1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * linux/fs/nfs/pagelist.c
   4 *
   5 * A set of helper functions for managing NFS read and write requests.
   6 * The main purpose of these routines is to provide support for the
   7 * coalescing of several requests into a single RPC call.
   8 *
   9 * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no>
  10 *
  11 */
  12
  13#include <linux/slab.h>
  14#include <linux/file.h>
  15#include <linux/sched.h>
  16#include <linux/sunrpc/clnt.h>
  17#include <linux/nfs.h>
  18#include <linux/nfs3.h>
  19#include <linux/nfs4.h>
  20#include <linux/nfs_fs.h>
  21#include <linux/nfs_page.h>
  22#include <linux/nfs_mount.h>
  23#include <linux/export.h>
  24
  25#include "internal.h"
  26#include "pnfs.h"
  27#include "nfstrace.h"
  28
  29#define NFSDBG_FACILITY		NFSDBG_PAGECACHE
  30
  31static struct kmem_cache *nfs_page_cachep;
  32static const struct rpc_call_ops nfs_pgio_common_ops;
  33
  34static struct nfs_pgio_mirror *
  35nfs_pgio_get_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
  36{
  37	if (desc->pg_ops->pg_get_mirror)
  38		return desc->pg_ops->pg_get_mirror(desc, idx);
  39	return &desc->pg_mirrors[0];
  40}
  41
  42struct nfs_pgio_mirror *
  43nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc)
  44{
  45	return nfs_pgio_get_mirror(desc, desc->pg_mirror_idx);
  46}
  47EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror);
  48
  49static u32
  50nfs_pgio_set_current_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
  51{
  52	if (desc->pg_ops->pg_set_mirror)
  53		return desc->pg_ops->pg_set_mirror(desc, idx);
  54	return desc->pg_mirror_idx;
  55}
  56
  57void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
  58		       struct nfs_pgio_header *hdr,
  59		       void (*release)(struct nfs_pgio_header *hdr))
  60{
  61	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
  62
  63
  64	hdr->req = nfs_list_entry(mirror->pg_list.next);
  65	hdr->inode = desc->pg_inode;
  66	hdr->cred = nfs_req_openctx(hdr->req)->cred;
  67	hdr->io_start = req_offset(hdr->req);
  68	hdr->good_bytes = mirror->pg_count;
  69	hdr->io_completion = desc->pg_io_completion;
  70	hdr->dreq = desc->pg_dreq;
  71	hdr->release = release;
  72	hdr->completion_ops = desc->pg_completion_ops;
  73	if (hdr->completion_ops->init_hdr)
  74		hdr->completion_ops->init_hdr(hdr);
  75
  76	hdr->pgio_mirror_idx = desc->pg_mirror_idx;
  77}
  78EXPORT_SYMBOL_GPL(nfs_pgheader_init);
  79
  80void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
  81{
  82	unsigned int new = pos - hdr->io_start;
  83
  84	trace_nfs_pgio_error(hdr, error, pos);
  85	if (hdr->good_bytes > new) {
  86		hdr->good_bytes = new;
  87		clear_bit(NFS_IOHDR_EOF, &hdr->flags);
  88		if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags))
  89			hdr->error = error;
  90	}
  91}
  92
  93static inline struct nfs_page *
  94nfs_page_alloc(void)
  95{
  96	struct nfs_page	*p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL);
 
  97	if (p)
  98		INIT_LIST_HEAD(&p->wb_list);
  99	return p;
 100}
 101
 102static inline void
 103nfs_page_free(struct nfs_page *p)
 104{
 105	kmem_cache_free(nfs_page_cachep, p);
 106}
 107
 108/**
 109 * nfs_iocounter_wait - wait for i/o to complete
 110 * @l_ctx: nfs_lock_context with io_counter to use
 111 *
 112 * returns -ERESTARTSYS if interrupted by a fatal signal.
 113 * Otherwise returns 0 once the io_count hits 0.
 114 */
 115int
 116nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
 117{
 118	return wait_var_event_killable(&l_ctx->io_count,
 119				       !atomic_read(&l_ctx->io_count));
 120}
 121
 122/**
 123 * nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O
 124 * to complete
 125 * @task: the rpc_task that should wait
 126 * @l_ctx: nfs_lock_context with io_counter to check
 127 *
 128 * Returns true if there is outstanding I/O to wait on and the
 129 * task has been put to sleep.
 130 */
 131bool
 132nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
 133{
 134	struct inode *inode = d_inode(l_ctx->open_context->dentry);
 135	bool ret = false;
 136
 137	if (atomic_read(&l_ctx->io_count) > 0) {
 138		rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL);
 139		ret = true;
 140	}
 141
 142	if (atomic_read(&l_ctx->io_count) == 0) {
 143		rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task);
 144		ret = false;
 145	}
 146
 147	return ret;
 148}
 149EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);
 150
 151/*
 152 * nfs_page_lock_head_request - page lock the head of the page group
 153 * @req: any member of the page group
 154 */
 155struct nfs_page *
 156nfs_page_group_lock_head(struct nfs_page *req)
 157{
 158	struct nfs_page *head = req->wb_head;
 159
 160	while (!nfs_lock_request(head)) {
 161		int ret = nfs_wait_on_request(head);
 162		if (ret < 0)
 163			return ERR_PTR(ret);
 164	}
 165	if (head != req)
 166		kref_get(&head->wb_kref);
 167	return head;
 168}
 169
 170/*
 171 * nfs_unroll_locks -  unlock all newly locked reqs and wait on @req
 172 * @head: head request of page group, must be holding head lock
 173 * @req: request that couldn't lock and needs to wait on the req bit lock
 174 *
 175 * This is a helper function for nfs_lock_and_join_requests
 176 * returns 0 on success, < 0 on error.
 177 */
 178static void
 179nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)
 180{
 181	struct nfs_page *tmp;
 182
 183	/* relinquish all the locks successfully grabbed this run */
 184	for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
 185		if (!kref_read(&tmp->wb_kref))
 186			continue;
 187		nfs_unlock_and_release_request(tmp);
 188	}
 189}
 190
 191/*
 192 * nfs_page_group_lock_subreq -  try to lock a subrequest
 193 * @head: head request of page group
 194 * @subreq: request to lock
 195 *
 196 * This is a helper function for nfs_lock_and_join_requests which
 197 * must be called with the head request and page group both locked.
