1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * linux/net/sunrpc/xdr.c
   4 *
   5 * Generic XDR support.
   6 *
   7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/slab.h>
  12#include <linux/types.h>
  13#include <linux/string.h>
  14#include <linux/kernel.h>
  15#include <linux/pagemap.h>
  16#include <linux/errno.h>
  17#include <linux/sunrpc/xdr.h>
  18#include <linux/sunrpc/msg_prot.h>
  19#include <linux/bvec.h>
  20#include <trace/events/sunrpc.h>
  21
  22static void _copy_to_pages(struct page **, size_t, const char *, size_t);
  23
  24
  25/*
  26 * XDR functions for basic NFS types
  27 */
  28__be32 *
  29xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
  30{
  31	unsigned int	quadlen = XDR_QUADLEN(obj->len);
  32
  33	p[quadlen] = 0;		/* zero trailing bytes */
  34	*p++ = cpu_to_be32(obj->len);
  35	memcpy(p, obj->data, obj->len);
  36	return p + XDR_QUADLEN(obj->len);
  37}
  38EXPORT_SYMBOL_GPL(xdr_encode_netobj);
  39
  40__be32 *
  41xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
  42{
  43	unsigned int	len;
  44
  45	if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
  46		return NULL;
  47	obj->len  = len;
  48	obj->data = (u8 *) p;
  49	return p + XDR_QUADLEN(len);
  50}
  51EXPORT_SYMBOL_GPL(xdr_decode_netobj);
  52
  53/**
  54 * xdr_encode_opaque_fixed - Encode fixed length opaque data
  55 * @p: pointer to current position in XDR buffer.
  56 * @ptr: pointer to data to encode (or NULL)
  57 * @nbytes: size of data.
  58 *
  59 * Copy the array of data of length nbytes at ptr to the XDR buffer
  60 * at position p, then align to the next 32-bit boundary by padding
  61 * with zero bytes (see RFC1832).
  62 * Note: if ptr is NULL, only the padding is performed.
  63 *
  64 * Returns the updated current XDR buffer position
  65 *
  66 */
  67__be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
  68{
  69	if (likely(nbytes != 0)) {
  70		unsigned int quadlen = XDR_QUADLEN(nbytes);
  71		unsigned int padding = (quadlen << 2) - nbytes;
  72
  73		if (ptr != NULL)
  74			memcpy(p, ptr, nbytes);
  75		if (padding != 0)
  76			memset((char *)p + nbytes, 0, padding);
  77		p += quadlen;
  78	}
  79	return p;
  80}
  81EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
  82
  83/**
  84 * xdr_encode_opaque - Encode variable length opaque data
  85 * @p: pointer to current position in XDR buffer.
  86 * @ptr: pointer to data to encode (or NULL)
  87 * @nbytes: size of data.
  88 *
  89 * Returns the updated current XDR buffer position
  90 */
  91__be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
  92{
  93	*p++ = cpu_to_be32(nbytes);
  94	return xdr_encode_opaque_fixed(p, ptr, nbytes);
  95}
  96EXPORT_SYMBOL_GPL(xdr_encode_opaque);
  97
  98__be32 *
  99xdr_encode_string(__be32 *p, const char *string)
 100{
 101	return xdr_encode_array(p, string, strlen(string));
 102}
 103EXPORT_SYMBOL_GPL(xdr_encode_string);
 104
 105__be32 *
 106xdr_decode_string_inplace(__be32 *p, char **sp,
 107			  unsigned int *lenp, unsigned int maxlen)
 108{
 109	u32 len;
 110
 111	len = be32_to_cpu(*p++);
 112	if (len > maxlen)
 113		return NULL;
 114	*lenp = len;
 115	*sp = (char *) p;
 116	return p + XDR_QUADLEN(len);
 117}
 118EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
 119
 120/**
 121 * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
 122 * @buf: XDR buffer where string resides
 123 * @len: length of string, in bytes
 124 *
 125 */
 126void xdr_terminate_string(const struct xdr_buf *buf, const u32 len)
 127{
 128	char *kaddr;
 129
 130	kaddr = kmap_atomic(buf->pages[0]);
 131	kaddr[buf->page_base + len] = '\0';
 132	kunmap_atomic(kaddr);
 133}
 134EXPORT_SYMBOL_GPL(xdr_terminate_string);
 135
 136size_t xdr_buf_pagecount(const struct xdr_buf *buf)
 137{
 138	if (!buf->page_len)
 139		return 0;
 140	return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 141}
 142
 143int
 144xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
 145{
 146	size_t i, n = xdr_buf_pagecount(buf);
 147
 148	if (n != 0 && buf->bvec == NULL) {
 149		buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
 150		if (!buf->bvec)
 151			return -ENOMEM;
 152		for (i = 0; i < n; i++) {
 153			bvec_set_page(&buf->bvec[i], buf->pages[i], PAGE_SIZE,
 154				      0);
 
