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 */ 55bool separate_tx_rx_irq = 1; 56module_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 */ 61unsigned int rx_drain_timeout_msecs = 10000; 62module_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 */ 67unsigned int rx_stall_timeout_msecs = 60000; 68module_param(rx_stall_timeout_msecs, uint, 0444); 69 70unsigned int xenvif_max_queues; 71module_param_named(max_queues, xenvif_max_queues, uint, 0644); 72MODULE_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 80static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT; 81module_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 93static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, 94 u8 status); 95 96static void make_tx_response(struct xenvif_queue *queue, 97 struct xen_netif_tx_request *txp, 98 s8 st); 99static void push_tx_responses(struct xenvif_queue *queue); 100 101static inline int tx_work_todo(struct xenvif_queue *queue); 102 103static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, 104 u16 id, 105 s8 st, 106 u16 offset, 107 u16 size, 108 u16 flags); 109 110static inline unsigned long idx_to_pfn(struct xenvif_queue *queue, 111 u16 idx) 112{ 113 return page_to_pfn(queue->mmap_pages[idx]); 114} 115 116static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue, 117 u16 idx) 118{ 119 return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx)); 120} 121 122#define callback_param(vif, pending_idx) \ 123 (vif->pending_tx_info[pending_idx].callback_struct) 124 125/* Find the containing VIF's structure from a pointer in pending_tx_info array 126 */ 127static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf) 128{ 129 u16 pending_idx = ubuf->desc; 130 struct pending_tx_info *temp = 131 container_of(ubuf, struct pending_tx_info, callback_struct); 132 return container_of(temp - pending_idx, 133 struct xenvif_queue, 134 pending_tx_info[0]); 135} 136 137static u16 frag_get_pending_idx(skb_frag_t *frag) 138{ 139 return (u16)frag->page_offset; 140} 141 142static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx) 143{ 144 frag->page_offset = pending_idx; 145} 146 147static inline pending_ring_idx_t pending_index(unsigned i) 148{ 149 return i & (MAX_PENDING_REQS-1); 150} 151 152bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed) 153{ 154 RING_IDX prod, cons; 155 156 do { 157 prod = queue->rx.sring->req_prod; 158 cons = queue->rx.req_cons; 159 160 if (prod - cons >= needed) 161 return true; 162 163 queue->rx.sring->req_event = prod + 1; 164 165 /* Make sure event is visible before we check prod 166 * again. 167 */ 168 mb(); 169 } while (queue->rx.sring->req_prod != prod); 170 171 return false; 172} 173 174void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb) 175{ 176 unsigned long flags; 177 178 spin_lock_irqsave(&queue->rx_queue.lock, flags); 179 180 __skb_queue_tail(&queue->rx_queue, skb); 181 182 queue->rx_queue_len += skb->len; 183 if (queue->rx_queue_len > queue->rx_queue_max) 184 netif_tx_stop_queue(netdev_get_tx_queue(queue->vif->dev, queue->id)); 185 186 spin_unlock_irqrestore(&queue->rx_queue.lock, flags); 187} 188 189static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue) 190{ 191 struct sk_buff *skb; 192 193 spin_lock_irq(&queue->rx_queue.lock); 194 195 skb = __skb_dequeue(&queue->rx_queue); 196 if (skb) 197 queue->rx_queue_len -= skb->len; 198 199 spin_unlock_irq(&queue->rx_queue.lock); 200 201 return skb; 202} 203 204static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue) 205{ 206 spin_lock_irq(&queue->rx_queue.lock); 207 208 if (queue->rx_queue_len < queue->rx_queue_max) 209 netif_tx_wake_queue(netdev_get_tx_queue(queue->vif->dev, queue->id)); 210 211 spin_unlock_irq(&queue->rx_queue.lock); 212} 213 214 215static void xenvif_rx_queue_purge(struct xenvif_queue *queue) 216{ 217 struct sk_buff *skb; 218 while ((skb = xenvif_rx_dequeue(queue)) != NULL) 219 kfree_skb(skb); 220} 221 222static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue) 223{ 224 struct sk_buff *skb; 225 226 for(;;) { 227 skb = skb_peek(&queue->rx_queue); 228 if (!skb) 229 break; 230 if (time_before(jiffies, XENVIF_RX_CB(skb)->expires)) 231 break; 232 xenvif_rx_dequeue(queue); 233 kfree_skb(skb); 234 } 235} 236 237struct netrx_pending_operations { 238 unsigned copy_prod, copy_cons; 239 unsigned meta_prod, meta_cons; 240 struct gnttab_copy *copy; 241 struct xenvif_rx_meta *meta; 242 int copy_off; 243 grant_ref_t copy_gref; 244}; 245 246static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif_queue *queue, 247 struct netrx_pending_operations *npo) 248{ 249 struct xenvif_rx_meta *meta; 250 struct xen_netif_rx_request *req; 251 252 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++); 253 254 meta = npo->meta + npo->meta_prod++; 255 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE; 256 meta->gso_size = 0; 257 meta->size = 0; 258 meta->id = req->id; 259 260 npo->copy_off = 0; 261 npo->copy_gref = req->gref; 262 263 return meta; 264} 265 266/* 267 * Set up the grant operations for this fragment. If it's a flipping 268 * interface, we also set up the unmap request from here. 269 */ 270static void xenvif_gop_frag_copy(struct xenvif_queue *queue, struct sk_buff *skb, 271 struct netrx_pending_operations *npo, 272 struct page *page, unsigned long size, 273 unsigned long offset, int *head) 274{ 275 struct gnttab_copy *copy_gop; 276 struct xenvif_rx_meta *meta; 277 unsigned long bytes; 278 int gso_type = XEN_NETIF_GSO_TYPE_NONE; 279 280 /* Data must not cross a page boundary. */ 281 BUG_ON(size + offset > PAGE_SIZE<<compound_order(page)); 282 283 meta = npo->meta + npo->meta_prod - 1; 284 285 /* Skip unused frames from start of page */ 286 page += offset >> PAGE_SHIFT; 287 offset &= ~PAGE_MASK; 288 289 while (size > 0) { 290 struct xen_page_foreign *foreign; 291 292 BUG_ON(offset >= PAGE_SIZE); 293 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET); 294 295 if (npo->copy_off == MAX_BUFFER_OFFSET) 296 meta = get_next_rx_buffer(queue, npo); 297 298 bytes = PAGE_SIZE - offset; 299 if (bytes > size) 300 bytes = size; 301 302 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET) 303 bytes = MAX_BUFFER_OFFSET - npo->copy_off; 304 305 copy_gop = npo->copy + npo->copy_prod++; 306 copy_gop->flags = GNTCOPY_dest_gref; 307 copy_gop->len = bytes; 308 309 foreign = xen_page_foreign(page); 310 if (foreign) { 311 copy_gop->source.domid = foreign->domid; 312 copy_gop->source.u.ref = foreign->gref; 313 copy_gop->flags |= GNTCOPY_source_gref; 314 } else { 315 copy_gop->source.domid = DOMID_SELF; 316 copy_gop->source.u.gmfn = 317 virt_to_mfn(page_address(page)); 318 } 319 copy_gop->source.offset = offset; 320 321 copy_gop->dest.domid = queue->vif->domid; 322 copy_gop->dest.offset = npo->copy_off; 323 copy_gop->dest.u.ref = npo->copy_gref; 324 325 npo->copy_off += bytes; 326 meta->size += bytes; 327 328 offset += bytes; 329 size -= bytes; 330 331 /* Next frame */ 332 if (offset == PAGE_SIZE && size) { 333 BUG_ON(!PageCompound(page)); 334 page++; 335 offset = 0; 336 } 337 338 /* Leave a gap for the GSO descriptor. */ 339 if (skb_is_gso(skb)) { 340 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) 341 gso_type = XEN_NETIF_GSO_TYPE_TCPV4; 342 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) 343 gso_type = XEN_NETIF_GSO_TYPE_TCPV6; 344 } 345 346 if (*head && ((1 << gso_type) & queue->vif->gso_mask)) 347 queue->rx.req_cons++; 348 349 *head = 0; /* There must be something in this buffer now. */ 350 351 } 352} 353 354/* 355 * Prepare an SKB to be transmitted to the frontend. 356 * 357 * This function is responsible for allocating grant operations, meta 358 * structures, etc. 359 * 360 * It returns the number of meta structures consumed. The number of 361 * ring slots used is always equal to the number of meta slots used 362 * plus the number of GSO descriptors used. Currently, we use either 363 * zero GSO descriptors (for non-GSO packets) or one descriptor (for 364 * frontend-side LRO). 365 */ 366static int xenvif_gop_skb(struct sk_buff *skb, 367 struct netrx_pending_operations *npo, 368 struct xenvif_queue *queue) 369{ 370 struct xenvif *vif = netdev_priv(skb->dev); 371 int nr_frags = skb_shinfo(skb)->nr_frags; 372 int i; 373 struct xen_netif_rx_request *req; 374 struct xenvif_rx_meta *meta; 375 unsigned char *data; 376 int head = 1; 377 int old_meta_prod; 378 int gso_type; 379 380 old_meta_prod = npo->meta_prod; 381 382 gso_type = XEN_NETIF_GSO_TYPE_NONE; 383 if (skb_is_gso(skb)) { 384 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) 385 gso_type = XEN_NETIF_GSO_TYPE_TCPV4; 386 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) 387 gso_type = XEN_NETIF_GSO_TYPE_TCPV6; 388 } 389 390 /* Set up a GSO prefix descriptor, if necessary */ 391 if ((1 << gso_type) & vif->gso_prefix_mask) { 392 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++); 393 meta = npo->meta + npo->meta_prod++; 394 meta->gso_type = gso_type; 395 meta->gso_size = skb_shinfo(skb)->gso_size; 396 meta->size = 0; 397 meta->id = req->id; 398 } 399 400 req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons++); 401 meta = npo->meta + npo->meta_prod++; 402 403 if ((1 << gso_type) & vif->gso_mask) { 404 meta->gso_type = gso_type; 405 meta->gso_size = skb_shinfo(skb)->gso_size; 406 } else { 407 meta->gso_type = XEN_NETIF_GSO_TYPE_NONE; 408 meta->gso_size = 0; 409 } 410 411 meta->size = 0; 412 meta->id = req->id; 413 npo->copy_off = 0; 414 npo->copy_gref = req->gref; 415 416 data = skb->data; 417 while (data < skb_tail_pointer(skb)) { 418 unsigned int offset = offset_in_page(data); 419 unsigned int len = PAGE_SIZE - offset; 420 421 if (data + len > skb_tail_pointer(skb)) 422 len = skb_tail_pointer(skb) - data; 423 424 xenvif_gop_frag_copy(queue, skb, npo, 425 virt_to_page(data), len, offset, &head); 426 data += len; 427 } 428 429 for (i = 0; i < nr_frags; i++) { 430 xenvif_gop_frag_copy(queue, skb, npo, 431 skb_frag_page(&skb_shinfo(skb)->frags[i]), 432 skb_frag_size(&skb_shinfo(skb)->frags[i]), 433 skb_shinfo(skb)->frags[i].page_offset, 434 &head); 435 } 436 437 return npo->meta_prod - old_meta_prod; 438} 439 440/* 441 * This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was 442 * used to set up the operations on the top of 443 * netrx_pending_operations, which have since been done. Check that 444 * they didn't give any errors and advance over them. 445 */ 446static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots, 447 struct netrx_pending_operations *npo) 448{ 449 struct gnttab_copy *copy_op; 450 int status = XEN_NETIF_RSP_OKAY; 451 int i; 452 453 for (i = 0; i < nr_meta_slots; i++) { 454 copy_op = npo->copy + npo->copy_cons++; 455 if (copy_op->status != GNTST_okay) { 456 netdev_dbg(vif->dev, 457 "Bad status %d from copy to DOM%d.\n", 458 copy_op->status, vif->domid); 459 status = XEN_NETIF_RSP_ERROR; 460 } 461 } 462 463 return status; 464} 465 466static void xenvif_add_frag_responses(struct xenvif_queue *queue, int status, 467 struct xenvif_rx_meta *meta, 468 int nr_meta_slots) 469{ 470 int i; 471 unsigned long offset; 472 473 /* No fragments used */ 474 if (nr_meta_slots <= 1) 475 return; 476 477 nr_meta_slots--; 478 479 for (i = 0; i < nr_meta_slots; i++) { 480 int flags; 481 if (i == nr_meta_slots - 1) 482 flags = 0; 483 else 484 flags = XEN_NETRXF_more_data; 485 486 offset = 0; 487 make_rx_response(queue, meta[i].id, status, offset, 488 meta[i].size, flags); 489 } 490} 491 492void xenvif_kick_thread(struct xenvif_queue *queue) 493{ 494 wake_up(&queue->wq); 495} 496 497static void xenvif_rx_action(struct xenvif_queue *queue) 498{ 499 s8 status; 500 u16 flags; 501 struct xen_netif_rx_response *resp; 502 struct sk_buff_head rxq; 503 struct sk_buff *skb; 504 LIST_HEAD(notify); 505 int ret; 506 unsigned long offset; 507 bool need_to_notify = false; 508 509 struct netrx_pending_operations npo = { 510 .copy = queue->grant_copy_op, 511 .meta = queue->meta, 512 }; 513 514 skb_queue_head_init(&rxq); 515 516 while (xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX) 517 && (skb = xenvif_rx_dequeue(queue)) != NULL) { 518 RING_IDX old_req_cons; 519 RING_IDX ring_slots_used; 520 521 queue->last_rx_time = jiffies; 522 523 old_req_cons = queue->rx.req_cons; 524 XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue); 525 ring_slots_used = queue->rx.req_cons - old_req_cons; 526 527 __skb_queue_tail(&rxq, skb); 528 } 529 530 BUG_ON(npo.meta_prod > ARRAY_SIZE(queue->meta)); 531 532 if (!npo.copy_prod) 533 goto done; 534 535 BUG_ON(npo.copy_prod > MAX_GRANT_COPY_OPS); 536 gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod); 537 538 while ((skb = __skb_dequeue(&rxq)) != NULL) { 539 540 if ((1 << queue->meta[npo.meta_cons].gso_type) & 541 queue->vif->gso_prefix_mask) { 542 resp = RING_GET_RESPONSE(&queue->rx, 543 queue->rx.rsp_prod_pvt++); 544 545 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data; 546 547 resp->offset = queue->meta[npo.meta_cons].gso_size; 548 resp->id = queue->meta[npo.meta_cons].id; 549 resp->status = XENVIF_RX_CB(skb)->meta_slots_used; 550 551 npo.meta_cons++; 552 XENVIF_RX_CB(skb)->meta_slots_used--; 553 } 554 555 556 queue->stats.tx_bytes += skb->len; 557 queue->stats.tx_packets++; 558 559 status = xenvif_check_gop(queue->vif, 560 XENVIF_RX_CB(skb)->meta_slots_used, 561 &npo); 562 563 if (XENVIF_RX_CB(skb)->meta_slots_used == 1) 564 flags = 0; 565 else 566 flags = XEN_NETRXF_more_data; 567 568 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */ 569 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated; 570 else if (skb->ip_summed == CHECKSUM_UNNECESSARY) 571 /* remote but checksummed. */ 572 flags |= XEN_NETRXF_data_validated; 573 574 offset = 0; 575 resp = make_rx_response(queue, queue->meta[npo.meta_cons].id, 576 status, offset, 577 queue->meta[npo.meta_cons].size, 578 flags); 579 580 if ((1 << queue->meta[npo.meta_cons].gso_type) & 581 queue->vif->gso_mask) { 582 struct xen_netif_extra_info *gso = 583 (struct xen_netif_extra_info *) 584 RING_GET_RESPONSE(&queue->rx, 585 queue->rx.rsp_prod_pvt++); 586 587 resp->flags |= XEN_NETRXF_extra_info; 588 589 gso->u.gso.type = queue->meta[npo.meta_cons].gso_type; 590 gso->u.gso.size = queue->meta[npo.meta_cons].gso_size; 591 gso->u.gso.pad = 0; 592 gso->u.gso.features = 0; 593 594 gso->type = XEN_NETIF_EXTRA_TYPE_GSO; 595 gso->flags = 0; 596 } 597 598 xenvif_add_frag_responses(queue, status, 599 queue->meta + npo.meta_cons + 1, 600 XENVIF_RX_CB(skb)->meta_slots_used); 601 602 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret); 603 604 need_to_notify |= !!ret; 605 606 npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used; 607 dev_kfree_skb(skb); 608 } 609 610done: 611 if (need_to_notify) 612 notify_remote_via_irq(queue->rx_irq); 613} 614 615void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue) 616{ 617 int more_to_do; 618 619 RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do); 620 621 if (more_to_do) 622 napi_schedule(&queue->napi); 623} 624 625static void tx_add_credit(struct xenvif_queue *queue) 626{ 627 unsigned long max_burst, max_credit; 628 629 /* 630 * Allow a burst big enough to transmit a jumbo packet of up to 128kB. 631 * Otherwise the interface can seize up due to insufficient credit. 632 */ 633 max_burst = RING_GET_REQUEST(&queue->tx, queue->tx.req_cons)->size; 634 max_burst = min(max_burst, 131072UL); 635 max_burst = max(max_burst, queue->credit_bytes); 636 637 /* Take care that adding a new chunk of credit doesn't wrap to zero. */ 638 max_credit = queue->remaining_credit + queue->credit_bytes; 639 if (max_credit < queue->remaining_credit) 640 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */ 641 642 queue->remaining_credit = min(max_credit, max_burst); 643} 644 645void xenvif_tx_credit_callback(unsigned long data) 646{ 647 struct xenvif_queue *queue = (struct xenvif_queue *)data; 648 tx_add_credit(queue); 649 xenvif_napi_schedule_or_enable_events(queue); 650} 651 652static void xenvif_tx_err(struct xenvif_queue *queue, 653 struct xen_netif_tx_request *txp, RING_IDX end) 654{ 655 RING_IDX cons = queue->tx.req_cons; 656 unsigned long flags; 657 658 do { 659 spin_lock_irqsave(&queue->response_lock, flags); 660 make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR); 661 push_tx_responses(queue); 662 spin_unlock_irqrestore(&queue->response_lock, flags); 663 if (cons == end) 664 break; 665 txp = RING_GET_REQUEST(&queue->tx, cons++); 666 } while (1); 667 queue->tx.req_cons = cons; 668} 669 670static void xenvif_fatal_tx_err(struct xenvif *vif) 671{ 672 netdev_err(vif->dev, "fatal error; disabling device\n"); 673 vif->disabled = true; 674 /* Disable the vif from queue 0's kthread */ 675 if (vif->queues) 676 xenvif_kick_thread(&vif->queues[0]); 677} 678 679static int xenvif_count_requests(struct xenvif_queue *queue, 680 struct xen_netif_tx_request *first, 681 struct xen_netif_tx_request *txp, 682 int work_to_do) 683{ 684 RING_IDX cons = queue->tx.req_cons; 685 int slots = 0; 686 int drop_err = 0; 687 int more_data; 688 689 if (!(first->flags & XEN_NETTXF_more_data)) 690 return 0; 691 692 do { 693 struct xen_netif_tx_request dropped_tx = { 0 }; 694 695 if (slots >= work_to_do) { 696 netdev_err(queue->vif->dev, 697 "Asked for %d slots but exceeds this limit\n", 698 work_to_do); 699 xenvif_fatal_tx_err(queue->vif); 700 return -ENODATA; 701 } 702 703 /* This guest is really using too many slots and 704 * considered malicious. 705 */ 706 if (unlikely(slots >= fatal_skb_slots)) { 707 netdev_err(queue->vif->dev, 708 "Malicious frontend using %d slots, threshold %u\n", 709 slots, fatal_skb_slots); 710 xenvif_fatal_tx_err(queue->vif); 711 return -E2BIG; 712 } 713 714 /* Xen network protocol had implicit dependency on 715 * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to 716 * the historical MAX_SKB_FRAGS value 18 to honor the 717 * same behavior as before. Any packet using more than 718 * 18 slots but less than fatal_skb_slots slots is 719 * dropped 720 */ 721 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) { 722 if (net_ratelimit()) 723 netdev_dbg(queue->vif->dev, 724 "Too many slots (%d) exceeding limit (%d), dropping packet\n", 725 slots, XEN_NETBK_LEGACY_SLOTS_MAX); 726 drop_err = -E2BIG; 727 } 728 729 if (drop_err) 730 txp = &dropped_tx; 731 732 memcpy(txp, RING_GET_REQUEST(&queue->tx, cons + slots), 733 sizeof(*txp)); 734 735 /* If the guest submitted a frame >= 64 KiB then 736 * first->size overflowed and following slots will 737 * appear to be larger than the frame. 738 * 739 * This cannot be fatal error as there are buggy 740 * frontends that do this. 741 * 742 * Consume all slots and drop the packet. 