 198 * On error, it returns with the page group unlocked.
 199 */
 200static int
 201nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)
 202{
 203	int ret;
 204
 205	if (!kref_get_unless_zero(&subreq->wb_kref))
 206		return 0;
 207	while (!nfs_lock_request(subreq)) {
 208		nfs_page_group_unlock(head);
 209		ret = nfs_wait_on_request(subreq);
 210		if (!ret)
 211			ret = nfs_page_group_lock(head);
 212		if (ret < 0) {
 213			nfs_unroll_locks(head, subreq);
 214			nfs_release_request(subreq);
 215			return ret;
 216		}
 217	}
 218	return 0;
 219}
 220
 221/*
 222 * nfs_page_group_lock_subrequests -  try to lock the subrequests
 223 * @head: head request of page group
 224 *
 225 * This is a helper function for nfs_lock_and_join_requests which
 226 * must be called with the head request locked.
 227 */
 228int nfs_page_group_lock_subrequests(struct nfs_page *head)
 229{
 230	struct nfs_page *subreq;
 231	int ret;
 232
 233	ret = nfs_page_group_lock(head);
 234	if (ret < 0)
 235		return ret;
 236	/* lock each request in the page group */
 237	for (subreq = head->wb_this_page; subreq != head;
 238			subreq = subreq->wb_this_page) {
 239		ret = nfs_page_group_lock_subreq(head, subreq);
 240		if (ret < 0)
 241			return ret;
 242	}
 243	nfs_page_group_unlock(head);
 244	return 0;
 245}
 246
 247/*
 248 * nfs_page_set_headlock - set the request PG_HEADLOCK
 249 * @req: request that is to be locked
 250 *
 251 * this lock must be held when modifying req->wb_head
 252 *
 253 * return 0 on success, < 0 on error
 254 */
 255int
 256nfs_page_set_headlock(struct nfs_page *req)
 257{
 258	if (!test_and_set_bit(PG_HEADLOCK, &req->wb_flags))
 259		return 0;
 260
 261	set_bit(PG_CONTENDED1, &req->wb_flags);
 262	smp_mb__after_atomic();
 263	return wait_on_bit_lock(&req->wb_flags, PG_HEADLOCK,
 264				TASK_UNINTERRUPTIBLE);
 265}
 266
 267/*
 268 * nfs_page_clear_headlock - clear the request PG_HEADLOCK
 269 * @req: request that is to be locked
 270 */
 271void
 272nfs_page_clear_headlock(struct nfs_page *req)
 273{
 274	smp_mb__before_atomic();
 275	clear_bit(PG_HEADLOCK, &req->wb_flags);
 276	smp_mb__after_atomic();
 277	if (!test_bit(PG_CONTENDED1, &req->wb_flags))
 278		return;
 279	wake_up_bit(&req->wb_flags, PG_HEADLOCK);
 280}
 281
 282/*
 283 * nfs_page_group_lock - lock the head of the page group
 284 * @req: request in group that is to be locked
 285 *
 286 * this lock must be held when traversing or modifying the page
 287 * group list
 288 *
 289 * return 0 on success, < 0 on error
 290 */
 291int
 292nfs_page_group_lock(struct nfs_page *req)
 293{
 294	int ret;
 295
 296	ret = nfs_page_set_headlock(req);
 297	if (ret || req->wb_head == req)
 298		return ret;
 299	return nfs_page_set_headlock(req->wb_head);
 300}
 301
 302/*
 303 * nfs_page_group_unlock - unlock the head of the page group
 304 * @req: request in group that is to be unlocked
 305 */
 306void
 307nfs_page_group_unlock(struct nfs_page *req)
 308{
 309	if (req != req->wb_head)
 310		nfs_page_clear_headlock(req->wb_head);
 311	nfs_page_clear_headlock(req);
 312}
 313
 314/*
 315 * nfs_page_group_sync_on_bit_locked
 316 *
 317 * must be called with page group lock held
 318 */
 319static bool
 320nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
 321{
 322	struct nfs_page *head = req->wb_head;
 323	struct nfs_page *tmp;
 324
 325	WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags));
 326	WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags));
 327
 328	tmp = req->wb_this_page;
 329	while (tmp != req) {
 330		if (!test_bit(bit, &tmp->wb_flags))
 331			return false;
 332		tmp = tmp->wb_this_page;
 333	}
 334
 335	/* true! reset all bits */
 336	tmp = req;
 337	do {
 338		clear_bit(bit, &tmp->wb_flags);
 339		tmp = tmp->wb_this_page;
 340	} while (tmp != req);
 341
 342	return true;
 343}
 344
 345/*
 346 * nfs_page_group_sync_on_bit - set bit on current request, but only
 347 *   return true if the bit is set for all requests in page group
 348 * @req - request in page group
 349 * @bit - PG_* bit that is used to sync page group
 350 */
 351bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit)
 352{
 353	bool ret;
 354
 355	nfs_page_group_lock(req);
 356	ret = nfs_page_group_sync_on_bit_locked(req, bit);
 357	nfs_page_group_unlock(req);
 358
 359	return ret;
 360}
 361
 362/*
 363 * nfs_page_group_init - Initialize the page group linkage for @req
 364 * @req - a new nfs request
 365 * @prev - the previous request in page group, or NULL if @req is the first
 366 *         or only request in the group (the head).
