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Merge tag 'microblaze-4.0-rc4' of git://git.monstr.eu/linux-2.6-microblaze
[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
100 static inline int tx_work_todo(struct xenvif_queue *queue);
101
102 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
103 u16 id,
104 s8 st,
105 u16 offset,
106 u16 size,
107 u16 flags);
108
109 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
110 u16 idx)
111 {
112 return page_to_pfn(queue->mmap_pages[idx]);
113 }
114
115 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
116 u16 idx)
117 {
118 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
119 }
120
121 #define callback_param(vif, pending_idx) \
122 (vif->pending_tx_info[pending_idx].callback_struct)
123
124 /* Find the containing VIF's structure from a pointer in pending_tx_info array
125 */
126 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
127 {
128 u16 pending_idx = ubuf->desc;
129 struct pending_tx_info *temp =
130 container_of(ubuf, struct pending_tx_info, callback_struct);
131 return container_of(temp - pending_idx,
132 struct xenvif_queue,
133 pending_tx_info[0]);
134 }
135
136 static u16 frag_get_pending_idx(skb_frag_t *frag)
137 {
138 return (u16)frag->page_offset;
139 }
140
141 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
142 {
143 frag->page_offset = pending_idx;
144 }
145
146 static inline pending_ring_idx_t pending_index(unsigned i)
147 {
148 return i & (MAX_PENDING_REQS-1);
149 }
150
151 bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed)
152 {
153 RING_IDX prod, cons;
154
155 do {
156 prod = queue->rx.sring->req_prod;
157 cons = queue->rx.req_cons;
158
159 if (prod - cons >= needed)
160 return true;
161
162 queue->rx.sring->req_event = prod + 1;
163
164 /* Make sure event is visible before we check prod
165 * again.
166 */
167 mb();
168 } while (queue->rx.sring->req_prod != prod);
169
170 return false;
171 }
172
173 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
174 {
175 unsigned long flags;
176
177 spin_lock_irqsave(&queue->rx_queue.lock, flags);
178
179 __skb_queue_tail(&queue->rx_queue, skb);
180
181 queue->rx_queue_len += skb->len;
182 if (queue->rx_queue_len > queue->rx_queue_max)
183 netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
184
185 spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
186 }
187
188 static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
189 {
190 struct sk_buff *skb;
191
192 spin_lock_irq(&queue->rx_queue.lock);
193
194 skb = __skb_dequeue(&queue->rx_queue);
195 if (skb)
196 queue->rx_queue_len -= skb->len;
197
198 spin_unlock_irq(&queue->rx_queue.lock);
199
200 return skb;
201 }
202
203 static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue)
204 {
205 spin_lock_irq(&queue->rx_queue.lock);
206
207 if (queue->rx_queue_len < queue->rx_queue_max)
208 netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
209
210 spin_unlock_irq(&queue->rx_queue.lock);
211 }
212
213
214 static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
215 {
216 struct sk_buff *skb;
217 while ((skb = xenvif_rx_dequeue(queue)) != NULL)
218 kfree_skb(skb);
219 }
220
221 static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
222 {
223 struct sk_buff *skb;
224
225 for(;;) {
226 skb = skb_peek(&queue->rx_queue);
227 if (!skb)
228 break;
229 if (time_before(jiffies, XENVIF_RX_CB(skb)->expires))
230 break;
231 xenvif_rx_dequeue(queue);
232 kfree_skb(skb);
233 }
234 }
235
236 struct netrx_pending_operations {
237 unsigned copy_prod, copy_cons;
238 unsigned meta_prod, meta_cons;
239 struct gnttab_copy *copy;
240 struct xenvif_rx_meta *meta;
241 int copy_off;
242 grant_ref_t copy_gref;
243 };
244
245 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue,
246 struct netrx_pending_operations *npo)
247 {
248 struct xenvif_rx_meta *meta;
249 struct xen_netif_rx_request *req;
250
251 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
252
253 meta = npo->meta + npo->meta_prod++;
254 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
255 meta->gso_size = 0;
256 meta->size = 0;
257 meta->id = req->id;
258
259 npo->copy_off = 0;
260 npo->copy_gref = req->gref;
261
262 return meta;
263 }
264
265 /*
266 * Set up the grant operations for this fragment. If it's a flipping
267 * interface, we also set up the unmap request from here.
268 */
269 static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb,
270 struct netrx_pending_operations *npo,
271 struct page *page, unsigned long size,
272 unsigned long offset, int *head)
273 {
274 struct gnttab_copy *copy_gop;
275 struct xenvif_rx_meta *meta;
276 unsigned long bytes;
277 int gso_type = XEN_NETIF_GSO_TYPE_NONE;
278
279 /* Data must not cross a page boundary. */
280 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
281
282 meta = npo->meta + npo->meta_prod - 1;
283
284 /* Skip unused frames from start of page */
285 page += offset >> PAGE_SHIFT;
286 offset &= ~PAGE_MASK;
287
288 while (size > 0) {
289 struct xen_page_foreign *foreign;
290
291 BUG_ON(offset >= PAGE_SIZE);
292 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
293
294 if (npo->copy_off == MAX_BUFFER_OFFSET)
295 meta = get_next_rx_buffer(queue, npo);
296
297 bytes = PAGE_SIZE - offset;
298 if (bytes > size)
299 bytes = size;
300
301 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
302 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
303
304 copy_gop = npo->copy + npo->copy_prod++;
305 copy_gop->flags = GNTCOPY_dest_gref;
306 copy_gop->len = bytes;
307
308 foreign = xen_page_foreign(page);
309 if (foreign) {
310 copy_gop->source.domid = foreign->domid;
311 copy_gop->source.u.ref = foreign->gref;
312 copy_gop->flags |= GNTCOPY_source_gref;
313 } else {
314 copy_gop->source.domid = DOMID_SELF;
315 copy_gop->source.u.gmfn =
316 virt_to_mfn(page_address(page));
317 }
318 copy_gop->source.offset = offset;
319
320 copy_gop->dest.domid = queue->vif->domid;
321 copy_gop->dest.offset = npo->copy_off;
322 copy_gop->dest.u.ref = npo->copy_gref;
323
324 npo->copy_off += bytes;
325 meta->size += bytes;
326
327 offset += bytes;
328 size -= bytes;
329
330 /* Next frame */
331 if (offset == PAGE_SIZE && size) {
332 BUG_ON(!PageCompound(page));
333 page++;
334 offset = 0;
335 }
336
337 /* Leave a gap for the GSO descriptor. */
338 if (skb_is_gso(skb)) {
339 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
340 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
341 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
342 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
343 }
344
345 if (*head && ((1 << gso_type) & queue->vif->gso_mask))
346 queue->rx.req_cons++;
347
348 *head = 0; /* There must be something in this buffer now. */
349
350 }
351 }
352
353 /*
354 * Prepare an SKB to be transmitted to the frontend.
355 *
356 * This function is responsible for allocating grant operations, meta
357 * structures, etc.
358 *
359 * It returns the number of meta structures consumed. The number of
360 * ring slots used is always equal to the number of meta slots used
361 * plus the number of GSO descriptors used. Currently, we use either
362 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
363 * frontend-side LRO).