 155		}
 156	}
 157	return 0;
 158}
 159
 160void
 161xdr_free_bvec(struct xdr_buf *buf)
 162{
 163	kfree(buf->bvec);
 164	buf->bvec = NULL;
 165}
 166
 167/**
 168 * xdr_buf_to_bvec - Copy components of an xdr_buf into a bio_vec array
 169 * @bvec: bio_vec array to populate
 170 * @bvec_size: element count of @bio_vec
 171 * @xdr: xdr_buf to be copied
 172 *
 173 * Returns the number of entries consumed in @bvec.
 174 */
 175unsigned int xdr_buf_to_bvec(struct bio_vec *bvec, unsigned int bvec_size,
 176			     const struct xdr_buf *xdr)
 177{
 178	const struct kvec *head = xdr->head;
 179	const struct kvec *tail = xdr->tail;
 180	unsigned int count = 0;
 181
 182	if (head->iov_len) {
 183		bvec_set_virt(bvec++, head->iov_base, head->iov_len);
 184		++count;
 185	}
 186
 187	if (xdr->page_len) {
 188		unsigned int offset, len, remaining;
 189		struct page **pages = xdr->pages;
 190
 191		offset = offset_in_page(xdr->page_base);
 192		remaining = xdr->page_len;
 193		while (remaining > 0) {
 194			len = min_t(unsigned int, remaining,
 195				    PAGE_SIZE - offset);
 196			bvec_set_page(bvec++, *pages++, len, offset);
 197			remaining -= len;
 198			offset = 0;
 199			if (unlikely(++count > bvec_size))
 200				goto bvec_overflow;
 201		}
 202	}
 203
 204	if (tail->iov_len) {
 205		bvec_set_virt(bvec, tail->iov_base, tail->iov_len);
 206		if (unlikely(++count > bvec_size))
 207			goto bvec_overflow;
 208	}
 209
 210	return count;
 211
 212bvec_overflow:
 213	pr_warn_once("%s: bio_vec array overflow\n", __func__);
 214	return count - 1;
 215}
 216
 217/**
 218 * xdr_inline_pages - Prepare receive buffer for a large reply
 219 * @xdr: xdr_buf into which reply will be placed
 220 * @offset: expected offset where data payload will start, in bytes
 221 * @pages: vector of struct page pointers
 222 * @base: offset in first page where receive should start, in bytes
 223 * @len: expected size of the upper layer data payload, in bytes
 224 *
 225 */
 226void
 227xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
 228		 struct page **pages, unsigned int base, unsigned int len)
 229{
 230	struct kvec *head = xdr->head;
 231	struct kvec *tail = xdr->tail;
 232	char *buf = (char *)head->iov_base;
 233	unsigned int buflen = head->iov_len;
 234
 235	head->iov_len  = offset;
 236
 237	xdr->pages = pages;
 238	xdr->page_base = base;
 239	xdr->page_len = len;
 240
 241	tail->iov_base = buf + offset;
 242	tail->iov_len = buflen - offset;
 243	xdr->buflen += len;
 244}
 245EXPORT_SYMBOL_GPL(xdr_inline_pages);
 246
 247/*
 248 * Helper routines for doing 'memmove' like operations on a struct xdr_buf
 249 */
 250
 251/**
 252 * _shift_data_left_pages
 253 * @pages: vector of pages containing both the source and dest memory area.
 254 * @pgto_base: page vector address of destination
 255 * @pgfrom_base: page vector address of source
 256 * @len: number of bytes to copy
 257 *
 258 * Note: the addresses pgto_base and pgfrom_base are both calculated in
 259 *       the same way:
 260 *            if a memory area starts at byte 'base' in page 'pages[i]',
 261 *            then its address is given as (i << PAGE_CACHE_SHIFT) + base
 262 * Alse note: pgto_base must be < pgfrom_base, but the memory areas
 263 * 	they point to may overlap.
 264 */
 265static void
 266_shift_data_left_pages(struct page **pages, size_t pgto_base,
 267			size_t pgfrom_base, size_t len)
 268{
 269	struct page **pgfrom, **pgto;
 270	char *vfrom, *vto;
 271	size_t copy;
 272
 273	BUG_ON(pgfrom_base <= pgto_base);
 274
 275	if (!len)
 276		return;
 277
 278	pgto = pages + (pgto_base >> PAGE_SHIFT);
 279	pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
 280
 281	pgto_base &= ~PAGE_MASK;
 282	pgfrom_base &= ~PAGE_MASK;
 283
 284	do {
 285		if (pgto_base >= PAGE_SIZE) {
 286			pgto_base = 0;
 287			pgto++;
 288		}
 289		if (pgfrom_base >= PAGE_SIZE){
 290			pgfrom_base = 0;
 291			pgfrom++;
 292		}
 293
 294		copy = len;
 295		if (copy > (PAGE_SIZE - pgto_base))
 296			copy = PAGE_SIZE - pgto_base;
 297		if (copy > (PAGE_SIZE - pgfrom_base))
 298			copy = PAGE_SIZE - pgfrom_base;
 299
 300		vto = kmap_atomic(*pgto);
 301		if (*pgto != *pgfrom) {
 302			vfrom = kmap_atomic(*pgfrom);
 303			memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
 304			kunmap_atomic(vfrom);
 305		} else
 306			memmove(vto + pgto_base, vto + pgfrom_base, copy);
 307		flush_dcache_page(*pgto);
 308		kunmap_atomic(vto);
 309
 310		pgto_base += copy;
 311		pgfrom_base += copy;
 312
 313	} while ((len -= copy) != 0);
 314}
 315
 316/**
 317 * _shift_data_right_pages
 318 * @pages: vector of pages containing both the source and dest memory area.
 319 * @pgto_base: page vector address of destination
 320 * @pgfrom_base: page vector address of source
 321 * @len: number of bytes to copy
 322 *
 323 * Note: the addresses pgto_base and pgfrom_base are both calculated in
 324 *       the same way:
 325 *            if a memory area starts at byte 'base' in page 'pages[i]',
 326 *            then its address is given as (i << PAGE_SHIFT) + base
 327 * Also note: pgfrom_base must be < pgto_base, but the memory areas
 328 * 	they point to may overlap.
 329 */
 330static void
 331_shift_data_right_pages(struct page **pages, size_t pgto_base,
 332		size_t pgfrom_base, size_t len)
 333{
 334	struct page **pgfrom, **pgto;
 335	char *vfrom, *vto;
 336	size_t copy;
 337
 338	BUG_ON(pgto_base <= pgfrom_base);
 339
 340	if (!len)
 341		return;
 342
 343	pgto_base += len;
 344	pgfrom_base += len;
 345
 346	pgto = pages + (pgto_base >> PAGE_SHIFT);
 347	pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
 348
 349	pgto_base &= ~PAGE_MASK;
 350	pgfrom_base &= ~PAGE_MASK;
 351
 352	do {
 353		/* Are any pointers crossing a page boundary? */
 354		if (pgto_base == 0) {
 355			pgto_base = PAGE_SIZE;
 356			pgto--;
 357		}
 358		if (pgfrom_base == 0) {
 359			pgfrom_base = PAGE_SIZE;
 360			pgfrom--;
 361		}
 362
 363		copy = len;
 364		if (copy > pgto_base)
 365			copy = pgto_base;
 366		if (copy > pgfrom_base)
 367			copy = pgfrom_base;
 368		pgto_base -= copy;
 369		pgfrom_base -= copy;
 370
 371		vto = kmap_atomic(*pgto);
 372		if (*pgto != *pgfrom) {
 373			vfrom = kmap_atomic(*pgfrom);
 374			memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
 375			kunmap_atomic(vfrom);
 376		} else
 377			memmove(vto + pgto_base, vto + pgfrom_base, copy);
 378		flush_dcache_page(*pgto);
 379		kunmap_atomic(vto);
 380
 381	} while ((len -= copy) != 0);
 382}
 383
 384/**
 385 * _copy_to_pages
 386 * @pages: array of pages
 387 * @pgbase: page vector address of destination
 388 * @p: pointer to source data
 389 * @len: length
 390 *
 391 * Copies data from an arbitrary memory location into an array of pages
 392 * The copy is assumed to be non-overlapping.
 393 */
 394static void
 395_copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
 396{
 397	struct page **pgto;
 398	char *vto;
 399	size_t copy;
 400
 401	if (!len)
 402		return;
 403
 404	pgto = pages + (pgbase >> PAGE_SHIFT);
 405	pgbase &= ~PAGE_MASK;
 406
 407	for (;;) {
 408		copy = PAGE_SIZE - pgbase;
 409		if (copy > len)
 410			copy = len;
 411
 412		vto = kmap_atomic(*pgto);
 413		memcpy(vto + pgbase, p, copy);
 414		kunmap_atomic(vto);
 415
 416		len -= copy;
 417		if (len == 0)
 418			break;
 419
 420		pgbase += copy;
 421		if (pgbase == PAGE_SIZE) {
 422			flush_dcache_page(*pgto);
 423			pgbase = 0;
 424			pgto++;
 425		}
 426		p += copy;
 427	}
 428	flush_dcache_page(*pgto);
 429}
 430
 431/**
 432 * _copy_from_pages
 433 * @p: pointer to destination
 434 * @pages: array of pages
 435 * @pgbase: offset of source data
 436 * @len: length
 437 *
 438 * Copies data into an arbitrary memory location from an array of pages
 439 * The copy is assumed to be non-overlapping.
 440 */
 441void
 442_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
 443{
 444	struct page **pgfrom;
 445	char *vfrom;
 446	size_t copy;
 447
 448	if (!len)
 449		return;
 450
 451	pgfrom = pages + (pgbase >> PAGE_SHIFT);
 452	pgbase &= ~PAGE_MASK;
 453
 454	do {
 455		copy = PAGE_SIZE - pgbase;
 456		if (copy > len)
 457			copy = len;
 458
 459		vfrom = kmap_atomic(*pgfrom);
 460		memcpy(p, vfrom + pgbase, copy);
 461		kunmap_atomic(vfrom);
 462
 463		pgbase += copy;
 464		if (pgbase == PAGE_SIZE) {
 465			pgbase = 0;
 466			pgfrom++;
 467		}
 468		p += copy;
 469
 470	} while ((len -= copy) != 0);
 471}
 472EXPORT_SYMBOL_GPL(_copy_from_pages);
 473
 474static void xdr_buf_iov_zero(const struct kvec *iov, unsigned int base,
 475			     unsigned int len)
 476{
 477	if (base >= iov->iov_len)
 478		return;
 479	if (len > iov->iov_len - base)
 480		len = iov->iov_len - base;
 481	memset(iov->iov_base + base, 0, len);
 482}
 483
 484/**
 485 * xdr_buf_pages_zero
 486 * @buf: xdr_buf
 487 * @pgbase: beginning offset
 488 * @len: length
 489 */
 490static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase,
 491			       unsigned int len)
 492{
 493	struct page **pages = buf->pages;
 494	struct page **page;
 495	char *vpage;
 496	unsigned int zero;
 497
 498	if (!len)
 499		return;
 500	if (pgbase >= buf->page_len) {
 501		xdr_buf_iov_zero(buf->tail, pgbase - buf->page_len, len);
 502		return;
 503	}
 504	if (pgbase + len > buf->page_len) {
 505		xdr_buf_iov_zero(buf->tail, 0, pgbase + len - buf->page_len);
 506		len = buf->page_len - pgbase;
 507	}
 508
 509	pgbase += buf->page_base;
 510
 511	page = pages + (pgbase >> PAGE_SHIFT);
 512	pgbase &= ~PAGE_MASK;
 513
 514	do {
 515		zero = PAGE_SIZE - pgbase;
 516		if (zero > len)
 517			zero = len;
 518
 519		vpage = kmap_atomic(*page);
 520		memset(vpage + pgbase, 0, zero);
 521		kunmap_atomic(vpage);
 522
 523		flush_dcache_page(*page);
 524		pgbase = 0;
 525		page++;
 526
 527	} while ((len -= zero) != 0);
 528}
 529
 530static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf,
 531					      unsigned int buflen, gfp_t gfp)
 532{
 533	unsigned int i, npages, pagelen;
 534
 535	if (!(buf->flags & XDRBUF_SPARSE_PAGES))
 536		return buflen;
 537	if (buflen <= buf->head->iov_len)
 538		return buflen;
 539	pagelen = buflen - buf->head->iov_len;
 540	if (pagelen > buf->page_len)
 541		pagelen = buf->page_len;
 542	npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT;
 543	for (i = 0; i < npages; i++) {
 544		if (!buf->pages[i])
 545			continue;
 546		buf->pages[i] = alloc_page(gfp);
 547		if (likely(buf->pages[i]))
 548			continue;
 549		buflen -= pagelen;
 550		pagelen = i << PAGE_SHIFT;
 551		if (pagelen > buf->page_base)
 552			buflen += pagelen - buf->page_base;
 553		break;
 554	}
 555	return buflen;
 556}
 557
 558static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)
