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Merge tag 'for-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/kishon/linux...
[deliverable/linux.git] / drivers / net / xen-netback / netback.c
1 /*
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
7 *
8 * Copyright (c) 2002-2005, K A Fraser
9 *
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:
15 *
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:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
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
32 * IN THE SOFTWARE.
33 */
34
35 #include "common.h"
36
37 #include <linux/kthread.h>
38 #include <linux/if_vlan.h>
39 #include <linux/udp.h>
40 #include <linux/highmem.h>
41
42 #include <net/tcp.h>
43
44 #include <xen/xen.h>
45 #include <xen/events.h>
46 #include <xen/interface/memory.h>
47
48 #include <asm/xen/hypercall.h>
49 #include <asm/xen/page.h>
50
51 /* Provide an option to disable split event channels at load time as
52 * event channels are limited resource. Split event channels are
53 * enabled by default.
54 */
55 bool separate_tx_rx_irq = 1;
56 module_param(separate_tx_rx_irq, bool, 0644);
57
58 /* The time that packets can stay on the guest Rx internal queue
59 * before they are dropped.
60 */
61 unsigned int rx_drain_timeout_msecs = 10000;
62 module_param(rx_drain_timeout_msecs, uint, 0444);
63
64 /* The length of time before the frontend is considered unresponsive
65 * because it isn't providing Rx slots.
66 */
67 unsigned int rx_stall_timeout_msecs = 60000;
68 module_param(rx_stall_timeout_msecs, uint, 0444);
69
70 unsigned int xenvif_max_queues;
71 module_param_named(max_queues, xenvif_max_queues, uint, 0644);
72 MODULE_PARM_DESC(max_queues,
73 "Maximum number of queues per virtual interface");
74
75 /*
76 * This is the maximum slots a skb can have. If a guest sends a skb
77 * which exceeds this limit it is considered malicious.
78 */
79 #define FATAL_SKB_SLOTS_DEFAULT 20
80 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
81 module_param(fatal_skb_slots, uint, 0444);
82
83 /* The amount to copy out of the first guest Tx slot into the skb's
84 * linear area. If the first slot has more data, it will be mapped
85 * and put into the first frag.
86 *
87 * This is sized to avoid pulling headers from the frags for most
88 * TCP/IP packets.
89 */
90 #define XEN_NETBACK_TX_COPY_LEN 128
91
92
93 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
94 u8 status);
95
96 static void make_tx_response(struct xenvif_queue *queue,
97 struct xen_netif_tx_request *txp,
98 s8 st);
99 static void push_tx_responses(struct xenvif_queue *queue);
100
101 static inline int tx_work_todo(struct xenvif_queue *queue);
102
103 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
104 u16 id,
105 s8 st,
106 u16 offset,
107 u16 size,
108 u16 flags);
109
110 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
111 u16 idx)
112 {
113 return page_to_pfn(queue->mmap_pages[idx]);
114 }
115
116 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
117 u16 idx)
118 {
119 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
120 }
121
122 #define callback_param(vif, pending_idx) \
123 (vif->pending_tx_info[pending_idx].callback_struct)
124
125 /* Find the containing VIF's structure from a pointer in pending_tx_info array
126 */
127 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
128 {
129 u16 pending_idx = ubuf->desc;
130 struct pending_tx_info *temp =
131 container_of(ubuf, struct pending_tx_info, callback_struct);
132 return container_of(temp - pending_idx,
133 struct xenvif_queue,
134 pending_tx_info[0]);
135 }
136
137 static u16 frag_get_pending_idx(skb_frag_t *frag)
138 {
139 return (u16)frag->page_offset;
140 }
141
142 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
143 {
144 frag->page_offset = pending_idx;
145 }
146
147 static inline pending_ring_idx_t pending_index(unsigned i)
148 {
149 return i & (MAX_PENDING_REQS-1);
150 }
151
152 bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed)
153 {
154 RING_IDX prod, cons;
155
156 do {
157 prod = queue->rx.sring->req_prod;
158 cons = queue->rx.req_cons;
159
160 if (prod - cons >= needed)
161 return true;
162
163 queue->rx.sring->req_event = prod + 1;
164
165 /* Make sure event is visible before we check prod
166 * again.
167 */
168 mb();
169 } while (queue->rx.sring->req_prod != prod);
170
171 return false;
172 }
173
174 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
175 {
176 unsigned long flags;
177
178 spin_lock_irqsave(&queue->rx_queue.lock, flags);
179
180 __skb_queue_tail(&queue->rx_queue, skb);
181
182 queue->rx_queue_len += skb->len;
183 if (queue->rx_queue_len > queue->rx_queue_max)
184 netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
185
186 spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
187 }
188
189 static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
190 {
191 struct sk_buff *skb;
192
193 spin_lock_irq(&queue->rx_queue.lock);
194
195 skb = __skb_dequeue(&queue->rx_queue);
196 if (skb)
197 queue->rx_queue_len -= skb->len;
198
199 spin_unlock_irq(&queue->rx_queue.lock);
200
201 return skb;
202 }
203
204 static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue)
205 {
206 spin_lock_irq(&queue->rx_queue.lock);
207
208 if (queue->rx_queue_len < queue->rx_queue_max)
209 netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
210
211 spin_unlock_irq(&queue->rx_queue.lock);
212 }
213
214
215 static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
216 {
217 struct sk_buff *skb;
218 while ((skb = xenvif_rx_dequeue(queue)) != NULL)
219 kfree_skb(skb);
220 }
221
222 static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
223 {
224 struct sk_buff *skb;
225
226 for(;;) {
227 skb = skb_peek(&queue->rx_queue);
228 if (!skb)
229 break;
230 if (time_before(jiffies, XENVIF_RX_CB(skb)->expires))
231 break;
232 xenvif_rx_dequeue(queue);
233 kfree_skb(skb);
234 }
235 }
236
237 struct netrx_pending_operations {
238 unsigned copy_prod, copy_cons;
239 unsigned meta_prod, meta_cons;
240 struct gnttab_copy *copy;
241 struct xenvif_rx_meta *meta;
242 int copy_off;
243 grant_ref_t copy_gref;
244 };
245
246 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue,
247 struct netrx_pending_operations *npo)
248 {
249 struct xenvif_rx_meta *meta;
250 struct xen_netif_rx_request *req;
251
252 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
253
254 meta = npo->meta + npo->meta_prod++;
255 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
256 meta->gso_size = 0;
257 meta->size = 0;
258 meta->id = req->id;
259
260 npo->copy_off = 0;
261 npo->copy_gref = req->gref;
262
263 return meta;
264 }
265
266 /*
267 * Set up the grant operations for this fragment. If it's a flipping
268 * interface, we also set up the unmap request from here.
