Commit 451c0ba9 authored by Al Viro's avatar Al Viro
Browse files

unify the rest of iov_iter_get_pages()/iov_iter_get_pages_alloc() guts 



same as for pipes and xarrays; after that iov_iter_get_pages() becomes
a wrapper for __iov_iter_get_pages_alloc().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 68fe506f

lib/iov_iter.c

+27 −59
Original line number Diff line number Diff line
@@ -1448,19 +1448,18 @@ static struct page *first_bvec_segment(const struct iov_iter *i, 
	return page;

}



ssize_t iov_iter_get_pages(struct iov_iter *i,

		   struct page **pages, size_t maxsize, unsigned maxpages,

		   size_t *start)

static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,

		   struct page ***pages, size_t maxsize,

		   unsigned int maxpages, size_t *start)

{

	int n, res;



	if (maxsize > i->count)

		maxsize = i->count;

	if (!maxsize || !maxpages)

	if (!maxsize)

		return 0;

	if (maxsize > MAX_RW_COUNT)

		maxsize = MAX_RW_COUNT;

	BUG_ON(!pages);



	if (likely(user_backed_iter(i))) {

		unsigned int gup_flags = 0;
@@ -1477,83 +1476,52 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, 
		n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);

		if (n > maxpages)

			n = maxpages;

		res = get_user_pages_fast(addr, n, gup_flags, pages);

		if (!*pages) {

			*pages = get_pages_array(n);

			if (!*pages)

				return -ENOMEM;

		}

		res = get_user_pages_fast(addr, n, gup_flags, *pages);

		if (unlikely(res <= 0))

			return res;

		return min_t(size_t, maxsize, res * PAGE_SIZE - *start);

	}

	if (iov_iter_is_bvec(i)) {

		struct page **p;

		struct page *page;



		page = first_bvec_segment(i, &maxsize, start);

		n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);

		if (n > maxpages)

			n = maxpages;

		p = *pages;

		if (!p) {

			*pages = p = get_pages_array(n);

			if (!p)

				return -ENOMEM;

		}

		for (int k = 0; k < n; k++)

			get_page(*pages++ = page++);

			get_page(*p++ = page++);

		return min_t(size_t, maxsize, n * PAGE_SIZE - *start);

	}

	if (iov_iter_is_pipe(i))

		return pipe_get_pages(i, &pages, maxsize, maxpages, start);

		return pipe_get_pages(i, pages, maxsize, maxpages, start);

	if (iov_iter_is_xarray(i))

		return iter_xarray_get_pages(i, &pages, maxsize, maxpages, start);

		return iter_xarray_get_pages(i, pages, maxsize, maxpages, start);

	return -EFAULT;

}

EXPORT_SYMBOL(iov_iter_get_pages);



static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,

		   struct page ***pages, size_t maxsize,

ssize_t iov_iter_get_pages(struct iov_iter *i,

		   struct page **pages, size_t maxsize, unsigned maxpages,

		   size_t *start)

{

	struct page **p;

	int n, res;



	if (maxsize > i->count)

		maxsize = i->count;

	if (!maxsize)

	if (!maxpages)

		return 0;

	if (maxsize > MAX_RW_COUNT)

		maxsize = MAX_RW_COUNT;



	if (likely(user_backed_iter(i))) {

		unsigned int gup_flags = 0;

		unsigned long addr;



		if (iov_iter_rw(i) != WRITE)

			gup_flags |= FOLL_WRITE;

		if (i->nofault)

			gup_flags |= FOLL_NOFAULT;



		addr = first_iovec_segment(i, &maxsize);

		*start = addr % PAGE_SIZE;

		addr &= PAGE_MASK;

		n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);

		*pages = p = get_pages_array(n);

		if (!p)

			return -ENOMEM;

		res = get_user_pages_fast(addr, n, gup_flags, p);

		if (unlikely(res <= 0))

			return res;

		return min_t(size_t, maxsize, res * PAGE_SIZE - *start);

	}

	if (iov_iter_is_bvec(i)) {

		struct page *page;

	BUG_ON(!pages);



		page = first_bvec_segment(i, &maxsize, start);

		n = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);

		*pages = p = get_pages_array(n);

		if (!p)

			return -ENOMEM;

		for (int k = 0; k < n; k++)

			get_page(*p++ = page++);

		return min_t(size_t, maxsize, n * PAGE_SIZE - *start);

	}

	if (iov_iter_is_pipe(i))

		return pipe_get_pages(i, pages, maxsize, ~0U, start);

	if (iov_iter_is_xarray(i))

		return iter_xarray_get_pages(i, pages, maxsize, ~0U, start);

	return -EFAULT;

	return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start);

}

EXPORT_SYMBOL(iov_iter_get_pages);



ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,

		   struct page ***pages, size_t maxsize,
@@ -1563,7 +1531,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 


	*pages = NULL;



	len = __iov_iter_get_pages_alloc(i, pages, maxsize, start);

	len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);

	if (len <= 0) {

		kvfree(*pages);

		*pages = NULL;