743 */ 744 if (!drop_err && txp->size > first->size) { 745 if (net_ratelimit()) 746 netdev_dbg(queue->vif->dev, 747 "Invalid tx request, slot size %u > remaining size %u\n", 748 txp->size, first->size); 749 drop_err = -EIO; 750 } 751 752 first->size -= txp->size; 753 slots++; 754 755 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) { 756 netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %x, size: %u\n", 757 txp->offset, txp->size); 758 xenvif_fatal_tx_err(queue->vif); 759 return -EINVAL; 760 } 761 762 more_data = txp->flags & XEN_NETTXF_more_data; 763 764 if (!drop_err) 765 txp++; 766 767 } while (more_data); 768 769 if (drop_err) { 770 xenvif_tx_err(queue, first, cons + slots); 771 return drop_err; 772 } 773 774 return slots; 775} 776 777 778struct xenvif_tx_cb { 779 u16 pending_idx; 780}; 781 782#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb) 783 784static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue, 785 u16 pending_idx, 786 struct xen_netif_tx_request *txp, 787 struct gnttab_map_grant_ref *mop) 788{ 789 queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx]; 790 gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx), 791 GNTMAP_host_map | GNTMAP_readonly, 792 txp->gref, queue->vif->domid); 793 794 memcpy(&queue->pending_tx_info[pending_idx].req, txp, 795 sizeof(*txp)); 796} 797 798static inline struct sk_buff *xenvif_alloc_skb(unsigned int size) 799{ 800 struct sk_buff *skb = 801 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN, 802 GFP_ATOMIC | __GFP_NOWARN); 803 if (unlikely(skb == NULL)) 804 return NULL; 805 806 /* Packets passed to netif_rx() must have some headroom. */ 807 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); 808 809 /* Initialize it here to avoid later surprises */ 810 skb_shinfo(skb)->destructor_arg = NULL; 811 812 return skb; 813} 814 815static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue, 816 struct sk_buff *skb, 817 struct xen_netif_tx_request *txp, 818 struct gnttab_map_grant_ref *gop) 819{ 820 struct skb_shared_info *shinfo = skb_shinfo(skb); 821 skb_frag_t *frags = shinfo->frags; 822 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 823 int start; 824 pending_ring_idx_t index; 825 unsigned int nr_slots, frag_overflow = 0; 826 827 /* At this point shinfo->nr_frags is in fact the number of 828 * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. 829 */ 830 if (shinfo->nr_frags > MAX_SKB_FRAGS) { 831 frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS; 832 BUG_ON(frag_overflow > MAX_SKB_FRAGS); 833 shinfo->nr_frags = MAX_SKB_FRAGS; 834 } 835 nr_slots = shinfo->nr_frags; 836 837 /* Skip first skb fragment if it is on same page as header fragment. */ 838 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx); 839 840 for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots; 841 shinfo->nr_frags++, txp++, gop++) { 842 index = pending_index(queue->pending_cons++); 843 pending_idx = queue->pending_ring[index]; 844 xenvif_tx_create_map_op(queue, pending_idx, txp, gop); 845 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx); 846 } 847 848 if (frag_overflow) { 849 struct sk_buff *nskb = xenvif_alloc_skb(0); 850 if (unlikely(nskb == NULL)) { 851 if (net_ratelimit()) 852 netdev_err(queue->vif->dev, 853 "Can't allocate the frag_list skb.\n"); 854 return NULL; 855 } 856 857 shinfo = skb_shinfo(nskb); 858 frags = shinfo->frags; 859 860 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow; 861 shinfo->nr_frags++, txp++, gop++) { 862 index = pending_index(queue->pending_cons++); 863 pending_idx = queue->pending_ring[index]; 864 xenvif_tx_create_map_op(queue, pending_idx, txp, gop); 865 frag_set_pending_idx(&frags[shinfo->nr_frags], 866 pending_idx); 867 } 868 869 skb_shinfo(skb)->frag_list = nskb; 870 } 871 872 return gop; 873} 874 875static inline void xenvif_grant_handle_set(struct xenvif_queue *queue, 876 u16 pending_idx, 877 grant_handle_t handle) 878{ 879 if (unlikely(queue->grant_tx_handle[pending_idx] != 880 NETBACK_INVALID_HANDLE)) { 881 netdev_err(queue->vif->dev, 882 "Trying to overwrite active handle! pending_idx: %x\n", 883 pending_idx); 884 BUG(); 885 } 886 queue->grant_tx_handle[pending_idx] = handle; 887} 888 889static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue, 890 u16 pending_idx) 891{ 892 if (unlikely(queue->grant_tx_handle[pending_idx] == 893 NETBACK_INVALID_HANDLE)) { 894 netdev_err(queue->vif->dev, 895 "Trying to unmap invalid handle! pending_idx: %x\n", 896 pending_idx); 897 BUG(); 898 } 899 queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE; 900} 901 902static int xenvif_tx_check_gop(struct xenvif_queue *queue, 903 struct sk_buff *skb, 904 struct gnttab_map_grant_ref **gopp_map, 905 struct gnttab_copy **gopp_copy) 906{ 907 struct gnttab_map_grant_ref *gop_map = *gopp_map; 908 u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 909 /* This always points to the shinfo of the skb being checked, which 910 * could be either the first or the one on the frag_list 911 */ 912 struct skb_shared_info *shinfo = skb_shinfo(skb); 913 /* If this is non-NULL, we are currently checking the frag_list skb, and 914 * this points to the shinfo of the first one 915 */ 916 struct skb_shared_info *first_shinfo = NULL; 917 int nr_frags = shinfo->nr_frags; 918 const bool sharedslot = nr_frags && 919 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx; 920 int i, err; 921 922 /* Check status of header. */ 923 err = (*gopp_copy)->status; 924 if (unlikely(err)) { 925 if (net_ratelimit()) 926 netdev_dbg(queue->vif->dev, 927 "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n", 928 (*gopp_copy)->status, 929 pending_idx, 930 (*gopp_copy)->source.u.ref); 931 /* The first frag might still have this slot mapped */ 932 if (!sharedslot) 933 xenvif_idx_release(queue, pending_idx, 934 XEN_NETIF_RSP_ERROR); 935 } 936 (*gopp_copy)++; 937 938check_frags: 939 for (i = 0; i < nr_frags; i++, gop_map++) { 940 int j, newerr; 941 942 pending_idx = frag_get_pending_idx(&shinfo->frags[i]); 943 944 /* Check error status: if okay then remember grant handle. */ 945 newerr = gop_map->status; 946 947 if (likely(!newerr)) { 948 xenvif_grant_handle_set(queue, 949 pending_idx, 950 gop_map->handle); 951 /* Had a previous error? Invalidate this fragment. */ 952 if (unlikely(err)) { 953 xenvif_idx_unmap(queue, pending_idx); 954 /* If the mapping of the first frag was OK, but 955 * the header's copy failed, and they are 956 * sharing a slot, send an error 