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Commit 8442fa46 authored by Al Viro's avatar Al Viro
Browse files

iov_iter.c: convert iov_iter_zero() to iterate_and_advance 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 1b17f1f2

mm/iov_iter.c

+12 −86
Original line number Diff line number Diff line
@@ -349,50 +349,6 @@ static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t 
	return wanted - bytes;

}



static size_t zero_iovec(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 = __clear_user(buf, copy);

	copy -= left;

	skip += copy;

	bytes -= copy;



	while (unlikely(!left && bytes)) {

		iov++;

		buf = iov->iov_base;

		copy = min(bytes, iov->iov_len);

		left = __clear_user(buf, copy);

		copy -= left;

		skip = 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;

}



/*

 * 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
@@ -548,43 +504,6 @@ static size_t copy_page_from_iter_bvec(struct page *page, size_t offset, 
	return wanted;

}



static size_t zero_bvec(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_t(size_t, bytes, bvec->bv_len - skip);



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

	skip += copy;

	bytes -= copy;

	while (bytes) {

		bvec++;

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

		memzero_page(bvec->bv_page, bvec->bv_offset, copy);

		skip = copy;

		bytes -= copy;

	}

	if (skip == bvec->bv_len) {

		bvec++;

		skip = 0;

	}

	i->count -= wanted - bytes;

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

	i->bvec = bvec;

	i->iov_offset = skip;

	return wanted - bytes;

}



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

			 struct iov_iter *i)

{
@@ -625,11 +544,18 @@ EXPORT_SYMBOL(copy_from_iter); 


size_t iov_iter_zero(size_t bytes, struct iov_iter *i)

{

	if (i->type & ITER_BVEC) {

		return zero_bvec(bytes, i);

	} else {

		return zero_iovec(bytes, 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)

	)



	return bytes;

}

EXPORT_SYMBOL(iov_iter_zero);