364 */
365 static int xenvif_gop_skb(struct sk_buff *skb,
366 struct netrx_pending_operations *npo,
367 struct xenvif_queue *queue)
368 {
369 struct xenvif *vif = netdev_priv(skb->dev);
370 int nr_frags = skb_shinfo(skb)->nr_frags;
371 int i;
372 struct xen_netif_rx_request *req;
373 struct xenvif_rx_meta *meta;
374 unsigned char *data;
375 int head = 1;
376 int old_meta_prod;
377 int gso_type;
378
379 old_meta_prod = npo->meta_prod;
380
381 gso_type = XEN_NETIF_GSO_TYPE_NONE;
382 if (skb_is_gso(skb)) {
383 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
384 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
385 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
386 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
387 }
388
389 /* Set up a GSO prefix descriptor, if necessary */
390 if ((1 << gso_type) & vif->gso_prefix_mask) {
391 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
392 meta = npo->meta + npo->meta_prod++;
393 meta->gso_type = gso_type;
394 meta->gso_size = skb_shinfo(skb)->gso_size;
395 meta->size = 0;
396 meta->id = req->id;
397 }
398
399 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++);
400 meta = npo->meta + npo->meta_prod++;
401
402 if ((1 << gso_type) & vif->gso_mask) {
403 meta->gso_type = gso_type;
404 meta->gso_size = skb_shinfo(skb)->gso_size;
405 } else {
406 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
407 meta->gso_size = 0;
408 }
409
410 meta->size = 0;
411 meta->id = req->id;
412 npo->copy_off = 0;
413 npo->copy_gref = req->gref;
414
415 data = skb->data;
416 while (data < skb_tail_pointer(skb)) {
417 unsigned int offset = offset_in_page(data);
418 unsigned int len = PAGE_SIZE - offset;
419
420 if (data + len > skb_tail_pointer(skb))
421 len = skb_tail_pointer(skb) - data;
422
423 xenvif_gop_frag_copy(queue, skb, npo,
424 virt_to_page(data), len, offset, &head);
425 data += len;
426 }
427
428 for (i = 0; i < nr_frags; i++) {
429 xenvif_gop_frag_copy(queue, skb, npo,
430 skb_frag_page(&skb_shinfo(skb)->frags[i]),
431 skb_frag_size(&skb_shinfo(skb)->frags[i]),
432 skb_shinfo(skb)->frags[i].page_offset,
433 &head);
434 }
435
436 return npo->meta_prod - old_meta_prod;
437 }
438
439 /*
440 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
441 * used to set up the operations on the top of
442 * netrx_pending_operations, which have since been done. Check that
443 * they didn't give any errors and advance over them.
444 */
445 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
446 struct netrx_pending_operations *npo)
447 {
448 struct gnttab_copy *copy_op;
449 int status = XEN_NETIF_RSP_OKAY;
450 int i;
451
452 for (i = 0; i < nr_meta_slots; i++) {
453 copy_op = npo->copy + npo->copy_cons++;
454 if (copy_op->status != GNTST_okay) {
455 netdev_dbg(vif->dev,
456 "Bad status %d from copy to DOM%d.\n",
457 copy_op->status, vif->domid);
458 status = XEN_NETIF_RSP_ERROR;
459 }
460 }
461
462 return status;
463 }
464
465 static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status,
466 struct xenvif_rx_meta *meta,
467 int nr_meta_slots)
468 {
469 int i;
470 unsigned long offset;
471
472 /* No fragments used */
473 if (nr_meta_slots <= 1)
474 return;
475
476 nr_meta_slots--;
477
478 for (i = 0; i < nr_meta_slots; i++) {
479 int flags;
480 if (i == nr_meta_slots - 1)
481 flags = 0;
482 else
483 flags = XEN_NETRXF_more_data;
484
485 offset = 0;
486 make_rx_response(queue, meta[i].id, status, offset,
487 meta[i].size, flags);
488 }
489 }
490
491 void xenvif_kick_thread(struct xenvif_queue *queue)
492 {
493 wake_up(&queue->wq);
494 }
495
496 static void xenvif_rx_action(struct xenvif_queue *queue)
497 {
498 s8 status;
499 u16 flags;
500 struct xen_netif_rx_response *resp;
501 struct sk_buff_head rxq;
502 struct sk_buff *skb;
503 LIST_HEAD(notify);
504 int ret;
505 unsigned long offset;
506 bool need_to_notify = false;
507
508 struct netrx_pending_operations npo = {
509 .copy = queue->grant_copy_op,
510 .meta = queue->meta,
511 };
512
513 skb_queue_head_init(&rxq);
514
515 while (xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX)
516 && (skb = xenvif_rx_dequeue(queue)) != NULL) {
517 RING_IDX old_req_cons;
518 RING_IDX ring_slots_used;
519
520 queue->last_rx_time = jiffies;
521
522 old_req_cons = queue->rx.req_cons;
523 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
524 ring_slots_used = queue->rx.req_cons - old_req_cons;
525
526 __skb_queue_tail(&rxq, skb);
527 }
528
529 BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
530
531 if (!npo.copy_prod)
532 goto done;
533
534 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
535 gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
536
537 while ((skb = __skb_dequeue(&rxq)) != NULL) {
538
539 if ((1 << queue->meta[npo.meta_cons].gso_type) &
540 queue->vif->gso_prefix_mask) {
541 resp = RING_GET_RESPONSE(&queue->rx,
542 queue->rx.rsp_prod_pvt++);
543
544 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
545
546 resp->offset = queue->meta[npo.meta_cons].gso_size;
547 resp->id = queue->meta[npo.meta_cons].id;
548 resp->status = XENVIF_RX_CB(skb)->meta_slots_used;
549
550 npo.meta_cons++;
551 XENVIF_RX_CB(skb)->meta_slots_used--;
552 }
553
554
555 queue->stats.tx_bytes += skb->len;
556 queue->stats.tx_packets++;
557
558 status = xenvif_check_gop(queue->vif,
559 XENVIF_RX_CB(skb)->meta_slots_used,
560 &npo);
561
562 if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
563 flags = 0;
564 else
565 flags = XEN_NETRXF_more_data;
566
567 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
568 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
569 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
570 /* remote but checksummed. */
571 flags |= XEN_NETRXF_data_validated;
572
573 offset = 0;
574 resp = make_rx_response(queue, queue->meta[npo.meta_cons].id,
575 status, offset,
576 queue->meta[npo.meta_cons].size,
577 flags);
578
579 if ((1 << queue->meta[npo.meta_cons].gso_type) &
580 queue->vif->gso_mask) {
581 struct xen_netif_extra_info *gso =
582 (struct xen_netif_extra_info *)
583 RING_GET_RESPONSE(&queue->rx,
584 queue->rx.rsp_prod_pvt++);
585
586 resp->flags |= XEN_NETRXF_extra_info;
587
588 gso->u.gso.type = queue->meta[npo.meta_cons].gso_type;
589 gso->u.gso.size = queue->meta[npo.meta_cons].gso_size;
590 gso->u.gso.pad = 0;
591 gso->u.gso.features = 0;
592
593 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
594 gso->flags = 0;
595 }
596
597 xenvif_add_frag_responses(queue, status,
598 queue->meta + npo.meta_cons + 1,
599 XENVIF_RX_CB(skb)->meta_slots_used);
600
601 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret);
602
603 need_to_notify |= !!ret;
604
605 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
606 dev_kfree_skb(skb);
607 }
608
609 done:
610 if (need_to_notify)
611 notify_remote_via_irq(queue->rx_irq);
612 }
613
614 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
615 {
616 int more_to_do;
617
618 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
619
620 if (more_to_do)
621 napi_schedule(&queue->napi);
622 }
623
624 static void tx_add_credit(struct xenvif_queue *queue)
625 {
626 unsigned long max_burst, max_credit;
627
628 /*
629 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
630 * Otherwise the interface can seize up due to insufficient credit.
