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spi: core: add hook flash_read_supported to spi_master
[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 #include <xen/page.h>
48
49 #include <asm/xen/hypercall.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 = true;
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 unsigned int extra_count,
99 s8 st);
100 static void push_tx_responses(struct xenvif_queue *queue);
101
102 static inline int tx_work_todo(struct xenvif_queue *queue);
103
104 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
105 u16 id,
106 s8 st,
107 u16 offset,
108 u16 size,
109 u16 flags);
110
111 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
112 u16 idx)
113 {
114 return page_to_pfn(queue->mmap_pages[idx]);
115 }
116
117 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
118 u16 idx)
119 {
120 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
121 }
122
123 #define callback_param(vif, pending_idx) \
124 (vif->pending_tx_info[pending_idx].callback_struct)
125
126 /* Find the containing VIF's structure from a pointer in pending_tx_info array
127 */
128 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
129 {
130 u16 pending_idx = ubuf->desc;
131 struct pending_tx_info *temp =
132 container_of(ubuf, struct pending_tx_info, callback_struct);
133 return container_of(temp - pending_idx,
134 struct xenvif_queue,
135 pending_tx_info[0]);
136 }
137
138 static u16 frag_get_pending_idx(skb_frag_t *frag)
139 {
140 return (u16)frag->page_offset;
141 }
142
143 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
144 {
145 frag->page_offset = pending_idx;
146 }
147
148 static inline pending_ring_idx_t pending_index(unsigned i)
149 {
150 return i & (MAX_PENDING_REQS-1);
151 }
152
153 static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
154 {
155 RING_IDX prod, cons;
156 struct sk_buff *skb;
157 int needed;
158
159 skb = skb_peek(&queue->rx_queue);
160 if (!skb)
161 return false;
162
163 needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
164 if (skb_is_gso(skb))
165 needed++;
166
167 do {
168 prod = queue->rx.sring->req_prod;
169 cons = queue->rx.req_cons;
170
171 if (prod - cons >= needed)
172 return true;
173
174 queue->rx.sring->req_event = prod + 1;
175
176 /* Make sure event is visible before we check prod
177 * again.
178 */
179 mb();
180 } while (queue->rx.sring->req_prod != prod);
181
182 return false;
183 }
184
185 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
186 {
187 unsigned long flags;
188
189 spin_lock_irqsave(&queue->rx_queue.lock, flags);
190
191 __skb_queue_tail(&queue->rx_queue, skb);
192
193 queue->rx_queue_len += skb->len;
194 if (queue->rx_queue_len > queue->rx_queue_max)
195 netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
196
197 spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
198 }
199
200 static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
201 {
202 struct sk_buff *skb;
203
204 spin_lock_irq(&queue->rx_queue.lock);
205
206 skb = __skb_dequeue(&queue->rx_queue);
207 if (skb)
208 queue->rx_queue_len -= skb->len;
209
210 spin_unlock_irq(&queue->rx_queue.lock);
211
212 return skb;
213 }
214
215 static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue)
216 {
217 spin_lock_irq(&queue->rx_queue.lock);
218
219 if (queue->rx_queue_len < queue->rx_queue_max)
220 netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id));
221
222 spin_unlock_irq(&queue->rx_queue.lock);
223 }
224
225
226 static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
227 {
228 struct sk_buff *skb;
229 while ((skb = xenvif_rx_dequeue(queue)) != NULL)
230 kfree_skb(skb);
231 }
232
233 static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
234 {
235 struct sk_buff *skb;
236
237 for(;;) {
238 skb = skb_peek(&queue->rx_queue);
239 if (!skb)
240 break;
241 if (time_before(jiffies, XENVIF_RX_CB(skb)->expires))
242 break;
243 xenvif_rx_dequeue(queue);
244 kfree_skb(skb);
245 }
246 }
247
248 struct netrx_pending_operations {
249 unsigned copy_prod, copy_cons;
250 unsigned meta_prod, meta_cons;
251 struct gnttab_copy *copy;
252 struct xenvif_rx_meta *meta;
253 int copy_off;
254 grant_ref_t copy_gref;
255 };
256
257 static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue,
258 struct netrx_pending_operations *npo)
259 {
260 struct xenvif_rx_meta *meta;
261 struct xen_netif_rx_request req;
262
263 RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
264
265 meta = npo->meta + npo->meta_prod++;
266 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
267 meta->gso_size = 0;
268 meta->size = 0;
269 meta->id = req.id;
270
271 npo->copy_off = 0;
272 npo->copy_gref = req.gref;
273
274 return meta;
275 }
276
277 struct gop_frag_copy {
278 struct xenvif_queue *queue;
279 struct netrx_pending_operations *npo;
280 struct xenvif_rx_meta *meta;
281 int head;
282 int gso_type;
283
284 struct page *page;
285 };
286
287 static void xenvif_setup_copy_gop(unsigned long gfn,
288 unsigned int offset,
289 unsigned int *len,
290 struct gop_frag_copy *info)
291 {
292 struct gnttab_copy *copy_gop;
293 struct xen_page_foreign *foreign;
294 /* Convenient aliases */
295 struct xenvif_queue *queue = info->queue;
296 struct netrx_pending_operations *npo = info->npo;
297 struct page *page = info->page;
298
299 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
300
301 if (npo->copy_off == MAX_BUFFER_OFFSET)
302 info->meta = get_next_rx_buffer(queue, npo);
303
304 if (npo->copy_off + *len > MAX_BUFFER_OFFSET)
305 *len = MAX_BUFFER_OFFSET - npo->copy_off;
306
307 copy_gop = npo->copy + npo->copy_prod++;
308 copy_gop->flags = GNTCOPY_dest_gref;
309 copy_gop->len = *len;
310
311 foreign = xen_page_foreign(page);
312 if (foreign) {
313 copy_gop->source.domid = foreign->domid;
314 copy_gop->source.u.ref = foreign->gref;
315 copy_gop->flags |= GNTCOPY_source_gref;
316 } else {
317 copy_gop->source.domid = DOMID_SELF;
318 copy_gop->source.u.gmfn = gfn;
319 }
320 copy_gop->source.offset = offset;
321
322 copy_gop->dest.domid = queue->vif->domid;
323 copy_gop->dest.offset = npo->copy_off;
324 copy_gop->dest.u.ref = npo->copy_gref;
325
326 npo->copy_off += *len;
327 info->meta->size += *len;
328
329 /* Leave a gap for the GSO descriptor. */
330 if (info->head && ((1 << info->gso_type) & queue->vif->gso_mask))
331 queue->rx.req_cons++;
332
333 info->head = 0; /* There must be something in this buffer now */
334 }
335
336 static void xenvif_gop_frag_copy_grant(unsigned long gfn,
337 unsigned offset,
338 unsigned int len,
339 void *data)
340 {
341 unsigned int bytes;
342
343 while (len) {
344 bytes = len;
345 xenvif_setup_copy_gop(gfn, offset, &bytes, data);
346 offset += bytes;
347 len -= bytes;
348 }
349 }
350
351 /*
352 * Set up the grant operations for this fragment. If it's a flipping
353 * interface, we also set up the unmap request from here.
354 */
355 static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb,
356 struct netrx_pending_operations *npo,
357 struct page *page, unsigned long size,
358 unsigned long offset, int *head)
359 {
360 struct gop_frag_copy info = {
361 .queue = queue,
362 .npo = npo,
363 .head = *head,
364 .gso_type = XEN_NETIF_GSO_TYPE_NONE,
365 };
366 unsigned long bytes;
367
368 if (skb_is_gso(skb)) {
369 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
370 info.gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
371 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
372 info.gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
373 }
374
375 /* Data must not cross a page boundary. */
376 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page));
377
378 info.meta = npo->meta + npo->meta_prod - 1;
379
380 /* Skip unused frames from start of page */
381 page += offset >> PAGE_SHIFT;
382 offset &= ~PAGE_MASK;
383
384 while (size > 0) {
385 BUG_ON(offset >= PAGE_SIZE);
386
387 bytes = PAGE_SIZE - offset;
388 if (bytes > size)
389 bytes = size;
390
391 info.page = page;
392 gnttab_foreach_grant_in_range(page, offset, bytes,
393 xenvif_gop_frag_copy_grant,
394 &info);
395 size -= bytes;
396 offset = 0;
397
398 /* Next page */
399 if (size) {
400 BUG_ON(!PageCompound(page));
401 page++;
402 }
403 }
404
405 *head = info.head;
406 }
407
408 /*
409 * Prepare an SKB to be transmitted to the frontend.
