diff options
Diffstat (limited to 'drivers/net')
-rw-r--r-- | drivers/net/xen-netback/common.h | 27 | ||||
-rw-r--r-- | drivers/net/xen-netback/interface.c | 47 | ||||
-rw-r--r-- | drivers/net/xen-netback/netback.c | 217 |
3 files changed, 106 insertions, 185 deletions
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index 08ae01b41c83..ba30a6d9fefa 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -136,12 +136,10 @@ struct xenvif { char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */ struct xen_netif_rx_back_ring rx; struct sk_buff_head rx_queue; - - /* 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. + /* Set when the RX interrupt is triggered by the frontend. + * The worker thread may need to wake the queue. */ - RING_IDX rx_req_cons_peek; + bool rx_event; /* Given MAX_BUFFER_OFFSET of 4096 the worst case is that each * head/fragment page uses 2 copy operations because it @@ -198,8 +196,6 @@ void xenvif_xenbus_fini(void); int xenvif_schedulable(struct xenvif *vif); -int xenvif_rx_ring_full(struct xenvif *vif); - int xenvif_must_stop_queue(struct xenvif *vif); /* (Un)Map communication rings. */ @@ -211,21 +207,20 @@ int xenvif_map_frontend_rings(struct xenvif *vif, /* Check for SKBs from frontend and schedule backend processing */ void xenvif_check_rx_xenvif(struct xenvif *vif); -/* Queue an SKB for transmission to the frontend */ -void xenvif_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb); -/* Notify xenvif that ring now has space to send an skb to the frontend */ -void xenvif_notify_tx_completion(struct xenvif *vif); - /* Prevent the device from generating any further traffic. */ void xenvif_carrier_off(struct xenvif *vif); -/* Returns number of ring slots required to send an skb to the frontend */ -unsigned int xenvif_count_skb_slots(struct xenvif *vif, struct sk_buff *skb); - int xenvif_tx_action(struct xenvif *vif, int budget); -void xenvif_rx_action(struct xenvif *vif); int xenvif_kthread(void *data); +void xenvif_kick_thread(struct xenvif *vif); + +/* Determine whether the needed number of slots (req) are available, + * and set req_event if not. + */ +bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed); + +void xenvif_stop_queue(struct xenvif *vif); extern bool separate_tx_rx_irq; diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 870f1fa58370..1dcb9606e6e0 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -46,11 +46,6 @@ int xenvif_schedulable(struct xenvif *vif) return netif_running(vif->dev) && netif_carrier_ok(vif->dev); } -static int xenvif_rx_schedulable(struct xenvif *vif) -{ - return xenvif_schedulable(vif) && !xenvif_rx_ring_full(vif); -} - static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id) { struct xenvif *vif = dev_id; @@ -104,8 +99,8 @@ static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id) { struct xenvif *vif = dev_id; - if (xenvif_rx_schedulable(vif)) - netif_wake_queue(vif->dev); + vif->rx_event = true; + xenvif_kick_thread(vif); return IRQ_HANDLED; } @@ -121,24 +116,35 @@ static irqreturn_t xenvif_interrupt(int irq, void *dev_id) static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev) { struct xenvif *vif = netdev_priv(dev); + int min_slots_needed; BUG_ON(skb->dev != dev); /* Drop the packet if vif is not ready */ - if (vif->task == NULL) + if (vif->task == NULL || !xenvif_schedulable(vif)) goto drop; - /* Drop the packet if the target domain has no receive buffers. */ - if (!xenvif_rx_schedulable(vif)) - goto drop; + /* At best we'll need one slot for the header and one for each + * frag. + */ + min_slots_needed = 1 + skb_shinfo(skb)->nr_frags; - /* Reserve ring slots for the worst-case number of fragments. */ - vif->rx_req_cons_peek += xenvif_count_skb_slots(vif, skb); + /* If the skb is GSO then we'll also need an extra slot for the + * metadata. + */ + if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 || + skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) + min_slots_needed++; - if (vif->can_queue && xenvif_must_stop_queue(vif)) - netif_stop_queue(dev); + /* If the skb can't possibly fit in the remaining slots + * then turn off the queue to give the ring a chance to + * drain. + */ + if (!xenvif_rx_ring_slots_available(vif, min_slots_needed)) + xenvif_stop_queue(vif); - xenvif_queue_tx_skb(vif, skb); + skb_queue_tail(&vif->rx_queue, skb); + xenvif_kick_thread(vif); return