1 #include <linux/export.h>
3 #include <linux/pagemap.h>
4 #include <linux/slab.h>
5 #include <linux/vmalloc.h>
7 #define iterate_iovec(i, n, __v, __p, skip, STEP) { \
11 __v.iov_len = min(n, __p->iov_len - skip); \
12 if (likely(__v.iov_len)) { \
13 __v.iov_base = __p->iov_base + skip; \
15 __v.iov_len -= left; \
16 skip += __v.iov_len; \
21 while (unlikely(!left && n)) { \
23 __v.iov_len = min(n, __p->iov_len); \
24 if (unlikely(!__v.iov_len)) \
26 __v.iov_base = __p->iov_base; \
28 __v.iov_len -= left; \
35 #define iterate_bvec(i, n, __v, __p, skip, STEP) { \
38 __v.bv_len = min_t(size_t, n, __p->bv_len - skip); \
39 if (likely(__v.bv_len)) { \
40 __v.bv_page = __p->bv_page; \
41 __v.bv_offset = __p->bv_offset + skip; \
46 while (unlikely(n)) { \
48 __v.bv_len = min_t(size_t, n, __p->bv_len); \
49 if (unlikely(!__v.bv_len)) \
51 __v.bv_page = __p->bv_page; \
52 __v.bv_offset = __p->bv_offset; \
60 #define iterate_all_kinds(i, n, v, I, B) { \
61 size_t skip = i->iov_offset; \
62 if (unlikely(i->type & ITER_BVEC)) { \
63 const struct bio_vec *bvec; \
65 iterate_bvec(i, n, v, bvec, skip, (B)) \
67 const struct iovec *iov; \
69 iterate_iovec(i, n, v, iov, skip, (I)) \
73 #define iterate_and_advance(i, n, v, I, B) { \
74 size_t skip = i->iov_offset; \
75 if (unlikely(i->type & ITER_BVEC)) { \
76 const struct bio_vec *bvec; \
78 iterate_bvec(i, n, v, bvec, skip, (B)) \
79 if (skip == bvec->bv_len) { \
83 i->nr_segs -= bvec - i->bvec; \
86 const struct iovec *iov; \
88 iterate_iovec(i, n, v, iov, skip, (I)) \
89 if (skip == iov->iov_len) { \
93 i->nr_segs -= iov - i->iov; \
97 i->iov_offset = skip; \
100 static size_t copy_to_iter_iovec(void *from
, size_t bytes
, struct iov_iter
*i
)
102 size_t skip
, copy
, left
, wanted
;
103 const struct iovec
*iov
;
106 if (unlikely(bytes
> i
->count
))
109 if (unlikely(!bytes
))
114 skip
= i
->iov_offset
;
115 buf
= iov
->iov_base
+ skip
;
116 copy
= min(bytes
, iov
->iov_len
- skip
);
118 left
= __copy_to_user(buf
, from
, copy
);
123 while (unlikely(!left
&& bytes
)) {
126 copy
= min(bytes
, iov
->iov_len
);
127 left
= __copy_to_user(buf
, from
, copy
);
134 if (skip
== iov
->iov_len
) {
138 i
->count
-= wanted
- bytes
;
139 i
->nr_segs
-= iov
- i
->iov
;
141 i
->iov_offset
= skip
;
142 return wanted
- bytes
;
145 static size_t copy_from_iter_iovec(void *to
, size_t bytes
, struct iov_iter
*i
)
147 size_t skip
, copy
, left
, wanted
;
148 const struct iovec
*iov
;
151 if (unlikely(bytes
> i
->count
))
154 if (unlikely(!bytes
))
159 skip
= i
->iov_offset
;
160 buf
= iov
->iov_base
+ skip
;
161 copy
= min(bytes
, iov
->iov_len
- skip
);
163 left
= __copy_from_user(to
, buf
, copy
);
168 while (unlikely(!left
&& bytes
)) {
171 copy
= min(bytes
, iov
->iov_len
);
172 left
= __copy_from_user(to
, buf
, copy
);
179 if (skip
== iov
->iov_len
) {
183 i
->count
-= wanted
- bytes
;
184 i
->nr_segs
-= iov
- i
->iov
;
186 i
->iov_offset
= skip
;
187 return wanted
- bytes
;
190 static size_t copy_page_to_iter_iovec(struct page
*page
, size_t offset
, size_t bytes
,
193 size_t skip
, copy
, left
, wanted
;
194 const struct iovec
*iov
;
198 if (unlikely(bytes
> i
->count
))
201 if (unlikely(!bytes
))
206 skip
= i
->iov_offset
;
207 buf
= iov
->iov_base
+ skip
;
208 copy
= min(bytes
, iov
->iov_len
- skip
);
210 if (!fault_in_pages_writeable(buf
, copy
)) {
211 kaddr
= kmap_atomic(page
);
212 from
= kaddr
+ offset
;
214 /* first chunk, usually the only one */
215 left
= __copy_to_user_inatomic(buf
, from
, copy
);
221 while (unlikely(!left
&& bytes
)) {
224 copy
= min(bytes