410 *
411 * This function is responsible for allocating grant operations, meta
412 * structures, etc.
413 *
414 * It returns the number of meta structures consumed. The number of
415 * ring slots used is always equal to the number of meta slots used
416 * plus the number of GSO descriptors used. Currently, we use either
417 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
418 * frontend-side LRO).
419 */
420 static int xenvif_gop_skb(struct sk_buff *skb,
421 struct netrx_pending_operations *npo,
422 struct xenvif_queue *queue)
423 {
424 struct xenvif *vif = netdev_priv(skb->dev);
425 int nr_frags = skb_shinfo(skb)->nr_frags;
426 int i;
427 struct xen_netif_rx_request req;
428 struct xenvif_rx_meta *meta;
429 unsigned char *data;
430 int head = 1;
431 int old_meta_prod;
432 int gso_type;
433
434 old_meta_prod = npo->meta_prod;
435
436 gso_type = XEN_NETIF_GSO_TYPE_NONE;
437 if (skb_is_gso(skb)) {
438 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
439 gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
440 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
441 gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
442 }
443
444 /* Set up a GSO prefix descriptor, if necessary */
445 if ((1 << gso_type) & vif->gso_prefix_mask) {
446 RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
447 meta = npo->meta + npo->meta_prod++;
448 meta->gso_type = gso_type;
449 meta->gso_size = skb_shinfo(skb)->gso_size;
450 meta->size = 0;
451 meta->id = req.id;
452 }
453
454 RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
455 meta = npo->meta + npo->meta_prod++;
456
457 if ((1 << gso_type) & vif->gso_mask) {
458 meta->gso_type = gso_type;
459 meta->gso_size = skb_shinfo(skb)->gso_size;
460 } else {
461 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
462 meta->gso_size = 0;
463 }
464
465 meta->size = 0;
466 meta->id = req.id;
467 npo->copy_off = 0;
468 npo->copy_gref = req.gref;
469
470 data = skb->data;
471 while (data < skb_tail_pointer(skb)) {
472 unsigned int offset = offset_in_page(data);
473 unsigned int len = PAGE_SIZE - offset;
474
475 if (data + len > skb_tail_pointer(skb))
476 len = skb_tail_pointer(skb) - data;
477
478 xenvif_gop_frag_copy(queue, skb, npo,
479 virt_to_page(data), len, offset, &head);
480 data += len;
481 }
482
483 for (i = 0; i < nr_frags; i++) {
484 xenvif_gop_frag_copy(queue, skb, npo,
485 skb_frag_page(&skb_shinfo(skb)->frags[i]),
486 skb_frag_size(&skb_shinfo(skb)->frags[i]),
487 skb_shinfo(skb)->frags[i].page_offset,
488 &head);
489 }
490
491 return npo->meta_prod - old_meta_prod;
492 }
493
494 /*
495 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
496 * used to set up the operations on the top of
497 * netrx_pending_operations, which have since been done. Check that
498 * they didn't give any errors and advance over them.
499 */
500 static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
501 struct netrx_pending_operations *npo)
502 {
503 struct gnttab_copy *copy_op;
504 int status = XEN_NETIF_RSP_OKAY;
505 int i;
506
507 for (i = 0; i < nr_meta_slots; i++) {
508 copy_op = npo->copy + npo->copy_cons++;
509 if (copy_op->status != GNTST_okay) {
510 netdev_dbg(vif->dev,
511 "Bad status %d from copy to DOM%d.\n",
512 copy_op->status, vif->domid);
513 status = XEN_NETIF_RSP_ERROR;
514 }
515 }
516
517 return status;
518 }
519
520 static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status,
521 struct xenvif_rx_meta *meta,
522 int nr_meta_slots)
523 {
524 int i;
525 unsigned long offset;
526
527 /* No fragments used */
528 if (nr_meta_slots <= 1)
529 return;
530
531 nr_meta_slots--;
532
533 for (i = 0; i < nr_meta_slots; i++) {
534 int flags;
535 if (i == nr_meta_slots - 1)
536 flags = 0;
537 else
538 flags = XEN_NETRXF_more_data;
539
540 offset = 0;
541 make_rx_response(queue, meta[i].id, status, offset,
542 meta[i].size, flags);
543 }
544 }
545
546 void xenvif_kick_thread(struct xenvif_queue *queue)
547 {
548 wake_up(&queue->wq);
549 }
550
551 static void xenvif_rx_action(struct xenvif_queue *queue)
552 {
553 s8 status;
554 u16 flags;
555 struct xen_netif_rx_response *resp;
556 struct sk_buff_head rxq;
557 struct sk_buff *skb;
558 LIST_HEAD(notify);
559 int ret;
560 unsigned long offset;
561 bool need_to_notify = false;
562
563 struct netrx_pending_operations npo = {
564 .copy = queue->grant_copy_op,
565 .meta = queue->meta,
566 };
567
568 skb_queue_head_init(&rxq);
569
570 while (xenvif_rx_ring_slots_available(queue)
571 && (skb = xenvif_rx_dequeue(queue)) != NULL) {
572 queue->last_rx_time = jiffies;
573
574 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
575
576 __skb_queue_tail(&rxq, skb);
577 }
578
579 BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
580
581 if (!npo.copy_prod)
582 goto done;
583
584 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
585 gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
586
587 while ((skb = __skb_dequeue(&rxq)) != NULL) {
588
589 if ((1 << queue->meta[npo.meta_cons].gso_type) &
590 queue->vif->gso_prefix_mask) {
591 resp = RING_GET_RESPONSE(&queue->rx,
592 queue->rx.rsp_prod_pvt++);
593
594 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
595
596 resp->offset = queue->meta[npo.meta_cons].gso_size;
597 resp->id = queue->meta[npo.meta_cons].id;
598 resp->status = XENVIF_RX_CB(skb)->meta_slots_used;
599
600 npo.meta_cons++;
601 XENVIF_RX_CB(skb)->meta_slots_used--;
602 }
603
604
605 queue->stats.tx_bytes += skb->len;
606 queue->stats.tx_packets++;
607
608 status = xenvif_check_gop(queue->vif,
609 XENVIF_RX_CB(skb)->meta_slots_used,
610 &npo);
611
612 if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
613 flags = 0;
614 else
615 flags = XEN_NETRXF_more_data;
616
617 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
618 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
619 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
620 /* remote but checksummed. */
621 flags |= XEN_NETRXF_data_validated;
622
623 offset = 0;
624 resp = make_rx_response(queue, queue->meta[npo.meta_cons].id,
625 status, offset,
626 queue->meta[npo.meta_cons].size,
627 flags);
628
629 if ((1 << queue->meta[npo.meta_cons].gso_type) &
630 queue->vif->gso_mask) {
631 struct xen_netif_extra_info *gso =
632 (struct xen_netif_extra_info *)
633 RING_GET_RESPONSE(&queue->rx,
634 queue->rx.rsp_prod_pvt++);
635
636 resp->flags |= XEN_NETRXF_extra_info;
637
638 gso->u.gso.type = queue->meta[npo.meta_cons].gso_type;
639 gso->u.gso.size = queue->meta[npo.meta_cons].gso_size;
640 gso->u.gso.pad = 0;
641 gso->u.gso.features = 0;
642
643 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
644 gso->flags = 0;
645 }
646
647 xenvif_add_frag_responses(queue, status,
648 queue->meta + npo.meta_cons + 1,
649 XENVIF_RX_CB(skb)->meta_slots_used);
650
651 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret);
652
653 need_to_notify |= !!ret;
654
655 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
656 dev_kfree_skb(skb);
657 }
658
659 done:
660 if (need_to_notify)
661 notify_remote_via_irq(queue->rx_irq);
662 }
663
664 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
665 {
666 int more_to_do;
667
668 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
669
670 if (more_to_do)
671 napi_schedule(&queue->napi);
672 }
673
674 static void tx_add_credit(struct xenvif_queue *queue)
675 {
676 unsigned long max_burst, max_credit;
677
678 /*
679 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
680 * Otherwise the interface can seize up due to insufficient credit.
