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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>
This commit is contained in:
Tejun Heo 2014-09-02 14:46:01 -04:00
parent fbbb7f4e14
commit cdb4cba5a3
1 changed files with 8 additions and 7 deletions
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15
mm/percpu-vm.c
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@ -22,21 +22,22 @@ static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk,
/** /**
* pcpu_get_pages - get temp pages array * pcpu_get_pages - get temp pages array
* @chunk: chunk of interest * @chunk: chunk of interest
* @may_alloc: may allocate the array
* *
* Returns pointer to array of pointers to struct page which can be indexed * 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 * with pcpu_page_idx(). Note that there is only one array and accesses
* exclusion is the caller's responsibility. * should be serialized by pcpu_alloc_mutex.
* *
* RETURNS: * RETURNS:
* Pointer to temp pages array on success. * 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; static struct page **pages;
size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]); 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); pages = pcpu_mem_zalloc(pages_size);
return pages; 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 */ /* need to allocate and map pages, this chunk can't be immutable */
WARN_ON(chunk->immutable); WARN_ON(chunk->immutable);
pages = pcpu_get_pages(chunk, true); pages = pcpu_get_pages(chunk);
if (!pages) if (!pages)
return -ENOMEM; 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 * successful population attempt so the temp pages array must
* be available now. * be available now.
*/ */
pages = pcpu_get_pages(chunk, false); pages = pcpu_get_pages(chunk);
BUG_ON(!pages); BUG_ON(!pages);
/* unmap and free */ /* unmap and free */