending_idx].vif;
-               txp = &netbk->pending_tx_info[pending_idx].req;
+               txp = &vif->pending_tx_info[pending_idx].req;
 
                /* Check the remap error code. */
-               if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
+               if (unlikely(xen_netbk_tx_check_gop(vif, skb, &gop))) {
                        netdev_dbg(vif->dev, "netback grant failed.\n");
                        skb_shinfo(skb)->nr_frags = 0;
                        kfree_skb(skb);
@@ -1565,7 +1374,7 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk)
 
                data_len = skb->len;
                memcpy(skb->data,
-                      (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
+                      (void *)(idx_to_kaddr(vif, pending_idx)|txp->offset),
                       data_len);
                if (data_len < txp->size) {
                        /* Append the packet payload as a fragment. */
@@ -1573,7 +1382,8 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk)
                        txp->size -= data_len;
                } else {
                        /* Schedule a response immediately. */
-                       xen_netbk_idx_release(netbk, pending_idx, 
XEN_NETIF_RSP_OKAY);
+                       xen_netbk_idx_release(vif, pending_idx,
+                                             XEN_NETIF_RSP_OKAY);
                }
 
                if (txp->flags & XEN_NETTXF_csum_blank)
@@ -1581,7 +1391,7 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk)
                else if (txp->flags & XEN_NETTXF_data_validated)
                        skb->ip_summed = CHECKSUM_UNNECESSARY;
 
-               xen_netbk_fill_frags(netbk, skb);
+               xen_netbk_fill_frags(vif, skb);
 
                /*
                 * If the initial fragment was < PKT_PROT_LEN then
@@ -1609,53 +1419,61 @@ static void xen_netbk_tx_submit(struct xen_netbk *netbk)
                vif->dev->stats.rx_bytes += skb->len;
                vif->dev->stats.rx_packets++;
 
-               xenvif_receive_skb(vif, skb);
+               work_done++;
+
+               netif_receive_skb(skb);
        }
+
+       return work_done;
 }
 
 /* Called after netfront has transmitted */
-static void xen_netbk_tx_action(struct xen_netbk *netbk)
+int xen_netbk_tx_action(struct xenvif *vif, int budget)
 {
        unsigned nr_gops;
+       int work_done;
 
-       nr_gops = xen_netbk_tx_build_gops(netbk);
+       if (unlikely(!tx_work_todo(vif)))
+               return 0;
+
+       nr_gops = xen_netbk_tx_build_gops(vif);
 
        if (nr_gops == 0)
-               return;
+               return 0;
+
+       gnttab_batch_copy(vif->tx_copy_ops, nr_gops);
 
-       gnttab_batch_copy(netbk->tx_copy_ops, nr_gops);
+       work_done = xen_netbk_tx_submit(vif, nr_gops);
 
-       xen_netbk_tx_submit(netbk);
+       return work_done;
 }
 
-static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
+static void xen_netbk_idx_release(struct xenvif *vif, u16 pending_idx,
                                  u8 status)
 {
-       struct xenvif *vif;
        struct pending_tx_info *pending_tx_info;
        pending_ring_idx_t head;
        u16 peek; /* peek into next tx request */
 
-       BUG_ON(netbk->mmap_pages[pending_idx] == (void *)(~0UL));
+       BUG_ON(vif->mmap_pages[pending_idx] == (void *)(~0UL));
 
        /* Already complete? */
-       if (netbk->mmap_pages[pending_idx] == NULL)
+       if (vif->mmap_pages[pending_idx] == NULL)
                return;
 
-       pending_tx_info = &netbk->pending_tx_info[pending_idx];
+       pending_tx_info = &vif->pending_tx_info[pending_idx];
 
-       vif = pending_tx_info->vif;
        head = pending_tx_info->head;
 
-       BUG_ON(!pending_tx_is_head(netbk, head));
-       BUG_ON(netbk->pending_ring[pending_index(head)] != pending_idx);
+       BUG_ON(!pending_tx_is_head(vif, head));
+       BUG_ON(vif->pending_ring[pending_index(head)] != pending_idx);
 
        do {
                pending_ring_idx_t index;
                pending_ring_idx_t idx = pending_index(head);
-               u16 info_idx = netbk->pending_ring[idx];
+               u16 info_idx = vif->pending_ring[idx];
 
-               pending_tx_info = &netbk->pending_tx_info[info_idx];
+               pending_tx_info = &vif->pending_tx_info[info_idx];
                make_tx_response(vif, &pending_tx_info->req, status);
 
                /* Setting any number other than
@@ -1664,18 +1482,15 @@ static void xen_netbk_idx_release(struct xen_netbk 
*netbk, u16 pending_idx,
                 */
                pending_tx_info->head = 0;
 
-               index = pending_index(netbk->pending_prod++);
-               netbk->pending_ring[index] = netbk->pending_ring[info_idx];
+               index = pending_index(vif->pending_prod++);
+               vif->pending_ring[index] = vif->pending_ring[info_idx];
 
-               xenvif_put(vif);
+               peek = vif->pending_ring[pending_index(++head)];
 
-               peek = netbk->pending_ring[pending_index(++head)];
+       } while (!pending_tx_is_head(vif, peek));
 