681 */
682 max_burst = max(131072UL, queue->credit_bytes);
683
684 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
685 max_credit = queue->remaining_credit + queue->credit_bytes;
686 if (max_credit < queue->remaining_credit)
687 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
688
689 queue->remaining_credit = min(max_credit, max_burst);
690 }
691
692 void xenvif_tx_credit_callback(unsigned long data)
693 {
694 struct xenvif_queue *queue = (struct xenvif_queue *)data;
695 tx_add_credit(queue);
696 xenvif_napi_schedule_or_enable_events(queue);
697 }
698
699 static void xenvif_tx_err(struct xenvif_queue *queue,
700 struct xen_netif_tx_request *txp,
701 unsigned int extra_count, RING_IDX end)
702 {
703 RING_IDX cons = queue->tx.req_cons;
704 unsigned long flags;
705
706 do {
707 spin_lock_irqsave(&queue->response_lock, flags);
708 make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
709 push_tx_responses(queue);
710 spin_unlock_irqrestore(&queue->response_lock, flags);
711 if (cons == end)
712 break;
713 RING_COPY_REQUEST(&queue->tx, cons++, txp);
714 } while (1);
715 queue->tx.req_cons = cons;
716 }
717
718 static void xenvif_fatal_tx_err(struct xenvif *vif)
719 {
720 netdev_err(vif->dev, "fatal error; disabling device\n");
721 vif->disabled = true;
722 /* Disable the vif from queue 0's kthread */
723 if (vif->queues)
724 xenvif_kick_thread(&vif->queues[0]);
725 }
726
727 static int xenvif_count_requests(struct xenvif_queue *queue,
728 struct xen_netif_tx_request *first,
729 unsigned int extra_count,
730 struct xen_netif_tx_request *txp,
731 int work_to_do)
732 {
733 RING_IDX cons = queue->tx.req_cons;
734 int slots = 0;
735 int drop_err = 0;
736 int more_data;
737
738 if (!(first->flags & XEN_NETTXF_more_data))
739 return 0;
740
741 do {
742 struct xen_netif_tx_request dropped_tx = { 0 };
743
744 if (slots >= work_to_do) {
745 netdev_err(queue->vif->dev,
746 "Asked for %d slots but exceeds this limit\n",
747 work_to_do);
748 xenvif_fatal_tx_err(queue->vif);
749 return -ENODATA;
750 }
751
752 /* This guest is really using too many slots and
753 * considered malicious.
754 */
755 if (unlikely(slots >= fatal_skb_slots)) {
756 netdev_err(queue->vif->dev,
757 "Malicious frontend using %d slots, threshold %u\n",
758 slots, fatal_skb_slots);
759 xenvif_fatal_tx_err(queue->vif);
760 return -E2BIG;
761 }
762
763 /* Xen network protocol had implicit dependency on
764 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
765 * the historical MAX_SKB_FRAGS value 18 to honor the
766 * same behavior as before. Any packet using more than
767 * 18 slots but less than fatal_skb_slots slots is
768 * dropped
769 */
770 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
771 if (net_ratelimit())
772 netdev_dbg(queue->vif->dev,
773 "Too many slots (%d) exceeding limit (%d), dropping packet\n",
774 slots, XEN_NETBK_LEGACY_SLOTS_MAX);
775 drop_err = -E2BIG;
776 }
777
778 if (drop_err)
779 txp = &dropped_tx;
780
781 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
782
783 /* If the guest submitted a frame >= 64 KiB then
784 * first->size overflowed and following slots will
785 * appear to be larger than the frame.
786 *
787 * This cannot be fatal error as there are buggy
788 * frontends that do this.
789 *
790 * Consume all slots and drop the packet.
791 */
792 if (!drop_err && txp->size > first->size) {
793 if (net_ratelimit())
794 netdev_dbg(queue->vif->dev,
795 "Invalid tx request, slot size %u > remaining size %u\n",
796 txp->size, first->size);
797 drop_err = -EIO;
798 }
799
800 first->size -= txp->size;
801 slots++;
802
803 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
804 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
805 txp->offset, txp->size);
806 xenvif_fatal_tx_err(queue->vif);
807 return -EINVAL;
808 }
809
810 more_data = txp->flags & XEN_NETTXF_more_data;
811
812 if (!drop_err)
813 txp++;
814
815 } while (more_data);
816
817 if (drop_err) {
818 xenvif_tx_err(queue, first, extra_count, cons + slots);
819 return drop_err;
820 }
821
822 return slots;
823 }
824
825
826 struct xenvif_tx_cb {
827 u16 pending_idx;
828 };
829
830 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
831
832 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
833 u16 pending_idx,
834 struct xen_netif_tx_request *txp,
835 unsigned int extra_count,
836 struct gnttab_map_grant_ref *mop)
837 {
838 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
839 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
840 GNTMAP_host_map | GNTMAP_readonly,
841 txp->gref, queue->vif->domid);
842
843 memcpy(&queue->pending_tx_info[pending_idx].req, txp,
844 sizeof(*txp));
845 queue->pending_tx_info[pending_idx].extra_count = extra_count;
846 }
847
848 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
849 {
850 struct sk_buff *skb =
851 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
852 GFP_ATOMIC | __GFP_NOWARN);
853 if (unlikely(skb == NULL))
854 return NULL;
855
856 /* Packets passed to netif_rx() must have some headroom. */
857 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
858
859 /* Initialize it here to avoid later surprises */
860 skb_shinfo(skb)->destructor_arg = NULL;
861
862 return skb;
863 }
864
865 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
866 struct sk_buff *skb,
867 struct xen_netif_tx_request *txp,
868 struct gnttab_map_grant_ref *gop,
869 unsigned int frag_overflow,
870 struct sk_buff *nskb)
871 {
872 struct skb_shared_info *shinfo = skb_shinfo(skb);
873 skb_frag_t *frags = shinfo->frags;
874 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
875 int start;
876 pending_ring_idx_t index;
877 unsigned int nr_slots;
878
879 nr_slots = shinfo->nr_frags;
880
881 /* Skip first skb fragment if it is on same page as header fragment. */
882 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
883
884 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
885 shinfo->nr_frags++, txp++, gop++) {
886 index = pending_index(queue->pending_cons++);
887 pending_idx = queue->pending_ring[index];
888 xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
889 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
890 }
891
892 if (frag_overflow) {
893
894 shinfo = skb_shinfo(nskb);
895 frags = shinfo->frags;
896
897 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
898 shinfo->nr_frags++, txp++, gop++) {
899 index = pending_index(queue->pending_cons++);
900 pending_idx = queue->pending_ring[index];
901 xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
902 gop);
903 frag_set_pending_idx(&frags[shinfo->nr_frags],
904 pending_idx);
905 }
906
907 skb_shinfo(skb)->frag_list = nskb;
908 }
909
910 return gop;
911 }
912
913 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
914 u16 pending_idx,
915 grant_handle_t handle)
916 {
917 if (unlikely(queue->grant_tx_handle[pending_idx] !=
918 NETBACK_INVALID_HANDLE)) {
919 netdev_err(queue->vif->dev,
920 "Trying to overwrite active handle! pending_idx: 0x%x\n",
921 pending_idx);
922 BUG();
923 }
924 queue->grant_tx_handle[pending_idx] = handle;
925 }
926
927 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
928 u16 pending_idx)
929 {
930 if (unlikely(queue->grant_tx_handle[pending_idx] ==
931 NETBACK_INVALID_HANDLE)) {
932 netdev_err(queue->vif->dev,
