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: Tejun Heo <tj@kernel.org>
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index 47b47bf..d9e0b61 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -22,21 +22,22 @@
/**
* 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 @@
/* 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 @@
* 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 */