 367 */
 368static inline void
 369nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
 370{
 371	struct inode *inode;
 372	WARN_ON_ONCE(prev == req);
 373
 374	if (!prev) {
 375		/* a head request */
 376		req->wb_head = req;
 377		req->wb_this_page = req;
 378	} else {
 379		/* a subrequest */
 380		WARN_ON_ONCE(prev->wb_this_page != prev->wb_head);
 381		WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags));
 382		req->wb_head = prev->wb_head;
 383		req->wb_this_page = prev->wb_this_page;
 384		prev->wb_this_page = req;
 385
 386		/* All subrequests take a ref on the head request until
 387		 * nfs_page_group_destroy is called */
 388		kref_get(&req->wb_head->wb_kref);
 389
 390		/* grab extra ref and bump the request count if head request
 391		 * has extra ref from the write/commit path to handle handoff
 392		 * between write and commit lists. */
 393		if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
 394			inode = page_file_mapping(req->wb_page)->host;
 395			set_bit(PG_INODE_REF, &req->wb_flags);
 396			kref_get(&req->wb_kref);
 397			atomic_long_inc(&NFS_I(inode)->nrequests);
 398		}
 399	}
 400}
 401
 402/*
 403 * nfs_page_group_destroy - sync the destruction of page groups
 404 * @req - request that no longer needs the page group
 405 *
 406 * releases the page group reference from each member once all
 407 * members have called this function.
 408 */
 409static void
 410nfs_page_group_destroy(struct kref *kref)
 411{
 412	struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
 413	struct nfs_page *head = req->wb_head;
 414	struct nfs_page *tmp, *next;
 415
 416	if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN))
 417		goto out;
 418
 419	tmp = req;
 420	do {
 421		next = tmp->wb_this_page;
 422		/* unlink and free */
 423		tmp->wb_this_page = tmp;
 424		tmp->wb_head = tmp;
 425		nfs_free_request(tmp);
 426		tmp = next;
 427	} while (tmp != req);
 428out:
 429	/* subrequests must release the ref on the head request */
 430	if (head != req)
 431		nfs_release_request(head);
 432}
 433
 434static struct nfs_page *
 435__nfs_create_request(struct nfs_lock_context *l_ctx, struct page *page,
 436		   unsigned int pgbase, unsigned int offset,
 437		   unsigned int count)
 438{
 439	struct nfs_page		*req;
 440	struct nfs_open_context *ctx = l_ctx->open_context;
 441
 442	if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
 443		return ERR_PTR(-EBADF);
 444	/* try to allocate the request struct */
 445	req = nfs_page_alloc();
 446	if (req == NULL)
 447		return ERR_PTR(-ENOMEM);
 448
 449	req->wb_lock_context = l_ctx;
 450	refcount_inc(&l_ctx->count);
 451	atomic_inc(&l_ctx->io_count);
 452
 453	/* Initialize the request struct. Initially, we assume a
 454	 * long write-back delay. This will be adjusted in
 455	 * update_nfs_request below if the region is not locked. */
 456	req->wb_page    = page;
 457	if (page) {
 458		req->wb_index = page_index(page);
 459		get_page(page);
 460	}
 461	req->wb_offset  = offset;
 462	req->wb_pgbase	= pgbase;
 463	req->wb_bytes   = count;
 464	kref_init(&req->wb_kref);
 465	req->wb_nio = 0;
 466	return req;
 467}
 468
 469/**
 470 * nfs_create_request - Create an NFS read/write request.
 471 * @ctx: open context to use
 472 * @page: page to write
 473 * @offset: starting offset within the page for the write
 474 * @count: number of bytes to read/write
 475 *
 476 * The page must be locked by the caller. This makes sure we never
 477 * create two different requests for the same page.
 478 * User should ensure it is safe to sleep in this function.
 479 */
 480struct nfs_page *
 481nfs_create_request(struct nfs_open_context *ctx, struct page *page,
 482		   unsigned int offset, unsigned int count)
 483{
 484	struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
 485	struct nfs_page *ret;
 486
 487	if (IS_ERR(l_ctx))
 488		return ERR_CAST(l_ctx);
 489	ret = __nfs_create_request(l_ctx, page, offset, offset, count);
 490	if (!IS_ERR(ret))
 491		nfs_page_group_init(ret, NULL);
 492	nfs_put_lock_context(l_ctx);
 493	return ret;
 494}
 495
 496static struct nfs_page *
 497nfs_create_subreq(struct nfs_page *req,
 498		  unsigned int pgbase,
 499		  unsigned int offset,
 500		  unsigned int count)
 501{
 502	struct nfs_page *last;
 503	struct nfs_page *ret;
 504
 505	ret = __nfs_create_request(req->wb_lock_context, req->wb_page,
 506			pgbase, offset, count);
 507	if (!IS_ERR(ret)) {
 508		/* find the last request */
 509		for (last = req->wb_head;
 510		     last->wb_this_page != req->wb_head;
 511		     last = last->wb_this_page)
 512			;
 513
 514		nfs_lock_request(ret);
 515		ret->wb_index = req->wb_index;
 516		nfs_page_group_init(ret, last);
 517		ret->wb_nio = req->wb_nio;
 518	}
 519	return ret;
 520}
 521
 522/**
 523 * nfs_unlock_request - Unlock request and wake up sleepers.
 524 * @req: pointer to request
 525 */
 526void nfs_unlock_request(struct nfs_page *req)
 527{
 528	if (!NFS_WBACK_BUSY(req)) {
 529		printk(KERN_ERR "NFS: Invalid unlock attempted\n");
 530		BUG();
 531	}
 532	smp_mb__before_atomic();
 533	clear_bit(PG_BUSY, &req->wb_flags);
 534	smp_mb__after_atomic();
 535	if (!test_bit(PG_CONTENDED2, &req->wb_flags))
 536		return;
 537	wake_up_bit(&req->wb_flags, PG_BUSY);
 538}
 539
 540/**
 541 * nfs_unlock_and_release_request - Unlock request and release the nfs_page
 542 * @req: pointer to request
 543 */
 544void nfs_unlock_and_release_request(struct nfs_page *req)
 545{
 546	nfs_unlock_request(req);
 547	nfs_release_request(req);
 548}
 549
 550/*
 551 * nfs_clear_request - Free up all resources allocated to the request
 552 * @req:
 553 *
 554 * Release page and open context resources associated with a read/write
 555 * request after it has completed.