933 "Trying to unmap invalid handle! pending_idx: 0x%x\n",
934 pending_idx);
935 BUG();
936 }
937 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
938 }
939
940 static int xenvif_tx_check_gop(struct xenvif_queue *queue,
941 struct sk_buff *skb,
942 struct gnttab_map_grant_ref **gopp_map,
943 struct gnttab_copy **gopp_copy)
944 {
945 struct gnttab_map_grant_ref *gop_map = *gopp_map;
946 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
947 /* This always points to the shinfo of the skb being checked, which
948 * could be either the first or the one on the frag_list
949 */
950 struct skb_shared_info *shinfo = skb_shinfo(skb);
951 /* If this is non-NULL, we are currently checking the frag_list skb, and
952 * this points to the shinfo of the first one
953 */
954 struct skb_shared_info *first_shinfo = NULL;
955 int nr_frags = shinfo->nr_frags;
956 const bool sharedslot = nr_frags &&
957 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
958 int i, err;
959
960 /* Check status of header. */
961 err = (*gopp_copy)->status;
962 if (unlikely(err)) {
963 if (net_ratelimit())
964 netdev_dbg(queue->vif->dev,
965 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
966 (*gopp_copy)->status,
967 pending_idx,
968 (*gopp_copy)->source.u.ref);
969 /* The first frag might still have this slot mapped */
970 if (!sharedslot)
971 xenvif_idx_release(queue, pending_idx,
972 XEN_NETIF_RSP_ERROR);
973 }
974 (*gopp_copy)++;
975
976 check_frags:
977 for (i = 0; i < nr_frags; i++, gop_map++) {
978 int j, newerr;
979
980 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
981
982 /* Check error status: if okay then remember grant handle. */
983 newerr = gop_map->status;
984
985 if (likely(!newerr)) {
986 xenvif_grant_handle_set(queue,
987 pending_idx,
988 gop_map->handle);
989 /* Had a previous error? Invalidate this fragment. */
990 if (unlikely(err)) {
991 xenvif_idx_unmap(queue, pending_idx);
992 /* If the mapping of the first frag was OK, but
993 * the header's copy failed, and they are
994 * sharing a slot, send an error
995 */
996 if (i == 0 && sharedslot)
997 xenvif_idx_release(queue, pending_idx,
998 XEN_NETIF_RSP_ERROR);
999 else
1000 xenvif_idx_release(queue, pending_idx,
1001 XEN_NETIF_RSP_OKAY);
1002 }
1003 continue;
1004 }
1005
1006 /* Error on this fragment: respond to client with an error. */
1007 if (net_ratelimit())
1008 netdev_dbg(queue->vif->dev,
1009 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
1010 i,
1011 gop_map->status,
1012 pending_idx,
1013 gop_map->ref);
1014
1015 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
1016
1017 /* Not the first error? Preceding frags already invalidated. */
1018 if (err)
1019 continue;
1020
1021 /* First error: if the header haven't shared a slot with the
1022 * first frag, release it as well.
1023 */
1024 if (!sharedslot)
1025 xenvif_idx_release(queue,
1026 XENVIF_TX_CB(skb)->pending_idx,
1027 XEN_NETIF_RSP_OKAY);
1028
1029 /* Invalidate preceding fragments of this skb. */
1030 for (j = 0; j < i; j++) {
1031 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
1032 xenvif_idx_unmap(queue, pending_idx);
1033 xenvif_idx_release(queue, pending_idx,
1034 XEN_NETIF_RSP_OKAY);
1035 }
1036
1037 /* And if we found the error while checking the frag_list, unmap
1038 * the first skb's frags
1039 */
1040 if (first_shinfo) {
1041 for (j = 0; j < first_shinfo->nr_frags; j++) {
1042 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
1043 xenvif_idx_unmap(queue, pending_idx);
1044 xenvif_idx_release(queue, pending_idx,
1045 XEN_NETIF_RSP_OKAY);
1046 }
1047 }
1048
1049 /* Remember the error: invalidate all subsequent fragments. */
1050 err = newerr;
1051 }
1052
1053 if (skb_has_frag_list(skb) && !first_shinfo) {
1054 first_shinfo = skb_shinfo(skb);
1055 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
1056 nr_frags = shinfo->nr_frags;
1057
1058 goto check_frags;
1059 }
1060
1061 *gopp_map = gop_map;
1062 return err;
1063 }
1064
1065 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
1066 {
1067 struct skb_shared_info *shinfo = skb_shinfo(skb);
1068 int nr_frags = shinfo->nr_frags;
1069 int i;
1070 u16 prev_pending_idx = INVALID_PENDING_IDX;
1071
1072 for (i = 0; i < nr_frags; i++) {
1073 skb_frag_t *frag = shinfo->frags + i;
1074 struct xen_netif_tx_request *txp;
1075 struct page *page;
1076 u16 pending_idx;
1077
1078 pending_idx = frag_get_pending_idx(frag);
1079
1080 /* If this is not the first frag, chain it to the previous*/
1081 if (prev_pending_idx == INVALID_PENDING_IDX)
1082 skb_shinfo(skb)->destructor_arg =
1083 &callback_param(queue, pending_idx);
1084 else
1085 callback_param(queue, prev_pending_idx).ctx =
1086 &callback_param(queue, pending_idx);
1087
1088 callback_param(queue, pending_idx).ctx = NULL;
1089 prev_pending_idx = pending_idx;
1090
1091 txp = &queue->pending_tx_info[pending_idx].req;
1092 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
1093 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
1094 skb->len += txp->size;
1095 skb->data_len += txp->size;
1096 skb->truesize += txp->size;
1097
1098 /* Take an extra reference to offset network stack's put_page */
1099 get_page(queue->mmap_pages[pending_idx]);
1100 }
1101 }
1102
1103 static int xenvif_get_extras(struct xenvif_queue *queue,
1104 struct xen_netif_extra_info *extras,
1105 unsigned int *extra_count,
1106 int work_to_do)
1107 {
1108 struct xen_netif_extra_info extra;
1109 RING_IDX cons = queue->tx.req_cons;
1110
1111 do {
1112 if (unlikely(work_to_do-- <= 0)) {
1113 netdev_err(queue->vif->dev, "Missing extra info\n");
1114 xenvif_fatal_tx_err(queue->vif);
1115 return -EBADR;
1116 }
1117
1118 RING_COPY_REQUEST(&queue->tx, cons, &extra);
1119
1120 queue->tx.req_cons = ++cons;
1121 (*extra_count)++;
1122
1123 if (unlikely(!extra.type ||
1124 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1125 netdev_err(queue->vif->dev,
1126 "Invalid extra type: %d\n", extra.type);
1127 xenvif_fatal_tx_err(queue->vif);
1128 return -EINVAL;
1129 }
1130
1131 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1132 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1133
1134 return work_to_do;
1135 }
1136
1137 static int xenvif_set_skb_gso(struct xenvif *vif,
1138 struct sk_buff *skb,
1139 struct xen_netif_extra_info *gso)
1140 {
1141 if (!gso->u.gso.size) {
1142 netdev_err(vif->dev, "GSO size must not be zero.\n");
1143 xenvif_fatal_tx_err(vif);
1144 return -EINVAL;
1145 }
1146
1147 switch (gso->u.gso.type) {
1148 case XEN_NETIF_GSO_TYPE_TCPV4:
1149 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1150 break;
1151 case XEN_NETIF_GSO_TYPE_TCPV6:
1152 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
1153 break;
1154 default:
1155 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1156 xenvif_fatal_tx_err(vif);
1157 return -EINVAL;
1158 }
1159
1160 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1161 /* gso_segs will be calculated later */
1162
1163 return 0;
1164 }
1165
1166 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
1167 {
1168 bool recalculate_partial_csum = false;
1169
1170 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1171 * peers can fail to set NETRXF_csum_blank when sending a GSO
1172 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1173 * recalculate the partial checksum.
