2 * Back-end of the driver for virtual network devices. This portion of the
3 * driver exports a 'unified' network-device interface that can be accessed
4 * by any operating system that implements a compatible front end. A
5 * reference front-end implementation can be found in:
6 * drivers/net/xen-netfront.c
8 * Copyright (c) 2002-2005, K A Fraser
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
37 #include <linux/kthread.h>
38 #include <linux/if_vlan.h>
39 #include <linux/udp.h>
44 #include <xen/events.h>
45 #include <xen/interface/memory.h>
47 #include <asm/xen/hypercall.h>
48 #include <asm/xen/page.h>
50 struct pending_tx_info {
51 struct xen_netif_tx_request req;
54 typedef unsigned int pending_ring_idx_t;
56 struct netbk_rx_meta {
62 #define MAX_PENDING_REQS 256
64 /* Discriminate from any valid pending_idx value. */
65 #define INVALID_PENDING_IDX 0xFFFF
67 #define MAX_BUFFER_OFFSET PAGE_SIZE
69 /* extra field used in struct page */
72 #if BITS_PER_LONG < 64
74 #define GROUP_WIDTH (BITS_PER_LONG - IDX_WIDTH)
75 unsigned int group:GROUP_WIDTH;
76 unsigned int idx:IDX_WIDTH;
78 unsigned int group, idx;
86 struct task_struct *task;
88 struct sk_buff_head rx_queue;
89 struct sk_buff_head tx_queue;
91 struct timer_list net_timer;
93 struct page *mmap_pages[MAX_PENDING_REQS];
95 pending_ring_idx_t pending_prod;
96 pending_ring_idx_t pending_cons;
97 struct list_head net_schedule_list;
99 /* Protect the net_schedule_list in netif. */
100 spinlock_t net_schedule_list_lock;
102 atomic_t netfront_count;
104 struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
105 struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
107 u16 pending_ring[MAX_PENDING_REQS];
110 * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
111 * head/fragment page uses 2 copy operations because it
112 * straddles two buffers in the frontend.
114 struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
115 struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
118 static struct xen_netbk *xen_netbk;
119 static int xen_netbk_group_nr;
121 void xen_netbk_add_xenvif(struct xenvif *vif)
124 int min_netfront_count;
126 struct xen_netbk *netbk;
128 min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
129 for (i = 0; i < xen_netbk_group_nr; i++) {
130 int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
131 if (netfront_count < min_netfront_count) {
133 min_netfront_count = netfront_count;
137 netbk = &xen_netbk[min_group];
140 atomic_inc(&netbk->netfront_count);
143 void xen_netbk_remove_xenvif(struct xenvif *vif)
145 struct xen_netbk *netbk = vif->netbk;
147 atomic_dec(&netbk->netfront_count);
150 static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
151 static void make_tx_response(struct xenvif *vif,
152 struct xen_netif_tx_request *txp,
154 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
161 static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
164 return page_to_pfn(netbk->mmap_pages[idx]);
167 static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
170 return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
173 /* extra field used in struct page */
174 static inline void set_page_ext(struct page *pg, struct xen_netbk *netbk,
177 unsigned int group = netbk - xen_netbk;
178 union page_ext ext = { .e = { .group = group + 1, .idx = idx } };
180 BUILD_BUG_ON(sizeof(ext) > sizeof(ext.mapping));
181 pg->mapping = ext.mapping;
184 static int get_page_ext(struct page *pg,
185 unsigned int *pgroup, unsigned int *pidx)
187 union page_ext ext = { .mapping = pg->mapping };
188 struct xen_netbk *netbk;
189 unsigned int group, idx;
191 group = ext.e.group - 1;
193 if (group < 0 || group >= xen_netbk_group_nr)
196 netbk = &xen_netbk[group];
200 if ((idx < 0) || (idx >= MAX_PENDING_REQS))
203 if (netbk->mmap_pages[idx] != pg)
213 * This is the amount of packet we copy rather than map, so that the
214 * guest can't fiddle with the contents of the headers while we do
215 * packet processing on them (netfilter, routing, etc).