, iov
->iov_len
);
225 left
= __copy_to_user_inatomic(buf
, from
, copy
);
231 if (likely(!bytes
)) {
232 kunmap_atomic(kaddr
);
235 offset
= from
- kaddr
;
237 kunmap_atomic(kaddr
);
238 copy
= min(bytes
, iov
->iov_len
- skip
);
240 /* Too bad - revert to non-atomic kmap */
242 from
= kaddr
+ offset
;
243 left
= __copy_to_user(buf
, from
, copy
);
248 while (unlikely(!left
&& bytes
)) {
251 copy
= min(bytes
, iov
->iov_len
);
252 left
= __copy_to_user(buf
, from
, copy
);
260 if (skip
== iov
->iov_len
) {
264 i
->count
-= wanted
- bytes
;
265 i
->nr_segs
-= iov
- i
->iov
;
267 i
->iov_offset
= skip
;
268 return wanted
- bytes
;
271 static size_t copy_page_from_iter_iovec(struct page
*page
, size_t offset
, size_t bytes
,
274 size_t skip
, copy
, left
, wanted
;
275 const struct iovec
*iov
;
279 if (unlikely(bytes
> i
->count
))
282 if (unlikely(!bytes
))
287 skip
= i
->iov_offset
;
288 buf
= iov
->iov_base
+ skip
;
289 copy
= min(bytes
, iov
->iov_len
- skip
);
291 if (!fault_in_pages_readable(buf
, copy
)) {
292 kaddr
= kmap_atomic(page
);
295 /* first chunk, usually the only one */
296 left
= __copy_from_user_inatomic(to
, buf
, copy
);
302 while (unlikely(!left
&& bytes
)) {
305 copy
= min(bytes
, iov
->iov_len
);
306 left
= __copy_from_user_inatomic(to
, buf
, copy
);
312 if (likely(!bytes
)) {
313 kunmap_atomic(kaddr
);
318 kunmap_atomic(kaddr
);
319 copy
= min(bytes
, iov
->iov_len
- skip
);
321 /* Too bad - revert to non-atomic kmap */
324 left
= __copy_from_user(to
, buf
, copy
);
329 while (unlikely(!left
&& bytes
)) {
332 copy
= min(bytes
, iov
->iov_len
);
333 left
= __copy_from_user(to
, buf
, copy
);
341 if (skip
== iov
->iov_len
) {
345 i
->count
-= wanted
- bytes
;
346 i
->nr_segs
-= iov
- i
->iov
;
348 i
->iov_offset
= skip
;
349 return wanted
- bytes
;
353 * Fault in the first iovec of the given iov_iter, to a maximum length
354 * of bytes. Returns 0 on success, or non-zero if the memory could not be
355 * accessed (ie. because it is an invalid address).
357 * writev-intensive code may want this to prefault several iovecs -- that
358 * would be possible (callers must not rely on the fact that _only_ the
359 * first iovec will be faulted with the current implementation).
361 int iov_iter_fault_in_readable(struct iov_iter
*i
, size_t bytes
)
363 if (!(i
->type
& ITER_BVEC
)) {
364 char __user
*buf
= i
->iov
->iov_base
+ i
->iov_offset
;
365 bytes
= min(bytes
, i
->iov
->iov_len
- i
->iov_offset
);
366 return fault_in_pages_readable(buf
, bytes
);
370 EXPORT_SYMBOL(iov_iter_fault_in_readable
);
372 void iov_iter_init(struct iov_iter
*i
, int direction
,
373 const struct iovec
*iov
, unsigned long nr_segs
,
376 /* It will get better. Eventually... */
377 if (segment_eq(get_fs(), KERNEL_DS
))
378 direction
|= ITER_KVEC
;
381 i
->nr_segs
= nr_segs
;
385 EXPORT_SYMBOL(iov_iter_init
);
387 static void memcpy_from_page(char *to
, struct page
*page
, size_t offset
, size_t len
)
389 char *from
= kmap_atomic(page
);
390 memcpy(to
, from
+ offset
, len
);
394 static void memcpy_to_page(struct page
*page
, size_t offset
, char *from
, size_t len
)
396 char *to
= kmap_atomic(page
);
397 memcpy(to
+ offset
, from
, len
);
401 static void memzero_page(struct page
*page
, size_t offset
, size_t len
)
403 char *addr
= kmap_atomic(page
);
404 memset(addr
+ offset
, 0, len
);
408 static size_t copy_to_iter_bvec(void *from
, size_t bytes
, struct iov_iter
*i
)
410 size_t skip
, copy
, wanted
;
411 const struct bio_vec
*bvec
;
413 if (unlikely(bytes
> i
->count
))
416 if (unlikely(!bytes
))
421 skip
= i
