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 spin_lock_irqsave(&queue->response_lock, flags); 659 make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR); 660 spin_unlock_irqrestore(&queue->response_lock, flags); 661 if (cons == end) 662 break; 663 txp = RING_GET_REQUEST(&queue->tx, cons++); 664 } while (1); 665 queue->tx.req_cons = cons; 666 } 667 668 static void xenvif_fatal_tx_err(struct xenvif *vif) 669 { 670 netdev_err(vif->dev, "fatal error; disabling device\n"); 671 vif->disabled = true; 672 /* Disable the vif from queue 0's kthread */ 673 if (vif->queues) 674 xenvif_kick_thread(&vif->queues[0]); 675 } 676 677 static int xenvif_count_requests(struct xenvif_queue *queue, 678 struct xen_netif_tx_request *first, 679 struct xen_netif_tx_request *txp, 680 int work_to_do) 681 { 682 RING_IDX cons = queue->tx.req_cons; 683 int slots = 0; 684 int drop_err = 0; 685 int more_data; 686 687 if (!(first->flags & XEN_NETTXF_more_data)) 688 return 0; 689 690 do { 691 struct xen_netif_tx_request dropped_tx = { 0 }; 692 693 if (slots >= work_to_do) { 694 netdev_err(queue->vif->dev, 695 "Asked for %d slots but exceeds this limit\n", 696 work_to_do); 697 xenvif_fatal_tx_err(queue->vif); 698 return -ENODATA; 699 } 700 701 /* This guest is really using too many slots and 702 * considered malicious. 703 */ 704 if (unlikely(slots >= fatal_skb_slots)) { 705 netdev_err(queue->vif->dev, 706 "Malicious frontend using %d slots, threshold %u\n", 707 slots, fatal_skb_slots); 708 xenvif_fatal_tx_err(queue->vif); 709 return -E2BIG; 710 } 711 712 /* Xen network protocol had implicit dependency on 713 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to 714 * the historical MAX_SKB_FRAGS value 18 to honor the 715 * same behavior as before. Any packet using more than 716 * 18 slots but less than fatal_skb_slots slots is 717 * dropped 718 */ 719 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) { 720 if (net_ratelimit()) 721 netdev_dbg(queue->vif->dev, 722 "Too many slots (%d) exceeding limit (%d), dropping packet\n", 723 slots, XEN_NETBK_LEGACY_SLOTS_MAX); 724 drop_err = -E2BIG; 725 } 726 727 if (drop_err) 728 txp = &dropped_tx; 729 730 memcpy(txp, RING_GET_REQUEST(&queue->tx, cons + slots), 731 sizeof(*txp)); 732 733 /* If the guest submitted a frame >= 64 KiB then 734 * first->size overflowed and following slots will 735 * appear to be larger than the frame. 736 * 737 * This cannot be fatal error as there are buggy 738 * frontends that do this. 739 * 740 * Consume all slots and drop the packet. 741 */ 742 if (!drop_err && txp->size > first->size) { 743 if (net_ratelimit()) 744 netdev_dbg(queue->vif->dev, 745 "Invalid tx request, slot size %u > remaining size %u\n", 746 txp->size, first->size); 747 drop_err = -EIO; 748 } 749 750 first->size -= txp->size; 751 slots++; 752 753 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) { 754 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n", 755 txp->offset, txp->size); 756 xenvif_fatal_tx_err(queue->vif); 757 return -EINVAL; 758 } 759 760 more_data = txp->flags & XEN_NETTXF_more_data; 761 762 if (!drop_err) 763 txp++; 764 765 } while (more_data); 766 767 if (drop_err) { 768 xenvif_tx_err(queue, first, cons + slots); 769 return drop_err; 770 } 771 772 return slots; 773 } 774 775 776 struct xenvif_tx_cb { 777 u16 pending_idx; 778 }; 779 780 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb) 781 782 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue, 783 u16 pending_idx, 784 struct xen_netif_tx_request *txp, 785 struct gnttab_map_grant_ref *mop) 786 { 787 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx]; 788 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx), 789 GNTMAP_host_map | GNTMAP_readonly, 790 txp->gref, queue->vif->domid); 791 792 memcpy(&queue->pending_tx_info[pending_idx].req, txp, 793 sizeof(*txp)); 794 } 795 796 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size) 797 { 798 struct sk_buff *skb = 799 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN, 800 GFP_ATOMIC | __GFP_NOWARN); 801 if (unlikely(skb == NULL)) 802 return NULL; 803 804 /* Packets passed to netif_rx() must have some headroom. */ 805 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); 806 807 /* Initialize it here to avoid later surprises */ 808 skb_shinfo(skb)->destructor_arg = NULL; 809 810 return skb; 811 } 812 813 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue, 814 struct sk_buff *skb, 815 struct xen_netif_tx_request *txp, 816 struct gnttab_map_grant_ref *gop) 817 { 818 struct skb_shared_info *shinfo = skb_shinfo(skb); 819 skb_frag_t *frags = shinfo->frags; 820 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 821 int start; 822 pending_ring_idx_t index; 823 unsigned int nr_slots, frag_overflow = 0; 824 825 /* At this point shinfo->nr_frags is in fact the number of 826 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. 