 556 */
 557static void nfs_clear_request(struct nfs_page *req)
 558{
 559	struct page *page = req->wb_page;
 560	struct nfs_lock_context *l_ctx = req->wb_lock_context;
 561	struct nfs_open_context *ctx;
 562
 563	if (page != NULL) {
 564		put_page(page);
 565		req->wb_page = NULL;
 566	}
 567	if (l_ctx != NULL) {
 568		if (atomic_dec_and_test(&l_ctx->io_count)) {
 569			wake_up_var(&l_ctx->io_count);
 570			ctx = l_ctx->open_context;
 571			if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
 572				rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
 573		}
 574		nfs_put_lock_context(l_ctx);
 575		req->wb_lock_context = NULL;
 576	}
 577}
 578
 579/**
 580 * nfs_free_request - Release the count on an NFS read/write request
 581 * @req: request to release
 582 *
 583 * Note: Should never be called with the spinlock held!
 584 */
 585void nfs_free_request(struct nfs_page *req)
 586{
 587	WARN_ON_ONCE(req->wb_this_page != req);
 588
 589	/* extra debug: make sure no sync bits are still set */
 590	WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
 591	WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
 592	WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
 593	WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
 594	WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
 595
 596	/* Release struct file and open context */
 597	nfs_clear_request(req);
 598	nfs_page_free(req);
 599}
 600
 601void nfs_release_request(struct nfs_page *req)
 602{
 603	kref_put(&req->wb_kref, nfs_page_group_destroy);
 604}
 605EXPORT_SYMBOL_GPL(nfs_release_request);
 606
 607/**
 608 * nfs_wait_on_request - Wait for a request to complete.
 609 * @req: request to wait upon.
 610 *
 611 * Interruptible by fatal signals only.
 612 * The user is responsible for holding a count on the request.
 613 */
 614int
 615nfs_wait_on_request(struct nfs_page *req)
 616{
 617	if (!test_bit(PG_BUSY, &req->wb_flags))
 618		return 0;
 619	set_bit(PG_CONTENDED2, &req->wb_flags);
 620	smp_mb__after_atomic();
 621	return wait_on_bit_io(&req->wb_flags, PG_BUSY,
 622			      TASK_UNINTERRUPTIBLE);
 623}
 624EXPORT_SYMBOL_GPL(nfs_wait_on_request);
 625
 626/*
 627 * nfs_generic_pg_test - determine if requests can be coalesced
 628 * @desc: pointer to descriptor
 629 * @prev: previous request in desc, or NULL
 630 * @req: this request
 631 *
 632 * Returns zero if @req cannot be coalesced into @desc, otherwise it returns
 633 * the size of the request.
 634 */
 635size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 636			   struct nfs_page *prev, struct nfs_page *req)
 637{
 638	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 639
 640
 641	if (mirror->pg_count > mirror->pg_bsize) {
 642		/* should never happen */
 643		WARN_ON_ONCE(1);
 644		return 0;
 645	}
 646
 647	/*
 648	 * Limit the request size so that we can still allocate a page array
 649	 * for it without upsetting the slab allocator.
 650	 */
 651	if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
 652			sizeof(struct page *) > PAGE_SIZE)
 653		return 0;
 654
 655	return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
 656}
 657EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
 658
 659struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
 660{
 661	struct nfs_pgio_header *hdr = ops->rw_alloc_header();
 662
 663	if (hdr) {
 664		INIT_LIST_HEAD(&hdr->pages);
 665		hdr->rw_ops = ops;
 666	}
 667	return hdr;
 668}
 669EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
 670
 671/**
 672 * nfs_pgio_data_destroy - make @hdr suitable for reuse
 673 *
 674 * Frees memory and releases refs from nfs_generic_pgio, so that it may
 675 * be called again.
 676 *
 677 * @hdr: A header that has had nfs_generic_pgio called
 678 */
 679static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
 680{
 681	if (hdr->args.context)
 682		put_nfs_open_context(hdr->args.context);
 683	if (hdr->page_array.pagevec != hdr->page_array.page_array)
 684		kfree(hdr->page_array.pagevec);
 685}
 686
 687/*
 688 * nfs_pgio_header_free - Free a read or write header
 689 * @hdr: The header to free
 690 */
 691void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
 692{
 693	nfs_pgio_data_destroy(hdr);
 694	hdr->rw_ops->rw_free_header(hdr);
 695}
 696EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
 697
 698/**
 699 * nfs_pgio_rpcsetup - Set up arguments for a pageio call
 700 * @hdr: The pageio hdr
 701 * @count: Number of bytes to read
 702 * @how: How to commit data (writes only)
 703 * @cinfo: Commit information for the call (writes only)
 704 */
 705static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr,
 706			      unsigned int count,
 707			      int how, struct nfs_commit_info *cinfo)
 708{
 709	struct nfs_page *req = hdr->req;
 710
 711	/* Set up the RPC argument and reply structs
 712	 * NB: take care not to mess about with hdr->commit et al. */
 713
 714	hdr->args.fh     = NFS_FH(hdr->inode);
 715	hdr->args.offset = req_offset(req);
 716	/* pnfs_set_layoutcommit needs this */
 717	hdr->mds_offset = hdr->args.offset;
 718	hdr->args.pgbase = req->wb_pgbase;
 719	hdr->args.pages  = hdr->page_array.pagevec;
 720	hdr->args.count  = count;