957 */ 958 if (i == 0 && sharedslot) 959 xenvif_idx_release(queue, pending_idx, 960 XEN_NETIF_RSP_ERROR); 961 else 962 xenvif_idx_release(queue, pending_idx, 963 XEN_NETIF_RSP_OKAY); 964 } 965 continue; 966 } 967 968 /* Error on this fragment: respond to client with an error. */ 969 if (net_ratelimit()) 970 netdev_dbg(queue->vif->dev, 971 "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n", 972 i, 973 gop_map->status, 974 pending_idx, 975 gop_map->ref); 976 977 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR); 978 979 /* Not the first error? Preceding frags already invalidated. */ 980 if (err) 981 continue; 982 983 /* First error: if the header haven't shared a slot with the 984 * first frag, release it as well. 985 */ 986 if (!sharedslot) 987 xenvif_idx_release(queue, 988 XENVIF_TX_CB(skb)->pending_idx, 989 XEN_NETIF_RSP_OKAY); 990 991 /* Invalidate preceding fragments of this skb. */ 992 for (j = 0; j < i; j++) { 993 pending_idx = frag_get_pending_idx(&shinfo->frags[j]); 994 xenvif_idx_unmap(queue, pending_idx); 995 xenvif_idx_release(queue, pending_idx, 996 XEN_NETIF_RSP_OKAY); 997 } 998 999 /* And if we found the error while checking the frag_list, unmap 1000 * the first skb's frags 1001 */ 1002 if (first_shinfo) { 1003 for (j = 0; j < first_shinfo->nr_frags; j++) { 1004 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]); 1005 xenvif_idx_unmap(queue, pending_idx); 1006 xenvif_idx_release(queue, pending_idx, 1007 XEN_NETIF_RSP_OKAY); 1008 } 1009 } 1010 1011 /* Remember the error: invalidate all subsequent fragments. */ 1012 err = newerr; 1013 } 1014 1015 if (skb_has_frag_list(skb) && !first_shinfo) { 1016 first_shinfo = skb_shinfo(skb); 1017 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list); 1018 nr_frags = shinfo->nr_frags; 1019 1020 goto check_frags; 1021 } 1022 1023 *gopp_map = gop_map; 1024 return err; 1025} 1026 1027static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb) 1028{ 1029 struct skb_shared_info *shinfo = skb_shinfo(skb); 1030 int nr_frags = shinfo->nr_frags; 1031 int i; 1032 u16 prev_pending_idx = INVALID_PENDING_IDX; 1033 1034 for (i = 0; i < nr_frags; i++) { 1035 skb_frag_t *frag = shinfo->frags + i; 1036 struct xen_netif_tx_request *txp; 1037 struct page *page; 1038 u16 pending_idx; 1039 1040 pending_idx = frag_get_pending_idx(frag); 1041 1042 /* If this is not the first frag, chain it to the previous*/ 1043 if (prev_pending_idx == INVALID_PENDING_IDX) 1044 skb_shinfo(skb)->destructor_arg = 1045 &callback_param(queue, pending_idx); 1046 else 1047 callback_param(queue, prev_pending_idx).ctx = 1048 &callback_param(queue, pending_idx); 1049 1050 callback_param(queue, pending_idx).ctx = NULL; 1051 prev_pending_idx = pending_idx; 1052 1053 txp = &queue->pending_tx_info[pending_idx].req; 1054 page = virt_to_page(idx_to_kaddr(queue, pending_idx)); 1055 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size); 1056 skb->len += txp->size; 1057 skb->data_len += txp->size; 1058 skb->truesize += txp->size; 1059 1060 /* Take an extra reference to offset network stack's put_page */ 1061 get_page(queue->mmap_pages[pending_idx]); 1062 } 1063} 1064 1065static int xenvif_get_extras(struct xenvif_queue *queue, 1066 struct xen_netif_extra_info *extras, 1067 int work_to_do) 1068{ 1069 struct xen_netif_extra_info extra; 1070 RING_IDX cons = queue->tx.req_cons; 1071 1072 do { 1073 if (unlikely(work_to_do-- <= 0)) { 1074 netdev_err(queue->vif->dev, "Missing extra info\n"); 1075 xenvif_fatal_tx_err(queue->vif); 1076 return -EBADR; 1077 } 1078 1079 memcpy(&extra, RING_GET_REQUEST(&queue->tx, cons), 1080 sizeof(extra)); 1081 if (unlikely(!extra.type || 1082 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) { 1083 queue->tx.req_cons = ++cons; 1084 netdev_err(queue->vif->dev, 1085 "Invalid extra type: %d\n", extra.type); 1086 xenvif_fatal_tx_err(queue->vif); 1087 return -EINVAL; 1088 } 1089 1090 memcpy(&extras[extra.type - 1], &extra, sizeof(extra)); 1091 queue->tx.req_cons = ++cons; 1092 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE); 1093 1094 return work_to_do; 1095} 1096 1097static int xenvif_set_skb_gso(struct xenvif *vif, 1098 struct sk_buff *skb, 1099 struct xen_netif_extra_info *gso) 1100{ 1101 if (!gso->u.gso.size) { 1102 netdev_err(vif->dev, "GSO size must not be zero.\n"); 1103 xenvif_fatal_tx_err(vif); 1104 return -EINVAL; 1105 } 1106 1107 switch (gso->u.gso.type) { 1108 case XEN_NETIF_GSO_TYPE_TCPV4: 1109 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; 1110 break; 1111 case XEN_NETIF_GSO_TYPE_TCPV6: 1112 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; 1113 break; 1114 default: 1115 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type); 1116 xenvif_fatal_tx_err(vif); 1117 return -EINVAL; 1118 } 1119 1120 skb_shinfo(skb)->gso_size = gso->u.gso.size; 1121 /* gso_segs will be calculated later */ 1122 1123 return 0; 1124} 1125 1126static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb) 1127{ 1128 bool recalculate_partial_csum = false; 1129 1130 /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy 1131 * peers can fail to set NETRXF_csum_blank when sending a GSO 1132 * frame. In this case force the SKB to CHECKSUM_PARTIAL and 1133 * recalculate the partial checksum. 1134 */ 1135 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) { 1136 queue->stats.rx_gso_checksum_fixup++; 1137 skb->ip_summed = CHECKSUM_PARTIAL; 1138 recalculate_partial_csum = true; 1139 } 1140 1141 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */ 1142 if (skb->ip_summed != CHECKSUM_PARTIAL) 1143 return 0; 1144 1145 return skb_checksum_setup(skb, recalculate_partial_csum); 1146} 1147 1148static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size) 1149{ 1150 u64 now = get_jiffies_64(); 1151 u64 next_credit = queue->credit_window_start + 1152 msecs_to_jiffies(queue->credit_usec / 1000); 1153 1154 /* Timer could already be pending in rare cases. */ 1155 if (timer_pending(&queue->credit_timeout)) 1156 return true; 1157 1158 /* Passed the point where we can replenish credit? */ 1159 if (time_after_eq64(now, next_credit)) { 1160 queue->credit_window_start = now; 1161 tx_add_credit(queue); 1162 } 1163 1164 /* Still too big to send right now? Set a callback. */ 1165 if (size > queue->remaining_credit) { 1166 