827 */ 828 if (shinfo->nr_frags > MAX_SKB_FRAGS) { 829 frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS; 830 BUG_ON(frag_overflow > MAX_SKB_FRAGS); 831 shinfo->nr_frags = MAX_SKB_FRAGS; 832 } 833 nr_slots = shinfo->nr_frags; 834 835 /* Skip first skb fragment if it is on same page as header fragment. */ 836 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx); 837 838 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots; 839 shinfo->nr_frags++, txp++, gop++) { 840 index = pending_index(queue->pending_cons++); 841 pending_idx = queue->pending_ring[index]; 842 xenvif_tx_create_map_op(queue, pending_idx, txp, gop); 843 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx); 844 } 845 846 if (frag_overflow) { 847 struct sk_buff *nskb = xenvif_alloc_skb(0); 848 if (unlikely(nskb == NULL)) { 849 if (net_ratelimit()) 850 netdev_err(queue->vif->dev, 851 "Can't allocate the frag_list skb.\n"); 852 return NULL; 853 } 854 855 shinfo = skb_shinfo(nskb); 856 frags = shinfo->frags; 857 858 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow; 859 shinfo->nr_frags++, txp++, gop++) { 860 index = pending_index(queue->pending_cons++); 861 pending_idx = queue->pending_ring[index]; 862 xenvif_tx_create_map_op(queue, pending_idx, txp, gop); 863 frag_set_pending_idx(&frags[shinfo->nr_frags], 864 pending_idx); 865 } 866 867 skb_shinfo(skb)->frag_list = nskb; 868 } 869 870 return gop; 871 } 872 873 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue, 874 u16 pending_idx, 875 grant_handle_t handle) 876 { 877 if (unlikely(queue->grant_tx_handle[pending_idx] != 878 NETBACK_INVALID_HANDLE)) { 879 netdev_err(queue->vif->dev, 880 "Trying to overwrite active handle! pending_idx: %x\n", 881 pending_idx); 882 BUG(); 883 } 884 queue->grant_tx_handle[pending_idx] = handle; 885 } 886 887 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue, 888 u16 pending_idx) 889 { 890 if (unlikely(queue->grant_tx_handle[pending_idx] == 891 NETBACK_INVALID_HANDLE)) { 892 netdev_err(queue->vif->dev, 893 "Trying to unmap invalid handle! pending_idx: %x\n", 894 pending_idx); 895 BUG(); 896 } 897 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE; 898 } 899 900 static int xenvif_tx_check_gop(struct xenvif_queue *queue, 901 struct sk_buff *skb, 902 struct gnttab_map_grant_ref **gopp_map, 903 struct gnttab_copy **gopp_copy) 904 { 905 struct gnttab_map_grant_ref *gop_map = *gopp_map; 906 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 907 /* This always points to the shinfo of the skb being checked, which 908 * could be either the first or the one on the frag_list 909 */ 910 struct skb_shared_info *shinfo = skb_shinfo(skb); 911 /* If this is non-NULL, we are currently checking the frag_list skb, and 912 * this points to the shinfo of the first one 913 */ 914 struct skb_shared_info *first_shinfo = NULL; 915 int nr_frags = shinfo->nr_frags; 916 const bool sharedslot = nr_frags && 917 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx; 918 int i, err; 919 920 /* Check status of header. */ 921 err = (*gopp_copy)->status; 922 if (unlikely(err)) { 923 if (net_ratelimit()) 924 netdev_dbg(queue->vif->dev, 925 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n", 926 (*gopp_copy)->status, 927 pending_idx, 928 (*gopp_copy)->source.u.ref); 929 /* The first frag might still have this slot mapped */ 930 if (!sharedslot) 931 xenvif_idx_release(queue, pending_idx, 932 XEN_NETIF_RSP_ERROR); 933 } 934 (*gopp_copy)++; 935 936 check_frags: 937 for (i = 0; i < nr_frags; i++, gop_map++) { 938 int j, newerr; 939 940 pending_idx = frag_get_pending_idx(&shinfo->frags[i]); 941 942 /* Check error status: if okay then remember grant handle. */ 943 newerr = gop_map->status; 944 945 if (likely(!newerr)) { 946 xenvif_grant_handle_set(queue, 947 pending_idx, 948 gop_map->handle); 949 /* Had a previous error? Invalidate this fragment. */ 950 if (unlikely(err)) { 951 xenvif_idx_unmap(queue, pending_idx); 952 /* If the mapping of the first frag was OK, but 953 * the header's copy failed, and they are 954 * sharing a slot, send an error 955 */ 956 if (i == 0 && sharedslot) 957 xenvif_idx_release(queue, pending_idx, 958 XEN_NETIF_RSP_ERROR); 959 else 960 xenvif_idx_release(queue, pending_idx, 961 XEN_NETIF_RSP_OKAY); 962 } 963 continue; 964 } 965 966 /* Error on this fragment: respond to client with an error. */ 967 if (net_ratelimit()) 968 netdev_dbg(queue->vif->dev, 969 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n", 970 i, 971 gop_map->status, 972 pending_idx, 973 gop_map->ref); 974 975 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR); 976 977 /* Not the first error? Preceding frags already invalidated. */ 978 if (err) 979 continue; 980 981 /* First error: if the header haven't shared a slot with the 982 * first frag, release it as well. 983 */ 984 if (!sharedslot) 985 xenvif_idx_release(queue, 986 XENVIF_TX_CB(skb)->pending_idx, 987 XEN_NETIF_RSP_OKAY); 988 989 /* Invalidate preceding fragments of this skb. */ 990 for (j = 0; j < i; j++) { 991 pending_idx = frag_get_pending_idx(&shinfo->frags[j]); 992 xenvif_idx_unmap(queue, pending_idx); 