217 #define PKT_PROT_LEN (ETH_HLEN + \
219 sizeof(struct iphdr) + MAX_IPOPTLEN + \
220 sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
222 static u16 frag_get_pending_idx(skb_frag_t *frag)
224 return (u16)frag->page_offset;
227 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
229 frag->page_offset = pending_idx;
232 static inline pending_ring_idx_t pending_index(unsigned i)
234 return i & (MAX_PENDING_REQS-1);
237 static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
239 return MAX_PENDING_REQS -
240 netbk->pending_prod + netbk->pending_cons;
243 static void xen_netbk_kick_thread(struct xen_netbk *netbk)
248 static int max_required_rx_slots(struct xenvif *vif)
250 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
252 if (vif->can_sg || vif->gso || vif->gso_prefix)
253 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
258 int xen_netbk_rx_ring_full(struct xenvif *vif)
260 RING_IDX peek = vif->rx_req_cons_peek;
261 RING_IDX needed = max_required_rx_slots(vif);
263 return ((vif->rx.sring->req_prod - peek) < needed) ||
264 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
267 int xen_netbk_must_stop_queue(struct xenvif *vif)
269 if (!xen_netbk_rx_ring_full(vif))
272 vif->rx.sring->req_event = vif->rx_req_cons_peek +
273 max_required_rx_slots(vif);
274 mb(); /* request notification /then/ check the queue */
276 return xen_netbk_rx_ring_full(vif);
280 * Returns true if we should start a new receive buffer instead of
281 * adding 'size' bytes to a buffer which currently contains 'offset'
284 static bool start_new_rx_buffer(int offset, unsigned long size, int head)
286 /* simple case: we have completely filled the current buffer. */
287 if (offset == MAX_BUFFER_OFFSET)
291 * complex case: start a fresh buffer if the current frag
292 * would overflow the current buffer but only if:
293 * (i) this frag would fit completely in the next buffer
294 * and (ii) there is already some data in the current buffer
295 * and (iii) this is not the head buffer.
298 * - (i) stops us splitting a frag into two copies
299 * unless the frag is too large for a single buffer.
300 * - (ii) stops us from leaving a buffer pointlessly empty.
301 * - (iii) stops us leaving the first buffer
302 * empty. Strictly speaking this is already covered
303 * by (ii) but is explicitly checked because
304 * netfront relies on the first buffer being
305 * non-empty and can crash otherwise.
307 * This means we will effectively linearise small
308 * frags but do not needlessly split large buffers
309 * into multiple copies tend to give large frags their
310 * own buffers as before.
312 if ((offset + size > MAX_BUFFER_OFFSET) &&
313 (size <= MAX_BUFFER_OFFSET) && offset && !head)
320 * Figure out how many ring slots we're going to need to send @skb to
321 * the guest. This function is essentially a dry run of
322 * netbk_gop_frag_copy.
324 unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
329 count = DIV_ROUND_UP(skb_headlen(skb), PAGE_SIZE);
331 copy_off = skb_headlen(skb) % PAGE_SIZE;
333 if (skb_shinfo(skb)->gso_size)
336 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
337 unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
338 unsigned long offset = skb_shinfo(skb)->frags[i].page_offset;
341 offset &= ~PAGE_MASK;
344 BUG_ON(offset >= PAGE_SIZE);
345 BUG_ON(copy_off > MAX_BUFFER_OFFSET);
347 bytes = PAGE_SIZE - offset;
352 if (start_new_rx_buffer(copy_off, bytes, 0)) {
357 if (copy_off + bytes > MAX_BUFFER_OFFSET)
358 bytes = MAX_BUFFER_OFFSET - copy_off;
365 if (offset == PAGE_SIZE)
372 struct netrx_pending_operations {
373 unsigned copy_prod, copy_cons;
374 unsigned meta_prod, meta_cons;
375 struct gnttab_copy *copy;
376 struct netbk_rx_meta *meta;
378 grant_ref_t copy_gref;
381 static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
382 struct netrx_pending_operations *npo)
384 struct netbk_rx_meta *meta;
385 struct xen_netif_rx_request *req;
387 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
389 meta = npo->meta + npo->meta_prod++;
395 npo->copy_gref = req->gref;
401 * Set up the grant operations for this fragment. If it's a flipping
402 * interface, we also set up the unmap request from here.
404 static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
405 struct netrx_pending_operations *npo,
406 struct page *page, unsigned long size,
407 unsigned long offset, int *head)
409 struct gnttab_copy *copy_gop;
410 struct netbk_rx_meta *meta;
412 * These variables are used iff get_page_ext returns true,
413 * in which case they are guaranteed to be initialized.
415 unsigned int uninitialized_var(group), uninitialized_var(idx);
416 int foreign = get_page_ext(page, &group, &idx);
419 /* Data must not cross a page boundary. */
420 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
422 meta = npo->meta + npo->meta_prod - 1;
424 /* Skip unused frames from start of page */
425 page += offset >> PAGE_SHIFT;
426 offset &= ~PAGE_MASK;
429 BUG_ON(offset >= PAGE_SIZE);
430 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
432 bytes = PAGE_SIZE - offset;
437 if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
439 * Netfront requires there to be some data in the head
444 meta = get_next_rx_buffer(vif, npo);
447 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
448 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
450 copy_gop = npo->copy + npo->copy_prod++;
451 copy_gop->flags = GNTCOPY_dest_gref;
453 struct xen_netbk *netbk = &xen_netbk[group];
454 struct pending_tx_info *src_pend;
456 src_pend = &netbk->pending_tx_info[idx];
458 copy_gop->source.domid = src_pend->vif->domid;
459 copy_gop->source.u.ref = src_pend->req.gref;
460 copy_gop->flags |= GNTCOPY_source_gref;
462 void *vaddr = page_address(page);
463 copy_gop->source.domid = DOMID_SELF;
464 copy_gop->source.u.gmfn = virt_to_mfn(vaddr);
466 copy_gop->source.offset = offset;
467 copy_gop->dest.domid = vif->domid;
469 copy_gop->dest.offset = npo->copy_off;
470 copy_gop->dest.u.ref = npo->copy_gref;
471 copy_gop->len = bytes;
473 npo->copy_off += bytes;
480 if (offset == PAGE_SIZE && size) {
481 BUG_ON(!PageCompound(page));
486 /* Leave a gap for the GSO descriptor. */
487 if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
490 *head = 0; /* There must be something in this buffer now. */
496 * Prepare an SKB to be transmitted to the frontend.
