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Commit cdb4cba5 authored by Tejun Heo's avatar Tejun Heo
Browse files

percpu: remove @may_alloc from pcpu_get_pages() 



pcpu_get_pages() creates the temp pages array if not already allocated
and returns the pointer to it.  As the function is called from both
[de]population paths and depopulation can only happen after at least
one successful population, the param doesn't make any difference - the
allocation will always happen on the population path anyway.

Remove @may_alloc from pcpu_get_pages().  Also, add an lockdep
assertion pcpu_alloc_mutex instead of vaguely stating that the
exclusion is the caller's responsibility.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent fbbb7f4e

mm/percpu-vm.c

+8 −7
Original line number Diff line number Diff line
@@ -22,21 +22,22 @@ static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk, 
/**

 * pcpu_get_pages - get temp pages array

 * @chunk: chunk of interest

 * @may_alloc: may allocate the array

 *

 * Returns pointer to array of pointers to struct page which can be indexed

 * with pcpu_page_idx().  Note that there is only one array and access

 * exclusion is the caller's responsibility.

 * with pcpu_page_idx().  Note that there is only one array and accesses

 * should be serialized by pcpu_alloc_mutex.

 *

 * RETURNS:

 * Pointer to temp pages array on success.

 */

static struct page **pcpu_get_pages(struct pcpu_chunk *chunk, bool may_alloc)

static struct page **pcpu_get_pages(struct pcpu_chunk *chunk_alloc)

{

	static struct page **pages;

	size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]);



	if (!pages && may_alloc)

	lockdep_assert_held(&pcpu_alloc_mutex);



	if (!pages)

		pages = pcpu_mem_zalloc(pages_size);

	return pages;

}
@@ -287,7 +288,7 @@ static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size) 
	/* need to allocate and map pages, this chunk can't be immutable */

	WARN_ON(chunk->immutable);



	pages = pcpu_get_pages(chunk, true);

	pages = pcpu_get_pages(chunk);

	if (!pages)

		return -ENOMEM;
@@ -358,7 +359,7 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size) 
	 * successful population attempt so the temp pages array must

	 * be available now.

	 */

	pages = pcpu_get_pages(chunk, false);

	pages = pcpu_get_pages(chunk);

	BUG_ON(!pages);



	/* unmap and free */