993 xenvif_idx_release(queue, pending_idx, 994 XEN_NETIF_RSP_OKAY); 995 } 996 997 /* And if we found the error while checking the frag_list, unmap 998 * the first skb's frags 999 */ 1000 if (first_shinfo) { 1001 for (j = 0; j < first_shinfo->nr_frags; j++) { 1002 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]); 1003 xenvif_idx_unmap(queue, pending_idx); 1004 xenvif_idx_release(queue, pending_idx, 1005 XEN_NETIF_RSP_OKAY); 1006 } 1007 } 1008 1009 /* Remember the error: invalidate all subsequent fragments. */ 1010 err = newerr; 1011 } 1012 1013 if (skb_has_frag_list(skb) && !first_shinfo) { 1014 first_shinfo = skb_shinfo(skb); 1015 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list); 1016 nr_frags = shinfo->nr_frags; 1017 1018 goto check_frags; 1019 } 1020 1021 *gopp_map = gop_map; 1022 return err; 1023 } 1024 1025 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb) 1026 { 1027 struct skb_shared_info *shinfo = skb_shinfo(skb); 1028 int nr_frags = shinfo->nr_frags; 1029 int i; 1030 u16 prev_pending_idx = INVALID_PENDING_IDX; 1031 1032 for (i = 0; i < nr_frags; i++) { 1033 skb_frag_t *frag = shinfo->frags + i; 1034 struct xen_netif_tx_request *txp; 1035 struct page *page; 1036 u16 pending_idx; 1037 1038 pending_idx = frag_get_pending_idx(frag); 1039 1040 /* If this is not the first frag, chain it to the previous*/ 1041 if (prev_pending_idx == INVALID_PENDING_IDX) 1042 skb_shinfo(skb)->destructor_arg = 1043 &callback_param(queue, pending_idx); 1044 else 1045 callback_param(queue, prev_pending_idx).ctx = 1046 &callback_param(queue, pending_idx); 1047 1048 callback_param(queue, pending_idx).ctx = NULL; 1049 prev_pending_idx = pending_idx; 1050 1051 txp = &queue->pending_tx_info[pending_idx].req; 1052 page = virt_to_page(idx_to_kaddr(queue, pending_idx)); 1053 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size); 1054 skb->len += txp->size; 1055 skb->data_len += txp->size; 1056 skb->truesize += txp->size; 1057 1058 /* Take an extra reference to offset network stack's put_page */ 1059 get_page(queue->mmap_pages[pending_idx]); 1060 } 1061 } 1062 1063 static int xenvif_get_extras(struct xenvif_queue *queue, 1064 struct xen_netif_extra_info *extras, 1065 int work_to_do) 1066 { 1067 struct xen_netif_extra_info extra; 1068 RING_IDX cons = queue->tx.req_cons; 1069 1070 do { 1071 if (unlikely(work_to_do-- <= 0)) { 1072 netdev_err(queue->vif->dev, "Missing extra info\n"); 1073 xenvif_fatal_tx_err(queue->vif); 1074 return -EBADR; 1075 } 1076 1077 memcpy(&extra, RING_GET_REQUEST(&queue->tx, cons), 1078 sizeof(extra)); 1079 if (unlikely(!extra.type || 1080 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) { 1081 queue->tx.req_cons = ++cons; 1082 netdev_err(queue->vif->dev, 1083 "Invalid extra type: %d\n", extra.type); 1084 xenvif_fatal_tx_err(queue->vif); 1085 return -EINVAL; 1086 } 1087 1088 memcpy(&extras[extra.type - 1], &extra, sizeof(extra)); 1089 queue->tx.req_cons = ++cons; 1090 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE); 1091 1092 return work_to_do; 1093 } 1094 1095 static int xenvif_set_skb_gso(struct xenvif *vif, 1096 struct sk_buff *skb, 1097 struct xen_netif_extra_info *gso) 1098 { 1099 if (!gso->u.gso.size) { 1100 netdev_err(vif->dev, "GSO size must not be zero.\n"); 1101 xenvif_fatal_tx_err(vif); 1102 return -EINVAL; 1103 } 1104 1105 switch (gso->u.gso.type) { 1106 case XEN_NETIF_GSO_TYPE_TCPV4: 1107 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1108 break; 1109 case XEN_NETIF_GSO_TYPE_TCPV6: 1110 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1111 break; 1112 default: 1113 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type); 1114 xenvif_fatal_tx_err(vif); 1115 return -EINVAL; 1116 } 1117 1118 skb_shinfo(skb)->gso_size = gso->u.gso.size; 1119 /* gso_segs will be calculated later */ 1120 1121 return 0; 1122 } 1123 1124 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb) 1125 { 1126 bool recalculate_partial_csum = false; 1127 1128 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy 1129 * peers can fail to set NETRXF_csum_blank when sending a GSO 1130 * frame. In this case force the SKB to CHECKSUM_PARTIAL and 1131 * recalculate the partial checksum. 1132 */ 1133 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) { 1134 queue->stats.rx_gso_checksum_fixup++; 1135 skb->ip_summed = CHECKSUM_PARTIAL; 1136 recalculate_partial_csum = true; 1137 } 1138 1139 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */ 1140 if (skb->ip_summed != CHECKSUM_PARTIAL) 1141 return 0; 1142 1143 return skb_checksum_setup(skb, recalculate_partial_csum); 1144 } 1145 1146 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size) 1147 { 1148 u64 now = get_jiffies_64(); 1149 u64 next_credit = queue->credit_window_start + 1150 msecs_to_jiffies(queue->credit_usec / 1000); 1151 1152 /* Timer could already be pending in rare cases. */ 1153 if (timer_pending(&queue->credit_timeout)) 1154 return true; 1155 1156 /* Passed the point where we can replenish credit? */ 1157 