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authorLinus Torvalds <torvalds@linux-foundation.org>2015-03-13 10:55:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-03-13 10:55:32 -0700
commitf788baadbdd95b0309ab8e1565d5c425e197b8db (patch)
treeb0bd79b85eff2ee7bd36f2ab304d63ab7401645b /mm
parentMerge branch 'akpm' (patches from Andrew) (diff)
parentgadgetfs: really get rid of switching ->f_op (diff)
downloadlinux-dev-f788baadbdd95b0309ab8e1565d5c425e197b8db.tar.xz
linux-dev-f788baadbdd95b0309ab8e1565d5c425e197b8db.zip
Merge branch 'gadget' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull gadgetfs fixes from Al Viro: "Assorted fixes around AIO on gadgetfs: leaks, use-after-free, troubles caused by ->f_op flipping" * 'gadget' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: gadgetfs: really get rid of switching ->f_op gadgetfs: get rid of flipping ->f_op in ep_config() gadget: switch ep_io_operations to ->read_iter/->write_iter gadgetfs: use-after-free in ->aio_read() gadget/function/f_fs.c: switch to ->{read,write}_iter() gadget/function/f_fs.c: use put iov_iter into io_data gadget/function/f_fs.c: close leaks move iov_iter.c from mm/ to lib/ new helper: dup_iter()
Diffstat (limited to 'mm')
-rw-r--r--mm/Makefile2
-rw-r--r--mm/iov_iter.c753
2 files changed, 1 insertions, 754 deletions
diff --git a/mm/Makefile b/mm/Makefile
index 3c1caa2693bd..15dbe9903c27 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -21,7 +21,7 @@ obj-y := filemap.o mempool.o oom_kill.o \
mm_init.o mmu_context.o percpu.o slab_common.o \
compaction.o vmacache.o \
interval_tree.o list_lru.o workingset.o \
- iov_iter.o debug.o $(mmu-y)
+ debug.o $(mmu-y)
obj-y += init-mm.o
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
deleted file mode 100644
index 827732047da1..000000000000
--- a/mm/iov_iter.c
+++ /dev/null
@@ -1,753 +0,0 @@
-#include <linux/export.h>
-#include <linux/uio.h>
-#include <linux/pagemap.h>
-#include <linux/slab.h>
-#include <linux/vmalloc.h>
-#include <net/checksum.h>
-
-#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
- size_t left; \
- size_t wanted = n; \
- __p = i->iov; \
- __v.iov_len = min(n, __p->iov_len - skip); \
- if (likely(__v.iov_len)) { \
- __v.iov_base = __p->iov_base + skip; \
- left = (STEP); \
- __v.iov_len -= left; \
- skip += __v.iov_len; \
- n -= __v.iov_len; \
- } else { \
- left = 0; \
- } \
- while (unlikely(!left && n)) { \
- __p++; \
- __v.iov_len = min(n, __p->iov_len); \
- if (unlikely(!__v.iov_len)) \
- continue; \
- __v.iov_base = __p->iov_base; \
- left = (STEP); \
- __v.iov_len -= left; \
- skip = __v.iov_len; \
- n -= __v.iov_len; \
- } \
- n = wanted - n; \
-}
-
-#define iterate_kvec(i, n, __v, __p, skip, STEP) { \
- size_t wanted = n; \
- __p = i->kvec; \
- __v.iov_len = min(n, __p->iov_len - skip); \
- if (likely(__v.iov_len)) { \
- __v.iov_base = __p->iov_base + skip; \
- (void)(STEP); \
- skip += __v.iov_len; \
- n -= __v.iov_len; \
- } \
- while (unlikely(n)) { \
- __p++; \