 721	hdr->args.context = get_nfs_open_context(nfs_req_openctx(req));
 722	hdr->args.lock_context = req->wb_lock_context;
 723	hdr->args.stable  = NFS_UNSTABLE;
 724	switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
 725	case 0:
 726		break;
 727	case FLUSH_COND_STABLE:
 728		if (nfs_reqs_to_commit(cinfo))
 729			break;
 730		fallthrough;
 731	default:
 732		hdr->args.stable = NFS_FILE_SYNC;
 733	}
 734
 735	hdr->res.fattr   = &hdr->fattr;
 736	hdr->res.count   = 0;
 737	hdr->res.eof     = 0;
 738	hdr->res.verf    = &hdr->verf;
 739	nfs_fattr_init(&hdr->fattr);
 740}
 741
 742/**
 743 * nfs_pgio_prepare - Prepare pageio hdr to go over the wire
 744 * @task: The current task
 745 * @calldata: pageio header to prepare
 746 */
 747static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
 748{
 749	struct nfs_pgio_header *hdr = calldata;
 750	int err;
 751	err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
 752	if (err)
 753		rpc_exit(task, err);
 754}
 755
 756int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
 757		      const struct cred *cred, const struct nfs_rpc_ops *rpc_ops,
 758		      const struct rpc_call_ops *call_ops, int how, int flags)
 759{
 760	struct rpc_task *task;
 761	struct rpc_message msg = {
 762		.rpc_argp = &hdr->args,
 763		.rpc_resp = &hdr->res,
 764		.rpc_cred = cred,
 765	};
 766	struct rpc_task_setup task_setup_data = {
 767		.rpc_client = clnt,
 768		.task = &hdr->task,
 769		.rpc_message = &msg,
 770		.callback_ops = call_ops,
 771		.callback_data = hdr,
 772		.workqueue = nfsiod_workqueue,
 773		.flags = RPC_TASK_ASYNC | flags,
 774	};
 775
 
 
 
 776	hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
 777
 778	dprintk("NFS: initiated pgio call "
 779		"(req %s/%llu, %u bytes @ offset %llu)\n",
 780		hdr->inode->i_sb->s_id,
 781		(unsigned long long)NFS_FILEID(hdr->inode),
 782		hdr->args.count,
 783		(unsigned long long)hdr->args.offset);
 784
 785	task = rpc_run_task(&task_setup_data);
 786	if (IS_ERR(task))
 787		return PTR_ERR(task);
 788	rpc_put_task(task);
 789	return 0;
 790}
 791EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
 792
 793/**
 794 * nfs_pgio_error - Clean up from a pageio error
 795 * @hdr: pageio header
 796 */
 797static void nfs_pgio_error(struct nfs_pgio_header *hdr)
 798{
 799	set_bit(NFS_IOHDR_REDO, &hdr->flags);
 800	hdr->completion_ops->completion(hdr);
 801}
 802
 803/**
 804 * nfs_pgio_release - Release pageio data
 805 * @calldata: The pageio header to release
 806 */
 807static void nfs_pgio_release(void *calldata)
 808{
 809	struct nfs_pgio_header *hdr = calldata;
 810	hdr->completion_ops->completion(hdr);
 811}
 812
 813static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
 814				   unsigned int bsize)
 815{
 816	INIT_LIST_HEAD(&mirror->pg_list);
 817	mirror->pg_bytes_written = 0;
 818	mirror->pg_count = 0;
 819	mirror->pg_bsize = bsize;
 820	mirror->pg_base = 0;
 821	mirror->pg_recoalesce = 0;
 822}
 823
 824/**
 825 * nfs_pageio_init - initialise a page io descriptor
 826 * @desc: pointer to descriptor
 827 * @inode: pointer to inode
 828 * @pg_ops: pointer to pageio operations
 829 * @compl_ops: pointer to pageio completion operations
 830 * @rw_ops: pointer to nfs read/write operations
 831 * @bsize: io block size
 832 * @io_flags: extra parameters for the io function
 833 */
 834void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 835		     struct inode *inode,
 836		     const struct nfs_pageio_ops *pg_ops,
 837		     const struct nfs_pgio_completion_ops *compl_ops,
 838		     const struct nfs_rw_ops *rw_ops,
 839		     size_t bsize,
 840		     int io_flags)
 841{
 842	desc->pg_moreio = 0;
 843	desc->pg_inode = inode;
 844	desc->pg_ops = pg_ops;
 845	desc->pg_completion_ops = compl_ops;
 846	desc->pg_rw_ops = rw_ops;
 847	desc->pg_ioflags = io_flags;
 848	desc->pg_error = 0;
 849	desc->pg_lseg = NULL;
 850	desc->pg_io_completion = NULL;
 851	desc->pg_dreq = NULL;
 852	desc->pg_bsize = bsize;
 853
 854	desc->pg_mirror_count = 1;
 855	desc->pg_mirror_idx = 0;
 856
 857	desc->pg_mirrors_dynamic = NULL;
 858	desc->pg_mirrors = desc->pg_mirrors_static;
 859	nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
 860	desc->pg_maxretrans = 0;
 861}
 862
 863/**
 864 * nfs_pgio_result - Basic pageio error handling
 865 * @task: The task that ran
 866 * @calldata: Pageio header to check
 867 */
 868static void nfs_pgio_result(struct rpc_task *task, void *calldata)
 869{
 870	struct nfs_pgio_header *hdr = calldata;
 871	struct inode *inode = hdr->inode;
 872
 873	dprintk("NFS: %s: %5u, (status %d)\n", __func__,
 874		task->tk_pid, task->tk_status);
 875
 876	if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
 877		return;
 878	if (task->tk_status < 0)
 879		nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
 880	else
 881		hdr->rw_ops->rw_result(task, hdr);
 882}
 883
 884/*
 885 * Create an RPC task for the given read or write request and kick it.
 886 * The page must have been locked by the caller.
 887 *
 888 * It may happen that the page we're passed is not marked dirty.
 889 * This is the case if nfs_updatepage detects a conflicting request
 890 * that has been written but not committed.