1174 */
1175 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1176 queue->stats.rx_gso_checksum_fixup++;
1177 skb->ip_summed = CHECKSUM_PARTIAL;
1178 recalculate_partial_csum = true;
1179 }
1180
1181 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1182 if (skb->ip_summed != CHECKSUM_PARTIAL)
1183 return 0;
1184
1185 return skb_checksum_setup(skb, recalculate_partial_csum);
1186 }
1187
1188 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
1189 {
1190 u64 now = get_jiffies_64();
1191 u64 next_credit = queue->credit_window_start +
1192 msecs_to_jiffies(queue->credit_usec / 1000);
1193
1194 /* Timer could already be pending in rare cases. */
1195 if (timer_pending(&queue->credit_timeout))
1196 return true;
1197
1198 /* Passed the point where we can replenish credit? */
1199 if (time_after_eq64(now, next_credit)) {
1200 queue->credit_window_start = now;
1201 tx_add_credit(queue);
1202 }
1203
1204 /* Still too big to send right now? Set a callback. */
1205 if (size > queue->remaining_credit) {
1206 queue->credit_timeout.data =
1207 (unsigned long)queue;
1208 mod_timer(&queue->credit_timeout,
1209 next_credit);
1210 queue->credit_window_start = next_credit;
1211
1212 return true;
1213 }
1214
1215 return false;
1216 }
1217
1218 /* No locking is required in xenvif_mcast_add/del() as they are
1219 * only ever invoked from NAPI poll. An RCU list is used because
1220 * xenvif_mcast_match() is called asynchronously, during start_xmit.
1221 */
1222
1223 static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
1224 {
1225 struct xenvif_mcast_addr *mcast;
1226
1227 if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
1228 if (net_ratelimit())
1229 netdev_err(vif->dev,
1230 "Too many multicast addresses\n");
1231 return -ENOSPC;
1232 }
1233
1234 mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
1235 if (!mcast)
1236 return -ENOMEM;
1237
1238 ether_addr_copy(mcast->addr, addr);
1239 list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
1240 vif->fe_mcast_count++;
1241
1242 return 0;
1243 }
1244
1245 static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
1246 {
1247 struct xenvif_mcast_addr *mcast;
1248
1249 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
1250 if (ether_addr_equal(addr, mcast->addr)) {
1251 --vif->fe_mcast_count;
1252 list_del_rcu(&mcast->entry);
1253 kfree_rcu(mcast, rcu);
1254 break;
1255 }
1256 }
1257 }
1258
1259 bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
1260 {
1261 struct xenvif_mcast_addr *mcast;
1262
1263 rcu_read_lock();
1264 list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
1265 if (ether_addr_equal(addr, mcast->addr)) {
1266 rcu_read_unlock();
1267 return true;
1268 }
1269 }
1270 rcu_read_unlock();
1271
1272 return false;
1273 }
1274
1275 void xenvif_mcast_addr_list_free(struct xenvif *vif)
1276 {
1277 /* No need for locking or RCU here. NAPI poll and TX queue
1278 * are stopped.
1279 */
1280 while (!list_empty(&vif->fe_mcast_addr)) {
1281 struct xenvif_mcast_addr *mcast;
1282
1283 mcast = list_first_entry(&vif->fe_mcast_addr,
1284 struct xenvif_mcast_addr,
1285 entry);
1286 --vif->fe_mcast_count;
1287 list_del(&mcast->entry);
1288 kfree(mcast);
1289 }
1290 }
1291
1292 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
1293 int budget,
1294 unsigned *copy_ops,
1295 unsigned *map_ops)
1296 {
1297 struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
1298 struct sk_buff *skb, *nskb;
1299 int ret;
1300 unsigned int frag_overflow;
1301
1302 while (skb_queue_len(&queue->tx_queue) < budget) {
1303 struct xen_netif_tx_request txreq;
1304 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
1305 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1306 unsigned int extra_count;
1307 u16 pending_idx;
1308 RING_IDX idx;
1309 int work_to_do;
1310 unsigned int data_len;
1311 pending_ring_idx_t index;
1312
1313 if (queue->tx.sring->req_prod - queue->tx.req_cons >
1314 XEN_NETIF_TX_RING_SIZE) {
1315 netdev_err(queue->vif->dev,
1316 "Impossible number of requests. "
1317 "req_prod %d, req_cons %d, size %ld\n",
1318 queue->tx.sring->req_prod, queue->tx.req_cons,
1319 XEN_NETIF_TX_RING_SIZE);
1320 xenvif_fatal_tx_err(queue->vif);
1321 break;
1322 }
1323
1324 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
1325 if (!work_to_do)
1326 break;
1327
1328 idx = queue->tx.req_cons;
1329 rmb(); /* Ensure that we see the request before we copy it. */
1330 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
1331
1332 /* Credit-based scheduling. */
1333 if (txreq.size > queue->remaining_credit &&
1334 tx_credit_exceeded(queue, txreq.size))
1335 break;
1336
1337 queue->remaining_credit -= txreq.size;
1338
1339 work_to_do--;
1340 queue->tx.req_cons = ++idx;
1341
1342 memset(extras, 0, sizeof(extras));
1343 extra_count = 0;
1344 if (txreq.flags & XEN_NETTXF_extra_info) {
1345 work_to_do = xenvif_get_extras(queue, extras,
1346 &extra_count,
1347 work_to_do);
1348 idx = queue->tx.req_cons;
1349 if (unlikely(work_to_do < 0))
1350 break;
1351 }
1352
1353 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
1354 struct xen_netif_extra_info *extra;
1355
1356 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
1357 ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
1358
1359 make_tx_response(queue, &txreq, extra_count,
1360 (ret == 0) ?
1361 XEN_NETIF_RSP_OKAY :
1362 XEN_NETIF_RSP_ERROR);
1363 push_tx_responses(queue);
1364 continue;
1365 }
1366
1367 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
1368 struct xen_netif_extra_info *extra;
1369
1370 extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
1371 xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
1372
1373 make_tx_response(queue, &txreq, extra_count,
1374 XEN_NETIF_RSP_OKAY);
1375 push_tx_responses(queue);
1376 continue;
1377 }
1378
1379 ret = xenvif_count_requests(queue, &txreq, extra_count,
1380 txfrags, work_to_do);
1381 if (unlikely(ret < 0))
1382 break;
1383
1384 idx += ret;
1385
1386 if (unlikely(txreq.size < ETH_HLEN)) {
1387 netdev_dbg(queue->vif->dev,
1388 "Bad packet size: %d\n", txreq.size);
1389 xenvif_tx_err(queue, &txreq, extra_count, idx);
1390 break;
1391 }
1392
1393 /* No crossing a page as the payload mustn't fragment. */
1394 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
1395 netdev_err(queue->vif->dev,
1396 "txreq.offset: %u, size: %u, end: %lu\n",
1397 txreq.offset, txreq.size,
1398 (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
1399 xenvif_fatal_tx_err(queue->vif);
1400 break;
1401 }
1402
1403 index = pending_index(queue->pending_cons);
1404 pending_idx = queue->pending_ring[index];
1405
1406 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
1407 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
1408 XEN_NETBACK_TX_COPY_LEN : txreq.size;
1409
1410 skb = xenvif_alloc_skb(data_len);
1411 if (unlikely(skb == NULL)) {
1412 netdev_dbg(queue->vif->dev,
1413 "Can't allocate a skb in start_xmit.\n");
1414 xenvif_tx_err(queue, &txreq, extra_count, idx);
1415 break;
1416 }
1417
1418 skb_shinfo(skb)->nr_frags = ret;
1419 if (data_len < txreq.size)
1420 skb_shinfo(skb)->nr_frags++;
1421 /* At this point shinfo->nr_frags is in fact the number of
1422 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
1423 */
1424 frag_overflow = 0;
1425 nskb = NULL;
1426 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
1427 frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
1428 BUG_ON(frag_overflow > MAX_SKB_FRAGS);
1429 skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
1430 nskb = xenvif_alloc_skb(0);
1431 if (unlikely(nskb == NULL)) {
1432 kfree_skb(skb);
1433 xenvif_tx_err(queue, &txreq, extra_count, idx);
1434 if (net_ratelimit())
1435 netdev_err(queue->vif->dev,
1436 "Can't allocate the frag_list skb.\n");
1437 break;
1438 }
1439 }