- __v.iov_len = min(n, __p->iov_len); \
- if (unlikely(!__v.iov_len)) \
- continue; \
- __v.iov_base = __p->iov_base; \
- (void)(STEP); \
- skip = __v.iov_len; \
- n -= __v.iov_len; \
- } \
- n = wanted; \
-}
-
-#define iterate_bvec(i, n, __v, __p, skip, STEP) { \
- size_t wanted = n; \
- __p = i->bvec; \
- __v.bv_len = min_t(size_t, n, __p->bv_len - skip); \
- if (likely(__v.bv_len)) { \
- __v.bv_page = __p->bv_page; \
- __v.bv_offset = __p->bv_offset + skip; \
- (void)(STEP); \
- skip += __v.bv_len; \
- n -= __v.bv_len; \
- } \
- while (unlikely(n)) { \
- __p++; \
- __v.bv_len = min_t(size_t, n, __p->bv_len); \
- if (unlikely(!__v.bv_len)) \
- continue; \
- __v.bv_page = __p->bv_page; \
- __v.bv_offset = __p->bv_offset; \
- (void)(STEP); \
- skip = __v.bv_len; \
- n -= __v.bv_len; \
- } \
- n = wanted; \
-}
-
-#define iterate_all_kinds(i, n, v, I, B, K) { \
- size_t skip = i->iov_offset; \
- if (unlikely(i->type & ITER_BVEC)) { \
- const struct bio_vec *bvec; \
- struct bio_vec v; \
- iterate_bvec(i, n, v, bvec, skip, (B)) \
- } else if (unlikely(i->type & ITER_KVEC)) { \
- const struct kvec *kvec; \
- struct kvec v; \
- iterate_kvec(i, n, v, kvec, skip, (K)) \
- } else { \
- const struct iovec *iov; \
- struct iovec v; \
- iterate_iovec(i, n, v, iov, skip, (I)) \
- } \
-}
-
-#define iterate_and_advance(i, n, v, I, B, K) { \
- size_t skip = i->iov_offset; \
- if (unlikely(i->type & ITER_BVEC)) { \
- const struct bio_vec *bvec; \
- struct bio_vec v; \
- iterate_bvec(i, n, v, bvec, skip, (B)) \
- if (skip == bvec->bv_len) { \
- bvec++; \
- skip = 0; \
- } \
- i->nr_segs -= bvec - i->bvec; \
- i->bvec = bvec; \
- } else if (unlikely(i->type & ITER_KVEC)) { \
- const struct kvec *kvec; \
- struct kvec v; \
- iterate_kvec(i, n, v, kvec, skip, (K)) \
- if (skip == kvec->iov_len) { \
- kvec++; \
- skip = 0; \
- } \
- i->nr_segs -= kvec - i->kvec; \
- i->kvec = kvec; \
- } else { \
- const struct iovec *iov; \
- struct iovec v; \
- iterate_iovec(i, n, v, iov, skip, (I)) \
- if (skip == iov->iov_len) { \
- iov++; \
- skip = 0; \
- } \
- i->nr_segs -= iov - i->iov; \
- i->iov = iov; \
- } \
- i->count -= n; \
- i->iov_offset = skip; \
-}
-
-static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
- struct iov_iter *i)
-{
- size_t skip, copy, left, wanted;
- const struct iovec *iov;
- char __user *buf;
- void *kaddr, *from;
-
- if (unlikely(bytes > i->count))
- bytes = i->count;
-
- if (unlikely(!bytes))
- return 0;
-
- wanted = bytes;
- iov = i->iov;
- skip = i->iov_offset;
- buf = iov->iov_base + skip;
- copy = min(bytes, iov->iov_len - skip);
-
- if (!fault_in_pages_writeable(buf, copy)) {
- kaddr = kmap_atomic(page);
- from = kaddr + offset;
-
- /* first chunk, usually the only one */
- left = __copy_to_user_inatomic(buf, from, copy);
- copy -= left;
- skip += copy;
- from += copy;
- bytes -= copy;
-
- while (unlikely(!left && bytes)) {
- iov++;
- buf = iov->iov_base;
- copy = min(bytes, iov->iov_len);
- left = __copy_to_user_inatomic(buf, from, copy);
