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Commit 4b8164b9 authored Jan 31, 2015 by Al Viro

new helper: dup_iter()



Copy iter and kmemdup the underlying array for the copy.  Returns
a pointer to result of kmemdup() to be kfree()'d later.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

parent f5af19d1

include/linux/uio.h

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -98,6 +98,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter i, struct page **pages,
	size_t maxsize, size_t *start);		size_t maxsize, size_t *start);
	int iov_iter_npages(const struct iov_iter *i, int maxpages);		int iov_iter_npages(const struct iov_iter *i, int maxpages);

			const void dup_iter(struct iov_iter new, struct iov_iter *old, gfp_t flags);

	static inline size_t iov_iter_count(struct iov_iter *i)		static inline size_t iov_iter_count(struct iov_iter *i)
	{		{
	return i->count;		return i->count;

mm/iov_iter.c

+15 −0

Original line number	Original line	Diff line number	Diff line
	@@ -751,3 +751,18 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages)
	return npages;		return npages;
	}		}
	EXPORT_SYMBOL(iov_iter_npages);		EXPORT_SYMBOL(iov_iter_npages);

			const void dup_iter(struct iov_iter new, struct iov_iter *old, gfp_t flags)
			{
			new = old;
			if (new->type & ITER_BVEC)
			return new->bvec = kmemdup(new->bvec,
			new->nr_segs * sizeof(struct bio_vec),
			flags);
			else
			/* iovec and kvec have identical layout */
			return new->iov = kmemdup(new->iov,
			new->nr_segs * sizeof(struct iovec),
			flags);
			}
			EXPORT_SYMBOL(dup_iter);