 559{
 560	struct kvec *head = buf->head;
 561	struct kvec *tail = buf->tail;
 562	unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;
 563	unsigned int free_space, newlen;
 564
 565	if (sum > buf->len) {
 566		free_space = min_t(unsigned int, sum - buf->len, len);
 567		newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space,
 568						   GFP_KERNEL);
 569		free_space = newlen - buf->len;
 570		buf->len = newlen;
 571		len -= free_space;
 572		if (!len)
 573			return;
 574	}
 575
 576	if (buf->buflen > sum) {
 577		/* Expand the tail buffer */
 578		free_space = min_t(unsigned int, buf->buflen - sum, len);
 579		tail->iov_len += free_space;
 580		buf->len += free_space;
 581	}
 582}
 583
 584static void xdr_buf_tail_copy_right(const struct xdr_buf *buf,
 585				    unsigned int base, unsigned int len,
 586				    unsigned int shift)
 587{
 588	const struct kvec *tail = buf->tail;
 589	unsigned int to = base + shift;
 590
 591	if (to >= tail->iov_len)
 592		return;
 593	if (len + to > tail->iov_len)
 594		len = tail->iov_len - to;
 595	memmove(tail->iov_base + to, tail->iov_base + base, len);
 596}
 597
 598static void xdr_buf_pages_copy_right(const struct xdr_buf *buf,
 599				     unsigned int base, unsigned int len,
 600				     unsigned int shift)
 601{
 602	const struct kvec *tail = buf->tail;
 603	unsigned int to = base + shift;
 604	unsigned int pglen = 0;
 605	unsigned int talen = 0, tato = 0;
 606
 607	if (base >= buf->page_len)
 608		return;
 609	if (len > buf->page_len - base)
 610		len = buf->page_len - base;
 611	if (to >= buf->page_len) {
 612		tato = to - buf->page_len;
 613		if (tail->iov_len >= len + tato)
 614			talen = len;
 615		else if (tail->iov_len > tato)
 616			talen = tail->iov_len - tato;
 617	} else if (len + to >= buf->page_len) {
 618		pglen = buf->page_len - to;
 619		talen = len - pglen;
 620		if (talen > tail->iov_len)
 621			talen = tail->iov_len;
 622	} else
 623		pglen = len;
 624
 625	_copy_from_pages(tail->iov_base + tato, buf->pages,
 626			 buf->page_base + base + pglen, talen);
 627	_shift_data_right_pages(buf->pages, buf->page_base + to,
 628				buf->page_base + base, pglen);
 629}
 630
 631static void xdr_buf_head_copy_right(const struct xdr_buf *buf,
 632				    unsigned int base, unsigned int len,
 633				    unsigned int shift)
 634{
 635	const struct kvec *head = buf->head;
 636	const struct kvec *tail = buf->tail;
 637	unsigned int to = base + shift;
 638	unsigned int pglen = 0, pgto = 0;
 639	unsigned int talen = 0, tato = 0;
 640
 641	if (base >= head->iov_len)
 642		return;
 643	if (len > head->iov_len - base)
 644		len = head->iov_len - base;
 645	if (to >= buf->page_len + head->iov_len) {
 646		tato = to - buf->page_len - head->iov_len;
 647		talen = len;
 648	} else if (to >= head->iov_len) {
 649		pgto = to - head->iov_len;
 650		pglen = len;
 651		if (pgto + pglen > buf->page_len) {
 652			talen = pgto + pglen - buf->page_len;
 653			pglen -= talen;
 654		}
 655	} else {
 656		pglen = len - to;
 657		if (pglen > buf->page_len) {
 658			talen = pglen - buf->page_len;
 659			pglen = buf->page_len;
 660		}
 661	}
 662
 663	len -= talen;
 664	base += len;
 665	if (talen + tato > tail->iov_len)
 666		talen = tail->iov_len > tato ? tail->iov_len - tato : 0;
 667	memcpy(tail->iov_base + tato, head->iov_base + base, talen);
 668
 669	len -= pglen;
 670	base -= pglen;
 671	_copy_to_pages(buf->pages, buf->page_base + pgto, head->iov_base + base,
 672		       pglen);
 673
 674	base -= len;
 675	memmove(head->iov_base + to, head->iov_base + base, len);
 676}
 677
 678static void xdr_buf_tail_shift_right(const struct xdr_buf *buf,
 679				     unsigned int base, unsigned int len,
 680				     unsigned int shift)
 681{
 682	const struct kvec *tail = buf->tail;
 683
 684	if (base >= tail->iov_len || !shift || !len)
 685		return;
 686	xdr_buf_tail_copy_right(buf, base, len, shift);
 687}
 688
 689static void xdr_buf_pages_shift_right(const struct xdr_buf *buf,
 690				      unsigned int base, unsigned int len,
 691				      unsigned int shift)
 692{
 693	if (!shift || !len)
 694		return;
 695	if (base >= buf->page_len) {
 696		xdr_buf_tail_shift_right(buf, base - buf->page_len, len, shift);
 697		return;
 698	}
 699	if (base + len > buf->page_len)
 700		xdr_buf_tail_shift_right(buf, 0, base + len - buf->page_len,
 701					 shift);
 702	xdr_buf_pages_copy_right(buf, base, len, shift);
 703}
 704
 705static void xdr_buf_head_shift_right(const struct xdr_buf *buf,
 706				     unsigned int base, unsigned int len,
 707				     unsigned int shift)
 708{
 709	const struct kvec *head = buf->head;
 710
 711	if (!shift)
 712		return;
 713	if (base >= head->iov_len) {
 714		xdr_buf_pages_shift_right(buf, head->iov_len - base, len,
 715					  shift);
 716		return;
 717	}
 718	if (base + len > head->iov_len)
 719		xdr_buf_pages_shift_right(buf, 0, base + len - head->iov_len,
 720					  shift);
 721	xdr_buf_head_copy_right(buf, base, len, shift);
 722}
 723
 724static void xdr_buf_tail_copy_left(const struct xdr_buf *buf, unsigned int base,
 725				   unsigned int len, unsigned int shift)
 726{
 727	const struct kvec *tail = buf->tail;
 728
 729	if (base >= tail->iov_len)
 730		return;
 731	if (len > tail->iov_len - base)
 732		len = tail->iov_len - base;
 733	/* Shift data into head */
 734	if (shift > buf->page_len + base) {
 735		const struct kvec *head = buf->head;
 736		unsigned int hdto =
 737			head->iov_len + buf->page_len + base - shift;
 738		unsigned int hdlen = len;
 739
 740		if (WARN_ONCE(shift > head->iov_len + buf->page_len + base,
 741			      "SUNRPC: Misaligned data.\n"))
 742			return;
 743		if (hdto + hdlen > head->iov_len)
 744			hdlen = head->iov_len - hdto;
 745		memcpy(head->iov_base + hdto, tail->iov_base + base, hdlen);
 746		base += hdlen;
 747		len -= hdlen;
 748		if (!len)
 749			return;
 750	}
 751	/* Shift data into pages */
 752	if (shift > base) {
 753		unsigned int pgto = buf->page_len + base - shift;
 754		unsigned int pglen = len;
 755
 756		if (pgto + pglen > buf->page_len)
 757			pglen = buf->page_len - pgto;
 758		_copy_to_pages(buf->pages, buf->page_base + pgto,
 759			       tail->iov_base + base, pglen);
 760		base += pglen;
 761		len -= pglen;
 762		if (!len)
 763			return;
 764	}
 765	memmove(tail->iov_base + base - shift, tail->iov_base + base, len);
 766}
 767
 768static void xdr_buf_pages_copy_left(const struct xdr_buf *buf,
 769				    unsigned int base, unsigned int len,
 770				    unsigned int shift)
 771{
 772	unsigned int pgto;
 773
 774	if (base >= buf->page_len)
 775		return;
 776	if (len > buf->page_len - base)
 777		len = buf->page_len - base;
 778	/* Shift data into head */
 779	if (shift > base) {
 780		const struct kvec *head = buf->head;
 781		unsigned int hdto = head->iov_len + base - shift;
 782		unsigned int hdlen = len;
 783
 784		if (WARN_ONCE(shift > head->iov_len + base,
 785			      "SUNRPC: Misaligned data.\n"))
 786			return;
 787		if (hdto + hdlen > head->iov_len)
 788			hdlen = head->iov_len - hdto;
 789		_copy_from_pages(head->iov_base + hdto, buf->pages,
 790				 buf->page_base + base, hdlen);
 791		base += hdlen;
 792		len -= hdlen;
 793		if (!len)
 794			return;
 795	}
 796	pgto = base - shift;
 797	_shift_data_left_pages(buf->pages, buf->page_base + pgto,
 798			       buf->page_base + base, len);
 799}
 800
 801static void xdr_buf_tail_shift_left(const struct xdr_buf *buf,
 802				    unsigned int base, unsigned int len,
 803				    unsigned int shift)
 804{
 805	if (!shift || !len)
 806		return;
 807	xdr_buf_tail_copy_left(buf, base, len, shift);
 808}
 809
 810static void xdr_buf_pages_shift_left(const struct xdr_buf *buf,
 811				     unsigned int base, unsigned int len,
 812				     unsigned int shift)
 813{
 814	if (!shift || !len)
 815		return;
 816	if (base >= buf->page_len) {
 817		xdr_buf_tail_shift_left(buf, base - buf->page_len, len, shift);
 818		return;
 819	}
 820	xdr_buf_pages_copy_left(buf, base, len, shift);
 821	len += base;
 822	if (len <= buf->page_len)
 823		return;
 824	xdr_buf_tail_copy_left(buf, 0, len - buf->page_len, shift);
 825}
 826
 827static void xdr_buf_head_shift_left(const struct xdr_buf *buf,
 828				    unsigned int base, unsigned int len,
 829				    unsigned int shift)
 830{
 831	const struct kvec *head = buf->head;
 832	unsigned int bytes;
 833
 834	if (!shift || !len)
 835		return;
 836
 837	if (shift > base) {
 838		bytes = (shift - base);
 839		if (bytes >= len)
 840			return;
 841		base += bytes;
 842		len -= bytes;
 843	}
 844
 845	if (base < head->iov_len) {
 846		bytes = min_t(unsigned int, len, head->iov_len - base);
 847		memmove(head->iov_base + (base - shift),
 848			head->iov_base + base, bytes);
 849		base += bytes;
 850		len -= bytes;
 851	}
 852	xdr_buf_pages_shift_left(buf, base - head->iov_len, len, shift);
 853}
 854
 855/**
 856 * xdr_shrink_bufhead
 857 * @buf: xdr_buf
 858 * @len: new length of buf->head[0]
 859 *
 860 * Shrinks XDR buffer's header kvec buf->head[0], setting it to
 861 * 'len' bytes. The extra data is not lost, but is instead
 862 * moved into the inlined pages and/or the tail.
 863 */
 864static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
 865{
 866	struct kvec *head = buf->head;
 867	unsigned int shift, buflen = max(buf->len, len);
 868
 869	WARN_ON_ONCE(len > head->iov_len);
 870	if (head->iov_len > buflen) {
 871		buf->buflen -= head->iov_len - buflen;
 872		head->iov_len = buflen;
 873	}
 874	if (len >= head->iov_len)
 875		return 0;
 876	shift = head->iov_len - len;
 877	xdr_buf_try_expand(buf, shift);
 878	xdr_buf_head_shift_right(buf, len, buflen - len, shift);
 879	head->iov_len = len;
 880	buf->buflen -= shift;
 881	buf->len -= shift;
 882	return shift;
 883}
 884
 885/**
 886 * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
 887 * @buf: xdr_buf
 888 * @len: new page buffer length
 889 *
 890 * The extra data is not lost, but is instead moved into buf->tail.
 891 * Returns the actual number of bytes moved.
 892 */
 893static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
 894{
 895	unsigned int shift, buflen = buf->len - buf->head->iov_len;
 896
 897	WARN_ON_ONCE(len > buf->page_len);
 898	if (buf->head->iov_len >= buf->len || len > buflen)
 899		buflen = len;
 900	if (buf->page_len > buflen) {
 901		buf->buflen -= buf->page_len - buflen;
 902		buf->page_len = buflen;
 903	}
 904	if (len >= buf->page_len)
 905		return 0;
 906	shift = buf->page_len - len;
 907	xdr_buf_try_expand(buf, shift);
 908	xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
 909	buf->page_len = len;
 910	buf->len -= shift;
 911	buf->buflen -= shift;
 912	return shift;
 913}
 914
 
