Commit 821979f5 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

iov_iter: Convert iter_xarray to use folios 



Take advantage of how kmap_local_folio() works to simplify the loop.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarWilliam Kucharski <william.kucharski@oracle.com>
parent d9c19d32

lib/iov_iter.c

+14 −16
Original line number Diff line number Diff line
@@ -69,37 +69,35 @@ 
#define iterate_xarray(i, n, base, len, __off, STEP) {		\

	__label__ __out;					\

	size_t __off = 0;					\

	struct page *head = NULL;				\

	struct folio *folio;					\

	loff_t start = i->xarray_start + i->iov_offset;		\

	unsigned offset = start % PAGE_SIZE;			\

	pgoff_t index = start / PAGE_SIZE;			\

	int j;							\

								\

	XA_STATE(xas, i->xarray, index);			\

								\

	len = PAGE_SIZE - offset_in_page(start);		\

	rcu_read_lock();					\

	xas_for_each(&xas, head, ULONG_MAX) {			\

	xas_for_each(&xas, folio, ULONG_MAX) {			\

		unsigned left;					\

		if (xas_retry(&xas, head))			\

		size_t offset;					\

		if (xas_retry(&xas, folio))			\

			continue;				\

		if (WARN_ON(xa_is_value(head)))			\

		if (WARN_ON(xa_is_value(folio)))		\

			break;					\

		if (WARN_ON(PageHuge(head)))			\

		if (WARN_ON(folio_test_hugetlb(folio)))		\

			break;					\

		for (j = (head->index < index) ? index - head->index : 0; \

		     j < thp_nr_pages(head); j++) {		\

			void *kaddr = kmap_local_page(head + j);	\

			base = kaddr + offset;			\

			len = PAGE_SIZE - offset;		\

		offset = offset_in_folio(folio, start + __off);	\

		while (offset < folio_size(folio)) {		\

			base = kmap_local_folio(folio, offset);	\

			len = min(n, len);			\

			left = (STEP);				\

			kunmap_local(kaddr);			\

			kunmap_local(base);			\

			len -= left;				\

			__off += len;				\

			n -= len;				\

			if (left || n == 0)			\

				goto __out;			\

			offset = 0;				\

			offset += len;				\

			len = PAGE_SIZE;			\

		}						\

	}							\

__out:								\