if (time_after_eq64(now, next_credit)) { 1158 queue->credit_window_start = now; 1159 tx_add_credit(queue); 1160 } 1161 1162 /* Still too big to send right now? Set a callback. */ 1163 if (size > queue->remaining_credit) { 1164 queue->credit_timeout.data = 1165 (unsigned long)queue; 1166 queue->credit_timeout.function = 1167 tx_credit_callback; 1168 mod_timer(&queue->credit_timeout, 1169 next_credit); 1170 queue->credit_window_start = next_credit; 1171 1172 return true; 1173 } 1174 1175 return false; 1176 } 1177 1178 static void xenvif_tx_build_gops(struct xenvif_queue *queue, 1179 int budget, 1180 unsigned *copy_ops, 1181 unsigned *map_ops) 1182 { 1183 struct gnttab_map_grant_ref *gop = queue->tx_map_ops, *request_gop; 1184 struct sk_buff *skb; 1185 int ret; 1186 1187 while (skb_queue_len(&queue->tx_queue) < budget) { 1188 struct xen_netif_tx_request txreq; 1189 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX]; 1190 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1]; 1191 u16 pending_idx; 1192 RING_IDX idx; 1193 int work_to_do; 1194 unsigned int data_len; 1195 pending_ring_idx_t index; 1196 1197 if (queue->tx.sring->req_prod - queue->tx.req_cons > 1198 XEN_NETIF_TX_RING_SIZE) { 1199 netdev_err(queue->vif->dev, 1200 "Impossible number of requests. " 1201 "req_prod %d, req_cons %d, size %ld\n", 1202 queue->tx.sring->req_prod, queue->tx.req_cons, 1203 XEN_NETIF_TX_RING_SIZE); 1204 xenvif_fatal_tx_err(queue->vif); 1205 break; 1206 } 1207 1208 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx); 1209 if (!work_to_do) 1210 break; 1211 1212 idx = queue->tx.req_cons; 1213 rmb(); /* Ensure that we see the request before we copy it. */ 1214 memcpy(&txreq, RING_GET_REQUEST(&queue->tx, idx), sizeof(txreq)); 1215 1216 /* Credit-based scheduling. */ 1217 if (txreq.size > queue->remaining_credit && 1218 tx_credit_exceeded(queue, txreq.size)) 1219 break; 1220 1221 queue->remaining_credit -= txreq.size; 1222 1223 work_to_do--; 1224 queue->tx.req_cons = ++idx; 1225 1226 memset(extras, 0, sizeof(extras)); 1227 if (txreq.flags & XEN_NETTXF_extra_info) { 1228 work_to_do = xenvif_get_extras(queue, extras, 1229 work_to_do); 1230 idx = queue->tx.req_cons; 1231 if (unlikely(work_to_do < 0)) 1232 break; 1233 } 1234 1235 ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do); 1236 if (unlikely(ret < 0)) 1237 break; 1238 1239 idx += ret; 1240 1241 if (unlikely(txreq.size < ETH_HLEN)) { 1242 netdev_dbg(queue->vif->dev, 1243 "Bad packet size: %d\n", txreq.size); 1244 xenvif_tx_err(queue, &txreq, idx); 1245 break; 1246 } 1247 1248 /* No crossing a page as the payload mustn't fragment. */ 1249 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) { 1250 netdev_err(queue->vif->dev, 1251 "txreq.offset: %x, size: %u, end: %lu\n", 1252 txreq.offset, txreq.size, 1253 (txreq.offset&~PAGE_MASK) + txreq.size); 1254 xenvif_fatal_tx_err(queue->vif); 1255 break; 1256 } 1257 1258 index = pending_index(queue->pending_cons); 1259 pending_idx = queue->pending_ring[index]; 1260 1261 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN && 1262 ret < XEN_NETBK_LEGACY_SLOTS_MAX) ? 1263 XEN_NETBACK_TX_COPY_LEN : txreq.size; 1264 1265 skb = xenvif_alloc_skb(data_len); 1266 if (unlikely(skb == NULL)) { 1267 netdev_dbg(queue->vif->dev, 1268 "Can't allocate a skb in start_xmit.\n"); 1269 xenvif_tx_err(queue, &txreq, idx); 1270 break; 1271 } 1272 1273 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) { 1274 struct xen_netif_extra_info *gso; 1275 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1]; 1276 1277 if (xenvif_set_skb_gso(queue->vif, skb, gso)) { 1278 /* Failure in xenvif_set_skb_gso is fatal. */ 1279 kfree_skb(skb); 1280 break; 1281 } 1282 } 1283 1284 XENVIF_TX_CB(skb)->pending_idx = pending_idx; 1285 1286 __skb_put(skb, data_len); 1287 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref; 1288 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid; 1289 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset; 1290 1291 queue->tx_copy_ops[*copy_ops].dest.u.gmfn = 1292 virt_to_mfn(skb->data); 1293 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF; 1294 queue->tx_copy_ops[*copy_ops].dest.offset = 1295 offset_in_page(skb->data); 1296 1297 queue->tx_copy_ops[*copy_ops].len = data_len; 1298 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref; 1299 1300 (*copy_ops)++; 1301 1302 skb_shinfo(skb)->nr_frags = ret; 1303 if (data_len < txreq.size) { 1304 skb_shinfo(skb)->nr_frags++; 1305 frag_set_pending_idx(&skb_shinfo(skb)->frags[0], 1306 pending_idx); 1307 xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop); 1308 gop++; 1309 } else { 1310 frag_set_pending_idx(&skb_shinfo(skb)->frags[0], 1311 INVALID_PENDING_IDX); 1312 memcpy(&queue->pending_tx_info[pending_idx].req, &txreq, 1313 sizeof(txreq)); 1314 } 1315 1316 queue->pending_cons++; 1317 1318 request_gop = xenvif_get_requests(queue, skb, txfrags, gop); 1319 if (request_gop == NULL) { 1320 kfree_skb(skb); 1321 xenvif_tx_err(queue, &txreq, idx); 1322 break; 1323 } 1324 gop = request_gop; 1325 1326 __skb_queue_tail(&queue->tx_queue, skb); 1327 1328 queue->tx.req_cons = idx; 1329 1330 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) || 1331 (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops))) 1332 break; 1333 } 1334 1335 (*map_ops) = gop - queue->tx_map_ops; 1336 return; 1337 } 1338 1339 /* Consolidate skb with a frag_list into a brand new one with local pages on 1340 * frags. Returns 0 or -ENOMEM if can't allocate new pages. 