NETDEV_TX_OK; @@ -148,12 +154,6 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev) return NETDEV_TX_OK; } -void xenvif_notify_tx_completion(struct xenvif *vif) -{ - if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif)) - netif_wake_queue(vif->dev); -} - static struct net_device_stats *xenvif_get_stats(struct net_device *dev) { struct xenvif *vif = netdev_priv(dev); @@ -378,6 +378,8 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, if (err < 0) goto err; + init_waitqueue_head(&vif->wq); + if (tx_evtchn == rx_evtchn) { /* feature-split-event-channels == 0 */ err = bind_interdomain_evtchn_to_irqhandler( @@ -410,7 +412,6 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, disable_irq(vif->rx_irq); } - init_waitqueue_head(&vif->wq); task = kthread_create(xenvif_kthread, (void *)vif, "%s", vif->dev->name); if (IS_ERR(task)) { diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index acf13920e6d1..43341b82649c 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -138,36 +138,26 @@ static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif) vif->pending_prod + vif->pending_cons; } -static int max_required_rx_slots(struct xenvif *vif) +bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed) { - int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE); + RING_IDX prod, cons; - /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */ - if (vif->can_sg || vif->gso_mask || vif->gso_prefix_mask) - max += MAX_SKB_FRAGS + 1; /* extra_info + frags */ - - return max; -} - -int xenvif_rx_ring_full(struct xenvif *vif) -{ - RING_IDX peek = vif->rx_req_cons_peek; - RING_IDX needed = max_required_rx_slots(vif); + do { + prod = vif->rx.sring->req_prod; + cons = vif->rx.req_cons; - return ((vif->rx.sring->req_prod - peek) < needed) || - ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed); -} + if (prod - cons >= needed) + return true; -int xenvif_must_stop_queue(struct xenvif *vif) -{ - if (!xenvif_rx_ring_full(vif)) - return 0; + vif->rx.sring->req_event = prod + 1; - vif->rx.sring->req_event = vif->rx_req_cons_peek + - max_required_rx_slots(vif); - mb(); /* request notification /then/ check the queue */ + /* Make sure event is visible before we check prod + * again. + */ + mb(); + } while (vif->rx.sring->req_prod != prod); - return xenvif_rx_ring_full(vif); + return false; } /* @@ -210,93 +200,6 @@ static bool start_new_rx_buffer(int offset, unsigned long size, int head) return false; } -struct xenvif_count_slot_state { - unsigned long copy_off; - bool head; -}; - -unsigned int xenvif_count_frag_slots(struct xenvif *vif, - unsigned long offset, unsigned long size, - struct xenvif_count_slot_state *state) -{ - unsigned count = 0; - - offset &= ~PAGE_MASK; - - while (size > 0) { - unsigned long bytes; - - bytes = PAGE_SIZE - offset; - - if (bytes > size) - bytes = size; - - if (start_new_rx_buffer(state->copy_off, bytes, state->head)) { - count++; - state->copy_off = 0; - } - - if (state->copy_off + bytes > MAX_BUFFER_OFFSET) - bytes = MAX_BUFFER_OFFSET - state->copy_off; - - state->copy_off += bytes; - - offset += bytes; - size -= bytes; - - if (offset == PAGE_SIZE) - offset = 0; - - state->head = false; - } - - return count; -} - -/* - * Figure out how many ring slots we're going to need to send @skb to - * the guest. This function is essentially a dry run of - * xenvif_gop_frag_copy. - */ -unsigned int xenvif_count_skb_slots(struct xenvif *vif, struct sk_buff *skb) -{ - struct xenvif_count_slot_state state; - unsigned int count; - unsigned char *data; - unsigned i; - - state.head = true; - state.copy_off = 0; - - /* Slot for the first (partial) page of data. */ - count = 1; - - /* Need a slot for the GSO prefix for GSO extra data? */ - if (skb_shinfo(skb)->gso_size) - count++; - - data = skb->data; - while (data < skb_tail_pointer(skb)) { - unsigned long offset = offset_in_page(data); - unsigned long size = PAGE_SIZE - offset; - - if (data + size > skb_tail_pointer(skb)) - size = skb_tail_pointer(skb) - data; - - count += xenvif_count_frag_slots(vif, offset, size, &state); - - data += size; - } - - for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { - unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]); - unsigned long offset = skb_shinfo(skb)->frags[i].page_offset; - - count += xenvif_count_frag_slots(vif, offset, size, &state); - } - return count; -} - struct