 
 
 
 
 
 
 915/**
 916 * xdr_stream_pos - Return the current offset from the start of the xdr_stream
 917 * @xdr: pointer to struct xdr_stream
 918 */
 919unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
 920{
 921	return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
 922}
 923EXPORT_SYMBOL_GPL(xdr_stream_pos);
 924
 925static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
 926{
 927	unsigned int blen = xdr->buf->len;
 928
 929	xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
 930}
 931
 932static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
 933{
 934	xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
 935}
 936
 937/**
 938 * xdr_page_pos - Return the current offset from the start of the xdr pages
 939 * @xdr: pointer to struct xdr_stream
 940 */
 941unsigned int xdr_page_pos(const struct xdr_stream *xdr)
 942{
 943	unsigned int pos = xdr_stream_pos(xdr);
 944
 945	WARN_ON(pos < xdr->buf->head[0].iov_len);
 946	return pos - xdr->buf->head[0].iov_len;
 947}
 948EXPORT_SYMBOL_GPL(xdr_page_pos);
 949
 950/**
 951 * xdr_init_encode - Initialize a struct xdr_stream for sending data.
 952 * @xdr: pointer to xdr_stream struct
 953 * @buf: pointer to XDR buffer in which to encode data
 954 * @p: current pointer inside XDR buffer
 955 * @rqst: pointer to controlling rpc_rqst, for debugging
 956 *
 957 * Note: at the moment the RPC client only passes the length of our
 958 *	 scratch buffer in the xdr_buf's header kvec. Previously this
 959 *	 meant we needed to call xdr_adjust_iovec() after encoding the
 960 *	 data. With the new scheme, the xdr_stream manages the details
 961 *	 of the buffer length, and takes care of adjusting the kvec
 962 *	 length for us.
 963 */
 964void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
 965		     struct rpc_rqst *rqst)
 966{
 967	struct kvec *iov = buf->head;
 968	int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
 969
 970	xdr_reset_scratch_buffer(xdr);
 971	BUG_ON(scratch_len < 0);
 972	xdr->buf = buf;
 973	xdr->iov = iov;
 974	xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
 975	xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
 976	BUG_ON(iov->iov_len > scratch_len);
 977
 978	if (p != xdr->p && p != NULL) {
 979		size_t len;
 980
 981		BUG_ON(p < xdr->p || p > xdr->end);
 982		len = (char *)p - (char *)xdr->p;
 983		xdr->p = p;
 984		buf->len += len;
 985		iov->iov_len += len;
 986	}
 987	xdr->rqst = rqst;
 988}
 989EXPORT_SYMBOL_GPL(xdr_init_encode);
 990
 991/**
 992 * xdr_init_encode_pages - Initialize an xdr_stream for encoding into pages
 993 * @xdr: pointer to xdr_stream struct
 994 * @buf: pointer to XDR buffer into which to encode data
 995 * @pages: list of pages to decode into
 996 * @rqst: pointer to controlling rpc_rqst, for debugging
 997 *
 998 */
 999void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1000			   struct page **pages, struct rpc_rqst *rqst)
1001{
1002	xdr_reset_scratch_buffer(xdr);
1003
1004	xdr->buf = buf;
1005	xdr->page_ptr = pages;
1006	xdr->iov = NULL;
1007	xdr->p = page_address(*pages);
1008	xdr->end = (void *)xdr->p + min_t(u32, buf->buflen, PAGE_SIZE);
1009	xdr->rqst = rqst;
1010}
1011EXPORT_SYMBOL_GPL(xdr_init_encode_pages);
1012
1013/**
1014 * __xdr_commit_encode - Ensure all data is written to buffer
1015 * @xdr: pointer to xdr_stream
1016 *
1017 * We handle encoding across page boundaries by giving the caller a
1018 * temporary location to write to, then later copying the data into
1019 * place; xdr_commit_encode does that copying.
1020 *
1021 * Normally the caller doesn't need to call this directly, as the
1022 * following xdr_reserve_space will do it.  But an explicit call may be
1023 * required at the end of encoding, or any other time when the xdr_buf
1024 * data might be read.
1025 */
1026void __xdr_commit_encode(struct xdr_stream *xdr)
1027{
1028	size_t shift = xdr->scratch.iov_len;
1029	void *page;
1030
 
 
1031	page = page_address(*xdr->page_ptr);
1032	memcpy(xdr->scratch.iov_base, page, shift);
1033	memmove(page, page + shift, (void *)xdr->p - page);
1034	xdr_reset_scratch_buffer(xdr);
1035}
1036EXPORT_SYMBOL_GPL(__xdr_commit_encode);
1037
1038/*
1039 * The buffer space to be reserved crosses the boundary between
1040 * xdr->buf->head and xdr->buf->pages, or between two pages
1041 * in xdr->buf->pages.
1042 */
1043static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
1044						   size_t nbytes)
1045{
 
1046	int space_left;
1047	int frag1bytes, frag2bytes;
1048	void *p;
1049
1050	if (nbytes > PAGE_SIZE)
1051		goto out_overflow; /* Bigger buffers require special handling */
1052	if (xdr->buf->len + nbytes > xdr->buf->buflen)
1053		goto out_overflow; /* Sorry, we're totally out of space */
1054	frag1bytes = (xdr->end - xdr->p) << 2;
1055	frag2bytes = nbytes - frag1bytes;
1056	if (xdr->iov)
1057		xdr->iov->iov_len += frag1bytes;
1058	else
1059		xdr->buf->page_len += frag1bytes;
1060	xdr->page_ptr++;
1061	xdr->iov = NULL;
1062
1063	/*
1064	 * If the last encode didn't end exactly on a page boundary, the
1065	 * next one will straddle boundaries.  Encode into the next
1066	 * page, then copy it back later in xdr_commit_encode.  We use
1067	 * the "scratch" iov to track any temporarily unused fragment of
1068	 * space at the end of the previous buffer:
1069	 */
1070	xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
1071
1072	/*
1073	 * xdr->p is where the next encode will start after
1074	 * xdr_commit_encode() has shifted this one back:
1075	 */
1076	p = page_address(*xdr->page_ptr);
1077	xdr->p = p + frag2bytes;
1078	space_left = xdr->buf->buflen - xdr->buf->len;
1079	if (space_left - frag1bytes >= PAGE_SIZE)
1080		xdr->end = p + PAGE_SIZE;
1081	else
1082		xdr->end = p + space_left - frag1bytes;
1083
1084	xdr->buf->page_len += frag2bytes;
1085	xdr->buf->len += nbytes;
1086	return p;
1087out_overflow:
1088	trace_rpc_xdr_overflow(xdr, nbytes);
1089	return NULL;
1090}
1091
1092/**
1093 * xdr_reserve_space - Reserve buffer space for sending
1094 * @xdr: pointer to xdr_stream
1095 * @nbytes: number of bytes to reserve
1096 *
1097 * Checks that we have enough buffer space to encode 'nbytes' more
1098 * bytes of data. If so, update the total xdr_buf length, and
1099 * adjust the length of the current kvec.
1100 */
1101__be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1102{
1103	__be32 *p = xdr->p;
1104	__be32 *q;
1105
1106	xdr_commit_encode(xdr);
1107	/* align nbytes on the next 32-bit boundary */
1108	nbytes += 3;
1109	nbytes &= ~3;
1110	q = p + (nbytes >> 2);
1111	if (unlikely(q > xdr->end || q < p))
1112		return xdr_get_next_encode_buffer(xdr, nbytes);
1113	xdr->p = q;
1114	if (xdr->iov)
1115		xdr->iov->iov_len += nbytes;
1116	else
1117		xdr->buf->page_len += nbytes;
1118	xdr->buf->len += nbytes;
1119	return p;
1120}
1121EXPORT_SYMBOL_GPL(xdr_reserve_space);
1122
 
1123/**
1124 * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1125 * @xdr: pointer to xdr_stream
 
1126 * @nbytes: number of bytes to reserve
1127 *
1128 * The size argument passed to xdr_reserve_space() is determined based
1129 * on the number of bytes remaining in the current page to avoid
1130 * invalidating iov_base pointers when xdr_commit_encode() is called.
1131 *
1132 * Return values:
1133 *   %0: success
1134 *   %-EMSGSIZE: not enough space is available in @xdr
1135 */
1136int xdr_reserve_space_vec(struct xdr_stream *xdr, size_t nbytes)
1137{
1138	size_t thislen;
 
1139	__be32 *p;
1140
1141	/*
1142	 * svcrdma requires every READ payload to start somewhere
1143	 * in xdr->pages.
1144	 */
1145	if (xdr->iov == xdr->buf->head) {
1146		xdr->iov = NULL;
1147		xdr->end = xdr->p;
1148	}
1149
1150	/* XXX: Let's find a way to make this more efficient */
1151	while (nbytes) {
1152		thislen = xdr->buf->page_len % PAGE_SIZE;
1153		thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1154
1155		p = xdr_reserve_space(xdr, thislen);
1156		if (!p)
1157			return -EMSGSIZE;
1158
 
 
 