631 */
632 max_burst = RING_GET_REQUEST(&queue->tx, queue->tx.req_cons)->size;
633 max_burst = min(max_burst, 131072UL);
634 max_burst = max(max_burst, queue->credit_bytes);
635
636 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
637 max_credit = queue->remaining_credit + queue->credit_bytes;
638 if (max_credit < queue->remaining_credit)
639 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
640
641 queue->remaining_credit = min(max_credit, max_burst);
642 }
643
644 static void tx_credit_callback(unsigned long data)
645 {
646 struct xenvif_queue *queue = (struct xenvif_queue *)data;
647 tx_add_credit(queue);
648 xenvif_napi_schedule_or_enable_events(queue);
649 }
650
651 static void xenvif_tx_err(struct xenvif_queue *queue,
652 struct xen_netif_tx_request *txp, RING_IDX end)
653 {
654 RING_IDX cons = queue->tx.req_cons;
655 unsigned long flags;
656
657 do {
658 int notify;
659
660 spin_lock_irqsave(&queue->response_lock, flags);
661 make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
662 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
663 spin_unlock_irqrestore(&queue->response_lock, flags);
664 if (notify)
665 notify_remote_via_irq(queue->tx_irq);
666
667 if (cons == end)
668 break;
669 txp = RING_GET_REQUEST(&queue->tx, cons++);
670 } while (1);
671 queue->tx.req_cons = cons;
672 }
673
674 static void xenvif_fatal_tx_err(struct xenvif *vif)
675 {
676 netdev_err(vif->dev, "fatal error; disabling device\n");
677 vif->disabled = true;
678 /* Disable the vif from queue 0's kthread */
679 if (vif->queues)
680 xenvif_kick_thread(&vif->queues[0]);
681 }
682
683 static int xenvif_count_requests(struct xenvif_queue *queue,
684 struct xen_netif_tx_request *first,
685 struct xen_netif_tx_request *txp,
686 int work_to_do)
687 {
688 RING_IDX cons = queue->tx.req_cons;
689 int slots = 0;
690 int drop_err = 0;
691 int more_data;
692
693 if (!(first->flags & XEN_NETTXF_more_data))
694 return 0;
695
696 do {
697 struct xen_netif_tx_request dropped_tx = { 0 };
698
699 if (slots >= work_to_do) {
700 netdev_err(queue->vif->dev,
701 "Asked for %d slots but exceeds this limit\n",
702 work_to_do);
703 xenvif_fatal_tx_err(queue->vif);
704 return -ENODATA;
705 }
706
707 /* This guest is really using too many slots and
708 * considered malicious.
709 */
710 if (unlikely(slots >= fatal_skb_slots)) {
711 netdev_err(queue->vif->dev,
712 "Malicious frontend using %d slots, threshold %u\n",
713 slots, fatal_skb_slots);
714 xenvif_fatal_tx_err(queue->vif);
715 return -E2BIG;
716 }
717
718 /* Xen network protocol had implicit dependency on
719 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
720 * the historical MAX_SKB_FRAGS value 18 to honor the
721 * same behavior as before. Any packet using more than
722 * 18 slots but less than fatal_skb_slots slots is
723 * dropped
724 */
725 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
726 if (net_ratelimit())
727 netdev_dbg(queue->vif->dev,
728 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
729 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
730 drop_err = -E2BIG;
731 }
732
733 if (drop_err)
734 txp = &dropped_tx;
735
736 memcpy(txp, RING_GET_REQUEST(&queue->tx, cons + slots),
737 sizeof(*txp));
738
739 /* If the guest submitted a frame >= 64 KiB then
740 * first->size overflowed and following slots will
741 * appear to be larger than the frame.
742 *
743 * This cannot be fatal error as there are buggy
744 * frontends that do this.
745 *
746 * Consume all slots and drop the packet.
747 */
748 if (!drop_err && txp->size > first->size) {
749 if (net_ratelimit())
750 netdev_dbg(queue->vif->dev,
751 "Invalid tx request, slot size %u > remaining size %u\n",
752 txp->size, first->size);
753 drop_err = -EIO;
754 }
755
756 first->size -= txp->size;
757 slots++;
758
759 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
760 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n",
761 txp->offset, txp->size);
762 xenvif_fatal_tx_err(queue->vif);
763 return -EINVAL;
764 }
765
766 more_data = txp->flags & XEN_NETTXF_more_data;
767
768 if (!drop_err)
769 txp++;
770
771 } while (more_data);
772
773 if (drop_err) {
774 xenvif_tx_err(queue, first, cons + slots);
775 return drop_err;
776 }
777
778 return slots;
779 }
780
781
782 struct xenvif_tx_cb {
783 u16 pending_idx;
784 };
785
786 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
787
788 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
789 u16 pending_idx,
790 struct xen_netif_tx_request *txp,
791 struct gnttab_map_grant_ref *mop)
792 {
793 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
794 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
795 GNTMAP_host_map | GNTMAP_readonly,
796 txp->gref, queue->vif->domid);
797
798 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
799 sizeof(*txp));
800 }
801
802 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
803 {
804 struct sk_buff *skb =
805 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
806 GFP_ATOMIC | __GFP_NOWARN);
807 if (unlikely(skb == NULL))
808 return NULL;
809
810 /* Packets passed to netif_rx() must have some headroom. */
811 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
812
813 /* Initialize it here to avoid later surprises */
814 skb_shinfo(skb)->destructor_arg = NULL;
815
816 return skb;
817 }
818
819 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
820 struct sk_buff *skb,
821 struct xen_netif_tx_request *txp,
822 struct gnttab_map_grant_ref *gop)
823 {
824 struct skb_shared_info *shinfo = skb_shinfo(skb);
825 skb_frag_t *frags = shinfo->frags;
826 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
827 int start;
828 pending_ring_idx_t index;
829 unsigned int nr_slots, frag_overflow = 0;
830
831 /* At this point shinfo->nr_frags is in fact the number of
832 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
833 */
834 if (shinfo->nr_frags > MAX_SKB_FRAGS) {
835 frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS;
836 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
837 shinfo->nr_frags = MAX_SKB_FRAGS;
838 }
839 nr_slots = shinfo->nr_frags;
840
841 /* Skip first skb fragment if it is on same page as header fragment. */
842 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
843
844 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
845 shinfo->nr_frags++, txp++, gop++) {
846 index = pending_index(queue->pending_cons++);
847 pending_idx = queue->pending_ring[index];
848 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
849 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
850 }
851
852 if (frag_overflow) {
853 struct sk_buff *nskb = xenvif_alloc_skb(0);
854 if (unlikely(nskb == NULL)) {
855 if (net_ratelimit())
856 netdev_err(queue->vif->dev,
857 "Can't allocate the frag_list skb.\n");
858 return NULL;
859 }
860
861 shinfo = skb_shinfo(nskb);
862 frags = shinfo->frags;
863
864 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
865 shinfo->nr_frags++, txp++, gop++) {
866 index = pending_index(queue->pending_cons++);
867 pending_idx = queue->pending_ring[index];
868 xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
869 frag_set_pending_idx(&frags[shinfo->nr_frags],
870 pending_idx);
871 }
872
873 skb_shinfo(skb)->frag_list = nskb;
874 }
875
876 return gop;
877 }
878
879 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
880 u16 pending_idx,
881 grant_handle_t handle)
882 {
883 if (unlikely(queue->grant_tx_handle[pending_idx] !=
884 NETBACK_INVALID_HANDLE)) {
885 netdev_err(queue->vif->dev,
886 "Trying to overwrite active handle! pending_idx: %x\n",