1440
1441 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1442 struct xen_netif_extra_info *gso;
1443 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1444
1445 if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
1446 /* Failure in xenvif_set_skb_gso is fatal. */
1447 kfree_skb(skb);
1448 kfree_skb(nskb);
1449 break;
1450 }
1451 }
1452
1453 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
1454
1455 __skb_put(skb, data_len);
1456 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
1457 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
1458 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
1459
1460 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
1461 virt_to_gfn(skb->data);
1462 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
1463 queue->tx_copy_ops[*copy_ops].dest.offset =
1464 offset_in_page(skb->data) & ~XEN_PAGE_MASK;
1465
1466 queue->tx_copy_ops[*copy_ops].len = data_len;
1467 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
1468
1469 (*copy_ops)++;
1470
1471 if (data_len < txreq.size) {
1472 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1473 pending_idx);
1474 xenvif_tx_create_map_op(queue, pending_idx, &txreq,
1475 extra_count, gop);
1476 gop++;
1477 } else {
1478 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1479 INVALID_PENDING_IDX);
1480 memcpy(&queue->pending_tx_info[pending_idx].req,
1481 &txreq, sizeof(txreq));
1482 queue->pending_tx_info[pending_idx].extra_count =
1483 extra_count;
1484 }
1485
1486 queue->pending_cons++;
1487
1488 gop = xenvif_get_requests(queue, skb, txfrags, gop,
1489 frag_overflow, nskb);
1490
1491 __skb_queue_tail(&queue->tx_queue, skb);
1492
1493 queue->tx.req_cons = idx;
1494
1495 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1496 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1497 break;
1498 }
1499
1500 (*map_ops) = gop - queue->tx_map_ops;
1501 return;
1502 }
1503
1504 /* Consolidate skb with a frag_list into a brand new one with local pages on
1505 * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1506 */
1507 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1508 {
1509 unsigned int offset = skb_headlen(skb);
1510 skb_frag_t frags[MAX_SKB_FRAGS];
1511 int i, f;
1512 struct ubuf_info *uarg;
1513 struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1514
1515 queue->stats.tx_zerocopy_sent += 2;
1516 queue->stats.tx_frag_overflow++;
1517
1518 xenvif_fill_frags(queue, nskb);
1519 /* Subtract frags size, we will correct it later */
1520 skb->truesize -= skb->data_len;
1521 skb->len += nskb->len;
1522 skb->data_len += nskb->len;
1523
1524 /* create a brand new frags array and coalesce there */
1525 for (i = 0; offset < skb->len; i++) {
1526 struct page *page;
1527 unsigned int len;
1528
1529 BUG_ON(i >= MAX_SKB_FRAGS);
1530 page = alloc_page(GFP_ATOMIC);
1531 if (!page) {
1532 int j;
1533 skb->truesize += skb->data_len;
1534 for (j = 0; j < i; j++)
1535 put_page(frags[j].page.p);
1536 return -ENOMEM;
1537 }
1538
1539 if (offset + PAGE_SIZE < skb->len)
1540 len = PAGE_SIZE;
1541 else
1542 len = skb->len - offset;
1543 if (skb_copy_bits(skb, offset, page_address(page), len))
1544 BUG();
1545
1546 offset += len;
1547 frags[i].page.p = page;
1548 frags[i].page_offset = 0;
1549 skb_frag_size_set(&frags[i], len);
1550 }
1551
1552 /* Copied all the bits from the frag list -- free it. */
1553 skb_frag_list_init(skb);
1554 xenvif_skb_zerocopy_prepare(queue, nskb);
1555 kfree_skb(nskb);
1556
1557 /* Release all the original (foreign) frags. */
1558 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1559 skb_frag_unref(skb, f);
1560 uarg = skb_shinfo(skb)->destructor_arg;
1561 /* increase inflight counter to offset decrement in callback */
1562 atomic_inc(&queue->inflight_packets);
1563 uarg->callback(uarg, true);
1564 skb_shinfo(skb)->destructor_arg = NULL;
1565
1566 /* Fill the skb with the new (local) frags. */
1567 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1568 skb_shinfo(skb)->nr_frags = i;
1569 skb->truesize += i * PAGE_SIZE;
1570
1571 return 0;
1572 }
1573
1574 static int xenvif_tx_submit(struct xenvif_queue *queue)
1575 {
1576 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1577 struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1578 struct sk_buff *skb;
1579 int work_done = 0;
1580
1581 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1582 struct xen_netif_tx_request *txp;
1583 u16 pending_idx;
1584 unsigned data_len;
1585
1586 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1587 txp = &queue->pending_tx_info[pending_idx].req;
1588
1589 /* Check the remap error code. */
1590 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1591 /* If there was an error, xenvif_tx_check_gop is
1592 * expected to release all the frags which were mapped,
1593 * so kfree_skb shouldn't do it again
1594 */
1595 skb_shinfo(skb)->nr_frags = 0;
1596 if (skb_has_frag_list(skb)) {
1597 struct sk_buff *nskb =
1598 skb_shinfo(skb)->frag_list;
1599 skb_shinfo(nskb)->nr_frags = 0;
1600 }
1601 kfree_skb(skb);
1602 continue;
1603 }
1604
1605 data_len = skb->len;
1606 callback_param(queue, pending_idx).ctx = NULL;
1607 if (data_len < txp->size) {
1608 /* Append the packet payload as a fragment. */
1609 txp->offset += data_len;
1610 txp->size -= data_len;
1611 } else {
1612 /* Schedule a response immediately. */
1613 xenvif_idx_release(queue, pending_idx,
1614 XEN_NETIF_RSP_OKAY);
1615 }
1616
1617 if (txp->flags & XEN_NETTXF_csum_blank)
1618 skb->ip_summed = CHECKSUM_PARTIAL;
1619 else if (txp->flags & XEN_NETTXF_data_validated)
1620 skb->ip_summed = CHECKSUM_UNNECESSARY;
1621
1622 xenvif_fill_frags(queue, skb);
1623
1624 if (unlikely(skb_has_frag_list(skb))) {
1625 if (xenvif_handle_frag_list(queue, skb)) {
1626 if (net_ratelimit())
1627 netdev_err(queue->vif->dev,
1628 "Not enough memory to consolidate frag_list!\n");
1629 xenvif_skb_zerocopy_prepare(queue, skb);
1630 kfree_skb(skb);
1631 continue;
1632 }
1633 }
1634
1635 skb->dev = queue->vif->dev;
1636 skb->protocol = eth_type_trans(skb, skb->dev);
1637 skb_reset_network_header(skb);
1638
1639 if (checksum_setup(queue, skb)) {
1640 netdev_dbg(queue->vif->dev,
1641 "Can't setup checksum in net_tx_action\n");
1642 /* We have to set this flag to trigger the callback */
1643 if (skb_shinfo(skb)->destructor_arg)
1644 xenvif_skb_zerocopy_prepare(queue, skb);
1645 kfree_skb(skb);
1646 continue;
1647 }
1648
1649 skb_probe_transport_header(skb, 0);
1650
1651 /* If the packet is GSO then we will have just set up the
1652 * transport header offset in checksum_setup so it's now
1653 * straightforward to calculate gso_segs.
1654 */
1655 if (skb_is_gso(skb)) {
1656 int mss = skb_shinfo(skb)->gso_size;
1657 int hdrlen = skb_transport_header(skb) -
1658 skb_mac_header(skb) +
1659 tcp_hdrlen(skb);
1660
1661 skb_shinfo(skb)->gso_segs =
1662 DIV_ROUND_UP(skb->len - hdrlen, mss);
1663 }
1664
1665 queue->stats.rx_bytes += skb->len;
1666 queue->stats.rx_packets++;
1667
1668 work_done++;
1669
1670 /* Set this flag right before netif_receive_skb, otherwise
1671 * someone might think this packet already left netback, and
1672 * do a skb_copy_ubufs while we are still in control of the
1673 * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1674 */
1675 if (skb_shinfo(skb)->destructor_arg) {
1676 xenvif_skb_zerocopy_prepare(queue, skb);
1677 queue->stats.tx_zerocopy_sent++;
1678 }
1679
1680 netif_receive_skb(skb);
1681 }
1682
1683 return work_done;
1684 }
1685
1686 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1687 {
1688 unsigned long flags;
1689 pending_ring_idx_t index;
1690 struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1691
1692 /* This is the only place where we grab this lock, to protect callbacks
1693 * from each other.