1159		nbytes -= thislen;
1160	}
1161
1162	return 0;
1163}
1164EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1165
1166/**
1167 * xdr_truncate_encode - truncate an encode buffer
1168 * @xdr: pointer to xdr_stream
1169 * @len: new length of buffer
1170 *
1171 * Truncates the xdr stream, so that xdr->buf->len == len,
1172 * and xdr->p points at offset len from the start of the buffer, and
1173 * head, tail, and page lengths are adjusted to correspond.
1174 *
1175 * If this means moving xdr->p to a different buffer, we assume that
1176 * the end pointer should be set to the end of the current page,
1177 * except in the case of the head buffer when we assume the head
1178 * buffer's current length represents the end of the available buffer.
1179 *
1180 * This is *not* safe to use on a buffer that already has inlined page
1181 * cache pages (as in a zero-copy server read reply), except for the
1182 * simple case of truncating from one position in the tail to another.
1183 *
1184 */
1185void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1186{
1187	struct xdr_buf *buf = xdr->buf;
1188	struct kvec *head = buf->head;
1189	struct kvec *tail = buf->tail;
1190	int fraglen;
1191	int new;
1192
1193	if (len > buf->len) {
1194		WARN_ON_ONCE(1);
1195		return;
1196	}
1197	xdr_commit_encode(xdr);
1198
1199	fraglen = min_t(int, buf->len - len, tail->iov_len);
1200	tail->iov_len -= fraglen;
1201	buf->len -= fraglen;
1202	if (tail->iov_len) {
1203		xdr->p = tail->iov_base + tail->iov_len;
1204		WARN_ON_ONCE(!xdr->end);
1205		WARN_ON_ONCE(!xdr->iov);
1206		return;
1207	}
1208	WARN_ON_ONCE(fraglen);
1209	fraglen = min_t(int, buf->len - len, buf->page_len);
1210	buf->page_len -= fraglen;
1211	buf->len -= fraglen;
1212
1213	new = buf->page_base + buf->page_len;
1214
1215	xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1216
1217	if (buf->page_len) {
1218		xdr->p = page_address(*xdr->page_ptr);
1219		xdr->end = (void *)xdr->p + PAGE_SIZE;
1220		xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1221		WARN_ON_ONCE(xdr->iov);
1222		return;
1223	}
1224	if (fraglen)
1225		xdr->end = head->iov_base + head->iov_len;
1226	/* (otherwise assume xdr->end is already set) */
1227	xdr->page_ptr--;
1228	head->iov_len = len;
1229	buf->len = len;
1230	xdr->p = head->iov_base + head->iov_len;
1231	xdr->iov = buf->head;
1232}
1233EXPORT_SYMBOL(xdr_truncate_encode);
1234
1235/**
1236 * xdr_truncate_decode - Truncate a decoding stream
1237 * @xdr: pointer to struct xdr_stream
1238 * @len: Number of bytes to remove
1239 *
1240 */
1241void xdr_truncate_decode(struct xdr_stream *xdr, size_t len)
1242{
1243	unsigned int nbytes = xdr_align_size(len);
1244
1245	xdr->buf->len -= nbytes;
1246	xdr->nwords -= XDR_QUADLEN(nbytes);
1247}
1248EXPORT_SYMBOL_GPL(xdr_truncate_decode);
1249
1250/**
1251 * xdr_restrict_buflen - decrease available buffer space
1252 * @xdr: pointer to xdr_stream
1253 * @newbuflen: new maximum number of bytes available
1254 *
1255 * Adjust our idea of how much space is available in the buffer.
1256 * If we've already used too much space in the buffer, returns -1.
1257 * If the available space is already smaller than newbuflen, returns 0
1258 * and does nothing.  Otherwise, adjusts xdr->buf->buflen to newbuflen
1259 * and ensures xdr->end is set at most offset newbuflen from the start
1260 * of the buffer.
1261 */
1262int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1263{
1264	struct xdr_buf *buf = xdr->buf;
1265	int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1266	int end_offset = buf->len + left_in_this_buf;
1267
1268	if (newbuflen < 0 || newbuflen < buf->len)
1269		return -1;
1270	if (newbuflen > buf->buflen)
1271		return 0;
1272	if (newbuflen < end_offset)
1273		xdr->end = (void *)xdr->end + newbuflen - end_offset;
1274	buf->buflen = newbuflen;
1275	return 0;
1276}
1277EXPORT_SYMBOL(xdr_restrict_buflen);
1278
1279/**
1280 * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1281 * @xdr: pointer to xdr_stream
1282 * @pages: array of pages to insert
1283 * @base: starting offset of first data byte in @pages
1284 * @len: number of data bytes in @pages to insert
1285 *
1286 * After the @pages are added, the tail iovec is instantiated pointing to
1287 * end of the head buffer, and the stream is set up to encode subsequent
1288 * items into the tail.
1289 */
1290void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1291		 unsigned int len)
1292{
1293	struct xdr_buf *buf = xdr->buf;
1294	struct kvec *tail = buf->tail;
1295
1296	buf->pages = pages;
1297	buf->page_base = base;
1298	buf->page_len = len;
1299
1300	tail->iov_base = xdr->p;
1301	tail->iov_len = 0;
1302	xdr->iov = tail;
1303
1304	if (len & 3) {
1305		unsigned int pad = 4 - (len & 3);
1306
1307		BUG_ON(xdr->p >= xdr->end);
1308		tail->iov_base = (char *)xdr->p + (len & 3);
1309		tail->iov_len += pad;
1310		len += pad;
1311		*xdr->p++ = 0;
1312	}
1313	buf->buflen += len;
1314	buf->len += len;
1315}
1316EXPORT_SYMBOL_GPL(xdr_write_pages);
1317
1318static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1319				unsigned int base, unsigned int len)
1320{
1321	if (len > iov->iov_len)
1322		len = iov->iov_len;
1323	if (unlikely(base > len))
1324		base = len;
1325	xdr->p = (__be32*)(iov->iov_base + base);
1326	xdr->end = (__be32*)(iov->iov_base + len);
1327	xdr->iov = iov;
1328	xdr->page_ptr = NULL;
1329	return len - base;
1330}
1331
1332static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1333				      unsigned int base, unsigned int len)
1334{
1335	struct xdr_buf *buf = xdr->buf;
1336
1337	xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1338	return xdr_set_iov(xdr, buf->tail, base, len);
1339}
1340
1341static void xdr_stream_unmap_current_page(struct xdr_stream *xdr)
1342{
1343	if (xdr->page_kaddr) {
1344		kunmap_local(xdr->page_kaddr);
1345		xdr->page_kaddr = NULL;
1346	}
1347}
1348
1349static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1350				      unsigned int base, unsigned int len)
1351{
1352	unsigned int pgnr;
1353	unsigned int maxlen;
1354	unsigned int pgoff;
1355	unsigned int pgend;
1356	void *kaddr;
1357
1358	maxlen = xdr->buf->page_len;
1359	if (base >= maxlen)
1360		return 0;
1361	else
1362		maxlen -= base;
1363	if (len > maxlen)
1364		len = maxlen;
1365
1366	xdr_stream_unmap_current_page(xdr);
1367	xdr_stream_page_set_pos(xdr, base);
1368	base += xdr->buf->page_base;
1369
1370	pgnr = base >> PAGE_SHIFT;
1371	xdr->page_ptr = &xdr->buf->pages[pgnr];
1372
1373	if (PageHighMem(*xdr->page_ptr)) {
1374		xdr->page_kaddr = kmap_local_page(*xdr->page_ptr);
1375		kaddr = xdr->page_kaddr;
1376	} else
1377		kaddr = page_address(*xdr->page_ptr);
1378
1379	pgoff = base & ~PAGE_MASK;
1380	xdr->p = (__be32*)(kaddr + pgoff);
1381
1382	pgend = pgoff + len;
1383	if (pgend > PAGE_SIZE)
1384		pgend = PAGE_SIZE;
1385	xdr->end = (__be32*)(kaddr + pgend);
1386	xdr->iov = NULL;
1387	return len;
1388}
1389
1390static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1391			 unsigned int len)
1392{
1393	if (xdr_set_page_base(xdr, base, len) == 0) {
1394		base -= xdr->buf->page_len;
1395		xdr_set_tail_base(xdr, base, len);
1396	}
1397}
1398
1399static void xdr_set_next_page(struct xdr_stream *xdr)
1400{
1401	unsigned int newbase;
1402
1403	newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1404	newbase -= xdr->buf->page_base;
1405	if (newbase < xdr->buf->page_len)
1406		xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1407	else
1408		xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1409}
1410
1411static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1412{
1413	if (xdr->page_ptr != NULL)
1414		xdr_set_next_page(xdr);
1415	else if (xdr->iov == xdr->buf->head)
1416		xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1417	return xdr->p != xdr->end;
1418}
1419
1420/**
1421 * xdr_init_decode - Initialize an xdr_stream for decoding data.
1422 * @xdr: pointer to xdr_stream struct
1423 * @buf: pointer to XDR buffer from which to decode data
1424 * @p: current pointer inside XDR buffer
1425 * @rqst: pointer to controlling rpc_rqst, for debugging
1426 */
1427void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1428		     struct rpc_rqst *rqst)
1429{
1430	xdr->buf = buf;
1431	xdr->page_kaddr = NULL;
1432	xdr_reset_scratch_buffer(xdr);
1433	xdr->nwords = XDR_QUADLEN(buf->len);
1434	if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1435	    xdr_set_page_base(xdr, 0, buf->len) == 0)
1436		xdr_set_iov(xdr, buf->tail, 0, buf->len);
1437	if (p != NULL && p > xdr->p && xdr->end >= p) {
1438		xdr->nwords -= p - xdr->p;
1439		xdr->p = p;
1440	}
1441	xdr->rqst = rqst;
1442}
1443EXPORT_SYMBOL_GPL(xdr_init_decode);
1444
1445/**
1446 * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1447 * @xdr: pointer to xdr_stream struct
1448 * @buf: pointer to XDR buffer from which to decode data
1449 * @pages: list of pages to decode into
1450 * @len: length in bytes of buffer in pages
1451 */
1452void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1453			   struct page **pages, unsigned int len)
1454{
1455	memset(buf, 0, sizeof(*buf));
1456	buf->pages =  pages;
1457	buf->page_len =  len;
1458	buf->buflen =  len;
1459	buf->len = len;
1460	xdr_init_decode(xdr, buf, NULL, NULL);
1461}
1462EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1463
1464/**
1465 * xdr_finish_decode - Clean up the xdr_stream after decoding data.
1466 * @xdr: pointer to xdr_stream struct
1467 */
1468void xdr_finish_decode(struct xdr_stream *xdr)
1469{
1470	xdr_stream_unmap_current_page(xdr);
1471}
1472EXPORT_SYMBOL(xdr_finish_decode);
1473
