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