 891 */
 892int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
 893		     struct nfs_pgio_header *hdr)
 894{
 895	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 896
 897	struct nfs_page		*req;
 898	struct page		**pages,
 899				*last_page;
 900	struct list_head *head = &mirror->pg_list;
 901	struct nfs_commit_info cinfo;
 902	struct nfs_page_array *pg_array = &hdr->page_array;
 903	unsigned int pagecount, pageused;
 904	gfp_t gfp_flags = GFP_KERNEL;
 905
 906	pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);
 907	pg_array->npages = pagecount;
 908
 909	if (pagecount <= ARRAY_SIZE(pg_array->page_array))
 910		pg_array->pagevec = pg_array->page_array;
 911	else {
 912		pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);
 913		if (!pg_array->pagevec) {
 914			pg_array->npages = 0;
 915			nfs_pgio_error(hdr);
 916			desc->pg_error = -ENOMEM;
 917			return desc->pg_error;
 918		}
 919	}
 920
 921	nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
 922	pages = hdr->page_array.pagevec;
 923	last_page = NULL;
 924	pageused = 0;
 925	while (!list_empty(head)) {
 926		req = nfs_list_entry(head->next);
 927		nfs_list_move_request(req, &hdr->pages);
 928
 929		if (!last_page || last_page != req->wb_page) {
 930			pageused++;
 931			if (pageused > pagecount)
 932				break;
 933			*pages++ = last_page = req->wb_page;
 934		}
 935	}
 936	if (WARN_ON_ONCE(pageused != pagecount)) {
 937		nfs_pgio_error(hdr);
 938		desc->pg_error = -EINVAL;
 939		return desc->pg_error;
 940	}
 941
 942	if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
 943	    (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
 944		desc->pg_ioflags &= ~FLUSH_COND_STABLE;
 945
 946	/* Set up the argument struct */
 947	nfs_pgio_rpcsetup(hdr, mirror->pg_count, desc->pg_ioflags, &cinfo);
 948	desc->pg_rpc_callops = &nfs_pgio_common_ops;
 949	return 0;
 950}
 951EXPORT_SYMBOL_GPL(nfs_generic_pgio);
 952
 953static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
 954{
 955	struct nfs_pgio_header *hdr;
 956	int ret;
 957	unsigned short task_flags = 0;
 958
 959	hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
 960	if (!hdr) {
 961		desc->pg_error = -ENOMEM;
 962		return desc->pg_error;
 963	}
 964	nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
 965	ret = nfs_generic_pgio(desc, hdr);
 966	if (ret == 0) {
 967		if (NFS_SERVER(hdr->inode)->nfs_client->cl_minorversion)
 968			task_flags = RPC_TASK_MOVEABLE;
 969		ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
 970					hdr,
 971					hdr->cred,
 972					NFS_PROTO(hdr->inode),
 973					desc->pg_rpc_callops,
 974					desc->pg_ioflags,
 975					RPC_TASK_CRED_NOREF | task_flags);
 976	}
 977	return ret;
 978}
 979
 980static struct nfs_pgio_mirror *
 981nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
 982		unsigned int mirror_count)
 983{
 984	struct nfs_pgio_mirror *ret;
 985	unsigned int i;
 986
 987	kfree(desc->pg_mirrors_dynamic);
 988	desc->pg_mirrors_dynamic = NULL;
 989	if (mirror_count == 1)
 990		return desc->pg_mirrors_static;
 991	ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_KERNEL);
 992	if (ret != NULL) {
 993		for (i = 0; i < mirror_count; i++)
 994			nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
 995		desc->pg_mirrors_dynamic = ret;
 996	}
 997	return ret;
 998}
 999
1000/*
1001 * nfs_pageio_setup_mirroring - determine if mirroring is to be used
1002 *				by calling the pg_get_mirror_count op
1003 */
1004static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
1005				       struct nfs_page *req)
1006{
1007	unsigned int mirror_count = 1;
1008
1009	if (pgio->pg_ops->pg_get_mirror_count)
1010		mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
1011	if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)
1012		return;
1013
1014	if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {
1015		pgio->pg_error = -EINVAL;
1016		return;
1017	}
1018
1019	pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);
1020	if (pgio->pg_mirrors == NULL) {
1021		pgio->pg_error = -ENOMEM;
1022		pgio->pg_mirrors = pgio->pg_mirrors_static;
1023		mirror_count = 1;
1024	}
1025	pgio->pg_mirror_count = mirror_count;
1026}
1027
1028static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
1029{
1030	pgio->pg_mirror_count = 1;
1031	pgio->pg_mirror_idx = 0;
1032	pgio->pg_mirrors = pgio->pg_mirrors_static;
1033	kfree(pgio->pg_mirrors_dynamic);
1034	pgio->pg_mirrors_dynamic = NULL;
1035}
1036
1037static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
1038		const struct nfs_lock_context *l2)
1039{
1040	return l1->lockowner == l2->lockowner;
1041}
1042
1043/**
1044 * nfs_coalesce_size - test two requests for compatibility
1045 * @prev: pointer to nfs_page
1046 * @req: pointer to nfs_page
1047 * @pgio: pointer to nfs_pagio_descriptor
1048 *
1049 * The nfs_page structures 'prev' and 'req' are compared to ensure that the
1050 * page data area they describe is contiguous, and that their RPC
1051 * credentials, NFSv4 open state, and lockowners are the same.
1052 *
1053 * Returns size of the request that can be coalesced
1054 */
1055static unsigned int nfs_coalesce_size(struct nfs_page *prev,
1056				      struct nfs_page *req,
1057				      struct nfs_pageio_descriptor *pgio)
1058{
1059	struct file_lock_context *flctx;
1060
1061	if (prev) {
1062		if (!nfs_match_open_context(nfs_req_openctx(req), nfs_req_openctx(prev)))
1063			return 0;
1064		flctx = d_inode(nfs_req_openctx(req)->dentry)->i_flctx;
1065		if (flctx != NULL &&
1066		    !(list_empty_careful(&flctx->flc_posix) &&
1067		      list_empty_careful(&flctx->flc_flock)) &&
1068		    !nfs_match_lock_context(req->wb_lock_context,
1069					    prev->wb_lock_context))
1070			return 0;
1071		if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
1072			return 0;
1073		if (req->wb_page == prev->wb_page) {
1074			if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes)
1075				return 0;
1076		} else {
1077			if (req->wb_pgbase != 0 ||
1078			    prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE)
1079				return 0;
1080		}
1081	}
1082	return pgio->pg_ops->pg_test(pgio, prev, req);
1083}
1084
1085/**
1086 * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
1087 * @desc: destination io descriptor
1088 * @req: request
1089 *
1090 * If the request 'req' was successfully coalesced into the existing list
1091 * of pages 'desc', it returns the size of req.