queue->credit_timeout.data = 1167 (unsigned long)queue; 1168 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 1178static 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 (unsigned long)(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 */ 1342static 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, f; 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 1387 /* Copied all the bits from the frag list -- free it. */ 1388 skb_frag_list_init(skb); 1389 xenvif_skb_zerocopy_prepare(queue, nskb); 1390 kfree_skb(nskb); 1391 1392 /* Release all the original (foreign) frags. */ 1393 for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) 1394 skb_frag_unref(skb, f); 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 /* Fill the skb with the new (local) frags. */ 1402 memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t)); 1403 skb_shinfo(skb)->nr_frags = i; 1404 skb->truesize += i * PAGE_SIZE; 1405 1406 return 0; 1407} 1408 1409static int xenvif_tx_submit(struct xenvif_queue *queue) 1410{ 1411 struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops; 1412 struct gnttab_copy *gop_copy = queue->tx_copy_ops; 1413 struct sk_buff *skb; 1414 int work_done = 0; 1415 1416 while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) { 1417 struct xen_netif_tx_request *txp; 1418 u16 pending_idx; 1419 unsigned data_len; 1420 1421 pending_idx = XENVIF_TX_CB(skb)->pending_idx; 1422 txp = &queue->pending_tx_info[pending_idx].req; 1423 1424 /* Check the remap error code. */ 1425 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) { 1426 /* If there was an error, xenvif_tx_check_gop is 1427 * expected to release all the frags which were mapped, 1428 * so kfree_skb shouldn't do it again 1429 */ 1430 skb_shinfo(skb)->nr_frags = 0; 1431 if (skb_has_frag_list(skb)) { 1432 struct sk_buff *nskb = 1433 skb_shinfo(skb)->frag_list; 1434 skb_shinfo(nskb)->nr_frags = 0; 1435 } 1436 kfree_skb(skb); 1437 continue; 1438 } 1439 1440 data_len = skb->len; 1441 callback_param(queue, pending_idx).ctx = NULL; 1442 if (data_len < txp->size) { 1443 /* Append the packet payload as a fragment. */ 1444 txp->offset += data_len; 1445 txp->size -= data_len; 1446 } else { 1447 /* Schedule a response immediately. */ 1448 xenvif_idx_release(queue, pending_idx, 1449 XEN_NETIF_RSP_OKAY); 1450 } 1451 1452 if (txp->flags & XEN_NETTXF_csum_blank) 1453 skb->ip_summed = CHECKSUM_PARTIAL; 1454 else if (txp->flags & XEN_NETTXF_data_validated) 1455 skb->ip_summed = CHECKSUM_UNNECESSARY; 1456 1457 xenvif_fill_frags(queue, skb); 1458 1459 if (unlikely(skb_has_frag_list(skb))) { 1460 if (xenvif_handle_frag_list(queue, skb)) { 1461 if (net_ratelimit()) 1462 netdev_err(queue->vif->dev, 1463 "Not enough memory to consolidate frag_list!\n"); 1464 xenvif_skb_zerocopy_prepare(queue, skb); 1465 kfree_skb(skb); 1466 continue; 1467 } 1468 } 1469 1470 skb->dev = queue->vif->dev; 1471 skb->protocol = eth_type_trans(skb, skb->dev); 1472 skb_reset_network_header(skb); 1473 1474 if (checksum_setup(queue, skb)) { 1475 netdev_dbg(queue->vif->dev, 1476 "Can't setup checksum in net_tx_action\n"); 1477 /* We have to set this flag to trigger the callback */ 1478 if (skb_shinfo(skb)->destructor_arg) 1479 xenvif_skb_zerocopy_prepare(queue, skb); 1480 kfree_skb(skb); 1481 continue; 1482 } 1483 1484 skb_probe_transport_header(skb, 0); 1485 1486 /* If the packet is GSO then we will have just set up the 1487 * transport header offset in checksum_setup so it's now 1488 * straightforward to calculate gso_segs. 1489 */ 1490 if (skb_is_gso(skb)) { 1491 int mss = skb_shinfo(skb)->gso_size; 1492 int hdrlen = skb_transport_header(skb) - 1493 skb_mac_header(skb) + 1494 tcp_hdrlen(skb); 1495 1496 skb_shinfo(skb)->gso_segs = 1497 DIV_ROUND_UP(skb->len - hdrlen, mss); 1498 } 1499 1500 queue->stats.rx_bytes += skb->len; 1501 queue->stats.rx_packets++; 1502 1503 work_done++; 1504 1505 /* Set this flag right before netif_receive_skb, otherwise 1506 * someone might think this packet already left netback, and 1507 * do a skb_copy_ubufs while we are still in control of the 1508 * skb. E.g. the __pskb_pull_tail earlier can do such thing. 1509 */ 1510 if (skb_shinfo(skb)->destructor_arg) { 1511 xenvif_skb_zerocopy_prepare(queue, skb); 1512 queue->stats.tx_zerocopy_sent++; 1513 } 1514 1515 netif_receive_skb(skb); 1516 } 1517 1518 return work_done; 1519} 1520 1521void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success) 1522{ 1523 unsigned long flags; 1524 pending_ring_idx_t index; 1525 struct xenvif_queue *queue = ubuf_to_queue(ubuf); 1526 1527 /* This is the only place where we grab this lock, to protect callbacks 1528 * from each other. 1529 */ 1530 spin_lock_irqsave(&queue->callback_lock, flags); 1531 do { 1532 u16 pending_idx = ubuf->desc; 1533 ubuf = (struct ubuf_info *) ubuf->ctx; 1534 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >= 1535 MAX_PENDING_REQS); 1536 index = pending_index(queue->dealloc_prod); 1537 queue->dealloc_ring[index] = pending_idx; 1538 /* Sync with xenvif_tx_dealloc_action: 1539 * insert idx then incr producer. 1540 */ 1541 smp_wmb(); 1542 queue->dealloc_prod++; 1543 } while (ubuf); 1544 wake_up(&queue->dealloc_wq); 1545 spin_unlock_irqrestore(&queue->callback_lock, flags); 1546 1547 if (likely(zerocopy_success)) 1548 queue->stats.tx_zerocopy_success++; 1549 else 1550 queue->stats.tx_zerocopy_fail++; 1551 xenvif_skb_zerocopy_complete(queue); 1552} 1553 1554static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue) 1555{ 1556 struct gnttab_unmap_grant_ref *gop; 1557 pending_ring_idx_t dc, dp; 1558 u16 pending_idx, pending_idx_release[MAX_PENDING_REQS]; 1559 unsigned int i = 0; 1560 1561 dc = queue->dealloc_cons; 1562 gop = queue->tx_unmap_ops; 1563 1564 /* Free up any grants we have finished using */ 1565 do { 1566 dp = queue->dealloc_prod; 1567 1568 /* Ensure we see all indices enqueued by all 1569 * xenvif_zerocopy_callback(). 