887 pending_idx);
888 BUG();
889 }
890 queue->grant_tx_handle[pending_idx] = handle;
891 }
892
893 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
894 u16 pending_idx)
895 {
896 if (unlikely(queue->grant_tx_handle[pending_idx] ==
897 NETBACK_INVALID_HANDLE)) {
898 netdev_err(queue->vif->dev,
899 "Trying to unmap invalid handle! pending_idx: %x\n",
900 pending_idx);
901 BUG();
902 }
903 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
904 }
905
906 static int xenvif_tx_check_gop(struct xenvif_queue *queue,
907 struct sk_buff *skb,
908 struct gnttab_map_grant_ref **gopp_map,
909 struct gnttab_copy **gopp_copy)
910 {
911 struct gnttab_map_grant_ref *gop_map = *gopp_map;
912 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
913 /* This always points to the shinfo of the skb being checked, which
914 * could be either the first or the one on the frag_list
915 */
916 struct skb_shared_info *shinfo = skb_shinfo(skb);
917 /* If this is non-NULL, we are currently checking the frag_list skb, and
918 * this points to the shinfo of the first one
919 */
920 struct skb_shared_info *first_shinfo = NULL;
921 int nr_frags = shinfo->nr_frags;
922 const bool sharedslot = nr_frags &&
923 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
924 int i, err;
925
926 /* Check status of header. */
927 err = (*gopp_copy)->status;
928 if (unlikely(err)) {
929 if (net_ratelimit())
930 netdev_dbg(queue->vif->dev,
931 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
932 (*gopp_copy)->status,
933 pending_idx,
934 (*gopp_copy)->source.u.ref);
935 /* The first frag might still have this slot mapped */
936 if (!sharedslot)
937 xenvif_idx_release(queue, pending_idx,
938 XEN_NETIF_RSP_ERROR);
939 }
940 (*gopp_copy)++;
941
942 check_frags:
943 for (i = 0; i < nr_frags; i++, gop_map++) {
944 int j, newerr;
945
946 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
947
948 /* Check error status: if okay then remember grant handle. */
949 newerr = gop_map->status;
950
951 if (likely(!newerr)) {
952 xenvif_grant_handle_set(queue,
953 pending_idx,
954 gop_map->handle);
955 /* Had a previous error? Invalidate this fragment. */
956 if (unlikely(err)) {
957 xenvif_idx_unmap(queue, pending_idx);
958 /* If the mapping of the first frag was OK, but
959 * the header's copy failed, and they are
960 * sharing a slot, send an error
961 */
962 if (i == 0 && sharedslot)
963 xenvif_idx_release(queue, pending_idx,
964 XEN_NETIF_RSP_ERROR);
965 else
966 xenvif_idx_release(queue, pending_idx,
967 XEN_NETIF_RSP_OKAY);
968 }
969 continue;
970 }
971
972 /* Error on this fragment: respond to client with an error. */
973 if (net_ratelimit())
974 netdev_dbg(queue->vif->dev,
975 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
976 i,
977 gop_map->status,
978 pending_idx,
979 gop_map->ref);
980
981 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
982
983 /* Not the first error? Preceding frags already invalidated. */
984 if (err)
985 continue;
986
987 /* First error: if the header haven't shared a slot with the
988 * first frag, release it as well.
989 */
990 if (!sharedslot)
991 xenvif_idx_release(queue,
992 XENVIF_TX_CB(skb)->pending_idx,
993 XEN_NETIF_RSP_OKAY);
994
995 /* Invalidate preceding fragments of this skb. */
996 for (j = 0; j < i; j++) {
997 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
998 xenvif_idx_unmap(queue, pending_idx);
999 xenvif_idx_release(queue, pending_idx,
1000 XEN_NETIF_RSP_OKAY);
1001 }
1002
1003 /* And if we found the error while checking the frag_list, unmap
1004 * the first skb's frags
1005 */
1006 if (first_shinfo) {
1007 for (j = 0; j < first_shinfo->nr_frags; j++) {
1008 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
1009 xenvif_idx_unmap(queue, pending_idx);
1010 xenvif_idx_release(queue, pending_idx,
1011 XEN_NETIF_RSP_OKAY);
1012 }
1013 }
1014
1015 /* Remember the error: invalidate all subsequent fragments. */
1016 err = newerr;
1017 }
1018
1019 if (skb_has_frag_list(skb) && !first_shinfo) {
1020 first_shinfo = skb_shinfo(skb);
1021 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
1022 nr_frags = shinfo->nr_frags;
1023
1024 goto check_frags;
1025 }
1026
1027 *gopp_map = gop_map;
1028 return err;
1029 }
1030
1031 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
1032 {
1033 struct skb_shared_info *shinfo = skb_shinfo(skb);
1034 int nr_frags = shinfo->nr_frags;
1035 int i;
1036 u16 prev_pending_idx = INVALID_PENDING_IDX;
1037
1038 for (i = 0; i < nr_frags; i++) {
1039 skb_frag_t *frag = shinfo->frags + i;
1040 struct xen_netif_tx_request *txp;
1041 struct page *page;
1042 u16 pending_idx;
1043
1044 pending_idx = frag_get_pending_idx(frag);
1045
1046 /* If this is not the first frag, chain it to the previous*/
1047 if (prev_pending_idx == INVALID_PENDING_IDX)
1048 skb_shinfo(skb)->destructor_arg =
1049 &callback_param(queue, pending_idx);
1050 else
1051 callback_param(queue, prev_pending_idx).ctx =
1052 &callback_param(queue, pending_idx);
1053
1054 callback_param(queue, pending_idx).ctx = NULL;
1055 prev_pending_idx = pending_idx;
1056
1057 txp = &queue->pending_tx_info[pending_idx].req;
1058 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
1059 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1060 skb->len += txp->size;
1061 skb->data_len += txp->size;
1062 skb->truesize += txp->size;
1063
1064 /* Take an extra reference to offset network stack's put_page */
1065 get_page(queue->mmap_pages[pending_idx]);
1066 }
1067 }
1068
1069 static int xenvif_get_extras(struct xenvif_queue *queue,
1070 struct xen_netif_extra_info *extras,
1071 int work_to_do)
1072 {
1073 struct xen_netif_extra_info extra;
1074 RING_IDX cons = queue->tx.req_cons;
1075
1076 do {
1077 if (unlikely(work_to_do-- <= 0)) {
1078 netdev_err(queue->vif->dev, "Missing extra info\n");
1079 xenvif_fatal_tx_err(queue->vif);
1080 return -EBADR;
1081 }
1082
1083 memcpy(&extra, RING_GET_REQUEST(&queue->tx, cons),
1084 sizeof(extra));
1085 if (unlikely(!extra.type ||
1086 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1087 queue->tx.req_cons = ++cons;
1088 netdev_err(queue->vif->dev,
1089 "Invalid extra type: %d\n", extra.type);
1090 xenvif_fatal_tx_err(queue->vif);
1091 return -EINVAL;
1092 }
1093
1094 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1095 queue->tx.req_cons = ++cons;
1096 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1097
1098 return work_to_do;
1099 }
1100
1101 static int xenvif_set_skb_gso(struct xenvif *vif,
1102 struct sk_buff *skb,
1103 struct xen_netif_extra_info *gso)
1104 {
1105 if (!gso->u.gso.size) {
1106 netdev_err(vif->dev, "GSO size must not be zero.\n");
1107 xenvif_fatal_tx_err(vif);
1108 return -EINVAL;
1109 }
1110
1111 switch (gso->u.gso.type) {
1112 case XEN_NETIF_GSO_TYPE_TCPV4:
1113 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1114 break;
1115 case XEN_NETIF_GSO_TYPE_TCPV6:
1116 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1117 break;
1118 default:
1119 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1120 xenvif_fatal_tx_err(vif);
1121 return -EINVAL;
1122 }
1123
1124 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1125 /* gso_segs will be calculated later */
1126
1127 return 0;
1128 }
1129
1130 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
1131 {
1132 bool recalculate_partial_csum = false;
1133
1134 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1135 * peers can fail to set NETRXF_csum_blank when sending a GSO
1136 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1137 * recalculate the partial checksum.