- copy -= left;
- skip = copy;
- from += copy;
- bytes -= copy;
- }
- if (likely(!bytes)) {
- kunmap_atomic(kaddr);
- goto done;
- }
- offset = from - kaddr;
- buf += copy;
- kunmap_atomic(kaddr);
- copy = min(bytes, iov->iov_len - skip);
- }
- /* Too bad - revert to non-atomic kmap */
- kaddr = kmap(page);
- from = kaddr + offset;
- left = __copy_to_user(buf, from, copy);
- copy -= left;
- skip += copy;
- from += copy;
- bytes -= copy;
- while (unlikely(!left && bytes)) {
- iov++;
- buf = iov->iov_base;
- copy = min(bytes, iov->iov_len);
- left = __copy_to_user(buf, from, copy);
- copy -= left;
- skip = copy;
- from += copy;
- bytes -= copy;
- }
- kunmap(page);
-done:
- if (skip == iov->iov_len) {
- iov++;
- skip = 0;
- }
- i->count -= wanted - bytes;
- i->nr_segs -= iov - i->iov;
- i->iov = iov;
- i->iov_offset = skip;
- return wanted - bytes;
-}
-
-static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
- struct iov_iter *i)
-{
- size_t skip, copy, left, wanted;
- const struct iovec *iov;
- char __user *buf;
- void *kaddr, *to;
-
- if (unlikely(bytes > i->count))
- bytes = i->count;
-
- if (unlikely(!bytes))
- return 0;
-
- wanted = bytes;
- iov = i->iov;
- skip = i->iov_offset;
- buf = iov->iov_base + skip;
- copy = min(bytes, iov->iov_len - skip);
-
- if (!fault_in_pages_readable(buf, copy)) {
- kaddr = kmap_atomic(page);
- to = kaddr + offset;
-
- /* first chunk, usually the only one */
- left = __copy_from_user_inatomic(to, buf, copy);
- copy -= left;
- skip += copy;
- to += copy;
- bytes -= copy;
-
- while (unlikely(!left && bytes)) {
- iov++;
- buf = iov->iov_base;
- copy = min(bytes, iov->iov_len);
- left = __copy_from_user_inatomic(to, buf, copy);
- copy -= left;
- skip = copy;
- to += copy;
- bytes -= copy;
- }
- if (likely(!bytes)) {
- kunmap_atomic(kaddr);
- goto done;
- }
- offset = to - kaddr;
- buf += copy;
- kunmap_atomic(kaddr);
- copy = min(bytes, iov->iov_len - skip);
- }
- /* Too bad - revert to non-atomic kmap */
- kaddr = kmap(page);
- to = kaddr + offset;
- left = __copy_from_user(to, buf, copy);
- copy -= left;
- skip += copy;
- to += copy;
- bytes -= copy;
- while (unlikely(!left && bytes)) {
- iov++;
- buf = iov->iov_base;
- copy = min(bytes, iov->iov_len);
- left = __copy_from_user(to, buf, copy);
- copy -= left;
- skip = copy;
- to += copy;
- bytes -= copy;
- }
- kunmap(page);
-done:
- if (skip == iov->iov_len) {
- iov++;
- skip = 0;
- }
- i->count -= wanted - bytes;
- i->nr_segs -= iov - i->iov;
- i->iov = iov;
- i->iov_offset = skip;
- return wanted - bytes;
-}
-
-/*
- * Fault in the first iovec of the given iov_iter, to a maximum length
- * of bytes. Returns 0 on success, or non-zero if the memory could not be
- * accessed (ie. because it is an invalid address).
- *
- * writev-intensive code may want this to prefault several iovecs -- that
- * would be possible (callers must not rely on the fact that _only_ the
- * first iovec will be faulted with the current implementation).