1341 */ 1342 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb) 1343 { 1344 unsigned int offset = skb_headlen(skb); 1345 skb_frag_t frags[MAX_SKB_FRAGS]; 1346 int i; 1347 struct ubuf_info *uarg; 1348 struct sk_buff *nskb = skb_shinfo(skb)->frag_list; 1349 1350 queue->stats.tx_zerocopy_sent += 2; 1351 queue->stats.tx_frag_overflow++; 1352 1353 xenvif_fill_frags(queue, nskb); 1354 /* Subtract frags size, we will correct it later */ 1355 skb->truesize -= skb->data_len; 1356 skb->len += nskb->len; 1357 skb->data_len += nskb->len; 1358 1359 /* create a brand new frags array and coalesce there */ 1360 for (i = 0; offset < skb->len; i++) { 1361 struct page *page; 1362 unsigned int len; 1363 1364 BUG_ON(i >= MAX_SKB_FRAGS); 1365 page = alloc_page(GFP_ATOMIC); 1366 if (!page) { 1367 int j; 1368 skb->truesize += skb->data_len; 1369 for (j = 0; j < i; j++) 1370 put_page(frags[j].page.p); 1371 return -ENOMEM; 1372 } 1373 1374 if (offset + PAGE_SIZE < skb->len) 1375 len = PAGE_SIZE; 1376 else 1377 len = skb->len - offset; 1378 if (skb_copy_bits(skb, offset, page_address(page), len)) 1379 BUG(); 1380 1381 offset += len; 1382 frags[i].page.p = page; 1383 frags[i].page_offset = 0; 1384 skb_frag_size_set(&frags[i], len); 1385 } 1386 /* swap out with old one */ 1387 memcpy(skb_shinfo(skb)->frags, 1388 frags, 1389 i * sizeof(skb_frag_t)); 1390 skb_shinfo(skb)->nr_frags = i; 1391 skb->truesize += i * PAGE_SIZE; 1392 1393 /* remove traces of mapped pages and frag_list */ 1394 skb_frag_list_init(skb); 1395 uarg = skb_shinfo(skb)->destructor_arg; 1396 /* increase inflight counter to offset decrement in callback */ 1397 atomic_inc(&queue->inflight_packets); 1398 uarg->callback(uarg, true); 1399 skb_shinfo(skb)->destructor_arg = NULL; 1400 1401 xenvif_skb_zerocopy_prepare(queue, nskb); 1402 kfree_skb(nskb); 1403 1404 return 0; 1405 } 1406 1407 static int xenvif_tx_submit(struct xenvif_queue *queue) 1408 { 1409 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops; 1410 struct gnttab_copy *gop_copy = queue->tx_copy_ops; 1411 struct sk_buff *skb; 1412 int work_done = 0; 1413 1414 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) { 1415 struct xen_netif_tx_request *txp; 1416 u16 pending_idx; 1417 unsigned data_len; 1418 1419 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 1420 txp = &queue->pending_tx_info[pending_idx].req; 1421 1422 /* Check the remap error code. */ 1423 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) { 1424 /* If there was an error, xenvif_tx_check_gop is 1425 * expected to release all the frags which were mapped, 1426 * so kfree_skb shouldn't do it again 1427 */ 1428 skb_shinfo(skb)->nr_frags = 0; 1429 if (skb_has_frag_list(skb)) { 1430 struct sk_buff *nskb = 1431 skb_shinfo(skb)->frag_list; 1432 skb_shinfo(nskb)->nr_frags = 0; 1433 } 1434 kfree_skb(skb); 1435 continue; 1436 } 1437 1438 data_len = skb->len; 1439 callback_param(queue, pending_idx).ctx = NULL; 1440 if (data_len < txp->size) { 1441 /* Append the packet payload as a fragment. */ 1442 txp->offset += data_len; 1443 txp->size -= data_len; 1444 } else { 1445 /* Schedule a response immediately. */ 1446 xenvif_idx_release(queue, pending_idx, 1447 XEN_NETIF_RSP_OKAY); 1448 } 1449 1450 if (txp->flags & XEN_NETTXF_csum_blank) 1451 skb->ip_summed = CHECKSUM_PARTIAL; 1452 else if (txp->flags & XEN_NETTXF_data_validated) 1453 skb->ip_summed = CHECKSUM_UNNECESSARY; 1454 1455 xenvif_fill_frags(queue, skb); 1456 1457 if (unlikely(skb_has_frag_list(skb))) { 1458 if (xenvif_handle_frag_list(queue, skb)) { 1459 if (net_ratelimit()) 1460 netdev_err(queue->vif->dev, 1461 "Not enough memory to consolidate frag_list!\n"); 1462 xenvif_skb_zerocopy_prepare(queue, skb); 1463 kfree_skb(skb); 1464 continue; 1465 } 1466 } 1467 1468 skb->dev = queue->vif->dev; 1469 skb->protocol = eth_type_trans(skb, skb->dev); 1470 skb_reset_network_header(skb); 1471 1472 if (checksum_setup(queue, skb)) { 1473 netdev_dbg(queue->vif->dev, 1474 "Can't setup checksum in net_tx_action\n"); 1475 /* We have to set this flag to trigger the callback */ 1476 if (skb_shinfo(skb)->destructor_arg) 1477 xenvif_skb_zerocopy_prepare(queue, skb); 1478 kfree_skb(skb); 1479 continue; 1480 } 1481 1482 skb_probe_transport_header(skb, 0); 1483 1484 /* If the packet is GSO then we will have just set up the 1485 * transport header offset in checksum_setup so it's now 1486 * straightforward to calculate gso_segs. 1487 */ 1488 if (skb_is_gso(skb)) { 1489 int mss = skb_shinfo(skb)->gso_size; 1490 int hdrlen = skb_transport_header(skb) - 1491 skb_mac_header(skb) + 1492 tcp_hdrlen(skb); 1493 1494 skb_shinfo(skb)->gso_segs = 1495 DIV_ROUND_UP(skb->len - hdrlen, mss); 1496 } 1497 1498 queue->stats.rx_bytes += skb->len; 1499 queue->stats.rx_packets++; 1500 1501 work_done++; 1502 1503 /* Set this flag right before netif_receive_skb, otherwise 1504 * someone might think this packet already left netback, and 1505 * do a skb_copy_ubufs while we are still in control of the 1506 * skb. E.g. the __pskb_pull_tail earlier can do such thing. 