->iov_offset
;
422 copy
= min_t(size_t, bytes
, bvec
->bv_len
- skip
);
424 memcpy_to_page(bvec
->bv_page
, skip
+ bvec
->bv_offset
, from
, copy
);
430 copy
= min(bytes
, (size_t)bvec
->bv_len
);
431 memcpy_to_page(bvec
->bv_page
, bvec
->bv_offset
, from
, copy
);
436 if (skip
== bvec
->bv_len
) {
440 i
->count
-= wanted
- bytes
;
441 i
->nr_segs
-= bvec
- i
->bvec
;
443 i
->iov_offset
= skip
;
444 return wanted
- bytes
;
447 static size_t copy_from_iter_bvec(void *to
, size_t bytes
, struct iov_iter
*i
)
449 size_t skip
, copy
, wanted
;
450 const struct bio_vec
*bvec
;
452 if (unlikely(bytes
> i
->count
))
455 if (unlikely(!bytes
))
460 skip
= i
->iov_offset
;
462 copy
= min(bytes
, bvec
->bv_len
- skip
);
464 memcpy_from_page(to
, bvec
->bv_page
, bvec
->bv_offset
+ skip
, copy
);
472 copy
= min(bytes
, (size_t)bvec
->bv_len
);
473 memcpy_from_page(to
, bvec
->bv_page
, bvec
->bv_offset
, copy
);
478 if (skip
== bvec
->bv_len
) {
483 i
->nr_segs
-= bvec
- i
->bvec
;
485 i
->iov_offset
= skip
;
489 static size_t copy_page_to_iter_bvec(struct page
*page
, size_t offset
,
490 size_t bytes
, struct iov_iter
*i
)
492 void *kaddr
= kmap_atomic(page
);
493 size_t wanted
= copy_to_iter_bvec(kaddr
+ offset
, bytes
, i
);
494 kunmap_atomic(kaddr
);
498 static size_t copy_page_from_iter_bvec(struct page
*page
, size_t offset
,
499 size_t bytes
, struct iov_iter
*i
)
501 void *kaddr
= kmap_atomic(page
);
502 size_t wanted
= copy_from_iter_bvec(kaddr
+ offset
, bytes
, i
);
503 kunmap_atomic(kaddr
);
507 size_t copy_page_to_iter(struct page
*page
, size_t offset
, size_t bytes
,
510 if (i
->type
& ITER_BVEC
)
511 return copy_page_to_iter_bvec(page
, offset
, bytes
, i
);
513 return copy_page_to_iter_iovec(page
, offset
, bytes
, i
);
515 EXPORT_SYMBOL(copy_page_to_iter
);
517 size_t copy_page_from_iter(struct page
*page
, size_t offset
, size_t bytes
,
520 if (i
->type
& ITER_BVEC
)
521 return copy_page_from_iter_bvec(page
, offset
, bytes
, i
);
523 return copy_page_from_iter_iovec(page
, offset
, bytes
, i
);
525 EXPORT_SYMBOL(copy_page_from_iter
);
527 size_t copy_to_iter(void *addr
, size_t bytes
, struct iov_iter
*i
)
529 if (i
->type
& ITER_BVEC
)
530 return copy_to_iter_bvec(addr
, bytes
, i
);
532 return copy_to_iter_iovec(addr
, bytes
, i
);
534 EXPORT_SYMBOL(copy_to_iter
);
536 size_t copy_from_iter(void *addr
, size_t bytes
, struct iov_iter
*i
)
538 if (i
->type
& ITER_BVEC
)
539 return copy_from_iter_bvec(addr
, bytes
, i
);
541 return copy_from_iter_iovec(addr
, bytes
, i
);
543 EXPORT_SYMBOL(copy_from_iter
);
545 size_t iov_iter_zero(size_t bytes
, struct iov_iter
*i
)
547 if (unlikely(bytes
> i
->count
))
550 if (unlikely(!bytes
))
553 iterate_and_advance(i
, bytes
, v
,
554 __clear_user(v
.iov_base
, v
.iov_len
),
555 memzero_page(v
.bv_page
, v
.bv_offset
, v
.bv_len
)
560 EXPORT_SYMBOL(iov_iter_zero
);
562 size_t iov_iter_copy_from_user_atomic(struct page
*page
,
563 struct iov_iter
*i
, unsigned long offset
, size_t bytes
)
565 char *kaddr
= kmap_atomic(page
), *p
= kaddr
+ offset
;
566 iterate_all_kinds(i
, bytes
, v
,
567 __copy_from_user_inatomic((p
+= v
.iov_len
) - v
.iov_len
,
568 v
.iov_base
, v
.iov_len
),
569 memcpy_from_page((p
+= v
.bv_len
) - v
.bv_len
, v
.bv_page
,
570 v
.bv_offset
, v
.bv_len
)
572 kunmap_atomic(kaddr
);
575 EXPORT_SYMBOL(iov_iter_copy_from_user_atomic
);
577 void iov_iter_advance(struct iov_iter
*i
, size_t size
)
579 iterate_and_advance(i
, size
, v
, 0, 0)
581 EXPORT_SYMBOL(iov_iter_advance
);
584 * Return the count of just the current iov_iter segment.