269 */
270 static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb,
271 struct netrx_pending_operations *npo,
272 struct page *page, unsigned long size,
273 unsigned long offset, int *head)
274 {
275 struct gnttab_copy *copy_gop;
276 struct xenvif_rx_meta *meta;
277 unsigned long bytes;
278 int gso_type = XEN_NETIF_GSO_TYPE_NONE;
279
280 /* Data must not cross a page boundary. */
281 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
282
283 meta = npo->meta + npo->meta_prod - 1;
284
285 /* Skip unused frames from start of page */
286 page += offset >> PAGE_SHIFT;
287 offset &= ~PAGE_MASK;
288
289 while (size > 0) {
290 struct xen_page_foreign *foreign;
291
292 BUG_ON(offset >= PAGE_SIZE);
293 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
294
295 if (npo->copy_off == MAX_BUFFER_OFFSET)
296 meta = get_next_rx_buffer(queue, npo);
297
298 bytes = PAGE_SIZE - offset;
299 if (bytes > size)
300 bytes = size;
301
302 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
303 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
304
305 copy_gop = npo->copy + npo->copy_prod++;
306 copy_gop->flags = GNTCOPY_dest_gref;
307 copy_gop->len = bytes;
308
309 foreign = xen_page_foreign(page);
310 if (foreign) {
311 copy_gop->source.domid = foreign->domid;
312 copy_gop->source.u.ref = foreign->gref;
313 copy_gop->flags |= GNTCOPY_source_gref;
314 } else {
315 copy_gop->source.domid = DOMID_SELF;
316 copy_gop->source.u.gmfn =
317 virt_to_mfn(page_address(page));
318 }
319 copy_gop->source.offset = offset;
320
321 copy_gop->dest.domid = queue->vif->domid;
322 copy_gop->dest.offset = npo->copy_off;
323 copy_gop->dest.u.ref = npo->copy_gref;
324
325 npo->copy_off += bytes;
326 meta->size += bytes;
327
328 offset += bytes;
329 size -= bytes;
330
331 /* Next frame */
332 if (offset == PAGE_SIZE && size) {
333 BUG_ON(!PageCompound(page));
334 page++;
335 offset = 0;
336 }
337
338 /* Leave a gap for the GSO descriptor. */
339 if (skb_is_gso(skb)) {
340 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
341 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
342 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
343 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
344 }
345
346 if (*head && ((1 << gso_type) & queue->vif->gso_mask))
347 queue->rx.req_cons++;
348
349 *head = 0; /* There must be something in this buffer now. */
350
351 }
352 }
353
354 /*
355 * Prepare an SKB to be transmitted to the frontend.
356 *
357 * This function is responsible for allocating grant operations, meta
358 * structures, etc.
359 *
360 * It returns the number of meta structures consumed. The number of
361 * ring slots used is always equal to the number of meta slots used
362 * plus the number of GSO descriptors used. Currently, we use either
363 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
364 * frontend-side LRO).
365 */
366 static int xenvif_gop_skb(struct sk_buff *skb,
367 struct netrx_pending_operations *npo,
368 struct xenvif_queue *queue)
369 {
370 struct xenvif *vif = netdev_priv(skb->dev);
371 int nr_frags = skb_shinfo(skb)->nr_frags;
372 int i;
373 struct xen_netif_rx_request *req;
374 struct xenvif_rx_meta *meta;
375 unsigned char *data;
376 int head = 1;
377 int old_meta_prod;
378 int gso_type;
379
380 old_meta_prod = npo->meta_prod;
381
382 gso_type = XEN_NETIF_GSO_TYPE_NONE;
383 if (skb_is_gso(skb)) {
384 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
385 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
386 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
387 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
388 }
389
390 /* Set up a GSO prefix descriptor, if necessary */
391 if ((1 << gso_type) & vif->gso_prefix_mask) {
392 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
393 meta = npo->meta + npo->meta_prod++;
394 meta->gso_type = gso_type;
395 meta->gso_size = skb_shinfo(skb)->gso_size;
396 meta->size = 0;
397 meta->id = req->id;
398 }
399
400 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
401 meta = npo->meta + npo->meta_prod++;
402
403 if ((1 << gso_type) & vif->gso_mask) {
404 meta->gso_type = gso_type;
405 meta->gso_size = skb_shinfo(skb)->gso_size;
406 } else {
407 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
408 meta->gso_size = 0;
409 }
410
411 meta->size = 0;
412 meta->id = req->id;
413 npo->copy_off = 0;
414 npo->copy_gref = req->gref;
415
416 data = skb->data;
417 while (data < skb_tail_pointer(skb)) {
418 unsigned int offset = offset_in_page(data);
419 unsigned int len = PAGE_SIZE - offset;
420
421 if (data + len > skb_tail_pointer(skb))
422 len = skb_tail_pointer(skb) - data;
423
424 xenvif_gop_frag_copy(queue, skb, npo,
425 virt_to_page(data), len, offset, &head);
426 data += len;
427 }
428
429 for (i = 0; i < nr_frags; i++) {
430 xenvif_gop_frag_copy(queue, skb, npo,
431 skb_frag_page(&skb_shinfo(skb)->frags[i]),
432 skb_frag_size(&skb_shinfo(skb)->frags[i]),
433 skb_shinfo(skb)->frags[i].page_offset,
434 &head);
435 }
436
437 return npo->meta_prod - old_meta_prod;
438 }
439
440 /*
441 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
442 * used to set up the operations on the top of
443 * netrx_pending_operations, which have since been done. Check that
444 * they didn't give any errors and advance over them.
445 */
446 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
447 struct netrx_pending_operations *npo)
448 {
449 struct gnttab_copy *copy_op;
450 int status = XEN_NETIF_RSP_OKAY;
451 int i;
452
453 for (i = 0; i < nr_meta_slots; i++) {
454 copy_op = npo->copy + npo->copy_cons++;
455 if (copy_op->status != GNTST_okay) {
456 netdev_dbg(vif->dev,
457 "Bad status %d from copy to DOM%d.\n",
458 copy_op->status, vif->domid);
459 status = XEN_NETIF_RSP_ERROR;
460 }
461 }
462
463 return status;
464 }
465
466 static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status,
467 struct xenvif_rx_meta *meta,
468 int nr_meta_slots)
469 {
470 int i;
471 unsigned long offset;
472
473 /* No fragments used */
474 if (nr_meta_slots <= 1)
475 return;
476
477 nr_meta_slots--;
478
479 for (i = 0; i < nr_meta_slots; i++) {
480 int flags;
481 if (i == nr_meta_slots - 1)
482 flags = 0;
483 else
484 flags = XEN_NETRXF_more_data;
485
486 offset = 0;
487 make_rx_response(queue, meta[i].id, status, offset,
488 meta[i].size, flags);
489 }
490 }
491
492 void xenvif_kick_thread(struct xenvif_queue *queue)
493 {
494 wake_up(&queue->wq);
495 }
496
497 static void xenvif_rx_action(struct xenvif_queue *queue)
498 {
499 s8 status;
500 u16 flags;
501 struct xen_netif_rx_response *resp;
502 struct sk_buff_head rxq;
503 struct sk_buff *skb;
504 LIST_HEAD(notify);
505 int ret;
506 unsigned long offset;
507 bool need_to_notify = false;
508
509 struct netrx_pending_operations npo = {
510 .copy = queue->grant_copy_op,
511 .meta = queue->meta,
512 };
513
514 skb_queue_head_init(&rxq);
515
516 while (xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX)
517 && (skb = xenvif_rx_dequeue(queue)) != NULL) {
518 RING_IDX old_req_cons;
519 RING_IDX ring_slots_used;
520
521 queue->last_rx_time = jiffies;
522
523 old_req_cons = queue->rx.req_cons;
524 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
525 ring_slots_used = queue->rx.req_cons - old_req_cons;
526
527 __skb_queue_tail(&rxq, skb);
528 }
529
530 BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
531
532 if (!npo.copy_prod)
533 goto done;
534
535 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
536 gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
537
538 while ((skb = __skb_dequeue(&rxq)) != NULL) {
539
540 if ((1 << queue->meta[npo.meta_cons].gso_type) &
541 queue->vif->gso_prefix_mask) {
542 resp = RING_GET_RESPONSE(&queue->rx,
543 queue->rx.rsp_prod_pvt++);
544
545 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
546
547 resp->offset = queue->meta[npo.meta_cons].gso_size;
548 resp->id = queue->meta[npo.meta_cons].id;
549 resp->status = XENVIF_RX_CB(skb)->meta_slots_used;
550
551 npo.meta_cons++;
552 XENVIF_RX_CB(skb)->meta_slots_used--;
553 }
554
555
556 queue->stats.tx_bytes += skb->len;
557 queue->stats.tx_packets++;
558
559 status = xenvif_check_gop(queue->vif,
560 XENVIF_RX_CB(skb)->meta_slots_used,
561 &npo);
562
563 if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
564 flags = 0;
565 else
566 flags = XEN_NETRXF_more_data;
567
568 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
569 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
570 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
571 /* remote but checksummed. */
572 flags |= XEN_NETRXF_data_validated;
573
574 offset = 0;
575 resp = make_rx_response(queue, queue->meta[npo.meta_cons].id,
576 status, offset,
577 queue->meta[npo.meta_cons].size,
578 flags);
579
580 if ((1 << queue->meta[npo.meta_cons].gso_type) &
581 queue->vif->gso_mask) {
582 struct xen_netif_extra_info *gso =
583 (struct xen_netif_extra_info *)
584 RING_GET_RESPONSE(&queue->rx,
585 queue->rx.rsp_prod_pvt++);
586
587 resp->flags |= XEN_NETRXF_extra_info;
588
589 gso->u.gso.type = queue->meta[npo.meta_cons].gso_type;
590 gso->u.gso.size = queue->meta[npo.meta_cons].gso_size;
591 gso->u.gso.pad = 0;
592 gso->u.gso.features = 0;
593
594 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
595 gso->flags = 0;
596 }
597
598 xenvif_add_frag_responses(queue, status,
599 queue->meta + npo.meta_cons + 1,
600 XENVIF_RX_CB(skb)->meta_slots_used);
601
602 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret);
603
604 need_to_notify |= !!ret;
605
606 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
607 dev_kfree_skb(skb);
608 }
609
610 done:
611 if (need_to_notify)
612 notify_remote_via_irq(queue->rx_irq);
613 }
614
615 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
616 {
617 int more_to_do;
618
619 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
620
621 if (more_to_do)
622 napi_schedule(&queue->napi);
623 }
624
625 static void tx_add_credit(struct xenvif_queue *queue)
626 {
627 unsigned long max_burst, max_credit;
628
629 /*
630 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
631 * Otherwise the interface can seize up due to insufficient credit.