1694 */
1695 spin_lock_irqsave(&queue->callback_lock, flags);
1696 do {
1697 u16 pending_idx = ubuf->desc;
1698 ubuf = (struct ubuf_info *) ubuf->ctx;
1699 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1700 MAX_PENDING_REQS);
1701 index = pending_index(queue->dealloc_prod);
1702 queue->dealloc_ring[index] = pending_idx;
1703 /* Sync with xenvif_tx_dealloc_action:
1704 * insert idx then incr producer.
1705 */
1706 smp_wmb();
1707 queue->dealloc_prod++;
1708 } while (ubuf);
1709 spin_unlock_irqrestore(&queue->callback_lock, flags);
1710
1711 if (likely(zerocopy_success))
1712 queue->stats.tx_zerocopy_success++;
1713 else
1714 queue->stats.tx_zerocopy_fail++;
1715 xenvif_skb_zerocopy_complete(queue);
1716 }
1717
1718 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1719 {
1720 struct gnttab_unmap_grant_ref *gop;
1721 pending_ring_idx_t dc, dp;
1722 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1723 unsigned int i = 0;
1724
1725 dc = queue->dealloc_cons;
1726 gop = queue->tx_unmap_ops;
1727
1728 /* Free up any grants we have finished using */
1729 do {
1730 dp = queue->dealloc_prod;
1731
1732 /* Ensure we see all indices enqueued by all
1733 * xenvif_zerocopy_callback().
1734 */
1735 smp_rmb();
1736
1737 while (dc != dp) {
1738 BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1739 pending_idx =
1740 queue->dealloc_ring[pending_index(dc++)];
1741
1742 pending_idx_release[gop - queue->tx_unmap_ops] =
1743 pending_idx;
1744 queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1745 queue->mmap_pages[pending_idx];
1746 gnttab_set_unmap_op(gop,
1747 idx_to_kaddr(queue, pending_idx),
1748 GNTMAP_host_map,
1749 queue->grant_tx_handle[pending_idx]);
1750 xenvif_grant_handle_reset(queue, pending_idx);
1751 ++gop;
1752 }
1753
1754 } while (dp != queue->dealloc_prod);
1755
1756 queue->dealloc_cons = dc;
1757
1758 if (gop - queue->tx_unmap_ops > 0) {
1759 int ret;
1760 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1761 NULL,
1762 queue->pages_to_unmap,
1763 gop - queue->tx_unmap_ops);
1764 if (ret) {
1765 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1766 gop - queue->tx_unmap_ops, ret);
1767 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1768 if (gop[i].status != GNTST_okay)
1769 netdev_err(queue->vif->dev,
1770 " host_addr: 0x%llx handle: 0x%x status: %d\n",
1771 gop[i].host_addr,
1772 gop[i].handle,
1773 gop[i].status);
1774 }
1775 BUG();
1776 }
1777 }
1778
1779 for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1780 xenvif_idx_release(queue, pending_idx_release[i],
1781 XEN_NETIF_RSP_OKAY);
1782 }
1783
1784
1785 /* Called after netfront has transmitted */
1786 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1787 {
1788 unsigned nr_mops, nr_cops = 0;
1789 int work_done, ret;
1790
1791 if (unlikely(!tx_work_todo(queue)))
1792 return 0;
1793
1794 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1795
1796 if (nr_cops == 0)
1797 return 0;
1798
1799 gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1800 if (nr_mops != 0) {
1801 ret = gnttab_map_refs(queue->tx_map_ops,
1802 NULL,
1803 queue->pages_to_map,
1804 nr_mops);
1805 BUG_ON(ret);
1806 }
1807
1808 work_done = xenvif_tx_submit(queue);
1809
1810 return work_done;
1811 }
1812
1813 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1814 u8 status)
1815 {
1816 struct pending_tx_info *pending_tx_info;
1817 pending_ring_idx_t index;
1818 unsigned long flags;
1819
1820 pending_tx_info = &queue->pending_tx_info[pending_idx];
1821
1822 spin_lock_irqsave(&queue->response_lock, flags);
1823
1824 make_tx_response(queue, &pending_tx_info->req,
1825 pending_tx_info->extra_count, status);
1826
1827 /* Release the pending index before pusing the Tx response so
1828 * its available before a new Tx request is pushed by the
1829 * frontend.
1830 */
1831 index = pending_index(queue->pending_prod++);
1832 queue->pending_ring[index] = pending_idx;
1833
1834 push_tx_responses(queue);
1835
1836 spin_unlock_irqrestore(&queue->response_lock, flags);
1837 }
1838
1839
1840 static void make_tx_response(struct xenvif_queue *queue,
1841 struct xen_netif_tx_request *txp,
1842 unsigned int extra_count,
1843 s8 st)
1844 {
1845 RING_IDX i = queue->tx.rsp_prod_pvt;
1846 struct xen_netif_tx_response *resp;
1847
1848 resp = RING_GET_RESPONSE(&queue->tx, i);
1849 resp->id = txp->id;
1850 resp->status = st;
1851
1852 while (extra_count-- != 0)
1853 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1854
1855 queue->tx.rsp_prod_pvt = ++i;
1856 }
1857
1858 static void push_tx_responses(struct xenvif_queue *queue)
1859 {
1860 int notify;
1861
1862 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1863 if (notify)
1864 notify_remote_via_irq(queue->tx_irq);
1865 }
1866
1867 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
1868 u16 id,
1869 s8 st,
1870 u16 offset,
1871 u16 size,
1872 u16 flags)
1873 {
1874 RING_IDX i = queue->rx.rsp_prod_pvt;
1875 struct xen_netif_rx_response *resp;
1876
1877 resp = RING_GET_RESPONSE(&queue->rx, i);
1878 resp->offset = offset;
1879 resp->flags = flags;
1880 resp->id = id;
1881 resp->status = (s16)size;
1882 if (st < 0)
1883 resp->status = (s16)st;
1884
1885 queue->rx.rsp_prod_pvt = ++i;
1886
1887 return resp;
1888 }
1889
1890 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1891 {
1892 int ret;
1893 struct gnttab_unmap_grant_ref tx_unmap_op;
1894
1895 gnttab_set_unmap_op(&tx_unmap_op,
1896 idx_to_kaddr(queue, pending_idx),
1897 GNTMAP_host_map,
1898 queue->grant_tx_handle[pending_idx]);
1899 xenvif_grant_handle_reset(queue, pending_idx);
1900
1901 ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1902 &queue->mmap_pages[pending_idx], 1);
1903 if (ret) {
1904 netdev_err(queue->vif->dev,
1905 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1906 ret,
1907 pending_idx,
1908 tx_unmap_op.host_addr,
1909 tx_unmap_op.handle,
1910 tx_unmap_op.status);
1911 BUG();
1912 }
1913 }
1914
1915 static inline int tx_work_todo(struct xenvif_queue *queue)
1916 {
1917 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1918 return 1;
1919
1920 return 0;
1921 }
1922
1923 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1924 {
1925 return queue->dealloc_cons != queue->dealloc_prod;
1926 }
1927
1928 void xenvif_unmap_frontend_rings(struct xenvif_queue *queue)
1929 {
1930 if (queue->tx.sring)
1931 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1932 queue->tx.sring);
1933 if (queue->rx.sring)
1934 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1935 queue->rx.sring);
1936 }
1937
1938 int xenvif_map_frontend_rings(struct xenvif_queue *queue,
1939 grant_ref_t tx_ring_ref,
1940 grant_ref_t rx_ring_ref)
1941 {
1942 void *addr;
1943 struct xen_netif_tx_sring *txs;
1944 struct xen_netif_rx_sring *rxs;
1945
1946 int err = -ENOMEM;
1947
1948 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1949 &tx_ring_ref, 1, &addr);
1950 if (err)
1951 goto err;
1952
1953 txs = (struct xen_netif_tx_sring *)addr;
1954 BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1955
1956 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1957 &rx_ring_ref, 1, &addr);
