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