1474static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1475{
1476	unsigned int nwords = XDR_QUADLEN(nbytes);
1477	__be32 *p = xdr->p;
1478	__be32 *q = p + nwords;
1479
1480	if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1481		return NULL;
1482	xdr->p = q;
1483	xdr->nwords -= nwords;
1484	return p;
1485}
1486
1487static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1488{
1489	__be32 *p;
1490	char *cpdest = xdr->scratch.iov_base;
1491	size_t cplen = (char *)xdr->end - (char *)xdr->p;
1492
1493	if (nbytes > xdr->scratch.iov_len)
1494		goto out_overflow;
1495	p = __xdr_inline_decode(xdr, cplen);
1496	if (p == NULL)
1497		return NULL;
1498	memcpy(cpdest, p, cplen);
1499	if (!xdr_set_next_buffer(xdr))
1500		goto out_overflow;
1501	cpdest += cplen;
1502	nbytes -= cplen;
1503	p = __xdr_inline_decode(xdr, nbytes);
1504	if (p == NULL)
1505		return NULL;
1506	memcpy(cpdest, p, nbytes);
1507	return xdr->scratch.iov_base;
1508out_overflow:
1509	trace_rpc_xdr_overflow(xdr, nbytes);
1510	return NULL;
1511}
1512
1513/**
1514 * xdr_inline_decode - Retrieve XDR data to decode
1515 * @xdr: pointer to xdr_stream struct
1516 * @nbytes: number of bytes of data to decode
1517 *
1518 * Check if the input buffer is long enough to enable us to decode
1519 * 'nbytes' more bytes of data starting at the current position.
1520 * If so return the current pointer, then update the current
1521 * pointer position.
1522 */
1523__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1524{
1525	__be32 *p;
1526
1527	if (unlikely(nbytes == 0))
1528		return xdr->p;
1529	if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1530		goto out_overflow;
1531	p = __xdr_inline_decode(xdr, nbytes);
1532	if (p != NULL)
1533		return p;
1534	return xdr_copy_to_scratch(xdr, nbytes);
1535out_overflow:
1536	trace_rpc_xdr_overflow(xdr, nbytes);
1537	return NULL;
1538}
1539EXPORT_SYMBOL_GPL(xdr_inline_decode);
1540
1541static void xdr_realign_pages(struct xdr_stream *xdr)
1542{
1543	struct xdr_buf *buf = xdr->buf;
1544	struct kvec *iov = buf->head;
1545	unsigned int cur = xdr_stream_pos(xdr);
1546	unsigned int copied;
1547
1548	/* Realign pages to current pointer position */
1549	if (iov->iov_len > cur) {
1550		copied = xdr_shrink_bufhead(buf, cur);
1551		trace_rpc_xdr_alignment(xdr, cur, copied);
1552		xdr_set_page(xdr, 0, buf->page_len);
1553	}
1554}
1555
1556static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1557{
1558	struct xdr_buf *buf = xdr->buf;
1559	unsigned int nwords = XDR_QUADLEN(len);
1560	unsigned int copied;
1561
1562	if (xdr->nwords == 0)
1563		return 0;
1564
1565	xdr_realign_pages(xdr);
1566	if (nwords > xdr->nwords) {
1567		nwords = xdr->nwords;
1568		len = nwords << 2;
1569	}
1570	if (buf->page_len <= len)
1571		len = buf->page_len;
1572	else if (nwords < xdr->nwords) {
1573		/* Truncate page data and move it into the tail */
1574		copied = xdr_shrink_pagelen(buf, len);
1575		trace_rpc_xdr_alignment(xdr, len, copied);
1576	}
1577	return len;
1578}
1579
1580/**
1581 * xdr_read_pages - align page-based XDR data to current pointer position
1582 * @xdr: pointer to xdr_stream struct
1583 * @len: number of bytes of page data
1584 *
1585 * Moves data beyond the current pointer position from the XDR head[] buffer
1586 * into the page list. Any data that lies beyond current position + @len
1587 * bytes is moved into the XDR tail[]. The xdr_stream current position is
1588 * then advanced past that data to align to the next XDR object in the tail.
1589 *
1590 * Returns the number of XDR encoded bytes now contained in the pages
1591 */
1592unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1593{
1594	unsigned int nwords = XDR_QUADLEN(len);
1595	unsigned int base, end, pglen;
1596
1597	pglen = xdr_align_pages(xdr, nwords << 2);
1598	if (pglen == 0)
1599		return 0;
1600
1601	base = (nwords << 2) - pglen;
1602	end = xdr_stream_remaining(xdr) - pglen;
1603
1604	xdr_set_tail_base(xdr, base, end);
1605	return len <= pglen ? len : pglen;
1606}
1607EXPORT_SYMBOL_GPL(xdr_read_pages);
1608
1609/**
1610 * xdr_set_pagelen - Sets the length of the XDR pages
1611 * @xdr: pointer to xdr_stream struct
1612 * @len: new length of the XDR page data
1613 *
1614 * Either grows or shrinks the length of the xdr pages by setting pagelen to
1615 * @len bytes. When shrinking, any extra data is moved into buf->tail, whereas
1616 * when growing any data beyond the current pointer is moved into the tail.
1617 *
1618 * Returns True if the operation was successful, and False otherwise.
1619 */
1620void xdr_set_pagelen(struct xdr_stream *xdr, unsigned int len)
1621{
1622	struct xdr_buf *buf = xdr->buf;
1623	size_t remaining = xdr_stream_remaining(xdr);
1624	size_t base = 0;
1625
1626	if (len < buf->page_len) {
1627		base = buf->page_len - len;
1628		xdr_shrink_pagelen(buf, len);
1629	} else {
1630		xdr_buf_head_shift_right(buf, xdr_stream_pos(xdr),
1631					 buf->page_len, remaining);
1632		if (len > buf->page_len)
1633			xdr_buf_try_expand(buf, len - buf->page_len);
1634	}
1635	xdr_set_tail_base(xdr, base, remaining);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1636}
1637EXPORT_SYMBOL_GPL(xdr_set_pagelen);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1638
1639/**
1640 * xdr_enter_page - decode data from the XDR page
1641 * @xdr: pointer to xdr_stream struct
1642 * @len: number of bytes of page data
1643 *
1644 * Moves data beyond the current pointer position from the XDR head[] buffer
1645 * into the page list. Any data that lies beyond current position + "len"
1646 * bytes is moved into the XDR tail[]. The current pointer is then
1647 * repositioned at the beginning of the first XDR page.
1648 */
1649void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1650{
1651	len = xdr_align_pages(xdr, len);
1652	/*
1653	 * Position current pointer at beginning of tail, and
1654	 * set remaining message length.
1655	 */
1656	if (len != 0)
1657		xdr_set_page_base(xdr, 0, len);
1658}
1659EXPORT_SYMBOL_GPL(xdr_enter_page);
1660
1661static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1662
1663void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1664{
1665	buf->head[0] = *iov;
1666	buf->tail[0] = empty_iov;
1667	buf->page_len = 0;
1668	buf->buflen = buf->len = iov->iov_len;
1669}
1670EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1671
1672/**
1673 * xdr_buf_subsegment - set subbuf to a portion of buf
1674 * @buf: an xdr buffer
1675 * @subbuf: the result buffer
1676 * @base: beginning of range in bytes
1677 * @len: length of range in bytes
1678 *
1679 * sets @subbuf to an xdr buffer representing the portion of @buf of
1680 * length @len starting at offset @base.
1681 *
1682 * @buf and @subbuf may be pointers to the same struct xdr_buf.
1683 *
1684 * Returns -1 if base or length are out of bounds.
1685 */
1686int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1687		       unsigned int base, unsigned int len)
1688{
1689	subbuf->buflen = subbuf->len = len;
1690	if (base < buf->head[0].iov_len) {
1691		subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1692		subbuf->head[0].iov_len = min_t(unsigned int, len,
1693						buf->head[0].iov_len - base);
1694		len -= subbuf->head[0].iov_len;
1695		base = 0;
1696	} else {
1697		base -= buf->head[0].iov_len;
1698		subbuf->head[0].iov_base = buf->head[0].iov_base;
1699		subbuf->head[0].iov_len = 0;
1700	}
1701
1702	if (base < buf->page_len) {
1703		subbuf->page_len = min(buf->page_len - base, len);
1704		base += buf->page_base;
1705		subbuf->page_base = base & ~PAGE_MASK;
1706		subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1707		len -= subbuf->page_len;
1708		base = 0;
1709	} else {
1710		base -= buf->page_len;
1711		subbuf->pages = buf->pages;
1712		subbuf->page_base = 0;
1713		subbuf->page_len = 0;
1714	}
1715
1716	if (base < buf->tail[0].iov_len) {
1717		subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1718		subbuf->tail[0].iov_len = min_t(unsigned int, len,
1719						buf->tail[0].iov_len - base);
1720		len -= subbuf->tail[0].iov_len;
1721		base = 0;
1722	} else {
1723		base -= buf->tail[0].iov_len;
1724		subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1725		subbuf->tail[0].iov_len = 0;
1726	}
1727
1728	if (base || len)
1729		return -1;
1730	return 0;
1731}
1732EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1733
1734/**
1735 * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1736 * @xdr: an xdr_stream set up for decoding
1737 * @subbuf: the result buffer
1738 * @nbytes: length of @xdr to extract, in bytes
1739 *
1740 * Sets up @subbuf to represent a portion of @xdr. The portion
1741 * starts at the current offset in @xdr, and extends for a length
1742 * of @nbytes. If this is successful, @xdr is advanced to the next
1743 * XDR data item following that portion.
1744 *
1745 * Return values:
1746 *   %true: @subbuf has been initialized, and @xdr has been advanced.
1747 *   %false: a bounds error has occurred
1748 */
1749bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1750			   unsigned int nbytes)
1751{
1752	unsigned int start = xdr_stream_pos(xdr);
1753	unsigned int remaining, len;
1754
1755	/* Extract @subbuf and bounds-check the fn arguments */
1756	if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
1757		return false;
1758
1759	/* Advance @xdr by @nbytes */
1760	for (remaining = nbytes; remaining;) {
1761		if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1762			return false;
1763
1764		len = (char *)xdr->end - (char *)xdr->p;
1765		if (remaining <= len) {
1766			xdr->p = (__be32 *)((char *)xdr->p +
1767					(remaining + xdr_pad_size(nbytes)));
1768			break;
1769		}
 
