Commit 59dbd7d0 authored by Al Viro's avatar Al Viro
Browse files

iov_iter: massage calling conventions for first_{iovec,bvec}_segment() 



Pass maxsize by reference, return length via the same.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent dda8e5d1

lib/iov_iter.c

+18 −24
Original line number Diff line number Diff line
@@ -1294,8 +1294,7 @@ static ssize_t iter_xarray_get_pages(struct iov_iter *i, 


/* must be done on non-empty ITER_IOVEC one */

static unsigned long first_iovec_segment(const struct iov_iter *i,

					 size_t *size, size_t *start,

					 size_t maxsize)

					 size_t *size, size_t *start)

{

	size_t skip;

	long k;
@@ -1306,10 +1305,9 @@ static unsigned long first_iovec_segment(const struct iov_iter *i, 


		if (unlikely(!len))

			continue;

		if (len > maxsize)

			len = maxsize;

		*start = addr % PAGE_SIZE;

		if (*size > len)

			*size = len;

		*start = addr % PAGE_SIZE;

		return addr & PAGE_MASK;

	}

	BUG(); // if it had been empty, we wouldn't get called
@@ -1317,19 +1315,17 @@ static unsigned long first_iovec_segment(const struct iov_iter *i, 


/* must be done on non-empty ITER_BVEC one */

static struct page *first_bvec_segment(const struct iov_iter *i,

				       size_t *size, size_t *start,

				       size_t maxsize)

				       size_t *size, size_t *start)

{

	struct page *page;

	size_t skip = i->iov_offset, len;



	len = i->bvec->bv_len - skip;

	if (len > maxsize)

		len = maxsize;

	if (*size > len)

		*size = len;

	skip += i->bvec->bv_offset;

	page = i->bvec->bv_page + skip / PAGE_SIZE;

	*start = skip % PAGE_SIZE;

	*size = len;

	return page;

}
@@ -1337,7 +1333,6 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, 
		   struct page **pages, size_t maxsize, unsigned maxpages,

		   size_t *start)

{

	size_t len;

	int n, res;



	if (maxsize > i->count)
@@ -1356,25 +1351,25 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, 
		if (i->nofault)

			gup_flags |= FOLL_NOFAULT;



		addr = first_iovec_segment(i, &len, start, maxsize);

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

		addr = first_iovec_segment(i, &maxsize, start);

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

		if (n > maxpages)

			n = maxpages;

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

		if (unlikely(res <= 0))

			return res;

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

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

	}

	if (iov_iter_is_bvec(i)) {

		struct page *page;



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

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

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

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

		if (n > maxpages)

			n = maxpages;

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

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

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

		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);
@@ -1469,7 +1464,6 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 
		   size_t *start)

{

	struct page **p;

	size_t len;

	int n, res;



	if (maxsize > i->count)
@@ -1488,8 +1482,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 
		if (i->nofault)

			gup_flags |= FOLL_NOFAULT;



		addr = first_iovec_segment(i, &len, start, maxsize);

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

		addr = first_iovec_segment(i, &maxsize, start);

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

		p = get_pages_array(n);

		if (!p)

			return -ENOMEM;
@@ -1500,19 +1494,19 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, 
			return res;

		}

		*pages = p;

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

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

	}

	if (iov_iter_is_bvec(i)) {

		struct page *page;



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

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

		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, len, n * PAGE_SIZE - *start);

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

	}

	if (iov_iter_is_pipe(i))

		return pipe_get_pages_alloc(i, pages, maxsize, start);