- */
-int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
-{
- if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
- char __user *buf = i->iov->iov_base + i->iov_offset;
- bytes = min(bytes, i->iov->iov_len - i->iov_offset);
- return fault_in_pages_readable(buf, bytes);
- }
- return 0;
-}
-EXPORT_SYMBOL(iov_iter_fault_in_readable);
-
-void iov_iter_init(struct iov_iter *i, int direction,
- const struct iovec *iov, unsigned long nr_segs,
- size_t count)
-{
- /* It will get better. Eventually... */
- if (segment_eq(get_fs(), KERNEL_DS)) {
- direction |= ITER_KVEC;
- i->type = direction;
- i->kvec = (struct kvec *)iov;
- } else {
- i->type = direction;
- i->iov = iov;
- }
- i->nr_segs = nr_segs;
- i->iov_offset = 0;
- i->count = count;
-}
-EXPORT_SYMBOL(iov_iter_init);
-
-static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
-{
- char *from = kmap_atomic(page);
- memcpy(to, from + offset, len);
- kunmap_atomic(from);
-}
-
-static void memcpy_to_page(struct page *page, size_t offset, char *from, size_t len)
-{
- char *to = kmap_atomic(page);
- memcpy(to + offset, from, len);
- kunmap_atomic(to);
-}
-
-static void memzero_page(struct page *page, size_t offset, size_t len)
-{
- char *addr = kmap_atomic(page);
- memset(addr + offset, 0, len);
- kunmap_atomic(addr);
-}
-
-size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
-{
- char *from = addr;
- if (unlikely(bytes > i->count))
- bytes = i->count;
-
- if (unlikely(!bytes))
- return 0;
-
- iterate_and_advance(i, bytes, v,
- __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
- v.iov_len),
- memcpy_to_page(v.bv_page, v.bv_offset,
- (from += v.bv_len) - v.bv_len, v.bv_len),
- memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
- )
-
- return bytes;
-}
-EXPORT_SYMBOL(copy_to_iter);
-
-size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
-{
- char *to = addr;
- if (unlikely(bytes > i->count))
- bytes = i->count;
-
- if (unlikely(!bytes))
- return 0;
-
- iterate_and_advance(i, bytes, v,
- __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
- v.iov_len),
- memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
- v.bv_offset, v.bv_len),
- memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
- )
-
- return bytes;
-}
-EXPORT_SYMBOL(copy_from_iter);
-
-size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
-{
- char *to = addr;
- if (unlikely(bytes > i->count))
- bytes = i->count;
-
- if (unlikely(!bytes))
- return 0;
-
- iterate_and_advance(i, bytes, v,
- __copy_from_user_nocache((to += v.iov_len) - v.iov_len,
- v.iov_base, v.iov_len),
- memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
- v.bv_offset, v.bv_len),
- memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
- )
-
- return bytes;
-}
-EXPORT_SYMBOL(copy_from_iter_nocache);
-
-size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
- struct iov_iter *i)
-{
- if (i->type & (ITER_BVEC|ITER_KVEC)) {
- void *kaddr = kmap_atomic(page);
- size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
- kunmap_atomic(kaddr);
- return wanted;
- } else
- return copy_page_to_iter_iovec(page, offset, bytes, i);
-}
-EXPORT_SYMBOL(copy_page_to_iter);
-
-size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
- struct iov_iter *i)
-{
- if (i->type & (ITER_BVEC|ITER_KVEC)) {
- void *kaddr = kmap_atomic(page);
- size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
- kunmap_atomic(kaddr);
- return wanted;
- } else
- return copy_page_from_iter_iovec(page, offset, bytes, i);
-}
-EXPORT_SYMBOL(copy_page_from_iter);
-
-size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
-{
- if (unlikely(bytes > i->count))
- bytes = i->count;
-
- if (unlikely(!bytes))
- return 0;
-
- iterate_and_advance(i, bytes, v,
- __clear_user(v.iov_base, v.iov_len),
- memzero_page(v.bv_page, v.bv_offset, v.bv_len),
- memset(v.iov_base, 0, v.iov_len)
- )
-
- return bytes;
-}
-EXPORT_SYMBOL(iov_iter_zero);
-
-size_t iov_iter_copy_from_user_atomic(struct page *page,
- struct iov_iter *i, unsigned long offset, size_t bytes)
-{
- char *kaddr = kmap_atomic(page), *p = kaddr + offset;
- iterate_all_kinds(i, bytes, v,
- __copy_from_user_inatomic((p += v.iov_len) - v.iov_len,
- v.iov_base, v.iov_len),
- memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
- v.bv_offset, v.bv_len),
- memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
- )
- kunmap_atomic(kaddr);
- return bytes;
-}
-EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
-
-void iov_iter_advance(struct iov_iter *i, size_t size)
-{
- iterate_and_advance(i, size, v, 0, 0, 0)
-}
-EXPORT_SYMBOL(iov_iter_advance);
-
-/*
- * Return the count of just the current iov_iter segment.