498 * This function is responsible for allocating grant operations, meta
501 * It returns the number of meta structures consumed. The number of
502 * ring slots used is always equal to the number of meta slots used
503 * plus the number of GSO descriptors used. Currently, we use either
504 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
505 * frontend-side LRO).
507 static int netbk_gop_skb(struct sk_buff *skb,
508 struct netrx_pending_operations *npo)
510 struct xenvif *vif = netdev_priv(skb->dev);
511 int nr_frags = skb_shinfo(skb)->nr_frags;
513 struct xen_netif_rx_request *req;
514 struct netbk_rx_meta *meta;
519 old_meta_prod = npo->meta_prod;
521 /* Set up a GSO prefix descriptor, if necessary */
522 if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
523 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
524 meta = npo->meta + npo->meta_prod++;
525 meta->gso_size = skb_shinfo(skb)->gso_size;
530 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
531 meta = npo->meta + npo->meta_prod++;
533 if (!vif->gso_prefix)
534 meta->gso_size = skb_shinfo(skb)->gso_size;
541 npo->copy_gref = req->gref;
544 while (data < skb_tail_pointer(skb)) {
545 unsigned int offset = offset_in_page(data);
546 unsigned int len = PAGE_SIZE - offset;
548 if (data + len > skb_tail_pointer(skb))
549 len = skb_tail_pointer(skb) - data;
551 netbk_gop_frag_copy(vif, skb, npo,
552 virt_to_page(data), len, offset, &head);
556 for (i = 0; i < nr_frags; i++) {
557 netbk_gop_frag_copy(vif, skb, npo,
558 skb_frag_page(&skb_shinfo(skb)->frags[i]),
559 skb_frag_size(&skb_shinfo(skb)->frags[i]),
560 skb_shinfo(skb)->frags[i].page_offset,
564 return npo->meta_prod - old_meta_prod;
568 * This is a twin to netbk_gop_skb. Assume that netbk_gop_skb was
569 * used to set up the operations on the top of
570 * netrx_pending_operations, which have since been done. Check that
571 * they didn't give any errors and advance over them.
573 static int netbk_check_gop(struct xenvif *vif, int nr_meta_slots,
574 struct netrx_pending_operations *npo)
576 struct gnttab_copy *copy_op;
577 int status = XEN_NETIF_RSP_OKAY;
580 for (i = 0; i < nr_meta_slots; i++) {
581 copy_op = npo->copy + npo->copy_cons++;
582 if (copy_op->status != GNTST_okay) {
584 "Bad status %d from copy to DOM%d.\n",
585 copy_op->status, vif->domid);
586 status = XEN_NETIF_RSP_ERROR;
593 static void netbk_add_frag_responses(struct xenvif *vif, int status,
594 struct netbk_rx_meta *meta,
598 unsigned long offset;
600 /* No fragments used */
601 if (nr_meta_slots <= 1)
606 for (i = 0; i < nr_meta_slots; i++) {
608 if (i == nr_meta_slots - 1)
611 flags = XEN_NETRXF_more_data;
614 make_rx_response(vif, meta[i].id, status, offset,
615 meta[i].size, flags);
619 struct skb_cb_overlay {
623 static void xen_netbk_rx_action(struct xen_netbk *netbk)
625 struct xenvif *vif = NULL, *tmp;
628 struct xen_netif_rx_response *resp;
629 struct sk_buff_head rxq;
635 unsigned long offset;
636 struct skb_cb_overlay *sco;
638 struct netrx_pending_operations npo = {
639 .copy = netbk->grant_copy_op,
643 skb_queue_head_init(&rxq);
647 while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
648 vif = netdev_priv(skb->dev);
649 nr_frags = skb_shinfo(skb)->nr_frags;
651 sco = (struct skb_cb_overlay *)skb->cb;
652 sco->meta_slots_used = netbk_gop_skb(skb, &npo);
654 count += nr_frags + 1;
656 __skb_queue_tail(&rxq, skb);
658 /* Filled the batch queue? */
659 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
663 BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
668 BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
669 gnttab_batch_copy(netbk->grant_copy_op, npo.copy_prod);
671 while ((skb = __skb_dequeue(&rxq)) != NULL) {
672 sco = (struct skb_cb_overlay *)skb->cb;
674 vif = netdev_priv(skb->dev);
676 if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
677 resp = RING_GET_RESPONSE(&vif->rx,
678 vif->rx.rsp_prod_pvt++);
680 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