1138 */
1139 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1140 queue->stats.rx_gso_checksum_fixup++;
1141 skb->ip_summed = CHECKSUM_PARTIAL;
1142 recalculate_partial_csum = true;
1143 }
1144
1145 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1146 if (skb->ip_summed != CHECKSUM_PARTIAL)
1147 return 0;
1148
1149 return skb_checksum_setup(skb, recalculate_partial_csum);
1150 }
1151
1152 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
1153 {
1154 u64 now = get_jiffies_64();
1155 u64 next_credit = queue->credit_window_start +
1156 msecs_to_jiffies(queue->credit_usec / 1000);
1157
1158 /* Timer could already be pending in rare cases. */
1159 if (timer_pending(&queue->credit_timeout))
1160 return true;
1161
1162 /* Passed the point where we can replenish credit? */
1163 if (time_after_eq64(now, next_credit)) {
1164 queue->credit_window_start = now;
1165 tx_add_credit(queue);
1166 }
1167
1168 /* Still too big to send right now? Set a callback. */
1169 if (size > queue->remaining_credit) {
1170 queue->credit_timeout.data =
1171 (unsigned long)queue;
1172 queue->credit_timeout.function =
1173 tx_credit_callback;
1174 mod_timer(&queue->credit_timeout,
1175 next_credit);
1176 queue->credit_window_start = next_credit;
1177
1178 return true;
1179 }
1180
1181 return false;
1182 }
1183
1184 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
1185 int budget,
1186 unsigned *copy_ops,
1187 unsigned *map_ops)
1188 {
1189 struct gnttab_map_grant_ref *gop = queue->tx_map_ops, *request_gop;
1190 struct sk_buff *skb;
1191 int ret;
1192
1193 while (skb_queue_len(&queue->tx_queue) < budget) {
1194 struct xen_netif_tx_request txreq;
1195 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1196 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1197 u16 pending_idx;
1198 RING_IDX idx;
1199 int work_to_do;
1200 unsigned int data_len;
1201 pending_ring_idx_t index;
1202
1203 if (queue->tx.sring->req_prod - queue->tx.req_cons >
1204 XEN_NETIF_TX_RING_SIZE) {
1205 netdev_err(queue->vif->dev,
1206 "Impossible number of requests. "
1207 "req_prod %d, req_cons %d, size %ld\n",
1208 queue->tx.sring->req_prod, queue->tx.req_cons,
1209 XEN_NETIF_TX_RING_SIZE);
1210 xenvif_fatal_tx_err(queue->vif);
1211 break;
1212 }
1213
1214 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
1215 if (!work_to_do)
1216 break;
1217
1218 idx = queue->tx.req_cons;
1219 rmb(); /* Ensure that we see the request before we copy it. */
1220 memcpy(&txreq, RING_GET_REQUEST(&queue->tx, idx), sizeof(txreq));
1221
1222 /* Credit-based scheduling. */
1223 if (txreq.size > queue->remaining_credit &&
1224 tx_credit_exceeded(queue, txreq.size))
1225 break;
1226
1227 queue->remaining_credit -= txreq.size;
1228
1229 work_to_do--;
1230 queue->tx.req_cons = ++idx;
1231
1232 memset(extras, 0, sizeof(extras));
1233 if (txreq.flags & XEN_NETTXF_extra_info) {
1234 work_to_do = xenvif_get_extras(queue, extras,
1235 work_to_do);
1236 idx = queue->tx.req_cons;
1237 if (unlikely(work_to_do < 0))
1238 break;
1239 }
1240
1241 ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
1242 if (unlikely(ret < 0))
1243 break;
1244
1245 idx += ret;
1246
1247 if (unlikely(txreq.size < ETH_HLEN)) {
1248 netdev_dbg(queue->vif->dev,
1249 "Bad packet size: %d\n", txreq.size);
1250 xenvif_tx_err(queue, &txreq, idx);
1251 break;
1252 }
1253
1254 /* No crossing a page as the payload mustn't fragment. */
1255 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1256 netdev_err(queue->vif->dev,
1257 "txreq.offset: %x, size: %u, end: %lu\n",
1258 txreq.offset, txreq.size,
1259 (txreq.offset&~PAGE_MASK) + txreq.size);
1260 xenvif_fatal_tx_err(queue->vif);
1261 break;
1262 }
1263
1264 index = pending_index(queue->pending_cons);
1265 pending_idx = queue->pending_ring[index];
1266
1267 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
1268 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1269 XEN_NETBACK_TX_COPY_LEN : txreq.size;
1270
1271 skb = xenvif_alloc_skb(data_len);
1272 if (unlikely(skb == NULL)) {
1273 netdev_dbg(queue->vif->dev,
1274 "Can't allocate a skb in start_xmit.\n");
1275 xenvif_tx_err(queue, &txreq, idx);
1276 break;
1277 }
1278
1279 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1280 struct xen_netif_extra_info *gso;
1281 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1282
1283 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1284 /* Failure in xenvif_set_skb_gso is fatal. */
1285 kfree_skb(skb);
1286 break;
1287 }
1288 }
1289
1290 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
1291
1292 __skb_put(skb, data_len);
1293 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
1294 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
1295 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
1296
1297 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
1298 virt_to_mfn(skb->data);
1299 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
1300 queue->tx_copy_ops[*copy_ops].dest.offset =
1301 offset_in_page(skb->data);
1302
1303 queue->tx_copy_ops[*copy_ops].len = data_len;
1304 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1305
1306 (*copy_ops)++;
1307
1308 skb_shinfo(skb)->nr_frags = ret;
1309 if (data_len < txreq.size) {
1310 skb_shinfo(skb)->nr_frags++;
1311 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1312 pending_idx);
1313 xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);
1314 gop++;
1315 } else {
1316 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1317 INVALID_PENDING_IDX);
1318 memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,
1319 sizeof(txreq));
1320 }
1321
1322 queue->pending_cons++;
1323
1324 request_gop = xenvif_get_requests(queue, skb, txfrags, gop);
1325 if (request_gop == NULL) {
1326 kfree_skb(skb);
1327 xenvif_tx_err(queue, &txreq, idx);
1328 break;
1329 }
1330 gop = request_gop;
1331
1332 __skb_queue_tail(&queue->tx_queue, skb);
1333
1334 queue->tx.req_cons = idx;
1335
1336 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1337 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1338 break;
1339 }
1340
1341 (*map_ops) = gop - queue->tx_map_ops;
1342 return;
1343 }
1344
1345 /* Consolidate skb with a frag_list into a brand new one with local pages on