1958 if (err)
1959 goto err;
1960
1961 rxs = (struct xen_netif_rx_sring *)addr;
1962 BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1963
1964 return 0;
1965
1966 err:
1967 xenvif_unmap_frontend_rings(queue);
1968 return err;
1969 }
1970
1971 static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
1972 {
1973 struct xenvif *vif = queue->vif;
1974
1975 queue->stalled = true;
1976
1977 /* At least one queue has stalled? Disable the carrier. */
1978 spin_lock(&vif->lock);
1979 if (vif->stalled_queues++ == 0) {
1980 netdev_info(vif->dev, "Guest Rx stalled");
1981 netif_carrier_off(vif->dev);
1982 }
1983 spin_unlock(&vif->lock);
1984 }
1985
1986 static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
1987 {
1988 struct xenvif *vif = queue->vif;
1989
1990 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
1991 queue->stalled = false;
1992
1993 /* All queues are ready? Enable the carrier. */
1994 spin_lock(&vif->lock);
1995 if (--vif->stalled_queues == 0) {
1996 netdev_info(vif->dev, "Guest Rx ready");
1997 netif_carrier_on(vif->dev);
1998 }
1999 spin_unlock(&vif->lock);
2000 }
2001
2002 static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
2003 {
2004 RING_IDX prod, cons;
2005
2006 prod = queue->rx.sring->req_prod;
2007 cons = queue->rx.req_cons;
2008
2009 return !queue->stalled && prod - cons < 1
2010 && time_after(jiffies,
2011 queue->last_rx_time + queue->vif->stall_timeout);
2012 }
2013
2014 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
2015 {
2016 RING_IDX prod, cons;
2017
2018 prod = queue->rx.sring->req_prod;
2019 cons = queue->rx.req_cons;
2020
2021 return queue->stalled && prod - cons >= 1;
2022 }
2023
2024 static bool xenvif_have_rx_work(struct xenvif_queue *queue)
2025 {
2026 return xenvif_rx_ring_slots_available(queue)
2027 || (queue->vif->stall_timeout &&
2028 (xenvif_rx_queue_stalled(queue)
2029 || xenvif_rx_queue_ready(queue)))
2030 || kthread_should_stop()
2031 || queue->vif->disabled;
2032 }
2033
2034 static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
2035 {
2036 struct sk_buff *skb;
2037 long timeout;
2038
2039 skb = skb_peek(&queue->rx_queue);
2040 if (!skb)
2041 return MAX_SCHEDULE_TIMEOUT;
2042
2043 timeout = XENVIF_RX_CB(skb)->expires - jiffies;
2044 return timeout < 0 ? 0 : timeout;
2045 }
2046
2047 /* Wait until the guest Rx thread has work.
2048 *
2049 * The timeout needs to be adjusted based on the current head of the
2050 * queue (and not just the head at the beginning). In particular, if
2051 * the queue is initially empty an infinite timeout is used and this
2052 * needs to be reduced when a skb is queued.
2053 *
2054 * This cannot be done with wait_event_timeout() because it only
2055 * calculates the timeout once.
2056 */
2057 static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
2058 {
2059 DEFINE_WAIT(wait);
2060
2061 if (xenvif_have_rx_work(queue))
2062 return;
2063
2064 for (;;) {
2065 long ret;
2066
2067 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
2068 if (xenvif_have_rx_work(queue))
2069 break;
2070 ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
2071 if (!ret)
2072 break;
2073 }
2074 finish_wait(&queue->wq, &wait);
2075 }
2076
2077 int xenvif_kthread_guest_rx(void *data)
2078 {
2079 struct xenvif_queue *queue = data;
2080 struct xenvif *vif = queue->vif;
2081
2082 if (!vif->stall_timeout)
2083 xenvif_queue_carrier_on(queue);
2084
2085 for (;;) {
2086 xenvif_wait_for_rx_work(queue);
2087
2088 if (kthread_should_stop())
2089 break;
2090
2091 /* This frontend is found to be rogue, disable it in
2092 * kthread context. Currently this is only set when
2093 * netback finds out frontend sends malformed packet,
2094 * but we cannot disable the interface in softirq
2095 * context so we defer it here, if this thread is
2096 * associated with queue 0.
2097 */
2098 if (unlikely(vif->disabled && queue->id == 0)) {
2099 xenvif_carrier_off(vif);
2100 break;
2101 }
2102
2103 if (!skb_queue_empty(&queue->rx_queue))
2104 xenvif_rx_action(queue);
2105
2106 /* If the guest hasn't provided any Rx slots for a
2107 * while it's probably not responsive, drop the
2108 * carrier so packets are dropped earlier.
2109 */
2110 if (vif->stall_timeout) {
2111 if (xenvif_rx_queue_stalled(queue))
2112 xenvif_queue_carrier_off(queue);
2113 else if (xenvif_rx_queue_ready(queue))
2114 xenvif_queue_carrier_on(queue);
2115 }
2116
2117 /* Queued packets may have foreign pages from other
2118 * domains. These cannot be queued indefinitely as
2119 * this would starve guests of grant refs and transmit
2120 * slots.
2121 */
2122 xenvif_rx_queue_drop_expired(queue);
2123
2124 xenvif_rx_queue_maybe_wake(queue);
2125
2126 cond_resched();
2127 }
2128
2129 /* Bin any remaining skbs */
2130 xenvif_rx_queue_purge(queue);
2131
2132 return 0;
2133 }
2134
2135 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
2136 {
2137 /* Dealloc thread must remain running until all inflight
2138 * packets complete.
2139 */
2140 return kthread_should_stop() &&
2141 !atomic_read(&queue->inflight_packets);
2142 }
2143
2144 int xenvif_dealloc_kthread(void *data)
2145 {
2146 struct xenvif_queue *queue = data;
2147
2148 for (;;) {
2149 wait_event_interruptible(queue->dealloc_wq,
2150 tx_dealloc_work_todo(queue) ||
2151 xenvif_dealloc_kthread_should_stop(queue));
2152 if (xenvif_dealloc_kthread_should_stop(queue))
2153 break;
2154
2155 xenvif_tx_dealloc_action(queue);
2156 cond_resched();
2157 }
2158
2159 /* Unmap anything remaining*/
2160 if (tx_dealloc_work_todo(queue))
2161 xenvif_tx_dealloc_action(queue);
2162
2163 return 0;
2164 }
2165
2166 static int __init netback_init(void)
2167 {
2168 int rc = 0;
2169
2170 if (!xen_domain())
2171 return -ENODEV;
2172
2173 /* Allow as many queues as there are CPUs if user has not
2174 * specified a value.
2175 */
2176 if (xenvif_max_queues == 0)
2177 xenvif_max_queues = num_online_cpus();
2178
2179 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
2180 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
2181 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
2182 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
2183 }
2184
2185 rc = xenvif_xenbus_init();
2186 if (rc)
2187 goto failed_init;
2188
2189 #ifdef CONFIG_DEBUG_FS
2190 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
2191 if (IS_ERR_OR_NULL(xen_netback_dbg_root))
2192 pr_warn("Init of debugfs returned %ld!\n",
2193 PTR_ERR(xen_netback_dbg_root));
2194 #endif /* CONFIG_DEBUG_FS */
2195
2196 return 0;
2197
2198 failed_init:
2199 return rc;
2200 }
2201
2202 module_init(netback_init);
2203
2204 static void __exit netback_fini(void)
2205 {
2206 #ifdef CONFIG_DEBUG_FS
2207 if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
2208 debugfs_remove_recursive(xen_netback_dbg_root);
2209 #endif /* CONFIG_DEBUG_FS */
2210 xenvif_xenbus_fini();
2211 }
2212 module_exit(netback_fini);
2213
2214 MODULE_LICENSE("Dual BSD/GPL");
2215 MODULE_ALIAS("xen-backend:vif");
Linux kernel - Deliverables
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