netrx_pending_operations { unsigned copy_prod, copy_cons; unsigned meta_prod, meta_cons; @@ -557,12 +460,12 @@ struct skb_cb_overlay { int meta_slots_used; }; -static void xenvif_kick_thread(struct xenvif *vif) +void xenvif_kick_thread(struct xenvif *vif) { wake_up(&vif->wq); } -void xenvif_rx_action(struct xenvif *vif) +static void xenvif_rx_action(struct xenvif *vif) { s8 status; u16 flags; @@ -571,8 +474,6 @@ void xenvif_rx_action(struct xenvif *vif) struct sk_buff *skb; LIST_HEAD(notify); int ret; - int nr_frags; - int count; unsigned long offset; struct skb_cb_overlay *sco; int need_to_notify = 0; @@ -584,29 +485,44 @@ void xenvif_rx_action(struct xenvif *vif) skb_queue_head_init(&rxq); - count = 0; - while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) { - vif = netdev_priv(skb->dev); - nr_frags = skb_shinfo(skb)->nr_frags; + int max_slots_needed; + int i; + + /* We need a cheap worse case estimate for the number of + * slots we'll use. + */ + + max_slots_needed = DIV_ROUND_UP(offset_in_page(skb->data) + + skb_headlen(skb), + PAGE_SIZE); + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + unsigned int size; + size = skb_frag_size(&skb_shinfo(skb)->frags[i]); + max_slots_needed += DIV_ROUND_UP(size, PAGE_SIZE); + } + if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 || + skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) + max_slots_needed++; + + /* If the skb may not fit then bail out now */ + if (!xenvif_rx_ring_slots_available(vif, max_slots_needed)) { + skb_queue_head(&vif->rx_queue, skb); + need_to_notify = 1; + break; + } sco = (struct skb_cb_overlay *)skb->cb; sco->meta_slots_used = xenvif_gop_skb(skb, &npo); - - count += nr_frags + 1; + BUG_ON(sco->meta_slots_used > max_slots_needed); __skb_queue_tail(&rxq, skb); - - /* Filled the batch queue? */ - /* XXX FIXME: RX path dependent on MAX_SKB_FRAGS */ - if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE) - break; } BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta)); if (!npo.copy_prod) - return; + goto done; BUG_ON(npo.copy_prod > ARRAY_SIZE(vif->grant_copy_op)); gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod); @@ -614,8 +530,6 @@ void xenvif_rx_action(struct xenvif *vif) while ((skb = __skb_dequeue(&rxq)) != NULL) { sco = (struct skb_cb_overlay *)skb->cb; - vif = netdev_priv(skb->dev); - if ((1 << vif->meta[npo.meta_cons].gso_type) & vif->gso_prefix_mask) { resp = RING_GET_RESPONSE(&vif->rx, @@ -681,25 +595,13 @@ void xenvif_rx_action(struct xenvif *vif) if (ret) need_to_notify = 1; - xenvif_notify_tx_completion(vif); - npo.meta_cons += sco->meta_slots_used; dev_kfree_skb(skb); } +done: if (need_to_notify) notify_remote_via_irq(vif->rx_irq); - - /* More work to do? */ - if (!skb_queue_empty(&vif->rx_queue)) - xenvif_kick_thread(vif); -} - -void xenvif_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb) -{ - skb_queue_tail(&vif->rx_queue, skb); - - xenvif_kick_thread(vif); } void xenvif_check_rx_xenvif(struct xenvif *vif) @@ -1804,7 +1706,7 @@ static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif, static inline int rx_work_todo(struct xenvif *vif) { - return !skb_queue_empty(&vif->rx_queue); + return !skb_queue_empty(&vif->rx_queue) || vif->rx_event; } static inline int tx_work_todo(struct xenvif *vif) @@ -1854,8 +1756,6 @@ int xenvif_map_frontend_rings(struct xenvif *vif, rxs = (struct xen_netif_rx_sring *)addr; BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE); - vif->rx_req_cons_peek = 0; - return 0; err: @@ -1863,9 +1763,24 @@ err: return err; } +void xenvif_stop_queue(struct xenvif *vif) +{ + if (!vif->can_queue) + return; + + netif_stop_queue(vif->dev); +} + +static void xenvif_start_queue(struct xenvif *vif) +{ + if (xenvif_schedulable(vif)) + netif_wake_queue(vif->dev); +} + int xenvif_kthread(void *data) { struct xenvif *vif = data; + struct sk_buff *skb; while (!kthread_should_stop()) { wait_event_interruptible(vif->wq, @@ -1874,12 +1789,22 @@ int xenvif_kthread(void *data) if (kthread_should_stop()) break; - if (rx_work_todo(vif)) + if (!skb_queue_empty(&vif->rx_queue)) xenvif_rx_action(vif); + vif->rx_event = false; + + if (skb_queue_empty(&vif->rx_queue) && + netif_queue_stopped(vif->dev)) + xenvif_start_queue(vif); + cond_resched(); } + /* Bin any remaining skbs */ + while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) + dev_kfree_skb(skb); + return 0; } |