1346 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1347 */
1348 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1349 {
1350 unsigned int offset = skb_headlen(skb);
1351 skb_frag_t frags[MAX_SKB_FRAGS];
1352 int i, f;
1353 struct ubuf_info *uarg;
1354 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1355
1356 queue->stats.tx_zerocopy_sent += 2;
1357 queue->stats.tx_frag_overflow++;
1358
1359 xenvif_fill_frags(queue, nskb);
1360 /* Subtract frags size, we will correct it later */
1361 skb->truesize -= skb->data_len;
1362 skb->len += nskb->len;
1363 skb->data_len += nskb->len;
1364
1365 /* create a brand new frags array and coalesce there */
1366 for (i = 0; offset < skb->len; i++) {
1367 struct page *page;
1368 unsigned int len;
1369
1370 BUG_ON(i >= MAX_SKB_FRAGS);
1371 page = alloc_page(GFP_ATOMIC);
1372 if (!page) {
1373 int j;
1374 skb->truesize += skb->data_len;
1375 for (j = 0; j < i; j++)
1376 put_page(frags[j].page.p);
1377 return -ENOMEM;
1378 }
1379
1380 if (offset + PAGE_SIZE < skb->len)
1381 len = PAGE_SIZE;
1382 else
1383 len = skb->len - offset;
1384 if (skb_copy_bits(skb, offset, page_address(page), len))
1385 BUG();
1386
1387 offset += len;
1388 frags[i].page.p = page;
1389 frags[i].page_offset = 0;
1390 skb_frag_size_set(&frags[i], len);
1391 }
1392
1393 /* Copied all the bits from the frag list -- free it. */
1394 skb_frag_list_init(skb);
1395 xenvif_skb_zerocopy_prepare(queue, nskb);
1396 kfree_skb(nskb);
1397
1398 /* Release all the original (foreign) frags. */
1399 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1400 skb_frag_unref(skb, f);
1401 uarg = skb_shinfo(skb)->destructor_arg;
1402 /* increase inflight counter to offset decrement in callback */
1403 atomic_inc(&queue->inflight_packets);
1404 uarg->callback(uarg, true);
1405 skb_shinfo(skb)->destructor_arg = NULL;
1406
1407 /* Fill the skb with the new (local) frags. */
1408 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1409 skb_shinfo(skb)->nr_frags = i;
1410 skb->truesize += i * PAGE_SIZE;
1411
1412 return 0;
1413 }
1414
1415 static int xenvif_tx_submit(struct xenvif_queue *queue)
1416 {
1417 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1418 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1419 struct sk_buff *skb;
1420 int work_done = 0;
1421
1422 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1423 struct xen_netif_tx_request *txp;
1424 u16 pending_idx;
1425 unsigned data_len;
1426
1427 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1428 txp = &queue->pending_tx_info[pending_idx].req;
1429
1430 /* Check the remap error code. */
1431 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1432 /* If there was an error, xenvif_tx_check_gop is
1433 * expected to release all the frags which were mapped,
1434 * so kfree_skb shouldn't do it again
1435 */
1436 skb_shinfo(skb)->nr_frags = 0;
1437 if (skb_has_frag_list(skb)) {
1438 struct sk_buff *nskb =
1439 skb_shinfo(skb)->frag_list;
1440 skb_shinfo(nskb)->nr_frags = 0;
1441 }
1442 kfree_skb(skb);
1443 continue;
1444 }
1445
1446 data_len = skb->len;
1447 callback_param(queue, pending_idx).ctx = NULL;
1448 if (data_len < txp->size) {
1449 /* Append the packet payload as a fragment. */
1450 txp->offset += data_len;
1451 txp->size -= data_len;
1452 } else {
1453 /* Schedule a response immediately. */
1454 xenvif_idx_release(queue, pending_idx,
1455 XEN_NETIF_RSP_OKAY);
1456 }
1457
1458 if (txp->flags & XEN_NETTXF_csum_blank)
1459 skb->ip_summed = CHECKSUM_PARTIAL;
1460 else if (txp->flags & XEN_NETTXF_data_validated)
1461 skb->ip_summed = CHECKSUM_UNNECESSARY;
1462
1463 xenvif_fill_frags(queue, skb);
1464
1465 if (unlikely(skb_has_frag_list(skb))) {
1466 if (xenvif_handle_frag_list(queue, skb)) {
1467 if (net_ratelimit())
1468 netdev_err(queue->vif->dev,
1469 "Not enough memory to consolidate frag_list!\n");
1470 xenvif_skb_zerocopy_prepare(queue, skb);
1471 kfree_skb(skb);
1472 continue;
1473 }
1474 }
1475
1476 skb->dev = queue->vif->dev;
1477 skb->protocol = eth_type_trans(skb, skb->dev);
1478 skb_reset_network_header(skb);
1479
1480 if (checksum_setup(queue, skb)) {
1481 netdev_dbg(queue->vif->dev,
1482 "Can't setup checksum in net_tx_action\n");
1483 /* We have to set this flag to trigger the callback */
1484 if (skb_shinfo(skb)->destructor_arg)
1485 xenvif_skb_zerocopy_prepare(queue, skb);
1486 kfree_skb(skb);
1487 continue;
1488 }
1489
1490 skb_probe_transport_header(skb, 0);
1491
1492 /* If the packet is GSO then we will have just set up the
1493 * transport header offset in checksum_setup so it's now
1494 * straightforward to calculate gso_segs.
1495 */
1496 if (skb_is_gso(skb)) {
1497 int mss = skb_shinfo(skb)->gso_size;
1498 int hdrlen = skb_transport_header(skb) -
1499 skb_mac_header(skb) +
1500 tcp_hdrlen(skb);
1501
1502 skb_shinfo(skb)->gso_segs =
1503 DIV_ROUND_UP(skb->len - hdrlen, mss);
1504 }
1505
1506 queue->stats.rx_bytes += skb->len;
1507 queue->stats.rx_packets++;
1508
1509 work_done++;
1510
1511 /* Set this flag right before netif_receive_skb, otherwise
1512 * someone might think this packet already left netback, and
1513 * do a skb_copy_ubufs while we are still in control of the
1514 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1515 */
1516 if (skb_shinfo(skb)->destructor_arg) {
1517 xenvif_skb_zerocopy_prepare(queue, skb);
1518 queue->stats.tx_zerocopy_sent++;
1519 }
1520
1521 netif_receive_skb(skb);
1522 }
1523
1524 return work_done;
1525 }
1526
1527 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1528 {
1529 unsigned long flags;
1530 pending_ring_idx_t index;
1531 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1532
1533 /* This is the only place where we grab this lock, to protect callbacks
1534 * from each other.
1535 */
1536 spin_lock_irqsave(&queue->callback_lock, flags);
1537 do {
1538 u16 pending_idx = ubuf->desc;
1539 ubuf = (struct ubuf_info *) ubuf->ctx;
1540 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1541 MAX_PENDING_REQS);
1542 index = pending_index(queue->dealloc_prod);
1543 queue->dealloc_ring[index] = pending_idx;
1544 /* Sync with xenvif_tx_dealloc_action:
1545 * insert idx then incr producer.