632 */
633 max_burst = RING_GET_REQUEST(&queue->tx, queue->tx.req_cons)->size;
634 max_burst = min(max_burst, 131072UL);
635 max_burst = max(max_burst, queue->credit_bytes);
636
637 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
638 max_credit = queue->remaining_credit + queue->credit_bytes;
639 if (max_credit < queue->remaining_credit)
640 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
641
642 queue->remaining_credit = min(max_credit, max_burst);
643 }
644
645 static void tx_credit_callback(unsigned long data)
646 {
647 struct xenvif_queue *queue = (struct xenvif_queue *)data;
648 tx_add_credit(queue);
649 xenvif_napi_schedule_or_enable_events(queue);
650 }
651
652 static void xenvif_tx_err(struct xenvif_queue *queue,
653 struct xen_netif_tx_request *txp, RING_IDX end)
654 {
655 RING_IDX cons = queue->tx.req_cons;
656 unsigned long flags;
657
658 do {
659 spin_lock_irqsave(&queue->response_lock, flags);
660 make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
661 push_tx_responses(queue);
662 spin_unlock_irqrestore(&queue->response_lock, flags);
663 if (cons == end)
664 break;
665 txp = RING_GET_REQUEST(&queue->tx, cons++);
666 } while (1);
667 queue->tx.req_cons = cons;
668 }
669
670 static void xenvif_fatal_tx_err(struct xenvif *vif)
671 {
672 netdev_err(vif->dev, "fatal error; disabling device\n");
673 vif->disabled = true;
674 /* Disable the vif from queue 0's kthread */
675 if (vif->queues)
676 xenvif_kick_thread(&vif->queues[0]);
677 }
678
679 static int xenvif_count_requests(struct xenvif_queue *queue,
680 struct xen_netif_tx_request *first,
681 struct xen_netif_tx_request *txp,
682 int work_to_do)
683 {
684 RING_IDX cons = queue->tx.req_cons;
685 int slots = 0;
686 int drop_err = 0;
687 int more_data;
688
689 if (!(first->flags & XEN_NETTXF_more_data))
690 return 0;
691
692 do {
693 struct xen_netif_tx_request dropped_tx = { 0 };
694
695 if (slots >= work_to_do) {
696 netdev_err(queue->vif->dev,
697 "Asked for %d slots but exceeds this limit\n",
698 work_to_do);
699 xenvif_fatal_tx_err(queue->vif);
700 return -ENODATA;
701 }
702
703 /* This guest is really using too many slots and
704 * considered malicious.
705 */
706 if (unlikely(slots >= fatal_skb_slots)) {
707 netdev_err(queue->vif->dev,
708 "Malicious frontend using %d slots, threshold %u\n",
709 slots, fatal_skb_slots);
710 xenvif_fatal_tx_err(queue->vif);
711 return -E2BIG;
712 }
713
714 /* Xen network protocol had implicit dependency on
715 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
716 * the historical MAX_SKB_FRAGS value 18 to honor the
717 * same behavior as before. Any packet using more than
718 * 18 slots but less than fatal_skb_slots slots is
719 * dropped
720 */
721 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
722 if (net_ratelimit())
723 netdev_dbg(queue->vif->dev,
724 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
725 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
726 drop_err = -E2BIG;
727 }
728
729 if (drop_err)
730 txp = &dropped_tx;
731
732 memcpy(txp, RING_GET_REQUEST(&queue->tx, cons + slots),
733 sizeof(*txp));
734
735 /* If the guest submitted a frame >= 64 KiB then
736 * first->size overflowed and following slots will
737 * appear to be larger than the frame.
738 *
739 * This cannot be fatal error as there are buggy
740 * frontends that do this.
741 *
742 * Consume all slots and drop the packet.
