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csum_and_copy_..._iter()

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-11-24 01:08:00 -05:00
commit a604ec7e9f
2 changed files with 91 additions and 0 deletions
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2
include/linux/uio.h
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@ -124,6 +124,8 @@ static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
{ {
i->count = count; i->count = count;
} }
size_t csum_and_copy_to_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len); int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len); int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len);

89
mm/iov_iter.c
View file

@ -3,6 +3,7 @@
#include <linux/pagemap.h> #include <linux/pagemap.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <linux/vmalloc.h> #include <linux/vmalloc.h>
#include <net/checksum.h>
#define iterate_iovec(i, n, __v, __p, skip, STEP) { \ #define iterate_iovec(i, n, __v, __p, skip, STEP) { \
size_t left; \ size_t left; \
@ -586,6 +587,94 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
} }
EXPORT_SYMBOL(iov_iter_get_pages_alloc); 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) int iov_iter_npages(const struct iov_iter *i, int maxpages)
{ {
size_t size = i->count; size_t size = i->count;