1546 */
1547 smp_wmb();
1548 queue->dealloc_prod++;
1549 } while (ubuf);
1550 wake_up(&queue->dealloc_wq);
1551 spin_unlock_irqrestore(&queue->callback_lock, flags);
1552
1553 if (likely(zerocopy_success))
1554 queue->stats.tx_zerocopy_success++;
1555 else
1556 queue->stats.tx_zerocopy_fail++;
1557 xenvif_skb_zerocopy_complete(queue);
1558 }
1559
1560 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1561 {
1562 struct gnttab_unmap_grant_ref *gop;
1563 pending_ring_idx_t dc, dp;
1564 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1565 unsigned int i = 0;
1566
1567 dc = queue->dealloc_cons;
1568 gop = queue->tx_unmap_ops;
1569
1570 /* Free up any grants we have finished using */
1571 do {
1572 dp = queue->dealloc_prod;
1573
1574 /* Ensure we see all indices enqueued by all
1575 * xenvif_zerocopy_callback().
1576 */
1577 smp_rmb();
1578
1579 while (dc != dp) {
1580 BUG_ON(gop - queue->tx_unmap_ops > MAX_PENDING_REQS);
1581 pending_idx =
1582 queue->dealloc_ring[pending_index(dc++)];
1583
1584 pending_idx_release[gop-queue->tx_unmap_ops] =
1585 pending_idx;
1586 queue->pages_to_unmap[gop-queue->tx_unmap_ops] =
1587 queue->mmap_pages[pending_idx];
1588 gnttab_set_unmap_op(gop,
1589 idx_to_kaddr(queue, pending_idx),
1590 GNTMAP_host_map,
1591 queue->grant_tx_handle[pending_idx]);
1592 xenvif_grant_handle_reset(queue, pending_idx);
1593 ++gop;
1594 }
1595
1596 } while (dp != queue->dealloc_prod);
1597
1598 queue->dealloc_cons = dc;
1599
1600 if (gop - queue->tx_unmap_ops > 0) {
1601 int ret;
1602 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1603 NULL,
1604 queue->pages_to_unmap,
1605 gop - queue->tx_unmap_ops);
1606 if (ret) {
1607 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tx ret %d\n",
1608 gop - queue->tx_unmap_ops, ret);
1609 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1610 if (gop[i].status != GNTST_okay)
1611 netdev_err(queue->vif->dev,
1612 " host_addr: %llx handle: %x status: %d\n",
1613 gop[i].host_addr,
1614 gop[i].handle,
1615 gop[i].status);
1616 }
1617 BUG();
1618 }
1619 }
1620
1621 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1622 xenvif_idx_release(queue, pending_idx_release[i],
1623 XEN_NETIF_RSP_OKAY);
1624 }
1625
1626
1627 /* Called after netfront has transmitted */
1628 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1629 {
1630 unsigned nr_mops, nr_cops = 0;
1631 int work_done, ret;
1632
1633 if (unlikely(!tx_work_todo(queue)))
1634 return 0;
1635
1636 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1637
1638 if (nr_cops == 0)
1639 return 0;
1640
1641 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1642 if (nr_mops != 0) {
1643 ret = gnttab_map_refs(queue->tx_map_ops,
1644 NULL,
1645 queue->pages_to_map,
1646 nr_mops);
1647 BUG_ON(ret);
1648 }
1649
1650 work_done = xenvif_tx_submit(queue);
1651
1652 return work_done;
1653 }
1654
1655 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1656 u8 status)
1657 {
1658 struct pending_tx_info *pending_tx_info;
1659 pending_ring_idx_t index;
1660 int notify;
1661 unsigned long flags;
1662
1663 pending_tx_info = &queue->pending_tx_info[pending_idx];
1664
1665 spin_lock_irqsave(&queue->response_lock, flags);
1666
1667 make_tx_response(queue, &pending_tx_info->req, status);
1668
1669 /* Release the pending index before pusing the Tx response so
1670 * its available before a new Tx request is pushed by the
1671 * frontend.
1672 */
1673 index = pending_index(queue->pending_prod++);
1674 queue->pending_ring[index] = pending_idx;
1675
1676 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1677
1678 spin_unlock_irqrestore(&queue->response_lock, flags);
1679
1680 if (notify)
1681 notify_remote_via_irq(queue->tx_irq);
1682 }
1683
1684
1685 static void make_tx_response(struct xenvif_queue *queue,
1686 struct xen_netif_tx_request *txp,
1687 s8 st)
1688 {
1689 RING_IDX i = queue->tx.rsp_prod_pvt;
1690 struct xen_netif_tx_response *resp;
1691
1692 resp = RING_GET_RESPONSE(&queue->tx, i);
1693 resp->id = txp->id;
1694 resp->status = st;
1695
1696 if (txp->flags & XEN_NETTXF_extra_info)
1697 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1698
1699 queue->tx.rsp_prod_pvt = ++i;
1700 }
1701
1702 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
1703 u16 id,
1704 s8 st,
1705 u16 offset,
1706 u16 size,
1707 u16 flags)
1708 {
1709 RING_IDX i = queue->rx.rsp_prod_pvt;
1710 struct xen_netif_rx_response *resp;
1711
1712 resp = RING_GET_RESPONSE(&queue->rx, i);
1713 resp->offset = offset;
1714 resp->flags = flags;
1715 resp->id = id;
1716 resp->status = (s16)size;
1717 if (st < 0)
1718 resp->status = (s16)st;
1719
1720 queue->rx.rsp_prod_pvt = ++i;
1721
1722 return resp;
1723 }
1724
1725 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1726 {
1727 int ret;
1728 struct gnttab_unmap_grant_ref tx_unmap_op;
1729
1730 gnttab_set_unmap_op(&tx_unmap_op,
1731 idx_to_kaddr(queue, pending_idx),
1732 GNTMAP_host_map,
1733 queue->grant_tx_handle[pending_idx]);
1734 xenvif_grant_handle_reset(queue, pending_idx);
1735
1736 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1737 &queue->mmap_pages[pending_idx], 1);
1738 if (ret) {
1739 netdev_err(queue->vif->dev,
1740 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: %x status: %d\n",
1741 ret,
1742 pending_idx,
1743 tx_unmap_op.host_addr,
1744 tx_unmap_op.handle,
1745 tx_unmap_op.status);
1746 BUG();
1747 }
1748 }
1749
1750 static inline int tx_work_todo(struct xenvif_queue *queue)
1751 {
1752 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1753 return 1;
1754
1755 return 0;
1756 }
1757
1758 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1759 {
1760 return queue->dealloc_cons != queue->dealloc_prod;
1761 }
1762
1763 void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
1764 {
1765 if (queue->tx.sring)
1766 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1767 queue->tx.sring);
1768 if (queue->rx.sring)
1769 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1770 queue->rx.sring);
1771 }
1772
1773 int xenvif_map_frontend_rings(struct xenvif_queue *queue,
1774 grant_ref_t tx_ring_ref,
1775 grant_ref_t rx_ring_ref)
1776 {
1777 void *addr;
1778 struct xen_netif_tx_sring *txs;
1779 struct xen_netif_rx_sring *rxs;
1780
1781 int err = -ENOMEM;
1782
1783 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1784 tx_ring_ref, &addr);
1785 if (err)
1786 goto err;
1787
1788 txs = (struct xen_netif_tx_sring *)addr;
1789 BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE);
1790
1791 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1792 rx_ring_ref, &addr);
1793 if (err)
1794 goto err;
1795
1796 rxs = (struct xen_netif_rx_sring *)addr;
1797 BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE);
1798
1799 return 0;
1800
1801 err:
1802 xenvif_unmap_frontend_rings(queue);
1803 return err;
1804 }
1805