1570 */ 1571 smp_rmb(); 1572 1573 while (dc != dp) { 1574 BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS); 1575 pending_idx = 1576 queue->dealloc_ring[pending_index(dc++)]; 1577 1578 pending_idx_release[gop - queue->tx_unmap_ops] = 1579 pending_idx; 1580 queue->pages_to_unmap[gop - queue->tx_unmap_ops] = 1581 queue->mmap_pages[pending_idx]; 1582 gnttab_set_unmap_op(gop, 1583 idx_to_kaddr(queue, pending_idx), 1584 GNTMAP_host_map, 1585 queue->grant_tx_handle[pending_idx]); 1586 xenvif_grant_handle_reset(queue, pending_idx); 1587 ++gop; 1588 } 1589 1590 } while (dp != queue->dealloc_prod); 1591 1592 queue->dealloc_cons = dc; 1593 1594 if (gop - queue->tx_unmap_ops > 0) { 1595 int ret; 1596 ret = gnttab_unmap_refs(queue->tx_unmap_ops, 1597 NULL, 1598 queue->pages_to_unmap, 1599 gop - queue->tx_unmap_ops); 1600 if (ret) { 1601 netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tx ret %d\n", 1602 gop - queue->tx_unmap_ops, ret); 1603 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) { 1604 if (gop[i].status != GNTST_okay) 1605 netdev_err(queue->vif->dev, 1606 " host_addr: %llx handle: %x status: %d\n", 1607 gop[i].host_addr, 1608 gop[i].handle, 1609 gop[i].status); 1610 } 1611 BUG(); 1612 } 1613 } 1614 1615 for (i = 0; i < gop - queue->tx_unmap_ops; ++i) 1616 xenvif_idx_release(queue, pending_idx_release[i], 1617 XEN_NETIF_RSP_OKAY); 1618} 1619 1620 1621/* Called after netfront has transmitted */ 1622int xenvif_tx_action(struct xenvif_queue *queue, int budget) 1623{ 1624 unsigned nr_mops, nr_cops = 0; 1625 int work_done, ret; 1626 1627 if (unlikely(!tx_work_todo(queue))) 1628 return 0; 1629 1630 xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops); 1631 1632 if (nr_cops == 0) 1633 return 0; 1634 1635 gnttab_batch_copy(queue->tx_copy_ops, nr_cops); 1636 if (nr_mops != 0) { 1637 ret = gnttab_map_refs(queue->tx_map_ops, 1638 NULL, 1639 queue->pages_to_map, 1640 nr_mops); 1641 BUG_ON(ret); 1642 } 1643 1644 work_done = xenvif_tx_submit(queue); 1645 1646 return work_done; 1647} 1648 1649static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx, 1650 u8 status) 1651{ 1652 struct pending_tx_info *pending_tx_info; 1653 pending_ring_idx_t index; 1654 unsigned long flags; 1655 1656 pending_tx_info = &queue->pending_tx_info[pending_idx]; 1657 1658 spin_lock_irqsave(&queue->response_lock, flags); 1659 1660 make_tx_response(queue, &pending_tx_info->req, status); 1661 1662 /* Release the pending index before pusing the Tx response so 1663 * its available before a new Tx request is pushed by the 1664 * frontend. 1665 */ 1666 index = pending_index(queue->pending_prod++); 1667 queue->pending_ring[index] = pending_idx; 1668 1669 push_tx_responses(queue); 1670 1671 spin_unlock_irqrestore(&queue->response_lock, flags); 1672} 1673 1674 1675static void make_tx_response(struct xenvif_queue *queue, 1676 struct xen_netif_tx_request *txp, 1677 s8 st) 1678{ 1679 RING_IDX i = queue->tx.rsp_prod_pvt; 1680 struct xen_netif_tx_response *resp; 1681 1682 resp = RING_GET_RESPONSE(&queue->tx, i); 1683 resp->id = txp->id; 1684 resp->status = st; 1685 1686 if (txp->flags & XEN_NETTXF_extra_info) 1687 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL; 1688 1689 queue->tx.rsp_prod_pvt = ++i; 1690} 1691 1692static void push_tx_responses(struct xenvif_queue *queue) 1693{ 1694 int notify; 1695 1696 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify); 1697 if (notify) 1698 notify_remote_via_irq(queue->tx_irq); 1699} 1700 1701static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue, 1702 u16 id, 1703 s8 st, 1704 u16 offset, 1705 u16 size, 1706 u16 flags) 1707{ 1708 RING_IDX i = queue->rx.rsp_prod_pvt; 1709 struct xen_netif_rx_response *resp; 1710 1711 resp = RING_GET_RESPONSE(&queue->rx, i); 1712 resp->offset = offset; 1713 resp->flags = flags; 1714 resp->id = id; 1715 resp->status = (s16)size; 1716 if (st < 0) 1717 resp->status = (s16)st; 1718 1719 queue->rx.rsp_prod_pvt = ++i; 1720 1721 return resp; 1722} 1723 1724void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx) 1725{ 1726 int ret; 1727 struct gnttab_unmap_grant_ref tx_unmap_op; 1728 1729 gnttab_set_unmap_op(&tx_unmap_op, 1730 idx_to_kaddr(queue, pending_idx), 1731 GNTMAP_host_map, 1732 queue->grant_tx_handle[pending_idx]); 1733 xenvif_grant_handle_reset(queue, pending_idx); 1734 1735 ret = gnttab_unmap_refs(&tx_unmap_op, NULL, 1736 &queue->mmap_pages[pending_idx], 1); 1737 if (ret) { 1738 netdev_err(queue->vif->dev, 1739 "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: %x status: %d\n", 1740 ret, 1741 pending_idx, 1742 tx_unmap_op.host_addr, 1743 tx_unmap_op.handle, 1744 tx_unmap_op.status); 1745 BUG(); 1746 } 1747} 1748 1749static inline int tx_work_todo(struct xenvif_queue *queue) 1750{ 1751 if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))) 1752 return 1; 1753 1754 return 0; 1755} 1756 1757static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue) 1758{ 1759 return queue->dealloc_cons != queue->dealloc_prod; 1760} 1761 1762void xenvif_unmap_frontend_rings(struct xenvif_queue *queue) 1763{ 1764 if (queue->tx.sring) 1765 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif), 1766 queue->tx.sring); 1767 if (queue->rx.sring) 1768 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif), 1769 queue->rx.sring); 1770} 1771 1772int xenvif_map_frontend_rings(struct xenvif_queue *queue, 1773 grant_ref_t tx_ring_ref, 1774 grant_ref_t rx_ring_ref) 1775{ 1776 void *addr; 1777 struct xen_netif_tx_sring *txs; 1778 struct xen_netif_rx_sring *rxs; 1779 1780 int err = -ENOMEM; 1781 1782 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif), 1783 &tx_ring_ref, 1, &addr); 1784 if (err) 1785 goto err; 1786 1787 txs = (struct xen_netif_tx_sring *)addr; 1788 BACK_RING_INIT(&queue->tx, txs, PAGE_SIZE); 1789 1790 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif), 1791 &rx_ring_ref, 1, &addr); 1792 if (err) 1793 goto err; 1794 1795 rxs = (struct xen_netif_rx_sring *)addr; 1796 BACK_RING_INIT(&queue->rx, rxs, PAGE_SIZE); 1797 1798 return 0; 1799 1800err: 1801 xenvif_unmap_frontend_rings(queue); 1802 return err; 1803} 1804 1805static void xenvif_queue_carrier_off(struct xenvif_queue *queue) 1806{ 1807 struct xenvif *vif = queue->vif; 1808 1809 queue->stalled = true; 1810 1811 /* At least one queue has stalled? Disable the carrier. */ 1812 spin_lock(&vif->lock); 1813 if (vif->stalled_queues++ == 0) { 1814 netdev_info(vif->dev, "Guest Rx stalled"); 1815 netif_carrier_off(vif->dev); 1816 } 1817 spin_unlock(&vif->lock); 1818} 1819 1820static void xenvif_queue_carrier_on(struct xenvif_queue *queue) 1821{ 1822 struct xenvif *vif = queue->vif; 1823 1824 