743 */
744 if (!drop_err && txp->size > first->size) {
745 if (net_ratelimit())
746 netdev_dbg(queue->vif->dev,
747 "Invalid tx request, slot size %u > remaining size %u\n",
748 txp->size, first->size);
749 drop_err = -EIO;
750 }
751
752 first->size -= txp->size;
753 slots++;
754
755 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
756 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
757 txp->offset, txp->size);
758 xenvif_fatal_tx_err(queue->vif);
759 return -EINVAL;
760 }
761
762 more_data = txp->flags & XEN_NETTXF_more_data;
763
764 if (!drop_err)
765 txp++;
766
767 } while (more_data);
768
769 if (drop_err) {
770 xenvif_tx_err(queue, first, cons + slots);
771 return drop_err;
772 }
773
774 return slots;
775 }
776
777
778 struct xenvif_tx_cb {
779 u16 pending_idx;
780 };
781
782 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
783
784 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
785 u16 pending_idx,
786 struct xen_netif_tx_request *txp,
787 struct gnttab_map_grant_ref *mop)
788 {
789 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
790 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
791 GNTMAP_host_map | GNTMAP_readonly,
792 txp->gref, queue->vif->domid);
793
794 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
795 sizeof(*txp));
796 }
797
798 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
799 {
800 struct sk_buff *skb =
801 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
802 GFP_ATOMIC | __GFP_NOWARN);
803 if (unlikely(skb == NULL))
804 return NULL;
805
806 /* Packets passed to netif_rx() must have some headroom. */
807 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
808
809 /* Initialize it here to avoid later surprises */
810 skb_shinfo(skb)->destructor_arg = NULL;
811
812 return skb;
813 }
814
815 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
816 struct sk_buff *skb,
817 struct xen_netif_tx_request *txp,
818 struct gnttab_map_grant_ref *gop)
819 {
820 struct skb_shared_info *shinfo = skb_shinfo(skb);
821 skb_frag_t *frags = shinfo->frags;
822 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
823 int start;
824 pending_ring_idx_t index;
825 unsigned int nr_slots, frag_overflow = 0;
826
827 /* At this point shinfo->nr_frags is in fact the number of
828 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
829 */
830 if (shinfo->nr_frags > MAX_SKB_FRAGS) {
831 frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS;
832 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
833 shinfo->nr_frags = MAX_SKB_FRAGS;
834 }
835 nr_slots = shinfo->nr_frags;
836
837 /* Skip first skb fragment if it is on same page as header fragment. */
838 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
839
840 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
841 shinfo->nr_frags++, txp++, gop++) {
842 index = pending_index(queue->pending_cons++);
843 pending_idx = queue->pending_ring[index];
844 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
845 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
846 }
847
848 if (frag_overflow) {
849 struct sk_buff *nskb = xenvif_alloc_skb(0);
850 if (unlikely(nskb == NULL)) {
851 if (net_ratelimit())
852 netdev_err(queue->vif->dev,
853 "Can't allocate the frag_list skb.\n");
854 return NULL;
855 }
856
857 shinfo = skb_shinfo(nskb);
858 frags = shinfo->frags;
859
860 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
861 shinfo->nr_frags++, txp++, gop++) {
862 index = pending_index(queue->pending_cons++);
863 pending_idx = queue->pending_ring[index];
864 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
865 frag_set_pending_idx(&frags[shinfo->nr_frags],
866 pending_idx);
867 }
868
869 skb_shinfo(skb)->frag_list = nskb;
870 }
871
872 return gop;
873 }
874
875 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
876 u16 pending_idx,
877 grant_handle_t handle)
878 {
879 if (unlikely(queue->grant_tx_handle[pending_idx] !=
880 NETBACK_INVALID_HANDLE)) {
881 netdev_err(queue->vif->dev,
882 "Trying to overwrite active handle! pending_idx: %x\n",
883 pending_idx);
884 BUG();
885 }
886 queue->grant_tx_handle[pending_idx] = handle;
887 }
888
889 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
890 u16 pending_idx)
891 {
892 if (unlikely(queue->grant_tx_handle[pending_idx] ==
893 NETBACK_INVALID_HANDLE)) {
894 netdev_err(queue->vif->dev,
895 "Trying to unmap invalid handle! pending_idx: %x\n",
896 pending_idx);
897 BUG();
898 }
899 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
900 }
901
902 static int xenvif_tx_check_gop(struct xenvif_queue *queue,
903 struct sk_buff *skb,
904 struct gnttab_map_grant_ref **gopp_map,
905 struct gnttab_copy **gopp_copy)
906 {
907 struct gnttab_map_grant_ref *gop_map = *gopp_map;
908 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
909 /* This always points to the shinfo of the skb being checked, which
910 * could be either the first or the one on the frag_list
911 */
912 struct skb_shared_info *shinfo = skb_shinfo(skb);
913 /* If this is non-NULL, we are currently checking the frag_list skb, and
914 * this points to the shinfo of the first one
915 */
916 struct skb_shared_info *first_shinfo = NULL;
917 int nr_frags = shinfo->nr_frags;
918 const bool sharedslot = nr_frags &&
919 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
920 int i, err;
921
922 /* Check status of header. */
923 err = (*gopp_copy)->status;
924 if (unlikely(err)) {
925 if (net_ratelimit())
926 netdev_dbg(queue->vif->dev,
927 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
928 (*gopp_copy)->status,
929 pending_idx,
930 (*gopp_copy)->source.u.ref);
931 /* The first frag might still have this slot mapped */
932 if (!sharedslot)
933 xenvif_idx_release(queue, pending_idx,
934 XEN_NETIF_RSP_ERROR);
935 }
936 (*gopp_copy)++;
937
938 check_frags:
939 for (i = 0; i < nr_frags; i++, gop_map++) {
940 int j, newerr;
941
942 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
943
944 /* Check error status: if okay then remember grant handle. */
945 newerr = gop_map->status;
946
947 if (likely(!newerr)) {
948 xenvif_grant_handle_set(queue,
949 pending_idx,
950 gop_map->handle);
951 /* Had a previous error? Invalidate this fragment. */
952 if (unlikely(err)) {
953 xenvif_idx_unmap(queue, pending_idx);
954 /* If the mapping of the first frag was OK, but
955 * the header's copy failed, and they are
956 * sharing a slot, send an error
957 */
958 if (i == 0 && sharedslot)
959 xenvif_idx_release(queue, pending_idx,
960 XEN_NETIF_RSP_ERROR);
961 else
962 xenvif_idx_release(queue, pending_idx,
963 XEN_NETIF_RSP_OKAY);
964 }
965 continue;
966 }
967
968 /* Error on this fragment: respond to client with an error. */
969 if (net_ratelimit())
970 netdev_dbg(queue->vif->dev,
971 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
972 i,
973 gop_map->status,
974 pending_idx,
975 gop_map->ref);
976
977 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
978
979 /* Not the first error? Preceding frags already invalidated. */
980 if (err)
981 continue;
982
983 /* First error: if the header haven't shared a slot with the
984 * first frag, release it as well.
985 */
986 if (!sharedslot)
987 xenvif_idx_release(queue,
988 XENVIF_TX_CB(skb)->pending_idx,
989 XEN_NETIF_RSP_OKAY);
990
991 /* Invalidate preceding fragments of this skb. */
992 for (j = 0; j < i; j++) {
993 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
994 xenvif_idx_unmap(queue, pending_idx);
995 xenvif_idx_release(queue, pending_idx,
996 XEN_NETIF_RSP_OKAY);
997 }
998
999 /* And if we found the error while checking the frag_list, unmap
1000 * the first skb's frags
1001 */
1002 if (first_shinfo) {
1003 for (j = 0; j < first_shinfo->nr_frags; j++) {
1004 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
1005 xenvif_idx_unmap(queue, pending_idx);
1006 xenvif_idx_release(queue, pending_idx,
1007 XEN_NETIF_RSP_OKAY);
1008 }
1009 }
1010
1011 /* Remember the error: invalidate all subsequent fragments. */
1012 err = newerr;
1013 }
1014
1015 if (skb_has_frag_list(skb) && !first_shinfo) {
1016 first_shinfo = skb_shinfo(skb);
1017 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
1018 nr_frags = shinfo->nr_frags;
1019
1020 goto check_frags;
1021 }
1022
1023 *gopp_map = gop_map;
1024 return err;
1025 }
1026
1027 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
1028 {
1029 struct skb_shared_info *shinfo = skb_shinfo(skb);
1030 int nr_frags = shinfo->nr_frags;
1031 int i;
1032 u16 prev_pending_idx = INVALID_PENDING_IDX;
1033
1034 for (i = 0; i < nr_frags; i++) {
1035 skb_frag_t *frag = shinfo->frags + i;
1036 struct xen_netif_tx_request *txp;
1037 struct page *page;
1038 u16 pending_idx;
1039
1040 pending_idx = frag_get_pending_idx(frag);
1041
1042 /* If this is not the first frag, chain it to the previous*/
1043 if (prev_pending_idx == INVALID_PENDING_IDX)
1044 skb_shinfo(skb)->destructor_arg =
1045 &callback_param(queue, pending_idx);
1046 else
1047 callback_param(queue, prev_pending_idx).ctx =
1048 &callback_param(queue, pending_idx);
1049
1050 callback_param(queue, pending_idx).ctx = NULL;
1051 prev_pending_idx = pending_idx;
1052
1053 txp = &queue->pending_tx_info[pending_idx].req;
1054 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
1055 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1056 skb->len += txp->size;
1057 skb->data_len += txp->size;
1058 skb->truesize += txp->size;
1059
1060 /* Take an extra reference to offset network stack's put_page */
1061 get_page(queue->mmap_pages[pending_idx]);
1062 }
1063 }
1064
1065 static int xenvif_get_extras(struct xenvif_queue *queue,
1066 struct xen_netif_extra_info *extras,
1067 int work_to_do)
1068 {
1069 struct xen_netif_extra_info extra;
1070 RING_IDX cons = queue->tx.req_cons;
1071
1072 do {
1073 if (unlikely(work_to_do-- <= 0)) {
1074 netdev_err(queue->vif->dev, "Missing extra info\n");
1075 xenvif_fatal_tx_err(queue->vif);
1076 return -EBADR;
1077 }
1078
1079 memcpy(&extra, RING_GET_REQUEST(&queue->tx, cons),
1080 sizeof(extra));
1081 if (unlikely(!extra.type ||
1082 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1083 queue->tx.req_cons = ++cons;
1084 netdev_err(queue->vif->dev,
1085 "Invalid extra type: %d\n", extra.type);
1086 xenvif_fatal_tx_err(queue->vif);
1087 return -EINVAL;
1088 }
1089
1090 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1091 queue->tx.req_cons = ++cons;
1092 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1093
1094 return work_to_do;
1095 }
1096
1097 static int xenvif_set_skb_gso(struct xenvif *vif,
1098 struct sk_buff *skb,
1099 struct xen_netif_extra_info *gso)
1100 {
1101 if (!gso->u.gso.size) {
1102 netdev_err(vif->dev, "GSO size must not be zero.\n");
1103 xenvif_fatal_tx_err(vif);
1104 return -EINVAL;
1105 }
1106
1107 switch (gso->u.gso.type) {
1108 case XEN_NETIF_GSO_TYPE_TCPV4:
1109 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1110 break;
1111 case XEN_NETIF_GSO_TYPE_TCPV6:
1112 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1113 break;
1114 default:
1115 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1116 xenvif_fatal_tx_err(vif);
1117 return -EINVAL;
1118 }
1119
1120 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1121 /* gso_segs will be calculated later */
1122
1123 return 0;
1124 }
1125
1126 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
1127 {
1128 bool recalculate_partial_csum = false;
1129
1130 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1131 * peers can fail to set NETRXF_csum_blank when sending a GSO
1132 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1133 * recalculate the partial checksum.