682 resp->offset = netbk->meta[npo.meta_cons].gso_size;
683 resp->id = netbk->meta[npo.meta_cons].id;
684 resp->status = sco->meta_slots_used;
687 sco->meta_slots_used--;
691 vif->dev->stats.tx_bytes += skb->len;
692 vif->dev->stats.tx_packets++;
694 status = netbk_check_gop(vif, sco->meta_slots_used, &npo);
696 if (sco->meta_slots_used == 1)
699 flags = XEN_NETRXF_more_data;
701 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
702 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
703 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
704 /* remote but checksummed. */
705 flags |= XEN_NETRXF_data_validated;
708 resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
710 netbk->meta[npo.meta_cons].size,
713 if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
714 struct xen_netif_extra_info *gso =
715 (struct xen_netif_extra_info *)
716 RING_GET_RESPONSE(&vif->rx,
717 vif->rx.rsp_prod_pvt++);
719 resp->flags |= XEN_NETRXF_extra_info;
721 gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
722 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
724 gso->u.gso.features = 0;
726 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
730 netbk_add_frag_responses(vif, status,
731 netbk->meta + npo.meta_cons + 1,
732 sco->meta_slots_used);
734 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
736 if (ret && list_empty(&vif->notify_list))
737 list_add_tail(&vif->notify_list, ¬ify);
739 xenvif_notify_tx_completion(vif);
742 npo.meta_cons += sco->meta_slots_used;
746 list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) {
747 notify_remote_via_irq(vif->irq);
748 list_del_init(&vif->notify_list);
751 /* More work to do? */
752 if (!skb_queue_empty(&netbk->rx_queue) &&
753 !timer_pending(&netbk->net_timer))
754 xen_netbk_kick_thread(netbk);
757 void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
759 struct xen_netbk *netbk = vif->netbk;
761 skb_queue_tail(&netbk->rx_queue, skb);
763 xen_netbk_kick_thread(netbk);
766 static void xen_netbk_alarm(unsigned long data)
768 struct xen_netbk *netbk = (struct xen_netbk *)data;
769 xen_netbk_kick_thread(netbk);
772 static int __on_net_schedule_list(struct xenvif *vif)
774 return !list_empty(&vif->schedule_list);
777 /* Must be called with net_schedule_list_lock held */
778 static void remove_from_net_schedule_list(struct xenvif *vif)
780 if (likely(__on_net_schedule_list(vif))) {
781 list_del_init(&vif->schedule_list);
786 static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
788 struct xenvif *vif = NULL;
790 spin_lock_irq(&netbk->net_schedule_list_lock);
791 if (list_empty(&netbk->net_schedule_list))
794 vif = list_first_entry(&netbk->net_schedule_list,
795 struct xenvif, schedule_list);
801 remove_from_net_schedule_list(vif);
803 spin_unlock_irq(&netbk->net_schedule_list_lock);
807 void xen_netbk_schedule_xenvif(struct xenvif *vif)
810 struct xen_netbk *netbk = vif->netbk;
812 if (__on_net_schedule_list(vif))
815 spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
816 if (!__on_net_schedule_list(vif) &&
817 likely(xenvif_schedulable(vif))) {
818 list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
821 spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
825 if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
826 !list_empty(&netbk->net_schedule_list))
827 xen_netbk_kick_thread(netbk);
830 void xen_netbk_deschedule_xenvif(struct xenvif *vif)
832 struct xen_netbk *netbk = vif->netbk;
833 spin_lock_irq(&netbk->net_schedule_list_lock);
834 remove_from_net_schedule_list(vif);
835 spin_unlock_irq(&netbk->net_schedule_list_lock);
838 void xen_netbk_check_rx_xenvif(struct xenvif *vif)
842 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
845 xen_netbk_schedule_xenvif(vif);
848 static void tx_add_credit(struct xenvif *vif)
850 unsigned long max_burst, max_credit;
853 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
854 * Otherwise the interface can seize up due to insufficient credit.