1507 */ 1508 if (skb_shinfo(skb)->destructor_arg) { 1509 xenvif_skb_zerocopy_prepare(queue, skb); 1510 queue->stats.tx_zerocopy_sent++; 1511 } 1512 1513 netif_receive_skb(skb); 1514 } 1515 1516 return work_done; 1517 } 1518 1519 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success) 1520 { 1521 unsigned long flags; 1522 pending_ring_idx_t index; 1523 struct xenvif_queue *queue = ubuf_to_queue(ubuf); 1524 1525 /* This is the only place where we grab this lock, to protect callbacks 1526 * from each other. 1527 */ 1528 spin_lock_irqsave(&queue->callback_lock, flags); 1529 do { 1530 u16 pending_idx = ubuf->desc; 1531 ubuf = (struct ubuf_info *) ubuf->ctx; 1532 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >= 1533 MAX_PENDING_REQS); 1534 index = pending_index(queue->dealloc_prod); 1535 queue->dealloc_ring[index] = pending_idx; 1536 /* Sync with xenvif_tx_dealloc_action: 1537 * insert idx then incr producer. 1538 */ 1539 smp_wmb(); 1540 queue->dealloc_prod++; 1541 } while (ubuf); 1542 wake_up(&queue->dealloc_wq); 1543 spin_unlock_irqrestore(&queue->callback_lock, flags); 1544 1545 if (likely(zerocopy_success)) 1546 queue->stats.tx_zerocopy_success++; 1547 else 1548 queue->stats.tx_zerocopy_fail++; 1549 xenvif_skb_zerocopy_complete(queue); 1550 } 1551 1552 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue) 1553 { 1554 struct gnttab_unmap_grant_ref *gop; 1555 pending_ring_idx_t dc, dp; 1556 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS]; 1557 unsigned int i = 0; 1558 1559 dc = queue->dealloc_cons; 1560 gop = queue->tx_unmap_ops; 1561 1562 /* Free up any grants we have finished using */ 1563 do { 1564 dp = queue->dealloc_prod; 1565 1566 /* Ensure we see all indices enqueued by all 1567 * xenvif_zerocopy_callback(). 1568 */ 1569 smp_rmb(); 1570 1571 while (dc != dp) { 1572 BUG_ON(gop - queue->tx_unmap_ops > MAX_PENDING_REQS); 1573 pending_idx = 1574 queue->dealloc_ring[pending_index(dc++)]; 1575 1576 pending_idx_release[gop-queue->tx_unmap_ops] = 1577 pending_idx; 1578 queue->pages_to_unmap[gop-queue->tx_unmap_ops] = 1579 queue->mmap_pages[pending_idx]; 1580 gnttab_set_unmap_op(gop, 1581 idx_to_kaddr(queue, pending_idx), 1582 GNTMAP_host_map, 1583 queue->grant_tx_handle[pending_idx]); 1584 xenvif_grant_handle_reset(queue, pending_idx); 1585 ++gop; 1586 } 1587 1588 } while (dp != queue->dealloc_prod); 1589 1590 queue->dealloc_cons = dc; 1591 1592 if (gop - queue->tx_unmap_ops > 0) { 1593 int ret; 1594 ret = gnttab_unmap_refs(queue->tx_unmap_ops, 1595 NULL, 1596 queue->pages_to_unmap, 1597 gop - queue->tx_unmap_ops); 1598 if (ret) { 1599 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tx ret %d\n", 1600 gop - queue->tx_unmap_ops, ret); 1601 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) { 1602 if (gop[i].status != GNTST_okay) 1603 netdev_err(queue->vif->dev, 1604 " host_addr: %llx handle: %x status: %d\n", 1605 gop[i].host_addr, 1606 gop[i].handle, 1607 gop[i].status); 1608 } 1609 BUG(); 1610 } 1611 } 1612 1613 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) 1614 xenvif_idx_release(queue, pending_idx_release[i], 1615 XEN_NETIF_RSP_OKAY); 1616 } 1617 1618 1619 /* Called after netfront has transmitted */ 1620 int xenvif_tx_action(struct xenvif_queue *queue, int budget) 1621 { 1622 unsigned nr_mops, nr_cops = 0; 1623 int work_done, ret; 1624 1625 if (unlikely(!tx_work_todo(queue))) 1626 return 0; 1627 1628 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops); 1629 1630 if (nr_cops == 0) 1631 return 0; 1632 1633 gnttab_batch_copy(queue->tx_copy_ops, nr_cops); 1634 if (nr_mops != 0) { 1635 ret = gnttab_map_refs(queue->tx_map_ops, 1636 NULL, 1637 queue->pages_to_map, 1638 nr_mops); 1639 BUG_ON(ret); 1640 } 1641 1642 work_done = xenvif_tx_submit(queue); 1643 1644 return work_done; 1645 } 1646 1647 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, 1648 u8 status) 1649 { 1650 struct pending_tx_info *pending_tx_info; 1651 pending_ring_idx_t index; 1652 unsigned long flags; 1653 1654 pending_tx_info = &queue->pending_tx_info[pending_idx]; 1655 spin_lock_irqsave(&queue->response_lock, flags); 1656 make_tx_response(queue, &pending_tx_info->req, status); 1657 index = pending_index(queue->pending_prod); 1658 queue->pending_ring[index] = pending_idx; 1659 /* TX shouldn't use the index before we give it back here */ 1660 mb(); 1661 queue->pending_prod++; 1662 spin_unlock_irqrestore(&queue->response_lock, flags); 1663 } 1664 1665 1666 static void