586 size_t iov_iter_single_seg_count(const struct iov_iter
*i
)
590 else if (i
->type
& ITER_BVEC
)
591 return min(i
->count
, i
->bvec
->bv_len
- i
->iov_offset
);
593 return min(i
->count
, i
->iov
->iov_len
- i
->iov_offset
);
595 EXPORT_SYMBOL(iov_iter_single_seg_count
);
597 unsigned long iov_iter_alignment(const struct iov_iter
*i
)
599 unsigned long res
= 0;
600 size_t size
= i
->count
;
605 iterate_all_kinds(i
, size
, v
,
606 (res
|= (unsigned long)v
.iov_base
| v
.iov_len
, 0),
607 res
|= v
.bv_offset
| v
.bv_len
611 EXPORT_SYMBOL(iov_iter_alignment
);
613 ssize_t
iov_iter_get_pages(struct iov_iter
*i
,
614 struct page
**pages
, size_t maxsize
, unsigned maxpages
,
617 if (maxsize
> i
->count
)
623 iterate_all_kinds(i
, maxsize
, v
, ({
624 unsigned long addr
= (unsigned long)v
.iov_base
;
625 size_t len
= v
.iov_len
+ (*start
= addr
& (PAGE_SIZE
- 1));
629 if (len
> maxpages
* PAGE_SIZE
)
630 len
= maxpages
* PAGE_SIZE
;
631 addr
&= ~(PAGE_SIZE
- 1);
632 n
= DIV_ROUND_UP(len
, PAGE_SIZE
);
633 res
= get_user_pages_fast(addr
, n
, (i
->type
& WRITE
) != WRITE
, pages
);
634 if (unlikely(res
< 0))
636 return (res
== n
? len
: res
* PAGE_SIZE
) - *start
;
638 /* can't be more than PAGE_SIZE */
639 *start
= v
.bv_offset
;
640 get_page(*pages
= v
.bv_page
);
646 EXPORT_SYMBOL(iov_iter_get_pages
);
648 static struct page
**get_pages_array(size_t n
)
650 struct page
**p
= kmalloc(n
* sizeof(struct page
*), GFP_KERNEL
);
652 p
= vmalloc(n
* sizeof(struct page
*));
656 ssize_t
iov_iter_get_pages_alloc(struct iov_iter
*i
,
657 struct page
***pages
, size_t maxsize
,
662 if (maxsize
> i
->count
)
668 iterate_all_kinds(i
, maxsize
, v
, ({
669 unsigned long addr
= (unsigned long)v
.iov_base
;
670 size_t len
= v
.iov_len
+ (*start
= addr
& (PAGE_SIZE
- 1));
674 addr
&= ~(PAGE_SIZE
- 1);
675 n
= DIV_ROUND_UP(len
, PAGE_SIZE
);
676 p
= get_pages_array(n
);
679 res
= get_user_pages_fast(addr
, n
, (i
->type
& WRITE
) != WRITE
, p
);
680 if (unlikely(res
< 0)) {
685 return (res
== n
? len
: res
* PAGE_SIZE
) - *start
;
687 /* can't be more than PAGE_SIZE */
688 *start
= v
.bv_offset
;
689 *pages
= p
= get_pages_array(1);
692 get_page(*p
= v
.bv_page
);
698 EXPORT_SYMBOL(iov_iter_get_pages_alloc
);
700 int iov_iter_npages(const struct iov_iter
*i
, int maxpages
)
702 size_t size
= i
->count
;
708 iterate_all_kinds(i
, size
, v
, ({
709 unsigned long p
= (unsigned long)v
.iov_base
;
710 npages
+= DIV_ROUND_UP(p
+ v
.iov_len
, PAGE_SIZE
)
712 if (npages
>= maxpages
)
716 if (npages
>= maxpages
)
722 EXPORT_SYMBOL(iov_iter_npages
);