1092 */
1093static unsigned int
1094nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
1095		struct nfs_page *req)
1096{
1097	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1098	struct nfs_page *prev = NULL;
1099	unsigned int size;
1100
1101	if (list_empty(&mirror->pg_list)) {
1102		if (desc->pg_ops->pg_init)
1103			desc->pg_ops->pg_init(desc, req);
1104		if (desc->pg_error < 0)
1105			return 0;
1106		mirror->pg_base = req->wb_pgbase;
1107		mirror->pg_count = 0;
1108		mirror->pg_recoalesce = 0;
1109	} else
1110		prev = nfs_list_entry(mirror->pg_list.prev);
1111
1112	if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) {
1113		if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR)
1114			desc->pg_error = -ETIMEDOUT;
1115		else
1116			desc->pg_error = -EIO;
1117		return 0;
1118	}
1119
1120	size = nfs_coalesce_size(prev, req, desc);
1121	if (size < req->wb_bytes)
1122		return size;
1123	nfs_list_move_request(req, &mirror->pg_list);
1124	mirror->pg_count += req->wb_bytes;
1125	return req->wb_bytes;
1126}
1127
1128/*
1129 * Helper for nfs_pageio_add_request and nfs_pageio_complete
1130 */
1131static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
1132{
1133	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1134
1135	if (!list_empty(&mirror->pg_list)) {
1136		int error = desc->pg_ops->pg_doio(desc);
1137		if (error < 0)
1138			desc->pg_error = error;
1139		if (list_empty(&mirror->pg_list))
1140			mirror->pg_bytes_written += mirror->pg_count;
1141	}
1142}
1143
1144static void
1145nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc,
1146		struct nfs_page *req)
1147{
1148	LIST_HEAD(head);
1149
1150	nfs_list_move_request(req, &head);
1151	desc->pg_completion_ops->error_cleanup(&head, desc->pg_error);
1152}
1153
1154/**
1155 * __nfs_pageio_add_request - Attempt to coalesce a request into a page list.
1156 * @desc: destination io descriptor
1157 * @req: request
1158 *
1159 * This may split a request into subrequests which are all part of the
1160 * same page group. If so, it will submit @req as the last one, to ensure
1161 * the pointer to @req is still valid in case of failure.
1162 *
1163 * Returns true if the request 'req' was successfully coalesced into the
1164 * existing list of pages 'desc'.
1165 */
1166static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1167			   struct nfs_page *req)
1168{
1169	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1170	struct nfs_page *subreq;
1171	unsigned int size, subreq_size;
1172
1173	nfs_page_group_lock(req);
1174
1175	subreq = req;
1176	subreq_size = subreq->wb_bytes;
1177	for(;;) {
1178		size = nfs_pageio_do_add_request(desc, subreq);
1179		if (size == subreq_size) {
1180			/* We successfully submitted a request */
1181			if (subreq == req)
1182				break;
1183			req->wb_pgbase += size;
1184			req->wb_bytes -= size;
1185			req->wb_offset += size;
1186			subreq_size = req->wb_bytes;
1187			subreq = req;
1188			continue;
1189		}
1190		if (WARN_ON_ONCE(subreq != req)) {
1191			nfs_page_group_unlock(req);
1192			nfs_pageio_cleanup_request(desc, subreq);
1193			subreq = req;
1194			subreq_size = req->wb_bytes;
1195			nfs_page_group_lock(req);
1196		}
1197		if (!size) {
1198			/* Can't coalesce any more, so do I/O */
1199			nfs_page_group_unlock(req);
1200			desc->pg_moreio = 1;
1201			nfs_pageio_doio(desc);
1202			if (desc->pg_error < 0 || mirror->pg_recoalesce)
1203				return 0;
1204			/* retry add_request for this subreq */
1205			nfs_page_group_lock(req);
1206			continue;
1207		}
1208		subreq = nfs_create_subreq(req, req->wb_pgbase,
1209				req->wb_offset, size);
1210		if (IS_ERR(subreq))
1211			goto err_ptr;
1212		subreq_size = size;
1213	}
1214
1215	nfs_page_group_unlock(req);
1216	return 1;
1217err_ptr:
1218	desc->pg_error = PTR_ERR(subreq);
1219	nfs_page_group_unlock(req);
1220	return 0;
1221}
1222
1223static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
1224{
1225	struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1226	LIST_HEAD(head);
1227
1228	do {
1229		list_splice_init(&mirror->pg_list, &head);
 
1230
1231		while (!list_empty(&head)) {
1232			struct nfs_page *req;
1233
1234			req = list_first_entry(&head, struct nfs_page, wb_list);
1235			if (__nfs_pageio_add_request(desc, req))
1236				continue;
1237			if (desc->pg_error < 0) {
1238				list_splice_tail(&head, &mirror->pg_list);
1239				mirror->pg_recoalesce = 1;
1240				return 0;
1241			}
1242			break;
1243		}
1244	} while (mirror->pg_recoalesce);
1245	return 1;
1246}
1247
1248static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
1249		struct nfs_page *req)
1250{
1251	int ret;
1252
1253	do {
1254		ret = __nfs_pageio_add_request(desc, req);
1255		if (ret)
1256			break;
1257		if (desc->pg_error < 0)
1258			break;
1259		ret = nfs_do_recoalesce(desc);
1260	} while (ret);
1261
1262	return ret;
1263}
1264
1265static void nfs_pageio_error_cleanup(struct nfs_pageio_descriptor *desc)
1266{
1267	u32 midx;
1268	struct nfs_pgio_mirror *mirror;
1269
1270	if (!desc->pg_error)
1271		return;
1272
1273	for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1274		mirror = nfs_pgio_get_mirror(desc, midx);
1275		desc->pg_completion_ops->error_cleanup(&mirror->pg_list,
1276				desc->pg_error);
1277	}
1278}
1279
1280int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1281			   struct nfs_page *req)