1134 */
1135 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1136 queue->stats.rx_gso_checksum_fixup++;
1137 skb->ip_summed = CHECKSUM_PARTIAL;
1138 recalculate_partial_csum = true;
1139 }
1140
1141 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1142 if (skb->ip_summed != CHECKSUM_PARTIAL)
1143 return 0;
1144
1145 return skb_checksum_setup(skb, recalculate_partial_csum);
1146 }
1147
1148 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
1149 {
1150 u64 now = get_jiffies_64();
1151 u64 next_credit = queue->credit_window_start +
1152 msecs_to_jiffies(queue->credit_usec / 1000);
1153
1154 /* Timer could already be pending in rare cases. */
1155 if (timer_pending(&queue->credit_timeout))
1156 return true;
1157
1158 /* Passed the point where we can replenish credit? */
1159 if (time_after_eq64(now, next_credit)) {
1160 queue->credit_window_start = now;
1161 tx_add_credit(queue);
1162 }
1163
1164 /* Still too big to send right now? Set a callback. */
1165 if (size > queue->remaining_credit) {
1166 queue->credit_timeout.data =
1167 (unsigned long)queue;
1168 queue->credit_timeout.function =
1169 tx_credit_callback;
1170 mod_timer(&queue->credit_timeout,
1171 next_credit);
1172 queue->credit_window_start = next_credit;
1173
1174 return true;
1175 }
1176
1177 return false;
1178 }
1179
1180 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
1181 int budget,
1182 unsigned *copy_ops,
1183 unsigned *map_ops)
1184 {
1185 struct gnttab_map_grant_ref *gop = queue->tx_map_ops, *request_gop;
1186 struct sk_buff *skb;
1187 int ret;
1188
1189 while (skb_queue_len(&queue->tx_queue) < budget) {
1190 struct xen_netif_tx_request txreq;
1191 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1192 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1193 u16 pending_idx;
1194 RING_IDX idx;
1195 int work_to_do;
1196 unsigned int data_len;
1197 pending_ring_idx_t index;
1198
1199 if (queue->tx.sring->req_prod - queue->tx.req_cons >
1200 XEN_NETIF_TX_RING_SIZE) {
1201 netdev_err(queue->vif->dev,
1202 "Impossible number of requests. "
1203 "req_prod %d, req_cons %d, size %ld\n",
1204 queue->tx.sring->req_prod, queue->tx.req_cons,
1205 XEN_NETIF_TX_RING_SIZE);
1206 xenvif_fatal_tx_err(queue->vif);
1207 break;
1208 }
1209
1210 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
1211 if (!work_to_do)
1212 break;
1213
1214 idx = queue->tx.req_cons;
1215 rmb(); /* Ensure that we see the request before we copy it. */
1216 memcpy(&txreq, RING_GET_REQUEST(&queue->tx, idx), sizeof(txreq));
1217
1218 /* Credit-based scheduling. */
1219 if (txreq.size > queue->remaining_credit &&
1220 tx_credit_exceeded(queue, txreq.size))
1221 break;
1222
1223 queue->remaining_credit -= txreq.size;
1224
1225 work_to_do--;
1226 queue->tx.req_cons = ++idx;
1227
1228 memset(extras, 0, sizeof(extras));
1229 if (txreq.flags & XEN_NETTXF_extra_info) {
1230 work_to_do = xenvif_get_extras(queue, extras,
1231 work_to_do);
1232 idx = queue->tx.req_cons;
1233 if (unlikely(work_to_do < 0))
1234 break;
1235 }
1236
1237 ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
1238 if (unlikely(ret < 0))
1239 break;
1240
1241 idx += ret;
1242
1243 if (unlikely(txreq.size < ETH_HLEN)) {
1244 netdev_dbg(queue->vif->dev,
1245 "Bad packet size: %d\n", txreq.size);
1246 xenvif_tx_err(queue, &txreq, idx);
1247 break;
1248 }
1249
1250 /* No crossing a page as the payload mustn't fragment. */
1251 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1252 netdev_err(queue->vif->dev,
1253 "txreq.offset: %x, size: %u, end: %lu\n",
1254 txreq.offset, txreq.size,
1255 (txreq.offset&~PAGE_MASK) + txreq.size);
1256 xenvif_fatal_tx_err(queue->vif);
1257 break;
1258 }
1259
1260 index = pending_index(queue->pending_cons);
1261 pending_idx = queue->pending_ring[index];
1262
1263 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
1264 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1265 XEN_NETBACK_TX_COPY_LEN : txreq.size;
1266
1267 skb = xenvif_alloc_skb(data_len);
1268 if (unlikely(skb == NULL)) {
1269 netdev_dbg(queue->vif->dev,
1270 "Can't allocate a skb in start_xmit.\n");
1271 xenvif_tx_err(queue, &txreq, idx);
1272 break;
1273 }
1274
1275 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1276 struct xen_netif_extra_info *gso;
1277 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1278
1279 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1280 /* Failure in xenvif_set_skb_gso is fatal. */
1281 kfree_skb(skb);
1282 break;
1283 }
1284 }
1285
1286 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
1287
1288 __skb_put(skb, data_len);
1289 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
1290 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
1291 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
1292
1293 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
1294 virt_to_mfn(skb->data);
1295 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
1296 queue->tx_copy_ops[*copy_ops].dest.offset =
1297 offset_in_page(skb->data);
1298
1299 queue->tx_copy_ops[*copy_ops].len = data_len;
1300 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1301
1302 (*copy_ops)++;
1303
1304 skb_shinfo(skb)->nr_frags = ret;
1305 if (data_len < txreq.size) {
1306 skb_shinfo(skb)->nr_frags++;
1307 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1308 pending_idx);
1309 xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);
1310 gop++;
1311 } else {
1312 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1313 INVALID_PENDING_IDX);
1314 memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,
1315 sizeof(txreq));
1316 }
1317
1318 queue->pending_cons++;
1319
1320 request_gop = xenvif_get_requests(queue, skb, txfrags, gop);
1321 if (request_gop == NULL) {
1322 kfree_skb(skb);
1323 xenvif_tx_err(queue, &txreq, idx);
1324 break;
1325 }
1326 gop = request_gop;
1327
1328 __skb_queue_tail(&queue->tx_queue, skb);
1329
1330 queue->tx.req_cons = idx;
1331
1332 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1333 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1334 break;
1335 }
1336
1337 (*map_ops) = gop - queue->tx_map_ops;
1338 return;
1339 }