-       } while (!pending_tx_is_head(netbk, peek));
-
-       netbk->mmap_pages[pending_idx]->mapping = 0;
-       put_page(netbk->mmap_pages[pending_idx]);
-       netbk->mmap_pages[pending_idx] = NULL;
+       put_page(vif->mmap_pages[pending_idx]);
+       vif->mmap_pages[pending_idx] = NULL;
 }
 
 
@@ -1723,45 +1538,22 @@ static struct xen_netif_rx_response 
*make_rx_response(struct xenvif *vif,
        return resp;
 }
 
-static inline int rx_work_todo(struct xen_netbk *netbk)
+static inline int rx_work_todo(struct xenvif *vif)
 {
-       return !skb_queue_empty(&netbk->rx_queue);
+       return !skb_queue_empty(&vif->rx_queue);
 }
 
-static inline int tx_work_todo(struct xen_netbk *netbk)
+static inline int tx_work_todo(struct xenvif *vif)
 {
 
-       if ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX
-            < MAX_PENDING_REQS) &&
-            !list_empty(&netbk->net_schedule_list))
+       if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)) &&
+           (nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
+            < MAX_PENDING_REQS))
                return 1;
 
        return 0;
 }
 
-static int xen_netbk_kthread(void *data)
-{
-       struct xen_netbk *netbk = data;
-       while (!kthread_should_stop()) {
-               wait_event_interruptible(netbk->wq,
-                               rx_work_todo(netbk) ||
-                               tx_work_todo(netbk) ||
-                               kthread_should_stop());
-               cond_resched();
-
-               if (kthread_should_stop())
-                       break;
-
-               if (rx_work_todo(netbk))
-                       xen_netbk_rx_action(netbk);
-
-               if (tx_work_todo(netbk))
-                       xen_netbk_tx_action(netbk);
-       }
-
-       return 0;
-}
-
 void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
 {
        if (vif->tx.sring)
@@ -1807,11 +1599,29 @@ err:
        return err;
 }
 
+int xen_netbk_kthread(void *data)
+{
+       struct xenvif *vif = data;
+
+       while (!kthread_should_stop()) {
+               wait_event_interruptible(vif->wq,
+                                        rx_work_todo(vif) ||
+                                        kthread_should_stop());
+               if (kthread_should_stop())
+                       break;
+
+               if (rx_work_todo(vif))
+                       xen_netbk_rx_action(vif);
+
+               cond_resched();
+       }
+
+       return 0;
+}
+
 static int __init netback_init(void)
 {
-       int i;
        int rc = 0;
-       int group;
 
        if (!xen_domain())
                return -ENODEV;
@@ -1822,48 +1632,6 @@ static int __init netback_init(void)
                fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
        }
 
-       xen_netbk_group_nr = num_online_cpus();
-       xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
-       if (!xen_netbk)
-               return -ENOMEM;
-
-       for (group = 0; group < xen_netbk_group_nr; group++) {
-               struct xen_netbk *netbk = &xen_netbk[group];
-               skb_queue_head_init(&netbk->rx_queue);
-               skb_queue_head_init(&netbk->tx_queue);
-
-               init_timer(&netbk->net_timer);
-               netbk->net_timer.data = (unsigned long)netbk;
-               netbk->net_timer.function = xen_netbk_alarm;
-
-               netbk->pending_cons = 0;
-               netbk->pending_prod = MAX_PENDING_REQS;
-               for (i = 0; i < MAX_PENDING_REQS; i++)
-                       netbk->pending_ring[i] = i;
-
-               init_waitqueue_head(&netbk->wq);
-               netbk->task = kthread_create(xen_netbk_kthread,
-                                            (void *)netbk,
-                                            "netback/%u", group);
-
-               if (IS_ERR(netbk->task)) {
-                       pr_alert("kthread_create() fails at netback\n");
-                       del_timer(&netbk->net_timer);
-                       rc = PTR_ERR(netbk->task);
-                       goto failed_init;
-               }
-
-               kthread_bind(netbk->task, group);
-
-               INIT_LIST_HEAD(&netbk->net_schedule_list);
-
-               spin_lock_init(&netbk->net_schedule_list_lock);
-
-               atomic_set(&netbk->netfront_count, 0);
-
-               wake_up_process(netbk->task);
-       }
-
        rc = xenvif_xenbus_init();
        if (rc)
                goto failed_init;
@@ -1871,35 +1639,14 @@ static int __init netback_init(void)
        return 0;
 
 failed_init:
-       while (--group >= 0) {
-               struct xen_netbk *netbk = &xen_netbk[group];
-               del_timer(&netbk->net_timer);
-               kthread_stop(netbk->task);
-       }
-       vfree(xen_netbk);
        return rc;
-
 }
 
 module_init(netback_init);
 
 static void __exit netback_fini(void)
 {
-       int i, j;
-
        xenvif_xenbus_fini();
-
-       for (i = 0; i < xen_netbk_group_nr; i++) {
-               struct xen_netbk *netbk = &xen_netbk[i];
-               del_timer_sync(&netbk->net_timer);
-               kthread_stop(netbk->task);
-               for (j = 0; j < MAX_PENDING_REQS; j++) {
-                       if (netbk->mmap_pages[j])
-                               __free_page(netbk->mmap_pages[j]);
-               }
-       }
-
-       vfree(xen_netbk);
 }
 module_exit(netback_fini);
 
-- 
1.7.10.4


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