1806 static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
1807 {
1808 struct xenvif *vif = queue->vif;
1809
1810 queue->stalled = true;
1811
1812 /* At least one queue has stalled? Disable the carrier. */
1813 spin_lock(&vif->lock);
1814 if (vif->stalled_queues++ == 0) {
1815 netdev_info(vif->dev, "Guest Rx stalled");
1816 netif_carrier_off(vif->dev);
1817 }
1818 spin_unlock(&vif->lock);
1819 }
1820
1821 static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
1822 {
1823 struct xenvif *vif = queue->vif;
1824
1825 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
1826 queue->stalled = false;
1827
1828 /* All queues are ready? Enable the carrier. */
1829 spin_lock(&vif->lock);
1830 if (--vif->stalled_queues == 0) {
1831 netdev_info(vif->dev, "Guest Rx ready");
1832 netif_carrier_on(vif->dev);
1833 }
1834 spin_unlock(&vif->lock);
1835 }
1836
1837 static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
1838 {
1839 RING_IDX prod, cons;
1840
1841 prod = queue->rx.sring->req_prod;
1842 cons = queue->rx.req_cons;
1843
1844 return !queue->stalled
1845 && prod - cons < XEN_NETBK_RX_SLOTS_MAX
1846 && time_after(jiffies,
1847 queue->last_rx_time + queue->vif->stall_timeout);
1848 }
1849
1850 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
1851 {
1852 RING_IDX prod, cons;
1853
1854 prod = queue->rx.sring->req_prod;
1855 cons = queue->rx.req_cons;
1856
1857 return queue->stalled
1858 && prod - cons >= XEN_NETBK_RX_SLOTS_MAX;
1859 }
1860
1861 static bool xenvif_have_rx_work(struct xenvif_queue *queue)
1862 {
1863 return (!skb_queue_empty(&queue->rx_queue)
1864 && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX))
1865 || (queue->vif->stall_timeout &&
1866 (xenvif_rx_queue_stalled(queue)
1867 || xenvif_rx_queue_ready(queue)))
1868 || kthread_should_stop()
1869 || queue->vif->disabled;
1870 }
1871
1872 static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
1873 {
1874 struct sk_buff *skb;
1875 long timeout;
1876
1877 skb = skb_peek(&queue->rx_queue);
1878 if (!skb)
1879 return MAX_SCHEDULE_TIMEOUT;
1880
1881 timeout = XENVIF_RX_CB(skb)->expires - jiffies;
1882 return timeout < 0 ? 0 : timeout;
1883 }
1884
1885 /* Wait until the guest Rx thread has work.
1886 *
1887 * The timeout needs to be adjusted based on the current head of the
1888 * queue (and not just the head at the beginning). In particular, if
1889 * the queue is initially empty an infinite timeout is used and this
1890 * needs to be reduced when a skb is queued.
1891 *
1892 * This cannot be done with wait_event_timeout() because it only
1893 * calculates the timeout once.
1894 */
1895 static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
1896 {
1897 DEFINE_WAIT(wait);
1898
1899 if (xenvif_have_rx_work(queue))
1900 return;
1901
1902 for (;;) {
1903 long ret;
1904
1905 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
1906 if (xenvif_have_rx_work(queue))
1907 break;
1908 ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
1909 if (!ret)
1910 break;
1911 }
1912 finish_wait(&queue->wq, &wait);
1913 }
1914
1915 int xenvif_kthread_guest_rx(void *data)
1916 {
1917 struct xenvif_queue *queue = data;
1918 struct xenvif *vif = queue->vif;
1919
1920 if (!vif->stall_timeout)
1921 xenvif_queue_carrier_on(queue);
1922
1923 for (;;) {
1924 xenvif_wait_for_rx_work(queue);
1925
1926 if (kthread_should_stop())
1927 break;
1928
1929 /* This frontend is found to be rogue, disable it in
1930 * kthread context. Currently this is only set when
1931 * netback finds out frontend sends malformed packet,
1932 * but we cannot disable the interface in softirq
1933 * context so we defer it here, if this thread is
1934 * associated with queue 0.
1935 */
1936 if (unlikely(vif->disabled && queue->id == 0)) {
1937 xenvif_carrier_off(vif);
1938 break;
1939 }
1940
1941 if (!skb_queue_empty(&queue->rx_queue))
1942 xenvif_rx_action(queue);
1943
1944 /* If the guest hasn't provided any Rx slots for a
1945 * while it's probably not responsive, drop the
1946 * carrier so packets are dropped earlier.
1947 */
1948 if (vif->stall_timeout) {
1949 if (xenvif_rx_queue_stalled(queue))
1950 xenvif_queue_carrier_off(queue);
1951 else if (xenvif_rx_queue_ready(queue))
1952 xenvif_queue_carrier_on(queue);
1953 }
1954
1955 /* Queued packets may have foreign pages from other
1956 * domains. These cannot be queued indefinitely as
1957 * this would starve guests of grant refs and transmit
1958 * slots.
1959 */
1960 xenvif_rx_queue_drop_expired(queue);
1961
1962 xenvif_rx_queue_maybe_wake(queue);
1963
1964 cond_resched();
1965 }
1966
1967 /* Bin any remaining skbs */
1968 xenvif_rx_queue_purge(queue);
1969
1970 return 0;
1971 }
1972
1973 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1974 {
1975 /* Dealloc thread must remain running until all inflight
1976 * packets complete.
1977 */
1978 return kthread_should_stop() &&
1979 !atomic_read(&queue->inflight_packets);
1980 }
1981
1982 int xenvif_dealloc_kthread(void *data)
1983 {
1984 struct xenvif_queue *queue = data;
1985
1986 for (;;) {
1987 wait_event_interruptible(queue->dealloc_wq,
1988 tx_dealloc_work_todo(queue) ||
1989 xenvif_dealloc_kthread_should_stop(queue));
1990 if (xenvif_dealloc_kthread_should_stop(queue))
1991 break;
1992
1993 xenvif_tx_dealloc_action(queue);
1994 cond_resched();
1995 }
1996
1997 /* Unmap anything remaining*/
1998 if (tx_dealloc_work_todo(queue))
1999 xenvif_tx_dealloc_action(queue);
2000
2001 return 0;
2002 }
2003
2004 static int __init netback_init(void)
2005 {
2006 int rc = 0;
2007
2008 if (!xen_domain())
2009 return -ENODEV;
2010
2011 /* Allow as many queues as there are CPUs, by default */
2012 xenvif_max_queues = num_online_cpus();
2013
2014 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
2015 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
2016 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
2017 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
2018 }
2019
2020 rc = xenvif_xenbus_init();
2021 if (rc)
2022 goto failed_init;
2023
2024 #ifdef CONFIG_DEBUG_FS
2025 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
2026 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
2027 pr_warn("Init of debugfs returned %ld!\n",
2028 PTR_ERR(xen_netback_dbg_root));
2029 #endif /* CONFIG_DEBUG_FS */
2030
2031 return 0;
2032
2033 failed_init:
2034 return rc;
2035 }
2036
2037 module_init(netback_init);
2038
2039 static void __exit netback_fini(void)
2040 {
2041 #ifdef CONFIG_DEBUG_FS
2042 if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
2043 debugfs_remove_recursive(xen_netback_dbg_root);
2044 #endif /* CONFIG_DEBUG_FS */
2045 xenvif_xenbus_fini();
2046 }
2047 module_exit(netback_fini);
2048
2049 MODULE_LICENSE("Dual BSD/GPL");
2050 MODULE_ALIAS("xen-backend:vif");
Linux kernel - Deliverables
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