1340
1341 /* Consolidate skb with a frag_list into a brand new one with local pages on
1342 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1343 */
1344 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1345 {
1346 unsigned int offset = skb_headlen(skb);
1347 skb_frag_t frags[MAX_SKB_FRAGS];
1348 int i, f;
1349 struct ubuf_info *uarg;
1350 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1351
1352 queue->stats.tx_zerocopy_sent += 2;
1353 queue->stats.tx_frag_overflow++;
1354
1355 xenvif_fill_frags(queue, nskb);
1356 /* Subtract frags size, we will correct it later */
1357 skb->truesize -= skb->data_len;
1358 skb->len += nskb->len;
1359 skb->data_len += nskb->len;
1360
1361 /* create a brand new frags array and coalesce there */
1362 for (i = 0; offset < skb->len; i++) {
1363 struct page *page;
1364 unsigned int len;
1365
1366 BUG_ON(i >= MAX_SKB_FRAGS);
1367 page = alloc_page(GFP_ATOMIC);
1368 if (!page) {
1369 int j;
1370 skb->truesize += skb->data_len;
1371 for (j = 0; j < i; j++)
1372 put_page(frags[j].page.p);
1373 return -ENOMEM;
1374 }
1375
1376 if (offset + PAGE_SIZE < skb->len)
1377 len = PAGE_SIZE;
1378 else
1379 len = skb->len - offset;
1380 if (skb_copy_bits(skb, offset, page_address(page), len))
1381 BUG();
1382
1383 offset += len;
1384 frags[i].page.p = page;
1385 frags[i].page_offset = 0;
1386 skb_frag_size_set(&frags[i], len);
1387 }
1388
1389 /* Copied all the bits from the frag list -- free it. */
1390 skb_frag_list_init(skb);
1391 xenvif_skb_zerocopy_prepare(queue, nskb);
1392 kfree_skb(nskb);
1393
1394 /* Release all the original (foreign) frags. */
1395 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1396 skb_frag_unref(skb, f);
1397 uarg = skb_shinfo(skb)->destructor_arg;
1398 /* increase inflight counter to offset decrement in callback */
1399 atomic_inc(&queue->inflight_packets);
1400 uarg->callback(uarg, true);
1401 skb_shinfo(skb)->destructor_arg = NULL;
1402
1403 /* Fill the skb with the new (local) frags. */
1404 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1405 skb_shinfo(skb)->nr_frags = i;
1406 skb->truesize += i * PAGE_SIZE;
1407
1408 return 0;
1409 }
1410
1411 static int xenvif_tx_submit(struct xenvif_queue *queue)
1412 {
1413 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1414 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1415 struct sk_buff *skb;
1416 int work_done = 0;
1417
1418 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1419 struct xen_netif_tx_request *txp;
1420 u16 pending_idx;
1421 unsigned data_len;
1422
1423 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1424 txp = &queue->pending_tx_info[pending_idx].req;
1425
1426 /* Check the remap error code. */
1427 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1428 /* If there was an error, xenvif_tx_check_gop is
1429 * expected to release all the frags which were mapped,
1430 * so kfree_skb shouldn't do it again
1431 */
1432 skb_shinfo(skb)->nr_frags = 0;
1433 if (skb_has_frag_list(skb)) {
1434 struct sk_buff *nskb =
1435 skb_shinfo(skb)->frag_list;
1436 skb_shinfo(nskb)->nr_frags = 0;
1437 }
1438 kfree_skb(skb);
1439 continue;
1440 }
1441
1442 data_len = skb->len;
1443 callback_param(queue, pending_idx).ctx = NULL;
1444 if (data_len < txp->size) {
1445 /* Append the packet payload as a fragment. */
1446 txp->offset += data_len;
1447 txp->size -= data_len;
1448 } else {
1449 /* Schedule a response immediately. */
1450 xenvif_idx_release(queue, pending_idx,
1451 XEN_NETIF_RSP_OKAY);
1452 }
1453
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;
1458
1459 xenvif_fill_frags(queue, skb);
1460
1461 if (unlikely(skb_has_frag_list(skb))) {
1462 if (xenvif_handle_frag_list(queue, skb)) {
1463 if (net_ratelimit())
1464 netdev_err(queue->vif->dev,
1465 "Not enough memory to consolidate frag_list!\n");
1466 xenvif_skb_zerocopy_prepare(queue, skb);
1467 kfree_skb(skb);
1468 continue;
1469 }
1470 }
1471
1472 skb->dev = queue->vif->dev;
1473 skb->protocol = eth_type_trans(skb, skb->dev);
1474 skb_reset_network_header(skb);
1475
1476 if (checksum_setup(queue, skb)) {
1477 netdev_dbg(queue->vif->dev,
1478 "Can't setup checksum in net_tx_action\n");
1479 /* We have to set this flag to trigger the callback */
1480 if (skb_shinfo(skb)->destructor_arg)
1481 xenvif_skb_zerocopy_prepare(queue, skb);
1482 kfree_skb(skb);
1483 continue;
1484 }
1485
1486 skb_probe_transport_header(skb, 0);
1487
1488 /* If the packet is GSO then we will have just set up the
1489 * transport header offset in checksum_setup so it's now
1490 * straightforward to calculate gso_segs.
1491 */
1492 if (skb_is_gso(skb)) {
1493 int mss = skb_shinfo(skb)->gso_size;
1494 int hdrlen = skb_transport_header(skb) -
1495 skb_mac_header(skb) +
1496 tcp_hdrlen(skb);
1497
1498 skb_shinfo(skb)->gso_segs =
1499 DIV_ROUND_UP(skb->len - hdrlen, mss);
1500 }
1501
1502 queue->stats.rx_bytes += skb->len;
1503 queue->stats.rx_packets++;
1504
1505 work_done++;
1506
1507 /* Set this flag right before netif_receive_skb, otherwise
1508 * someone might think this packet already left netback, and
1509 * do a skb_copy_ubufs while we are still in control of the
1510 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1511 */
1512 if (skb_shinfo(skb)->destructor_arg) {
1513 xenvif_skb_zerocopy_prepare(queue, skb);
1514 queue->stats.tx_zerocopy_sent++;
1515 }
1516
1517 netif_receive_skb(skb);
1518 }
1519
1520 return work_done;
1521 }
1522
1523 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1524 {
1525 unsigned long flags;
1526 pending_ring_idx_t index;
1527 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1528
1529 /* This is the only place where we grab this lock, to protect callbacks
1530 * from each other.
1531 */
1532 spin_lock_irqsave(&queue->callback_lock, flags);
1533 do {
1534 u16 pending_idx = ubuf->desc;
1535 ubuf = (struct ubuf_info *) ubuf->ctx;
1536 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1537 MAX_PENDING_REQS);
1538 index = pending_index(queue->dealloc_prod);
1539 queue->dealloc_ring[index] = pending_idx;
1540 /* Sync with xenvif_tx_dealloc_action:
1541 * insert idx then incr producer.
