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Commit a604ec7e authored by Al Viro's avatar Al Viro
Browse files

csum_and_copy_..._iter() 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent a280455f

include/linux/uio.h

+2 −0
Original line number Diff line number Diff line
@@ -124,6 +124,8 @@ static inline void iov_iter_reexpand(struct iov_iter *i, size_t 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_toiovec(struct iovec *iov, unsigned char *kdata, int len);

mm/iov_iter.c

+89 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#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;					\
@@ -586,6 +587,94 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 
}

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;