 
 
1770
1771		xdr->p = (__be32 *)((char *)xdr->p + len);
1772		xdr->end = xdr->p;
1773		remaining -= len;
 
1774	}
1775
1776	xdr_stream_set_pos(xdr, start + nbytes);
1777	return true;
1778}
1779EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1780
1781/**
1782 * xdr_stream_move_subsegment - Move part of a stream to another position
1783 * @xdr: the source xdr_stream
1784 * @offset: the source offset of the segment
1785 * @target: the target offset of the segment
1786 * @length: the number of bytes to move
1787 *
1788 * Moves @length bytes from @offset to @target in the xdr_stream, overwriting
1789 * anything in its space. Returns the number of bytes in the segment.
1790 */
1791unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset,
1792					unsigned int target, unsigned int length)
1793{
1794	struct xdr_buf buf;
1795	unsigned int shift;
1796
1797	if (offset < target) {
1798		shift = target - offset;
1799		if (xdr_buf_subsegment(xdr->buf, &buf, offset, shift + length) < 0)
1800			return 0;
1801		xdr_buf_head_shift_right(&buf, 0, length, shift);
1802	} else if (offset > target) {
1803		shift = offset - target;
1804		if (xdr_buf_subsegment(xdr->buf, &buf, target, shift + length) < 0)
1805			return 0;
1806		xdr_buf_head_shift_left(&buf, shift, length, shift);
1807	}
1808	return length;
1809}
1810EXPORT_SYMBOL_GPL(xdr_stream_move_subsegment);
1811
1812/**
1813 * xdr_stream_zero - zero out a portion of an xdr_stream
1814 * @xdr: an xdr_stream to zero out
1815 * @offset: the starting point in the stream
1816 * @length: the number of bytes to zero
1817 */
1818unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset,
1819			     unsigned int length)
1820{
1821	struct xdr_buf buf;
1822
1823	if (xdr_buf_subsegment(xdr->buf, &buf, offset, length) < 0)
1824		return 0;
1825	if (buf.head[0].iov_len)
1826		xdr_buf_iov_zero(buf.head, 0, buf.head[0].iov_len);
1827	if (buf.page_len > 0)
1828		xdr_buf_pages_zero(&buf, 0, buf.page_len);
1829	if (buf.tail[0].iov_len)
1830		xdr_buf_iov_zero(buf.tail, 0, buf.tail[0].iov_len);
1831	return length;
1832}
1833EXPORT_SYMBOL_GPL(xdr_stream_zero);
1834
1835/**
1836 * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1837 * @buf: buf to be trimmed
1838 * @len: number of bytes to reduce "buf" by
1839 *
1840 * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1841 * that it's possible that we'll trim less than that amount if the xdr_buf is
1842 * too small, or if (for instance) it's all in the head and the parser has
1843 * already read too far into it.
1844 */
1845void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1846{
1847	size_t cur;
1848	unsigned int trim = len;
1849
1850	if (buf->tail[0].iov_len) {
1851		cur = min_t(size_t, buf->tail[0].iov_len, trim);
1852		buf->tail[0].iov_len -= cur;
1853		trim -= cur;
1854		if (!trim)
1855			goto fix_len;
1856	}
1857
1858	if (buf->page_len) {
1859		cur = min_t(unsigned int, buf->page_len, trim);
1860		buf->page_len -= cur;
1861		trim -= cur;
1862		if (!trim)
1863			goto fix_len;
1864	}
1865
1866	if (buf->head[0].iov_len) {
1867		cur = min_t(size_t, buf->head[0].iov_len, trim);
1868		buf->head[0].iov_len -= cur;
1869		trim -= cur;
1870	}
1871fix_len:
1872	buf->len -= (len - trim);
1873}
1874EXPORT_SYMBOL_GPL(xdr_buf_trim);
1875
1876static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1877				      void *obj, unsigned int len)
1878{
1879	unsigned int this_len;
1880
1881	this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1882	memcpy(obj, subbuf->head[0].iov_base, this_len);
1883	len -= this_len;
1884	obj += this_len;
1885	this_len = min_t(unsigned int, len, subbuf->page_len);
1886	_copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1887	len -= this_len;
1888	obj += this_len;
1889	this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1890	memcpy(obj, subbuf->tail[0].iov_base, this_len);
1891}
1892
1893/* obj is assumed to point to allocated memory of size at least len: */
1894int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1895			    void *obj, unsigned int len)
1896{
1897	struct xdr_buf subbuf;
1898	int status;
1899
1900	status = xdr_buf_subsegment(buf, &subbuf, base, len);
1901	if (status != 0)
1902		return status;
1903	__read_bytes_from_xdr_buf(&subbuf, obj, len);
1904	return 0;
1905}
1906EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1907
1908static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1909				     void *obj, unsigned int len)
1910{
1911	unsigned int this_len;
1912
1913	this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1914	memcpy(subbuf->head[0].iov_base, obj, this_len);
1915	len -= this_len;
1916	obj += this_len;
1917	this_len = min_t(unsigned int, len, subbuf->page_len);
1918	_copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1919	len -= this_len;
1920	obj += this_len;
1921	this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1922	memcpy(subbuf->tail[0].iov_base, obj, this_len);
1923}
1924
1925/* obj is assumed to point to allocated memory of size at least len: */
1926int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1927			   void *obj, unsigned int len)
1928{
1929	struct xdr_buf subbuf;
1930	int status;
1931
1932	status = xdr_buf_subsegment(buf, &subbuf, base, len);
1933	if (status != 0)
1934		return status;
1935	__write_bytes_to_xdr_buf(&subbuf, obj, len);
1936	return 0;
1937}
1938EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1939
1940int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1941{
1942	__be32	raw;
1943	int	status;
1944
1945	status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1946	if (status)
1947		return status;
1948	*obj = be32_to_cpu(raw);
1949	return 0;
1950}
1951EXPORT_SYMBOL_GPL(xdr_decode_word);
1952
1953int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1954{
1955	__be32	raw = cpu_to_be32(obj);
1956
1957	return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1958}
1959EXPORT_SYMBOL_GPL(xdr_encode_word);
1960
1961/* Returns 0 on success, or else a negative error code. */
1962static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1963			    struct xdr_array2_desc *desc, int encode)
1964{
1965	char *elem = NULL, *c;
1966	unsigned int copied = 0, todo, avail_here;
1967	struct page **ppages = NULL;
1968	int err;
1969
1970	if (encode) {
1971		if (xdr_encode_word(buf, base, desc->array_len) != 0)
1972			return -EINVAL;
1973	} else {
1974		if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1975		    desc->array_len > desc->array_maxlen ||
1976		    (unsigned long) base + 4 + desc->array_len *
1977				    desc->elem_size > buf->len)
1978			return -EINVAL;
1979	}
1980	base += 4;
1981
1982	if (!desc->xcode)
1983		return 0;
1984
1985	todo = desc->array_len * desc->elem_size;
1986
1987	/* process head */
1988	if (todo && base < buf->head->iov_len) {
1989		c = buf->head->iov_base + base;
1990		avail_here = min_t(unsigned int, todo,
1991				   buf->head->iov_len - base);
1992		todo -= avail_here;
1993
1994		while (avail_here >= desc->elem_size) {
1995			err = desc->xcode(desc, c);
1996			if (err)
1997				goto out;
1998			c += desc->elem_size;
1999			avail_here -= desc->elem_size;
2000		}
2001		if (avail_here) {
2002			if (!elem) {
2003				elem = kmalloc(desc->elem_size, GFP_KERNEL);
2004				err = -ENOMEM;
2005				if (!elem)
2006					goto out;
2007			}
2008			if (encode) {
2009				err = desc->xcode(desc, elem);
2010				if (err)
2011					goto out;
2012				memcpy(c, elem, avail_here);
2013			} else
2014				memcpy(elem, c, avail_here);
2015			copied = avail_here;
2016		}
2017		base = buf->head->iov_len;  /* align to start of pages */
2018	}
2019
2020	/* process pages array */
2021	base -= buf->head->iov_len;
2022	if (todo && base < buf->page_len) {
2023		unsigned int avail_page;
2024
2025		avail_here = min(todo, buf->page_len - base);
2026		todo -= avail_here;
2027
2028		base += buf->page_base;
2029		ppages = buf->pages + (base >> PAGE_SHIFT);
2030		base &= ~PAGE_MASK;
2031		avail_page = min_t(unsigned int, PAGE_SIZE - base,
2032					avail_here);
2033		c = kmap(*ppages) + base;
2034
2035		while (avail_here) {
2036			avail_here -= avail_page;
2037			if (copied || avail_page < desc->elem_size) {
2038				unsigned int l = min(avail_page,
2039					desc->elem_size - copied);
2040				if (!elem) {
2041					elem = kmalloc(desc->elem_size,
2042						       GFP_KERNEL);
2043					err = -ENOMEM;
2044					if (!elem)
2045						goto out;
2046				}
2047				if (encode) {
2048					if (!copied) {
2049						err = desc->xcode(desc, elem);
2050						if (err)
2051							goto out;
2052					}
2053					memcpy(c, elem + copied, l);
2054					copied += l;
2055					if (copied == desc->elem_size)
2056						copied = 0;
2057				} else {
2058					memcpy(elem + copied, c, l);
2059					copied += l;
2060					if (copied == desc->elem_size) {
2061						err = desc->xcode(desc, elem);
2062						if (err)
2063							goto out;
2064						copied = 0;
2065					}
2066				}
2067				avail_page -= l;
2068				c += l;
2069			}
2070			while (avail_page >= desc->elem_size) {
2071				err = desc->xcode(desc, c);
2072				if (err)
2073					goto out;
2074				c += desc->elem_size;
2075				avail_page -= desc->elem_size;
2076			}
2077			if (avail_page) {
2078				unsigned int l = min(avail_page,
2079					    desc->elem_size - copied);
2080				if (!elem) {
2081					elem = kmalloc(desc->elem_size,