1542 */
1543 smp_wmb();
1544 queue->dealloc_prod++;
1545 } while (ubuf);
1546 wake_up(&queue->dealloc_wq);
1547 spin_unlock_irqrestore(&queue->callback_lock, flags);
1548
1549 if (likely(zerocopy_success))
1550 queue->stats.tx_zerocopy_success++;
1551 else
1552 queue->stats.tx_zerocopy_fail++;
1553 xenvif_skb_zerocopy_complete(queue);
1554 }
1555
1556 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1557 {
1558 struct gnttab_unmap_grant_ref *gop;
1559 pending_ring_idx_t dc, dp;
1560 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1561 unsigned int i = 0;
1562
1563 dc = queue->dealloc_cons;
1564 gop = queue->tx_unmap_ops;
1565
1566 /* Free up any grants we have finished using */
1567 do {
1568 dp = queue->dealloc_prod;
1569
1570 /* Ensure we see all indices enqueued by all
1571 * xenvif_zerocopy_callback().
1572 */
1573 smp_rmb();
1574
1575 while (dc != dp) {
1576 BUG_ON(gop - queue->tx_unmap_ops > MAX_PENDING_REQS);
1577 pending_idx =
1578 queue->dealloc_ring[pending_index(dc++)];
1579
1580 pending_idx_release[gop-queue->tx_unmap_ops] =
1581 pending_idx;
1582 queue->pages_to_unmap[gop-queue->tx_unmap_ops] =
1583 queue->mmap_pages[pending_idx];
1584 gnttab_set_unmap_op(gop,
1585 idx_to_kaddr(queue, pending_idx),
1586 GNTMAP_host_map,
1587 queue->grant_tx_handle[pending_idx]);
1588 xenvif_grant_handle_reset(queue, pending_idx);
1589 ++gop;
1590 }
1591
1592 } while (dp != queue->dealloc_prod);
1593
1594 queue->dealloc_cons = dc;
1595
1596 if (gop - queue->tx_unmap_ops > 0) {
1597 int ret;
1598 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1599 NULL,
1600 queue->pages_to_unmap,
1601 gop - queue->tx_unmap_ops);
1602 if (ret) {
1603 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tx ret %d\n",
1604 gop - queue->tx_unmap_ops, ret);
1605 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1606 if (gop[i].status != GNTST_okay)
1607 netdev_err(queue->vif->dev,
1608 " host_addr: %llx handle: %x status: %d\n",
1609 gop[i].host_addr,
1610 gop[i].handle,
1611 gop[i].status);
1612 }
1613 BUG();
1614 }
1615 }
1616
1617 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1618 xenvif_idx_release(queue, pending_idx_release[i],
1619 XEN_NETIF_RSP_OKAY);
1620 }
1621
1622
1623 /* Called after netfront has transmitted */
1624 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1625 {
1626 unsigned nr_mops, nr_cops = 0;
1627 int work_done, ret;
1628
1629 if (unlikely(!tx_work_todo(queue)))
1630 return 0;
1631
1632 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1633
1634 if (nr_cops == 0)
1635 return 0;
1636
1637 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1638 if (nr_mops != 0) {
1639 ret = gnttab_map_refs(queue->tx_map_ops,
1640 NULL,
1641 queue->pages_to_map,
1642 nr_mops);
1643 BUG_ON(ret);
1644 }
1645
1646 work_done = xenvif_tx_submit(queue);
1647
1648 return work_done;
1649 }
1650
1651 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1652 u8 status)
1653 {
1654 struct pending_tx_info *pending_tx_info;
1655 pending_ring_idx_t index;
1656 unsigned long flags;
1657
1658 pending_tx_info = &queue->pending_tx_info[pending_idx];
1659
1660 spin_lock_irqsave(&queue->response_lock, flags);
1661
1662 make_tx_response(queue, &pending_tx_info->req, status);
1663
1664 /* Release the pending index before pusing the Tx response so
1665 * its available before a new Tx request is pushed by the
1666 * frontend.
1667 */
1668 index = pending_index(queue->pending_prod++);
1669 queue->pending_ring[index] = pending_idx;
1670
1671 push_tx_responses(queue);
1672
1673 spin_unlock_irqrestore(&queue->response_lock, flags);
1674 }
1675
1676
1677 static void make_tx_response(struct xenvif_queue *queue,
1678 struct xen_netif_tx_request *txp,
1679 s8 st)
1680 {
1681 RING_IDX i = queue->tx.rsp_prod_pvt;
1682 struct xen_netif_tx_response *resp;
1683
1684 resp = RING_GET_RESPONSE(&queue->tx, i);
1685 resp->id = txp->id;
1686 resp->status = st;
1687
1688 if (txp->flags & XEN_NETTXF_extra_info)
1689 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1690
1691 queue->tx.rsp_prod_pvt = ++i;
1692 }
1693
1694 static void push_tx_responses(struct xenvif_queue *queue)
1695 {
1696 int notify;
1697
1698 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1699 if (notify)
1700 notify_remote_via_irq(queue->tx_irq);
1701 }
1702
1703 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
1704 u16 id,
1705 s8 st,
1706 u16 offset,
1707 u16 size,
1708 u16 flags)
1709 {
1710 RING_IDX i = queue->rx.rsp_prod_pvt;
1711 struct xen_netif_rx_response *resp;
1712
1713 resp = RING_GET_RESPONSE(&queue->rx, i);
1714 resp->offset = offset;
1715 resp->flags = flags;
1716 resp->id = id;
1717 resp->status = (s16)size;
1718 if (st < 0)
1719 resp->status = (s16)st;
1720
1721 queue->rx.rsp_prod_pvt = ++i;
1722
1723 return resp;
1724 }
1725
1726 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1727 {
1728 int ret;
1729 struct gnttab_unmap_grant_ref tx_unmap_op;
1730
1731 gnttab_set_unmap_op(&tx_unmap_op,
1732 idx_to_kaddr(queue, pending_idx),
1733 GNTMAP_host_map,
1734 queue->grant_tx_handle[pending_idx]);
1735 xenvif_grant_handle_reset(queue, pending_idx);
1736
1737 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1738 &queue->mmap_pages[pending_idx], 1);
1739 if (ret) {
1740 netdev_err(queue->vif->dev,
1741 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: %x status: %d\n",
1742 ret,
1743 pending_idx,
1744 tx_unmap_op.host_addr,
1745 tx_unmap_op.handle,
1746 tx_unmap_op.status);
1747 BUG();
1748 }
1749 }
1750
1751 static inline int tx_work_todo(struct xenvif_queue *queue)
1752 {
1753 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1754 return 1;
1755
1756 return 0;
1757 }
1758
1759 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1760 {
1761 return queue->dealloc_cons != queue->dealloc_prod;
1762 }
1763
1764 void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
1765 {
1766 if (queue->tx.sring)
1767 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1768 queue->tx.sring);
1769 if (queue->rx.sring)
1770 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1771 queue->rx.sring);
1772 }
1773
1774 int xenvif_map_frontend_rings(struct xenvif_queue *queue,
1775 grant_ref_t tx_ring_ref,
1776 grant_ref_t rx_ring_ref)
1777 {
1778 void *addr;
1779 struct xen_netif_tx_sring *txs;
1780 struct xen_netif_rx_sring *rxs;
1781
1782 int err = -ENOMEM;
1783
1784 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1785 tx_ring_ref, &addr);
1786 if (err)
1787 goto err;
1788
1789 txs = (struct xen_netif_tx_sring *)addr;
1790 BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE);
1791
1792 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1793 rx_ring_ref, &addr);
1794 if (err)
1795 goto err;
1796
1797 rxs = (struct xen_netif_rx_sring *)addr;
1798 BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE);
1799
1800 return 0;
1801
1802 err:
1803 xenvif_unmap_frontend_rings(queue);
