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Commit 0dbca9a4 authored by Al Viro's avatar Al Viro
Browse files

iov_iter.c: convert copy_from_iter() to iterate_and_advance 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent d271524a

mm/iov_iter.c

+15 −91
Original line number Diff line number Diff line
@@ -142,51 +142,6 @@ static size_t copy_to_iter_iovec(void *from, size_t bytes, struct iov_iter *i) 
	return wanted - bytes;

}



static size_t copy_from_iter_iovec(void *to, size_t bytes, struct iov_iter *i)

{

	size_t skip, copy, left, wanted;

	const struct iovec *iov;

	char __user *buf;



	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);



	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;

	}



	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_to_iter_iovec(struct page *page, size_t offset, size_t bytes,

			 struct iov_iter *i)

{
@@ -444,48 +399,6 @@ static size_t copy_to_iter_bvec(void *from, size_t bytes, struct iov_iter *i) 
	return wanted - bytes;

}



static size_t copy_from_iter_bvec(void *to, size_t bytes, struct iov_iter *i)

{

	size_t skip, copy, wanted;

	const struct bio_vec *bvec;



	if (unlikely(bytes > i->count))

		bytes = i->count;



	if (unlikely(!bytes))

		return 0;



	wanted = bytes;

	bvec = i->bvec;

	skip = i->iov_offset;



	copy = min(bytes, bvec->bv_len - skip);



	memcpy_from_page(to, bvec->bv_page, bvec->bv_offset + skip, copy);



	to += copy;

	skip += copy;

	bytes -= copy;



	while (bytes) {

		bvec++;

		copy = min(bytes, (size_t)bvec->bv_len);

		memcpy_from_page(to, bvec->bv_page, bvec->bv_offset, copy);

		skip = copy;

		to += copy;

		bytes -= copy;

	}

	if (skip == bvec->bv_len) {

		bvec++;

		skip = 0;

	}

	i->count -= wanted;

	i->nr_segs -= bvec - i->bvec;

	i->bvec = bvec;

	i->iov_offset = skip;

	return wanted;

}



size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)

{

	if (i->type & ITER_BVEC)
@@ -497,10 +410,21 @@ EXPORT_SYMBOL(copy_to_iter); 


size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)

{

	if (i->type & ITER_BVEC)

		return copy_from_iter_bvec(addr, bytes, i);

	else

		return copy_from_iter_iovec(addr, bytes, 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)

	)



	return bytes;

}

EXPORT_SYMBOL(copy_from_iter);