2082						       GFP_KERNEL);
2083					err = -ENOMEM;
2084					if (!elem)
2085						goto out;
2086				}
2087				if (encode) {
2088					if (!copied) {
2089						err = desc->xcode(desc, elem);
2090						if (err)
2091							goto out;
2092					}
2093					memcpy(c, elem + copied, l);
2094					copied += l;
2095					if (copied == desc->elem_size)
2096						copied = 0;
2097				} else {
2098					memcpy(elem + copied, c, l);
2099					copied += l;
2100					if (copied == desc->elem_size) {
2101						err = desc->xcode(desc, elem);
2102						if (err)
2103							goto out;
2104						copied = 0;
2105					}
2106				}
2107			}
2108			if (avail_here) {
2109				kunmap(*ppages);
2110				ppages++;
2111				c = kmap(*ppages);
2112			}
2113
2114			avail_page = min(avail_here,
2115				 (unsigned int) PAGE_SIZE);
2116		}
2117		base = buf->page_len;  /* align to start of tail */
2118	}
2119
2120	/* process tail */
2121	base -= buf->page_len;
2122	if (todo) {
2123		c = buf->tail->iov_base + base;
2124		if (copied) {
2125			unsigned int l = desc->elem_size - copied;
2126
2127			if (encode)
2128				memcpy(c, elem + copied, l);
2129			else {
2130				memcpy(elem + copied, c, l);
2131				err = desc->xcode(desc, elem);
2132				if (err)
2133					goto out;
2134			}
2135			todo -= l;
2136			c += l;
2137		}
2138		while (todo) {
2139			err = desc->xcode(desc, c);
2140			if (err)
2141				goto out;
2142			c += desc->elem_size;
2143			todo -= desc->elem_size;
2144		}
2145	}
2146	err = 0;
2147
2148out:
2149	kfree(elem);
2150	if (ppages)
2151		kunmap(*ppages);
2152	return err;
2153}
2154
2155int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
2156		      struct xdr_array2_desc *desc)
2157{
2158	if (base >= buf->len)
2159		return -EINVAL;
2160
2161	return xdr_xcode_array2(buf, base, desc, 0);
2162}
2163EXPORT_SYMBOL_GPL(xdr_decode_array2);
2164
2165int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2166		      struct xdr_array2_desc *desc)
2167{
2168	if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2169	    buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2170		return -EINVAL;
2171
2172	return xdr_xcode_array2(buf, base, desc, 1);
2173}
2174EXPORT_SYMBOL_GPL(xdr_encode_array2);
2175
2176int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2177		    unsigned int len,
2178		    int (*actor)(struct scatterlist *, void *), void *data)
2179{
2180	int i, ret = 0;
2181	unsigned int page_len, thislen, page_offset;
2182	struct scatterlist      sg[1];
2183
2184	sg_init_table(sg, 1);
2185
2186	if (offset >= buf->head[0].iov_len) {
2187		offset -= buf->head[0].iov_len;
2188	} else {
2189		thislen = buf->head[0].iov_len - offset;
2190		if (thislen > len)
2191			thislen = len;
2192		sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2193		ret = actor(sg, data);
2194		if (ret)
2195			goto out;
2196		offset = 0;
2197		len -= thislen;
2198	}
2199	if (len == 0)
2200		goto out;
2201
2202	if (offset >= buf->page_len) {
2203		offset -= buf->page_len;
2204	} else {
2205		page_len = buf->page_len - offset;
2206		if (page_len > len)
2207			page_len = len;
2208		len -= page_len;
2209		page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2210		i = (offset + buf->page_base) >> PAGE_SHIFT;
2211		thislen = PAGE_SIZE - page_offset;
2212		do {
2213			if (thislen > page_len)
2214				thislen = page_len;
2215			sg_set_page(sg, buf->pages[i], thislen, page_offset);
2216			ret = actor(sg, data);
2217			if (ret)
2218				goto out;
2219			page_len -= thislen;
2220			i++;
2221			page_offset = 0;
2222			thislen = PAGE_SIZE;
2223		} while (page_len != 0);
2224		offset = 0;
2225	}
2226	if (len == 0)
2227		goto out;
2228	if (offset < buf->tail[0].iov_len) {
2229		thislen = buf->tail[0].iov_len - offset;
2230		if (thislen > len)
2231			thislen = len;
2232		sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2233		ret = actor(sg, data);
2234		len -= thislen;
2235	}
2236	if (len != 0)
2237		ret = -EINVAL;
2238out:
2239	return ret;
2240}
2241EXPORT_SYMBOL_GPL(xdr_process_buf);
2242
2243/**
2244 * xdr_stream_decode_opaque - Decode variable length opaque
2245 * @xdr: pointer to xdr_stream
2246 * @ptr: location to store opaque data
2247 * @size: size of storage buffer @ptr
2248 *
2249 * Return values:
2250 *   On success, returns size of object stored in *@ptr
2251 *   %-EBADMSG on XDR buffer overflow
2252 *   %-EMSGSIZE on overflow of storage buffer @ptr
2253 */
2254ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2255{
2256	ssize_t ret;
2257	void *p;
2258
2259	ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2260	if (ret <= 0)
2261		return ret;
2262	memcpy(ptr, p, ret);
2263	return ret;
2264}
2265EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2266
2267/**
2268 * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2269 * @xdr: pointer to xdr_stream
2270 * @ptr: location to store pointer to opaque data
2271 * @maxlen: maximum acceptable object size
2272 * @gfp_flags: GFP mask to use
2273 *
2274 * Return values:
2275 *   On success, returns size of object stored in *@ptr
2276 *   %-EBADMSG on XDR buffer overflow
2277 *   %-EMSGSIZE if the size of the object would exceed @maxlen
2278 *   %-ENOMEM on memory allocation failure
2279 */
2280ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2281		size_t maxlen, gfp_t gfp_flags)
2282{
2283	ssize_t ret;
2284	void *p;
2285
2286	ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2287	if (ret > 0) {
2288		*ptr = kmemdup(p, ret, gfp_flags);
2289		if (*ptr != NULL)
2290			return ret;
2291		ret = -ENOMEM;
2292	}
2293	*ptr = NULL;
2294	return ret;
2295}
2296EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2297
2298/**
2299 * xdr_stream_decode_string - Decode variable length string
2300 * @xdr: pointer to xdr_stream
2301 * @str: location to store string
2302 * @size: size of storage buffer @str
2303 *
2304 * Return values:
2305 *   On success, returns length of NUL-terminated string stored in *@str
2306 *   %-EBADMSG on XDR buffer overflow
2307 *   %-EMSGSIZE on overflow of storage buffer @str
2308 */
2309ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2310{
2311	ssize_t ret;
2312	void *p;
2313
2314	ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2315	if (ret > 0) {
2316		memcpy(str, p, ret);
2317		str[ret] = '\0';
2318		return strlen(str);
2319	}
2320	*str = '\0';
2321	return ret;
2322}
2323EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2324
2325/**
2326 * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2327 * @xdr: pointer to xdr_stream
2328 * @str: location to store pointer to string
2329 * @maxlen: maximum acceptable string length
2330 * @gfp_flags: GFP mask to use
2331 *
2332 * Return values:
2333 *   On success, returns length of NUL-terminated string stored in *@ptr
2334 *   %-EBADMSG on XDR buffer overflow
2335 *   %-EMSGSIZE if the size of the string would exceed @maxlen
2336 *   %-ENOMEM on memory allocation failure
2337 */
2338ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2339		size_t maxlen, gfp_t gfp_flags)
2340{
2341	void *p;
2342	ssize_t ret;
2343
2344	ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2345	if (ret > 0) {
2346		char *s = kmemdup_nul(p, ret, gfp_flags);
2347		if (s != NULL) {
2348			*str = s;
2349			return strlen(s);
2350		}
2351		ret = -ENOMEM;
2352	}
2353	*str = NULL;
2354	return ret;
2355}
2356EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);
2357
2358/**
2359 * xdr_stream_decode_opaque_auth - Decode struct opaque_auth (RFC5531 S8.2)
2360 * @xdr: pointer to xdr_stream
2361 * @flavor: location to store decoded flavor
2362 * @body: location to store decode body
2363 * @body_len: location to store length of decoded body
2364 *
2365 * Return values:
2366 *   On success, returns the number of buffer bytes consumed
2367 *   %-EBADMSG on XDR buffer overflow
2368 *   %-EMSGSIZE if the decoded size of the body field exceeds 400 octets
2369 */
2370ssize_t xdr_stream_decode_opaque_auth(struct xdr_stream *xdr, u32 *flavor,
2371				      void **body, unsigned int *body_len)
2372{
2373	ssize_t ret, len;
2374
2375	len = xdr_stream_decode_u32(xdr, flavor);
2376	if (unlikely(len < 0))
2377		return len;
2378	ret = xdr_stream_decode_opaque_inline(xdr, body, RPC_MAX_AUTH_SIZE);
2379	if (unlikely(ret < 0))
2380		return ret;
2381	*body_len = ret;
2382	return len + ret;
2383}
2384EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_auth);
2385
2386/**
2387 * xdr_stream_encode_opaque_auth - Encode struct opaque_auth (RFC5531 S8.2)
2388 * @xdr: pointer to xdr_stream
2389 * @flavor: verifier flavor to encode
2390 * @body: content of body to encode
2391 * @body_len: length of body to encode
2392 *
2393 * Return values:
2394 *   On success, returns length in bytes of XDR buffer consumed
2395 *   %-EBADMSG on XDR buffer overflow
2396 *   %-EMSGSIZE if the size of @body exceeds 400 octets
2397 */
2398ssize_t xdr_stream_encode_opaque_auth(struct xdr_stream *xdr, u32 flavor,
2399				      void *body, unsigned int body_len)
2400{
2401	ssize_t ret, len;
2402
2403	if (unlikely(body_len > RPC_MAX_AUTH_SIZE))
2404		return -EMSGSIZE;
2405	len = xdr_stream_encode_u32(xdr, flavor);
2406	if (unlikely(len < 0))
2407		return len;
2408	ret = xdr_stream_encode_opaque(xdr, body, body_len);
2409	if (unlikely(ret < 0))
2410		return ret;
2411	return len + ret;
2412}
2413EXPORT_SYMBOL_GPL(xdr_stream_encode_opaque_auth);