856 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
857 max_burst = min(max_burst, 131072UL);
858 max_burst = max(max_burst, vif->credit_bytes);
860 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
861 max_credit = vif->remaining_credit + vif->credit_bytes;
862 if (max_credit < vif->remaining_credit)
863 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
865 vif->remaining_credit = min(max_credit, max_burst);
868 static void tx_credit_callback(unsigned long data)
870 struct xenvif *vif = (struct xenvif *)data;
872 xen_netbk_check_rx_xenvif(vif);
875 static void netbk_tx_err(struct xenvif *vif,
876 struct xen_netif_tx_request *txp, RING_IDX end)
878 RING_IDX cons = vif->tx.req_cons;
881 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
884 txp = RING_GET_REQUEST(&vif->tx, cons++);
886 vif->tx.req_cons = cons;
887 xen_netbk_check_rx_xenvif(vif);
891 static int netbk_count_requests(struct xenvif *vif,
892 struct xen_netif_tx_request *first,
893 struct xen_netif_tx_request *txp,
896 RING_IDX cons = vif->tx.req_cons;
899 if (!(first->flags & XEN_NETTXF_more_data))
903 if (frags >= work_to_do) {
904 netdev_dbg(vif->dev, "Need more frags\n");
908 if (unlikely(frags >= MAX_SKB_FRAGS)) {
909 netdev_dbg(vif->dev, "Too many frags\n");
913 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags),
915 if (txp->size > first->size) {
916 netdev_dbg(vif->dev, "Frags galore\n");
920 first->size -= txp->size;
923 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
924 netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n",
925 txp->offset, txp->size);
928 } while ((txp++)->flags & XEN_NETTXF_more_data);
932 static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
937 page = alloc_page(GFP_KERNEL|__GFP_COLD);
940 set_page_ext(page, netbk, pending_idx);
941 netbk->mmap_pages[pending_idx] = page;
945 static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
948 struct xen_netif_tx_request *txp,
949 struct gnttab_copy *gop)
951 struct skb_shared_info *shinfo = skb_shinfo(skb);
952 skb_frag_t *frags = shinfo->frags;
953 u16 pending_idx = *((u16 *)skb->data);
956 /* Skip first skb fragment if it is on same page as header fragment. */
957 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
959 for (i = start; i < shinfo->nr_frags; i++, txp++) {
961 pending_ring_idx_t index;
962 struct pending_tx_info *pending_tx_info =
963 netbk->pending_tx_info;
965 index = pending_index(netbk->pending_cons++);
966 pending_idx = netbk->pending_ring[index];
967 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
971 gop->source.u.ref = txp->gref;
972 gop->source.domid = vif->domid;
973 gop->source.offset = txp->offset;
975 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
976 gop->dest.domid = DOMID_SELF;
977 gop->dest.offset = txp->offset;
979 gop->len = txp->size;
980 gop->flags = GNTCOPY_source_gref;
984 memcpy(&pending_tx_info[pending_idx].req, txp, sizeof(*txp));
986 pending_tx_info[pending_idx].vif = vif;
987 frag_set_pending_idx(&frags[i], pending_idx);
993 static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
995 struct gnttab_copy **gopp)
997 struct gnttab_copy *gop = *gopp;
998 u16 pending_idx = *((u16 *)skb->data);
999 struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
1000 struct xenvif *vif = pending_tx_info[pending_idx].vif;
1001 struct xen_netif_tx_request *txp;
1002 struct skb_shared_info *shinfo = skb_shinfo(skb);
1003 int nr_frags = shinfo->nr_frags;
1006 /* Check status of header. */
1008 if (unlikely(err)) {
1009 pending_ring_idx_t index;
1010 index = pending_index(netbk->pending_prod++);
1011 txp = &pending_tx_info[pending_idx].req;
1012 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
1013 netbk->pending_ring[index] = pending_idx;
1017 /* Skip first skb fragment if it is on same page as header fragment. */
1018 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
1020 for (i = start; i < nr_frags; i++) {
1022 pending_ring_idx_t index;
1024 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
1026 /* Check error status: if okay then remember grant handle. */
1027 newerr = (++gop)->status;
1028 if (likely(!newerr)) {
1029 /* Had a previous error? Invalidate this fragment. */
1031 xen_netbk_idx_release(netbk, pending_idx);
1035 /* Error on this fragment: respond to client with an error. */
1036 txp = &netbk->pending_tx_info[pending_idx].req;
1037 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
1038 index = pending_index(netbk->pending_prod++);
1039 netbk->pending_ring[index] = pending_idx;
1042 /* Not the first error? Preceding frags already invalidated. */
1046 /* First error: invalidate header and preceding fragments. */
1047 pending_idx = *((u16 *)skb->data);
1048 xen_netbk_idx_release(netbk, pending_idx);
1049 for (j = start; j < i; j++) {
1050 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1051 xen_netbk_idx_release(netbk, pending_idx);
1054 /* Remember the error: invalidate all subsequent fragments. */
1062 static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
1064 struct skb_shared_info *shinfo = skb_shinfo(skb);
1065 int nr_frags = shinfo->nr_frags;
1068 for (i = 0; i < nr_frags; i++) {
1069 skb_frag_t *frag = shinfo->frags + i;
1070 struct xen_netif_tx_request *txp;
1074 pending_idx = frag_get_pending_idx(frag);
1076 txp = &netbk->pending_tx_info[pending_idx].req;
1077 page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
1078 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1079 skb->len += txp->size;
1080 skb->data_len += txp->size;
1081 skb->truesize += txp->size;
1083 /* Take an extra reference to offset xen_netbk_idx_release */
1084 get_page(netbk->mmap_pages[pending_idx]);
1085 xen_netbk_idx_release(netbk, pending_idx);
1089 static int xen_netbk_get_extras(struct xenvif *vif,
1090 struct xen_netif_extra_info *extras,
1093 struct xen_netif_extra_info extra;
1094 RING_IDX cons = vif->tx.req_cons;
1097 if (unlikely(work_to_do-- <= 0)) {
1098 netdev_dbg(vif->dev, "Missing extra info\n");
1102 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1104 if (unlikely(!extra.type ||
1105 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1106 vif->tx.req_cons = ++cons;
1107 netdev_dbg(vif->dev,
1108 "Invalid extra type: %d\n", extra.type);
1112 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1113 vif->tx.req_cons = ++cons;
1114 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1119 static int netbk_set_skb_gso(struct xenvif *vif,
1120 struct sk_buff *skb,
1121 struct xen_netif_extra_info *gso)
1123 if (!gso->u.gso.size) {
1124 netdev_dbg(vif->dev, "GSO size must not be zero.\n");
1128 /* Currently only TCPv4 S.O. is supported. */
1129 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
1130 netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1134 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1135 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1137 /* Header must be checked, and gso_segs computed. */
1138 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1139 skb_shinfo(skb)->gso_segs = 0;
1144 static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1149 int recalculate_partial_csum = 0;
1152 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1153 * peers can fail to set NETRXF_csum_blank when sending a GSO
1154 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1155 * recalculate the partial checksum.