1282{
1283	u32 midx;
1284	unsigned int pgbase, offset, bytes;
1285	struct nfs_page *dupreq;
1286
1287	pgbase = req->wb_pgbase;
1288	offset = req->wb_offset;
1289	bytes = req->wb_bytes;
1290
1291	nfs_pageio_setup_mirroring(desc, req);
1292	if (desc->pg_error < 0)
1293		goto out_failed;
1294
1295	/* Create the mirror instances first, and fire them off */
1296	for (midx = 1; midx < desc->pg_mirror_count; midx++) {
1297		nfs_page_group_lock(req);
1298
1299		dupreq = nfs_create_subreq(req,
1300				pgbase, offset, bytes);
1301
1302		nfs_page_group_unlock(req);
1303		if (IS_ERR(dupreq)) {
1304			desc->pg_error = PTR_ERR(dupreq);
1305			goto out_failed;
1306		}
1307
1308		nfs_pgio_set_current_mirror(desc, midx);
1309		if (!nfs_pageio_add_request_mirror(desc, dupreq))
1310			goto out_cleanup_subreq;
1311	}
1312
1313	nfs_pgio_set_current_mirror(desc, 0);
1314	if (!nfs_pageio_add_request_mirror(desc, req))
1315		goto out_failed;
1316
1317	return 1;
1318
1319out_cleanup_subreq:
1320	nfs_pageio_cleanup_request(desc, dupreq);
1321out_failed:
1322	nfs_pageio_error_cleanup(desc);
1323	return 0;
1324}
1325
1326/*
1327 * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
1328 *				nfs_pageio_descriptor
1329 * @desc: pointer to io descriptor
1330 * @mirror_idx: pointer to mirror index
1331 */
1332static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
1333				       u32 mirror_idx)
1334{
1335	struct nfs_pgio_mirror *mirror;
1336	u32 restore_idx;
1337
1338	restore_idx = nfs_pgio_set_current_mirror(desc, mirror_idx);
1339	mirror = nfs_pgio_current_mirror(desc);
1340
1341	for (;;) {
1342		nfs_pageio_doio(desc);
1343		if (desc->pg_error < 0 || !mirror->pg_recoalesce)
1344			break;
1345		if (!nfs_do_recoalesce(desc))
1346			break;
1347	}
1348	nfs_pgio_set_current_mirror(desc, restore_idx);
1349}
1350
1351/*
1352 * nfs_pageio_resend - Transfer requests to new descriptor and resend
1353 * @hdr - the pgio header to move request from
1354 * @desc - the pageio descriptor to add requests to
1355 *
1356 * Try to move each request (nfs_page) from @hdr to @desc then attempt
1357 * to send them.
1358 *
1359 * Returns 0 on success and < 0 on error.
1360 */
1361int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
1362		      struct nfs_pgio_header *hdr)
1363{
1364	LIST_HEAD(pages);
1365
1366	desc->pg_io_completion = hdr->io_completion;
1367	desc->pg_dreq = hdr->dreq;
1368	list_splice_init(&hdr->pages, &pages);
1369	while (!list_empty(&pages)) {
1370		struct nfs_page *req = nfs_list_entry(pages.next);
1371
1372		if (!nfs_pageio_add_request(desc, req))
1373			break;
1374	}
1375	nfs_pageio_complete(desc);
1376	if (!list_empty(&pages)) {
1377		int err = desc->pg_error < 0 ? desc->pg_error : -EIO;
1378		hdr->completion_ops->error_cleanup(&pages, err);
1379		nfs_set_pgio_error(hdr, err, hdr->io_start);
1380		return err;
1381	}
1382	return 0;
1383}
1384EXPORT_SYMBOL_GPL(nfs_pageio_resend);
1385
1386/**
1387 * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
1388 * @desc: pointer to io descriptor
1389 */
1390void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
1391{
1392	u32 midx;
1393
1394	for (midx = 0; midx < desc->pg_mirror_count; midx++)
1395		nfs_pageio_complete_mirror(desc, midx);
1396
1397	if (desc->pg_error < 0)
1398		nfs_pageio_error_cleanup(desc);
1399	if (desc->pg_ops->pg_cleanup)
1400		desc->pg_ops->pg_cleanup(desc);
1401	nfs_pageio_cleanup_mirroring(desc);
1402}
1403
1404/**
1405 * nfs_pageio_cond_complete - Conditional I/O completion
1406 * @desc: pointer to io descriptor
1407 * @index: page index
1408 *
1409 * It is important to ensure that processes don't try to take locks
1410 * on non-contiguous ranges of pages as that might deadlock. This
1411 * function should be called before attempting to wait on a locked
1412 * nfs_page. It will complete the I/O if the page index 'index'
1413 * is not contiguous with the existing list of pages in 'desc'.
1414 */
1415void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
1416{
1417	struct nfs_pgio_mirror *mirror;
1418	struct nfs_page *prev;
1419	u32 midx;
1420
1421	for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1422		mirror = nfs_pgio_get_mirror(desc, midx);
1423		if (!list_empty(&mirror->pg_list)) {
1424			prev = nfs_list_entry(mirror->pg_list.prev);
1425			if (index != prev->wb_index + 1) {
1426				nfs_pageio_complete(desc);
1427				break;
1428			}
1429		}
1430	}
1431}
1432
1433/*
1434 * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
1435 */
1436void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
1437{
1438	nfs_pageio_complete(pgio);
1439}
1440
1441int __init nfs_init_nfspagecache(void)
1442{
1443	nfs_page_cachep = kmem_cache_create("nfs_page",
1444					    sizeof(struct nfs_page),
1445					    0, SLAB_HWCACHE_ALIGN,
1446					    NULL);
1447	if (nfs_page_cachep == NULL)
1448		return -ENOMEM;
1449
1450	return 0;
1451}
1452
1453void nfs_destroy_nfspagecache(void)
1454{
1455	kmem_cache_destroy(nfs_page_cachep);
1456}
1457
1458static const struct rpc_call_ops nfs_pgio_common_ops = {
1459	.rpc_call_prepare = nfs_pgio_prepare,
1460	.rpc_call_done = nfs_pgio_result,
1461	.rpc_release = nfs_pgio_release,
1462};
1463
1464const struct nfs_pageio_ops nfs_pgio_rw_ops = {
1465	.pg_test = nfs_generic_pg_test,
1466	.pg_doio = nfs_generic_pg_pgios,
1467};