- */
-size_t iov_iter_single_seg_count(const struct iov_iter *i)
-{
- if (i->nr_segs == 1)
- return i->count;
- else if (i->type & ITER_BVEC)
- return min(i->count, i->bvec->bv_len - i->iov_offset);
- else
- return min(i->count, i->iov->iov_len - i->iov_offset);
-}
-EXPORT_SYMBOL(iov_iter_single_seg_count);
-
-void iov_iter_kvec(struct iov_iter *i, int direction,
- const struct kvec *kvec, unsigned long nr_segs,
- size_t count)
-{
- BUG_ON(!(direction & ITER_KVEC));
- i->type = direction;
- i->kvec = kvec;
- i->nr_segs = nr_segs;
- i->iov_offset = 0;
- i->count = count;
-}
-EXPORT_SYMBOL(iov_iter_kvec);
-
-void iov_iter_bvec(struct iov_iter *i, int direction,
- const struct bio_vec *bvec, unsigned long nr_segs,
- size_t count)
-{
- BUG_ON(!(direction & ITER_BVEC));
- i->type = direction;
- i->bvec = bvec;
- i->nr_segs = nr_segs;
- i->iov_offset = 0;
- i->count = count;
-}
-EXPORT_SYMBOL(iov_iter_bvec);
-
-unsigned long iov_iter_alignment(const struct iov_iter *i)
-{
- unsigned long res = 0;
- size_t size = i->count;
-
- if (!size)
- return 0;
-
- iterate_all_kinds(i, size, v,
- (res |= (unsigned long)v.iov_base | v.iov_len, 0),
- res |= v.bv_offset | v.bv_len,
- res |= (unsigned long)v.iov_base | v.iov_len
- )
- return res;
-}
-EXPORT_SYMBOL(iov_iter_alignment);
-
-ssize_t iov_iter_get_pages(struct iov_iter *i,
- struct page **pages, size_t maxsize, unsigned maxpages,
- size_t *start)
-{
- if (maxsize > i->count)
- maxsize = i->count;
-
- if (!maxsize)
- return 0;
-
- iterate_all_kinds(i, maxsize, v, ({
- unsigned long addr = (unsigned long)v.iov_base;
- size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
- int n;
- int res;
-
- if (len > maxpages * PAGE_SIZE)
- len = maxpages * PAGE_SIZE;
- addr &= ~(PAGE_SIZE - 1);
- n = DIV_ROUND_UP(len, PAGE_SIZE);
- res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
- if (unlikely(res < 0))
- return res;
- return (res == n ? len : res * PAGE_SIZE) - *start;
- 0;}),({
- /* can't be more than PAGE_SIZE */
- *start = v.bv_offset;
- get_page(*pages = v.bv_page);
- return v.bv_len;
- }),({
- return -EFAULT;
- })
- )
- return 0;
-}
-EXPORT_SYMBOL(iov_iter_get_pages);
-
-static struct page **get_pages_array(size_t n)
-{
- struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
- if (!p)
- p = vmalloc(n * sizeof(struct page *));
- return p;
-}
-
-ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
- struct page ***pages, size_t maxsize,
- size_t *start)
-{
- struct page **p;
-
- if (maxsize > i->count)
- maxsize = i->count;
-
- if (!maxsize)
- return 0;
-
- iterate_all_kinds(i, maxsize, v, ({
- unsigned long addr = (unsigned long)v.iov_base;
- size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
- int n;
- int res;
-
- addr &= ~(PAGE_SIZE - 1);
- n = DIV_ROUND_UP(len, PAGE_SIZE);
- p = get_pages_array(n);
- if (!p)
- return -ENOMEM;
- res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
- if (unlikely(res < 0)) {
- kvfree(p);
- return res;
- }