1157 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1158 vif->rx_gso_checksum_fixup++;
1159 skb->ip_summed = CHECKSUM_PARTIAL;
1160 recalculate_partial_csum = 1;
1163 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1164 if (skb->ip_summed != CHECKSUM_PARTIAL)
1167 if (skb->protocol != htons(ETH_P_IP))
1170 iph = (void *)skb->data;
1171 th = skb->data + 4 * iph->ihl;
1172 if (th >= skb_tail_pointer(skb))
1175 skb->csum_start = th - skb->head;
1176 switch (iph->protocol) {
1178 skb->csum_offset = offsetof(struct tcphdr, check);
1180 if (recalculate_partial_csum) {
1181 struct tcphdr *tcph = (struct tcphdr *)th;
1182 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1183 skb->len - iph->ihl*4,
1188 skb->csum_offset = offsetof(struct udphdr, check);
1190 if (recalculate_partial_csum) {
1191 struct udphdr *udph = (struct udphdr *)th;
1192 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1193 skb->len - iph->ihl*4,
1198 if (net_ratelimit())
1199 netdev_err(vif->dev,
1200 "Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
1205 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
1214 static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1216 unsigned long now = jiffies;
1217 unsigned long next_credit =
1218 vif->credit_timeout.expires +
1219 msecs_to_jiffies(vif->credit_usec / 1000);
1221 /* Timer could already be pending in rare cases. */
1222 if (timer_pending(&vif->credit_timeout))
1225 /* Passed the point where we can replenish credit? */
1226 if (time_after_eq(now, next_credit)) {
1227 vif->credit_timeout.expires = now;
1231 /* Still too big to send right now? Set a callback. */
1232 if (size > vif->remaining_credit) {
1233 vif->credit_timeout.data =
1235 vif->credit_timeout.function =
1237 mod_timer(&vif->credit_timeout,
1246 static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
1248 struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
1249 struct sk_buff *skb;
1252 while (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1253 !list_empty(&netbk->net_schedule_list)) {
1255 struct xen_netif_tx_request txreq;
1256 struct xen_netif_tx_request txfrags[MAX_SKB_FRAGS];
1258 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1262 unsigned int data_len;
1263 pending_ring_idx_t index;
1265 /* Get a netif from the list with work to do. */
1266 vif = poll_net_schedule_list(netbk);
1270 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1276 idx = vif->tx.req_cons;
1277 rmb(); /* Ensure that we see the request before we copy it. */
1278 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1280 /* Credit-based scheduling. */
1281 if (txreq.size > vif->remaining_credit &&
1282 tx_credit_exceeded(vif, txreq.size)) {
1287 vif->remaining_credit -= txreq.size;
1290 vif->tx.req_cons = ++idx;
1292 memset(extras, 0, sizeof(extras));
1293 if (txreq.flags & XEN_NETTXF_extra_info) {
1294 work_to_do = xen_netbk_get_extras(vif, extras,
1296 idx = vif->tx.req_cons;
1297 if (unlikely(work_to_do < 0)) {
1298 netbk_tx_err(vif, &txreq, idx);
1303 ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
1304 if (unlikely(ret < 0)) {
1305 netbk_tx_err(vif, &txreq, idx - ret);
1310 if (unlikely(txreq.size < ETH_HLEN)) {
1311 netdev_dbg(vif->dev,
1312 "Bad packet size: %d\n", txreq.size);
1313 netbk_tx_err(vif, &txreq, idx);
1317 /* No crossing a page as the payload mustn't fragment. */
1318 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1319 netdev_dbg(vif->dev,
1320 "txreq.offset: %x, size: %u, end: %lu\n",
1321 txreq.offset, txreq.size,
1322 (txreq.offset&~PAGE_MASK) + txreq.size);
1323 netbk_tx_err(vif, &txreq, idx);
1327 index = pending_index(netbk->pending_cons);
1328 pending_idx = netbk->pending_ring[index];
1330 data_len = (txreq.size > PKT_PROT_LEN &&
1331 ret < MAX_SKB_FRAGS) ?
