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