Commit acbdeb83 authored by Al Viro's avatar Al Viro
Browse files

unify pipe_get_pages() and pipe_get_pages_alloc() 



	The differences between those two are
* pipe_get_pages() gets a non-NULL struct page ** value pointing to
preallocated array + array size.
* pipe_get_pages_alloc() gets an address of struct page ** variable that
contains NULL, allocates the array and (on success) stores its address in
that variable.

	Not hard to combine - always pass struct page ***, have
the previous pipe_get_pages_alloc() caller pass ~0U as cap for
array size.

Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c81ce28d

lib/iov_iter.c

+17 −32
Original line number Diff line number Diff line
@@ -1284,6 +1284,11 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i) 
}

EXPORT_SYMBOL(iov_iter_gap_alignment);



static struct page **get_pages_array(size_t n)

{

	return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL);

}



static inline ssize_t __pipe_get_pages(struct iov_iter *i,

				size_t maxsize,

				struct page **pages,
@@ -1317,10 +1322,11 @@ static inline ssize_t __pipe_get_pages(struct iov_iter *i, 
}



static ssize_t pipe_get_pages(struct iov_iter *i,

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

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

		   size_t *start)

{

	unsigned int npages, off;

	struct page **p;

	size_t capacity;



	if (!sanity(i))
@@ -1328,8 +1334,15 @@ static ssize_t pipe_get_pages(struct iov_iter *i, 


	*start = off = pipe_npages(i, &npages);

	capacity = min(npages, maxpages) * PAGE_SIZE - off;

	maxsize = min(maxsize, capacity);

	p = *pages;

	if (!p) {

		*pages = p = get_pages_array(DIV_ROUND_UP(maxsize + off, PAGE_SIZE));

		if (!p)

			return -ENOMEM;

	}



	return __pipe_get_pages(i, min(maxsize, capacity), pages, off);

	return __pipe_get_pages(i, maxsize, p, off);

}



static ssize_t iter_xarray_populate_pages(struct page **pages, struct xarray *xa,
@@ -1475,41 +1488,13 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, 
		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 -EFAULT;

}

EXPORT_SYMBOL(iov_iter_get_pages);



static struct page **get_pages_array(size_t n)

{

	return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL);

}



static ssize_t pipe_get_pages_alloc(struct iov_iter *i,

		   struct page ***pages, size_t maxsize,

		   size_t *start)

{

	struct page **p;

	unsigned int npages, off;

	ssize_t n;



	if (!sanity(i))

		return -EFAULT;



	*start = off = pipe_npages(i, &npages);

	n = npages * PAGE_SIZE - off;

	if (maxsize > n)

		maxsize = n;

	else

		npages = DIV_ROUND_UP(maxsize + off, PAGE_SIZE);

	*pages = p = get_pages_array(npages);

	if (!p)

		return -ENOMEM;

	return __pipe_get_pages(i, maxsize, p, off);

}



static ssize_t iter_xarray_get_pages_alloc(struct iov_iter *i,

					   struct page ***pages, size_t maxsize,

					   size_t *_start_offset)
@@ -1593,7 +1578,7 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, 
		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);

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

	if (iov_iter_is_xarray(i))

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

	return -EFAULT;