1332 PKT_PROT_LEN : txreq.size;
1334 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1335 GFP_ATOMIC | __GFP_NOWARN);
1336 if (unlikely(skb == NULL)) {
1337 netdev_dbg(vif->dev,
1338 "Can't allocate a skb in start_xmit.\n");
1339 netbk_tx_err(vif, &txreq, idx);
1343 /* Packets passed to netif_rx() must have some headroom. */
1344 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1346 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1347 struct xen_netif_extra_info *gso;
1348 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1350 if (netbk_set_skb_gso(vif, skb, gso)) {
1352 netbk_tx_err(vif, &txreq, idx);
1357 /* XXX could copy straight to head */
1358 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
1361 netbk_tx_err(vif, &txreq, idx);
1365 gop->source.u.ref = txreq.gref;
1366 gop->source.domid = vif->domid;
1367 gop->source.offset = txreq.offset;
1369 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1370 gop->dest.domid = DOMID_SELF;
1371 gop->dest.offset = txreq.offset;
1373 gop->len = txreq.size;
1374 gop->flags = GNTCOPY_source_gref;
1378 memcpy(&netbk->pending_tx_info[pending_idx].req,
1379 &txreq, sizeof(txreq));
1380 netbk->pending_tx_info[pending_idx].vif = vif;
1381 *((u16 *)skb->data) = pending_idx;
1383 __skb_put(skb, data_len);
1385 skb_shinfo(skb)->nr_frags = ret;
1386 if (data_len < txreq.size) {
1387 skb_shinfo(skb)->nr_frags++;
1388 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1391 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1392 INVALID_PENDING_IDX);
1395 netbk->pending_cons++;
1397 request_gop = xen_netbk_get_requests(netbk, vif,
1399 if (request_gop == NULL) {
1401 netbk_tx_err(vif, &txreq, idx);
1406 __skb_queue_tail(&netbk->tx_queue, skb);
1408 vif->tx.req_cons = idx;
1409 xen_netbk_check_rx_xenvif(vif);
1411 if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
1415 return gop - netbk->tx_copy_ops;
1418 static void xen_netbk_tx_submit(struct xen_netbk *netbk)
1420 struct gnttab_copy *gop = netbk->tx_copy_ops;
1421 struct sk_buff *skb;
1423 while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
1424 struct xen_netif_tx_request *txp;
1429 pending_idx = *((u16 *)skb->data);
1430 vif = netbk->pending_tx_info[pending_idx].vif;
1431 txp = &netbk->pending_tx_info[pending_idx].req;
1433 /* Check the remap error code. */
1434 if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
1435 netdev_dbg(vif->dev, "netback grant failed.\n");
1436 skb_shinfo(skb)->nr_frags = 0;
1441 data_len = skb->len;
1443 (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
1445 if (data_len < txp->size) {
1446 /* Append the packet payload as a fragment. */
1447 txp->offset += data_len;
1448 txp->size -= data_len;
1450 /* Schedule a response immediately. */
1451 xen_netbk_idx_release(netbk, pending_idx);
1454 if (txp->flags & XEN_NETTXF_csum_blank)
1455 skb->ip_summed = CHECKSUM_PARTIAL;
1456 else if (txp->flags & XEN_NETTXF_data_validated)
1457 skb->ip_summed = CHECKSUM_UNNECESSARY;
1459 xen_netbk_fill_frags(netbk, skb);
1462 * If the initial fragment was < PKT_PROT_LEN then
1463 * pull through some bytes from the other fragments to
1464 * increase the linear region to PKT_PROT_LEN bytes.