queue->last_rx_time = jiffies; /* Reset Rx stall detection. */ 1825 queue->stalled = false; 1826 1827 /* All queues are ready? Enable the carrier. */ 1828 spin_lock(&vif->lock); 1829 if (--vif->stalled_queues == 0) { 1830 netdev_info(vif->dev, "Guest Rx ready"); 1831 netif_carrier_on(vif->dev); 1832 } 1833 spin_unlock(&vif->lock); 1834} 1835 1836static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue) 1837{ 1838 RING_IDX prod, cons; 1839 1840 prod = queue->rx.sring->req_prod; 1841 cons = queue->rx.req_cons; 1842 1843 return !queue->stalled 1844 && prod - cons < XEN_NETBK_RX_SLOTS_MAX 1845 && time_after(jiffies, 1846 queue->last_rx_time + queue->vif->stall_timeout); 1847} 1848 1849static bool xenvif_rx_queue_ready(struct xenvif_queue *queue) 1850{ 1851 RING_IDX prod, cons; 1852 1853 prod = queue->rx.sring->req_prod; 1854 cons = queue->rx.req_cons; 1855 1856 return queue->stalled 1857 && prod - cons >= XEN_NETBK_RX_SLOTS_MAX; 1858} 1859 1860static bool xenvif_have_rx_work(struct xenvif_queue *queue) 1861{ 1862 return (!skb_queue_empty(&queue->rx_queue) 1863 && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX)) 1864 || (queue->vif->stall_timeout && 1865 (xenvif_rx_queue_stalled(queue) 1866 || xenvif_rx_queue_ready(queue))) 1867 || kthread_should_stop() 1868 || queue->vif->disabled; 1869} 1870 1871static long xenvif_rx_queue_timeout(struct xenvif_queue *queue) 1872{ 1873 struct sk_buff *skb; 1874 long timeout; 1875 1876 skb = skb_peek(&queue->rx_queue); 1877 if (!skb) 1878 return MAX_SCHEDULE_TIMEOUT; 1879 1880 timeout = XENVIF_RX_CB(skb)->expires - jiffies; 1881 return timeout < 0 ? 0 : timeout; 1882} 1883 1884/* Wait until the guest Rx thread has work. 1885 * 1886 * The timeout needs to be adjusted based on the current head of the 1887 * queue (and not just the head at the beginning). In particular, if 1888 * the queue is initially empty an infinite timeout is used and this 1889 * needs to be reduced when a skb is queued. 1890 * 1891 * This cannot be done with wait_event_timeout() because it only 1892 * calculates the timeout once. 1893 */ 1894static void xenvif_wait_for_rx_work(struct xenvif_queue *queue) 1895{ 1896 DEFINE_WAIT(wait); 1897 1898 if (xenvif_have_rx_work(queue)) 1899 return; 1900 1901 for (;;) { 1902 long ret; 1903 1904 prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE); 1905 if (xenvif_have_rx_work(queue)) 1906 break; 1907 ret = schedule_timeout(xenvif_rx_queue_timeout(queue)); 1908 if (!ret) 1909 break; 1910 } 1911 finish_wait(&queue->wq, &wait); 1912} 1913 1914int xenvif_kthread_guest_rx(void *data) 1915{ 1916 struct xenvif_queue *queue = data; 1917 struct xenvif *vif = queue->vif; 1918 1919 if (!vif->stall_timeout) 1920 xenvif_queue_carrier_on(queue); 1921 1922 for (;;) { 1923 xenvif_wait_for_rx_work(queue); 1924 1925 if (kthread_should_stop()) 1926 break; 1927 1928 /* This frontend is found to be rogue, disable it in 1929 * kthread context. Currently this is only set when 1930 * netback finds out frontend sends malformed packet, 1931 * but we cannot disable the interface in softirq 1932 * context so we defer it here, if this thread is 1933 * associated with queue 0. 1934 */ 1935 if (unlikely(vif->disabled && queue->id == 0)) { 1936 xenvif_carrier_off(vif); 1937 break; 1938 } 1939 1940 if (!skb_queue_empty(&queue->rx_queue)) 1941 xenvif_rx_action(queue); 1942 1943 /* If the guest hasn't provided any Rx slots for a 1944 * while it's probably not responsive, drop the 1945 * carrier so packets are dropped earlier. 1946 */ 1947 if (vif->stall_timeout) { 1948 if (xenvif_rx_queue_stalled(queue)) 1949 xenvif_queue_carrier_off(queue); 1950 else if (xenvif_rx_queue_ready(queue)) 1951 xenvif_queue_carrier_on(queue); 1952 } 1953 1954 /* Queued packets may have foreign pages from other 1955 * domains. These cannot be queued indefinitely as 1956 * this would starve guests of grant refs and transmit 1957 * slots. 1958 */ 1959 xenvif_rx_queue_drop_expired(queue); 1960 1961 xenvif_rx_queue_maybe_wake(queue); 1962 1963 cond_resched(); 1964 } 1965 1966 /* Bin any remaining skbs */ 1967 xenvif_rx_queue_purge(queue); 1968 1969 return 0; 1970} 1971 1972static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue) 1973{ 1974 /* Dealloc thread must remain running until all inflight 1975 * packets complete. 1976 */ 1977 return kthread_should_stop() && 1978 !atomic_read(&queue->inflight_packets); 1979} 1980 1981int xenvif_dealloc_kthread(void *data) 1982{ 1983 struct xenvif_queue *queue = data; 1984 1985 for (;;) { 1986 wait_event_interruptible(queue->dealloc_wq, 1987 tx_dealloc_work_todo(queue) || 1988 xenvif_dealloc_kthread_should_stop(queue)); 1989 if (xenvif_dealloc_kthread_should_stop(queue)) 1990 break; 1991 1992 xenvif_tx_dealloc_action(queue); 1993 cond_resched(); 1994 } 1995 1996 /* Unmap anything remaining*/ 1997 if (tx_dealloc_work_todo(queue)) 1998 xenvif_tx_dealloc_action(queue); 1999 2000 return 0; 2001} 2002 2003static int __init netback_init(void) 2004{ 2005 int rc = 0; 2006 2007 if (!xen_domain()) 2008 return -ENODEV; 2009 2010 /* Allow as many queues as there are CPUs if user has not 2011 * specified a value. 2012 */ 2013 if (xenvif_max_queues == 0) 2014 xenvif_max_queues = num_online_cpus(); 2015 2016 if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) { 2017 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n", 2018 fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX); 2019 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX; 2020 } 2021 2022 rc = xenvif_xenbus_init(); 2023 if (rc) 2024 goto failed_init; 2025 2026#ifdef CONFIG_DEBUG_FS 2027 xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL); 2028 if (IS_ERR_OR_NULL(xen_netback_dbg_root)) 2029 pr_warn("Init of debugfs returned %ld!\n", 2030 PTR_ERR(xen_netback_dbg_root)); 2031#endif /* CONFIG_DEBUG_FS */ 2032 2033 return 0; 2034 2035failed_init: 2036 return rc; 2037} 2038 2039module_init(netback_init); 2040 2041static void __exit netback_fini(void) 2042{ 2043#ifdef CONFIG_DEBUG_FS 2044 if (!IS_ERR_OR_NULL(xen_netback_dbg_root)) 2045 debugfs_remove_recursive(xen_netback_dbg_root); 2046#endif /* CONFIG_DEBUG_FS */ 2047 xenvif_xenbus_fini(); 2048} 2049module_exit(netback_fini); 2050 2051MODULE_LICENSE("Dual BSD/GPL"); 2052MODULE_ALIAS("xen-backend:vif"); 2053