make_tx_response(struct xenvif_queue *queue, 1667 struct xen_netif_tx_request *txp, 1668 s8 st) 1669 { 1670 RING_IDX i = queue->tx.rsp_prod_pvt; 1671 struct xen_netif_tx_response *resp; 1672 int notify; 1673 1674 resp = RING_GET_RESPONSE(&queue->tx, i); 1675 resp->id = txp->id; 1676 resp->status = st; 1677 1678 if (txp->flags & XEN_NETTXF_extra_info) 1679 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL; 1680 1681 queue->tx.rsp_prod_pvt = ++i; 1682 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); 1683 if (notify) 1684 notify_remote_via_irq(queue->tx_irq); 1685 } 1686 1687 static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, 1688 u16 id, 1689 s8 st, 1690 u16 offset, 1691 u16 size, 1692 u16 flags) 1693 { 1694 RING_IDX i = queue->rx.rsp_prod_pvt; 1695 struct xen_netif_rx_response *resp; 1696 1697 resp = RING_GET_RESPONSE(&queue->rx, i); 1698 resp->offset = offset; 1699 resp->flags = flags; 1700 resp->id = id; 1701 resp->status = (s16)size; 1702 if (st < 0) 1703 resp->status = (s16)st; 1704 1705 queue->rx.rsp_prod_pvt = ++i; 1706 1707 return resp; 1708 } 1709 1710 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx) 1711 { 1712 int ret; 1713 struct gnttab_unmap_grant_ref tx_unmap_op; 1714 1715 gnttab_set_unmap_op(&tx_unmap_op, 1716 idx_to_kaddr(queue, pending_idx), 1717 GNTMAP_host_map, 1718 queue->grant_tx_handle[pending_idx]); 1719 xenvif_grant_handle_reset(queue, pending_idx); 1720 1721 ret = gnttab_unmap_refs(&tx_unmap_op, NULL, 1722 &queue->mmap_pages[pending_idx], 1); 1723 if (ret) { 1724 netdev_err(queue->vif->dev, 1725 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: %x status: %d\n", 1726 ret, 1727 pending_idx, 1728 tx_unmap_op.host_addr, 1729 tx_unmap_op.handle, 1730 tx_unmap_op.status); 1731 BUG(); 1732 } 1733 } 1734 1735 static inline int tx_work_todo(struct xenvif_queue *queue) 1736 { 1737 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))) 1738 return 1; 1739 1740 return 0; 1741 } 1742 1743 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue) 1744 { 1745 return queue->dealloc_cons != queue->dealloc_prod; 1746 } 1747 1748 void xenvif_unmap_frontend_rings(struct xenvif_queue *queue) 1749 { 1750 if (queue->tx.sring) 1751 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif), 1752 queue->tx.sring); 1753 if (queue->rx.sring) 1754 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif), 1755 queue->rx.sring); 1756 } 1757 1758 int xenvif_map_frontend_rings(struct xenvif_queue *queue, 1759 grant_ref_t tx_ring_ref, 1760 grant_ref_t rx_ring_ref) 1761 { 1762 void *addr; 1763 struct xen_netif_tx_sring *txs; 1764 struct xen_netif_rx_sring *rxs; 1765 1766 int err = -ENOMEM; 1767 1768 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif), 1769 tx_ring_ref, &addr); 1770 if (err) 1771 goto err; 1772 1773 txs = (struct xen_netif_tx_sring *)addr; 1774 BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE); 1775 1776 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif), 1777 rx_ring_ref, &addr); 1778 if (err) 1779 goto err; 1780 1781 rxs = (struct xen_netif_rx_sring *)addr; 1782 BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE); 1783 1784 return 0; 1785 1786 err: 1787 xenvif_unmap_frontend_rings(queue); 1788 return err; 1789 } 1790 1791 static void xenvif_queue_carrier_off(struct xenvif_queue *queue) 1792 { 1793 struct xenvif *vif = queue->vif; 1794 1795 queue->stalled = true; 1796 1797 /* At least one queue has stalled? Disable the carrier. */ 1798 spin_lock(&vif->lock); 1799 if (vif->stalled_queues++ == 0) { 1800 netdev_info(vif->dev, "Guest Rx stalled"); 1801 netif_carrier_off(vif->dev); 1802 } 1803 spin_unlock(&vif->lock); 1804 } 1805 1806 static void xenvif_queue_carrier_on(struct xenvif_queue *queue) 1807 { 1808 struct xenvif *vif = queue->vif; 1809 1810 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */ 1811 queue->stalled = false; 1812 1813 /* All queues are ready? Enable the carrier. */ 1814 spin_lock(&vif->lock); 1815 if (--vif->stalled_queues == 0) { 1816 netdev_info(vif->dev, "Guest Rx ready"); 1817 netif_carrier_on(vif->dev); 1818 } 1819 spin_unlock(&vif->lock); 1820 } 1821 1822 static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue) 1823 { 1824 RING_IDX prod, cons; 1825 1826 prod = queue->rx.sring->req_prod; 1827 cons = queue->rx.req_cons; 1828 1829 return !queue->stalled 1830 && prod - cons < XEN_NETBK_RX_SLOTS_MAX 1831 && time_after(jiffies, 1832 queue->last_rx_time + queue->vif->stall_timeout); 1833 } 1834 1835 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue) 1836 { 1837 RING_IDX prod, cons; 1838 1839 prod = queue->rx.sring->req_prod; 1840 cons = queue->rx.req_cons; 1841 1842 return queue->stalled 1843 && prod - cons >= XEN_NETBK_RX_SLOTS_MAX; 1844 } 1845 1846 static bool xenvif_have_rx_work(struct xenvif_queue *queue) 1847 { 1848 return (!skb_queue_empty(&queue->rx_queue) 1849 && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX)) 1850 || (queue->vif->stall_timeout && 1851 (xenvif_rx_queue_stalled(queue) 1852 || xenvif_rx_queue_ready(queue))) 1853 || kthread_should_stop() 1854 || queue->vif->disabled; 1855 } 1856 1857 static long xenvif_rx_queue_timeout(struct xenvif_queue *queue) 1858 { 1859 struct sk_buff *skb; 1860 long timeout; 1861 1862 skb = skb_peek(&queue->rx_queue); 1863 if (!skb) 1864 return MAX_SCHEDULE_TIMEOUT; 1865 1866 timeout = XENVIF_RX_CB(skb)->expires - jiffies; 1867 return timeout < 0 ? 