1804 return err;
1805 }
1806
1807 static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
1808 {
1809 struct xenvif *vif = queue->vif;
1810
1811 queue->stalled = true;
1812
1813 /* At least one queue has stalled? Disable the carrier. */
1814 spin_lock(&vif->lock);
1815 if (vif->stalled_queues++ == 0) {
1816 netdev_info(vif->dev, "Guest Rx stalled");
1817 netif_carrier_off(vif->dev);
1818 }
1819 spin_unlock(&vif->lock);
1820 }
1821
1822 static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
1823 {
1824 struct xenvif *vif = queue->vif;
1825
1826 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
1827 queue->stalled = false;
1828
1829 /* All queues are ready? Enable the carrier. */
1830 spin_lock(&vif->lock);
1831 if (--vif->stalled_queues == 0) {
1832 netdev_info(vif->dev, "Guest Rx ready");
1833 netif_carrier_on(vif->dev);
1834 }
1835 spin_unlock(&vif->lock);
1836 }
1837
1838 static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
1839 {
1840 RING_IDX prod, cons;
1841
1842 prod = queue->rx.sring->req_prod;
1843 cons = queue->rx.req_cons;
1844
1845 return !queue->stalled
1846 && prod - cons < XEN_NETBK_RX_SLOTS_MAX
1847 && time_after(jiffies,
1848 queue->last_rx_time + queue->vif->stall_timeout);
1849 }
1850
1851 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
1852 {
1853 RING_IDX prod, cons;
1854
1855 prod = queue->rx.sring->req_prod;
1856 cons = queue->rx.req_cons;
1857
1858 return queue->stalled
1859 && prod - cons >= XEN_NETBK_RX_SLOTS_MAX;
1860 }
1861
1862 static bool xenvif_have_rx_work(struct xenvif_queue *queue)
1863 {
1864 return (!skb_queue_empty(&queue->rx_queue)
1865 && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX))
1866 || (queue->vif->stall_timeout &&
1867 (xenvif_rx_queue_stalled(queue)
1868 || xenvif_rx_queue_ready(queue)))
1869 || kthread_should_stop()
1870 || queue->vif->disabled;
1871 }
1872
1873 static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
1874 {
1875 struct sk_buff *skb;
1876 long timeout;
1877
1878 skb = skb_peek(&queue->rx_queue);
1879 if (!skb)
1880 return MAX_SCHEDULE_TIMEOUT;
1881
1882 timeout = XENVIF_RX_CB(skb)->expires - jiffies;
1883 return timeout < 0 ? 0 : timeout;
1884 }
1885
1886 /* Wait until the guest Rx thread has work.
1887 *
1888 * The timeout needs to be adjusted based on the current head of the
1889 * queue (and not just the head at the beginning). In particular, if
1890 * the queue is initially empty an infinite timeout is used and this
1891 * needs to be reduced when a skb is queued.
1892 *
1893 * This cannot be done with wait_event_timeout() because it only
1894 * calculates the timeout once.
1895 */
1896 static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
1897 {
1898 DEFINE_WAIT(wait);
1899
1900 if (xenvif_have_rx_work(queue))
1901 return;
1902
1903 for (;;) {
1904 long ret;
1905
1906 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
1907 if (xenvif_have_rx_work(queue))
1908 break;
1909 ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
1910 if (!ret)
1911 break;
1912 }
1913 finish_wait(&queue->wq, &wait);
1914 }
1915
1916 int xenvif_kthread_guest_rx(void *data)
1917 {
1918 struct xenvif_queue *queue = data;
1919 struct xenvif *vif = queue->vif;
1920
1921 if (!vif->stall_timeout)
1922 xenvif_queue_carrier_on(queue);
1923
1924 for (;;) {
1925 xenvif_wait_for_rx_work(queue);
1926
1927 if (kthread_should_stop())
1928 break;
1929
1930 /* This frontend is found to be rogue, disable it in
1931 * kthread context. Currently this is only set when
1932 * netback finds out frontend sends malformed packet,
1933 * but we cannot disable the interface in softirq
1934 * context so we defer it here, if this thread is
1935 * associated with queue 0.
1936 */
1937 if (unlikely(vif->disabled && queue->id == 0)) {
1938 xenvif_carrier_off(vif);
1939 break;
1940 }
1941
1942 if (!skb_queue_empty(&queue->rx_queue))
1943 xenvif_rx_action(queue);
1944
1945 /* If the guest hasn't provided any Rx slots for a
1946 * while it's probably not responsive, drop the
1947 * carrier so packets are dropped earlier.
1948 */
1949 if (vif->stall_timeout) {
1950 if (xenvif_rx_queue_stalled(queue))
1951 xenvif_queue_carrier_off(queue);
1952 else if (xenvif_rx_queue_ready(queue))
1953 xenvif_queue_carrier_on(queue);
1954 }
1955
1956 /* Queued packets may have foreign pages from other
1957 * domains. These cannot be queued indefinitely as
1958 * this would starve guests of grant refs and transmit
1959 * slots.
1960 */
1961 xenvif_rx_queue_drop_expired(queue);
1962
1963 xenvif_rx_queue_maybe_wake(queue);
1964
1965 cond_resched();
1966 }
1967
1968 /* Bin any remaining skbs */
1969 xenvif_rx_queue_purge(queue);
1970
1971 return 0;
1972 }
1973
1974 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1975 {
1976 /* Dealloc thread must remain running until all inflight
1977 * packets complete.
1978 */
1979 return kthread_should_stop() &&
1980 !atomic_read(&queue->inflight_packets);
1981 }
1982
1983 int xenvif_dealloc_kthread(void *data)
1984 {
1985 struct xenvif_queue *queue = data;
1986
1987 for (;;) {
1988 wait_event_interruptible(queue->dealloc_wq,
1989 tx_dealloc_work_todo(queue) ||
1990 xenvif_dealloc_kthread_should_stop(queue));
1991 if (xenvif_dealloc_kthread_should_stop(queue))
1992 break;
1993
1994 xenvif_tx_dealloc_action(queue);
1995 cond_resched();
1996 }
1997
1998 /* Unmap anything remaining*/
1999 if (tx_dealloc_work_todo(queue))
2000 xenvif_tx_dealloc_action(queue);
2001
2002 return 0;
2003 }
2004
2005 static int __init netback_init(void)
2006 {
2007 int rc = 0;
2008
2009 if (!xen_domain())
2010 return -ENODEV;
2011
2012 /* Allow as many queues as there are CPUs, by default */
2013 xenvif_max_queues = num_online_cpus();
2014
2015 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
2016 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
2017 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
2018 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
2019 }
2020
2021 rc = xenvif_xenbus_init();
2022 if (rc)
2023 goto failed_init;
2024
2025 #ifdef CONFIG_DEBUG_FS
2026 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
2027 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
2028 pr_warn("Init of debugfs returned %ld!\n",
2029 PTR_ERR(xen_netback_dbg_root));
2030 #endif /* CONFIG_DEBUG_FS */
2031
2032 return 0;
2033
2034 failed_init:
2035 return rc;
2036 }
2037
2038 module_init(netback_init);
2039
2040 static void __exit netback_fini(void)
2041 {
2042 #ifdef CONFIG_DEBUG_FS
2043 if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
2044 debugfs_remove_recursive(xen_netback_dbg_root);
2045 #endif /* CONFIG_DEBUG_FS */
2046 xenvif_xenbus_fini();
2047 }
2048 module_exit(netback_fini);
2049
2050 MODULE_LICENSE("Dual BSD/GPL");
2051 MODULE_ALIAS("xen-backend:vif");
Linux kernel - Deliverables
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