1466 if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
1467 int target = min_t(int, skb->len, PKT_PROT_LEN);
1468 __pskb_pull_tail(skb, target - skb_headlen(skb));
1471 skb->dev = vif->dev;
1472 skb->protocol = eth_type_trans(skb, skb->dev);
1474 if (checksum_setup(vif, skb)) {
1475 netdev_dbg(vif->dev,
1476 "Can't setup checksum in net_tx_action\n");
1481 vif->dev->stats.rx_bytes += skb->len;
1482 vif->dev->stats.rx_packets++;
1484 xenvif_receive_skb(vif, skb);
1488 /* Called after netfront has transmitted */
1489 static void xen_netbk_tx_action(struct xen_netbk *netbk)
1493 nr_gops = xen_netbk_tx_build_gops(netbk);
1498 gnttab_batch_copy(netbk->tx_copy_ops, nr_gops);
1500 xen_netbk_tx_submit(netbk);
1503 static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
1506 struct pending_tx_info *pending_tx_info;
1507 pending_ring_idx_t index;
1509 /* Already complete? */
1510 if (netbk->mmap_pages[pending_idx] == NULL)
1513 pending_tx_info = &netbk->pending_tx_info[pending_idx];
1515 vif = pending_tx_info->vif;
1517 make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
1519 index = pending_index(netbk->pending_prod++);
1520 netbk->pending_ring[index] = pending_idx;
1524 netbk->mmap_pages[pending_idx]->mapping = 0;
1525 put_page(netbk->mmap_pages[pending_idx]);
1526 netbk->mmap_pages[pending_idx] = NULL;
1529 static void make_tx_response(struct xenvif *vif,
1530 struct xen_netif_tx_request *txp,
1533 RING_IDX i = vif->tx.rsp_prod_pvt;
1534 struct xen_netif_tx_response *resp;
1537 resp = RING_GET_RESPONSE(&vif->tx, i);
1541 if (txp->flags & XEN_NETTXF_extra_info)
1542 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1544 vif->tx.rsp_prod_pvt = ++i;
1545 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1547 notify_remote_via_irq(vif->irq);
1550 static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1557 RING_IDX i = vif->rx.rsp_prod_pvt;
1558 struct xen_netif_rx_response *resp;
1560 resp = RING_GET_RESPONSE(&vif->rx, i);
1561 resp->offset = offset;
1562 resp->flags = flags;
1564 resp->status = (s16)size;
1566 resp->status = (s16)st;
1568 vif->rx.rsp_prod_pvt = ++i;
1573 static inline int rx_work_todo(struct xen_netbk *netbk)
1575 return !skb_queue_empty(&netbk->rx_queue);
1578 static inline int tx_work_todo(struct xen_netbk *netbk)
1581 if (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1582 !list_empty(&netbk->net_schedule_list))
1588 static int xen_netbk_kthread(void *data)
1590 struct xen_netbk *netbk = data;
1591 while (!kthread_should_stop()) {
1592 wait_event_interruptible(netbk->wq,
1593 rx_work_todo(netbk) ||
1594 tx_work_todo(netbk) ||
1595 kthread_should_stop());
1598 if (kthread_should_stop())
1601 if (rx_work_todo(netbk))
1602 xen_netbk_rx_action(netbk);
1604 if (tx_work_todo(netbk))
1605 xen_netbk_tx_action(netbk);
1611 void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
1614 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1617 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1621 int xen_netbk_map_frontend_rings(struct xenvif *vif,
1622 grant_ref_t tx_ring_ref,
1623 grant_ref_t rx_ring_ref)
1626 struct xen_netif_tx_sring *txs;
1627 struct xen_netif_rx_sring *rxs;
1631 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1632 tx_ring_ref, &addr);
1636 txs = (struct xen_netif_tx_sring *)addr;
1637 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1639 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1640 rx_ring_ref, &addr);
1644 rxs = (struct xen_netif_rx_sring *)addr;
1645 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1647 vif->rx_req_cons_peek = 0;
1652 xen_netbk_unmap_frontend_rings(vif);
1656 static int __init netback_init(void)
1665 xen_netbk_group_nr = num_online_cpus();
1666 xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
1670 for (group = 0; group < xen_netbk_group_nr; group++) {
1671 struct xen_netbk *netbk = &xen_netbk[group];
1672 skb_queue_head_init(&netbk->rx_queue);
1673 skb_queue_head_init(&netbk->tx_queue);
1675 init_timer(&netbk->net_timer);
1676 netbk->net_timer.data = (unsigned long)netbk;
1677 netbk->net_timer.function = xen_netbk_alarm;
1679 netbk->pending_cons = 0;
1680 netbk->pending_prod = MAX_PENDING_REQS;
1681 for (i = 0; i < MAX_PENDING_REQS; i++)
1682 netbk->pending_ring[i] = i;
1684 init_waitqueue_head(&netbk->wq);
1685 netbk->task = kthread_create(xen_netbk_kthread,
1687 "netback/%u", group);
1689 if (IS_ERR(netbk->task)) {
1690 printk(KERN_ALERT "kthread_create() fails at netback\n");
1691 del_timer(&netbk->net_timer);
1692 rc = PTR_ERR(netbk->task);
1696 kthread_bind(netbk->task, group);
1698 INIT_LIST_HEAD(&netbk->net_schedule_list);
1700 spin_lock_init(&netbk->net_schedule_list_lock);
1702 atomic_set(&netbk->netfront_count, 0);
1704 wake_up_process(netbk->task);
1707 rc = xenvif_xenbus_init();
1714 while (--group >= 0) {
1715 struct xen_netbk *netbk = &xen_netbk[group];
1716 for (i = 0; i < MAX_PENDING_REQS; i++) {
1717 if (netbk->mmap_pages[i])
1718 __free_page(netbk->mmap_pages[i]);
1720 del_timer(&netbk->net_timer);
1721 kthread_stop(netbk->task);
1728 module_init(netback_init);
1730 MODULE_LICENSE("Dual BSD/GPL");
1731 MODULE_ALIAS("xen-backend:vif");