0 : timeout; 1868 } 1869 1870 /* Wait until the guest Rx thread has work. 1871 * 1872 * The timeout needs to be adjusted based on the current head of the 1873 * queue (and not just the head at the beginning). In particular, if 1874 * the queue is initially empty an infinite timeout is used and this 1875 * needs to be reduced when a skb is queued. 1876 * 1877 * This cannot be done with wait_event_timeout() because it only 1878 * calculates the timeout once. 1879 */ 1880 static void xenvif_wait_for_rx_work(struct xenvif_queue *queue) 1881 { 1882 DEFINE_WAIT(wait); 1883 1884 if (xenvif_have_rx_work(queue)) 1885 return; 1886 1887 for (;;) { 1888 long ret; 1889 1890 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE); 1891 if (xenvif_have_rx_work(queue)) 1892 break; 1893 ret = schedule_timeout(xenvif_rx_queue_timeout(queue)); 1894 if (!ret) 1895 break; 1896 } 1897 finish_wait(&queue->wq, &wait); 1898 } 1899 1900 int xenvif_kthread_guest_rx(void *data) 1901 { 1902 struct xenvif_queue *queue = data; 1903 struct xenvif *vif = queue->vif; 1904 1905 if (!vif->stall_timeout) 1906 xenvif_queue_carrier_on(queue); 1907 1908 for (;;) { 1909 xenvif_wait_for_rx_work(queue); 1910 1911 if (kthread_should_stop()) 1912 break; 1913 1914 /* This frontend is found to be rogue, disable it in 1915 * kthread context. Currently this is only set when 1916 * netback finds out frontend sends malformed packet, 1917 * but we cannot disable the interface in softirq 1918 * context so we defer it here, if this thread is 1919 * associated with queue 0. 1920 */ 1921 if (unlikely(vif->disabled && queue->id == 0)) { 1922 xenvif_carrier_off(vif); 1923 break; 1924 } 1925 1926 if (!skb_queue_empty(&queue->rx_queue)) 1927 xenvif_rx_action(queue); 1928 1929 /* If the guest hasn't provided any Rx slots for a 1930 * while it's probably not responsive, drop the 1931 * carrier so packets are dropped earlier. 1932 */ 1933 if (vif->stall_timeout) { 1934 if (xenvif_rx_queue_stalled(queue)) 1935 xenvif_queue_carrier_off(queue); 1936 else if (xenvif_rx_queue_ready(queue)) 1937 xenvif_queue_carrier_on(queue); 1938 } 1939 1940 /* Queued packets may have foreign pages from other 1941 * domains. These cannot be queued indefinitely as 1942 * this would starve guests of grant refs and transmit 1943 * slots. 1944 */ 1945 xenvif_rx_queue_drop_expired(queue); 1946 1947 xenvif_rx_queue_maybe_wake(queue); 1948 1949 cond_resched(); 1950 } 1951 1952 /* Bin any remaining skbs */ 1953 xenvif_rx_queue_purge(queue); 1954 1955 return 0; 1956 } 1957 1958 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue) 1959 { 1960 /* Dealloc thread must remain running until all inflight 1961 * packets complete. 1962 */ 1963 return kthread_should_stop() && 1964 !atomic_read(&queue->inflight_packets); 1965 } 1966 1967 int xenvif_dealloc_kthread(void *data) 1968 { 1969 struct xenvif_queue *queue = data; 1970 1971 for (;;) { 1972 wait_event_interruptible(queue->dealloc_wq, 1973 tx_dealloc_work_todo(queue) || 1974 xenvif_dealloc_kthread_should_stop(queue)); 1975 if (xenvif_dealloc_kthread_should_stop(queue)) 1976 break; 1977 1978 xenvif_tx_dealloc_action(queue); 1979 cond_resched(); 1980 } 1981 1982 /* Unmap anything remaining*/ 1983 if (tx_dealloc_work_todo(queue)) 1984 xenvif_tx_dealloc_action(queue); 1985 1986 return 0; 1987 } 1988 1989 static int __init netback_init(void) 1990 { 1991 int rc = 0; 1992 1993 if (!xen_domain()) 1994 return -ENODEV; 1995 1996 /* Allow as many queues as there are CPUs, by default */ 1997 xenvif_max_queues = num_online_cpus(); 1998 1999 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) { 2000 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n", 2001 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX); 2002 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX; 2003 } 2004 2005 rc = xenvif_xenbus_init(); 2006 if (rc) 2007 goto failed_init; 2008 2009 #ifdef CONFIG_DEBUG_FS 2010 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL); 2011 if (IS_ERR_OR_NULL(xen_netback_dbg_root)) 2012 pr_warn("Init of debugfs returned %ld!\n", 2013 PTR_ERR(xen_netback_dbg_root)); 2014 #endif /* CONFIG_DEBUG_FS */ 2015 2016 return 0; 2017 2018 failed_init: 2019 return rc; 2020 } 2021 2022 module_init(netback_init); 2023 2024 static void __exit netback_fini(void) 2025 { 2026 #ifdef CONFIG_DEBUG_FS 2027 if (!IS_ERR_OR_NULL(xen_netback_dbg_root)) 2028 debugfs_remove_recursive(xen_netback_dbg_root); 2029 #endif /* CONFIG_DEBUG_FS */ 2030 xenvif_xenbus_fini(); 2031 } 2032 module_exit(netback_fini); 2033 2034 MODULE_LICENSE("Dual BSD/GPL"); 2035 MODULE_ALIAS("xen-backend:vif"); 2036