- *pages = p;
- return (res == n ? len : res * PAGE_SIZE) - *start;
- 0;}),({
- /* can't be more than PAGE_SIZE */
- *start = v.bv_offset;
- *pages = p = get_pages_array(1);
- if (!p)
- return -ENOMEM;
- get_page(*p = v.bv_page);
- return v.bv_len;
- }),({
- return -EFAULT;
- })
- )
- return 0;
-}
-EXPORT_SYMBOL(iov_iter_get_pages_alloc);
-
-size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
- struct iov_iter *i)
-{
- char *to = addr;
- __wsum sum, next;
- size_t off = 0;
- if (unlikely(bytes > i->count))
- bytes = i->count;
-
- if (unlikely(!bytes))
- return 0;
-
- sum = *csum;
- iterate_and_advance(i, bytes, v, ({
- int err = 0;
- next = csum_and_copy_from_user(v.iov_base,
- (to += v.iov_len) - v.iov_len,
- v.iov_len, 0, &err);
- if (!err) {
- sum = csum_block_add(sum, next, off);
- off += v.iov_len;
- }
- err ? v.iov_len : 0;
- }), ({
- char *p = kmap_atomic(v.bv_page);
- next = csum_partial_copy_nocheck(p + v.bv_offset,
- (to += v.bv_len) - v.bv_len,
- v.bv_len, 0);
- kunmap_atomic(p);
- sum = csum_block_add(sum, next, off);
- off += v.bv_len;
- }),({
- next = csum_partial_copy_nocheck(v.iov_base,
- (to += v.iov_len) - v.iov_len,
- v.iov_len, 0);
- sum = csum_block_add(sum, next, off);
- off += v.iov_len;
- })
- )
- *csum = sum;
- return bytes;
-}
-EXPORT_SYMBOL(csum_and_copy_from_iter);
-
-size_t csum_and_copy_to_iter(void *addr, size_t bytes, __wsum *csum,
- struct iov_iter *i)
-{
- char *from = addr;
- __wsum sum, next;
- size_t off = 0;
- if (unlikely(bytes > i->count))
- bytes = i->count;
-
- if (unlikely(!bytes))
- return 0;
-
- sum = *csum;
- iterate_and_advance(i, bytes, v, ({
- int err = 0;
- next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
- v.iov_base,
- v.iov_len, 0, &err);
- if (!err) {
- sum = csum_block_add(sum, next, off);
- off += v.iov_len;
- }
- err ? v.iov_len : 0;
- }), ({
- char *p = kmap_atomic(v.bv_page);
- next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len,
- p + v.bv_offset,
- v.bv_len, 0);
- kunmap_atomic(p);
- sum = csum_block_add(sum, next, off);
- off += v.bv_len;
- }),({
- next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len,
- v.iov_base,
- v.iov_len, 0);
- sum = csum_block_add(sum, next, off);
- off += v.iov_len;
- })
- )
- *csum = sum;
- return bytes;
-}
-EXPORT_SYMBOL(csum_and_copy_to_iter);
-
-int iov_iter_npages(const struct iov_iter *i, int maxpages)
-{
- size_t size = i->count;
- int npages = 0;
-
- if (!size)
- return 0;
-
- iterate_all_kinds(i, size, v, ({
- unsigned long p = (unsigned long)v.iov_base;
- npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
- - p / PAGE_SIZE;
- if (npages >= maxpages)
- return maxpages;
- 0;}),({
- npages++;
- if (npages >= maxpages)
- return maxpages;
- }),({
- unsigned long p = (unsigned long)v.iov_base;
- npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
- - p / PAGE_SIZE;
- if (npages >= maxpages)
- return maxpages;
- })
- )
- return npages;
-}
-EXPORT_SYMBOL(iov_iter_npages);