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	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);
		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)
		{
		return i->count;

mm/iov_iter.c

+15 −0

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