percpu: move common parts out of pcpu_[de]populate_chunk()

percpu-vm and percpu-km implement separate versions of
pcpu_[de]populate_chunk() and some part which is or should be common
are currently in the specific implementations.  Make the following
changes.

* Allocate area clearing is moved from the pcpu_populate_chunk()
  implementations to pcpu_alloc().  This makes percpu-km's version
  noop.

* Quick exit tests in pcpu_[de]populate_chunk() of percpu-vm are moved
  to their respective callers so that they are applied to percpu-km
  too.  This doesn't make any meaningful difference as both functions
  are noop for percpu-km; however, this is more consistent and will
  help implementing atomic allocation support.

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 1 insertions, 26 deletions

diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index d9e0b615492e..edf709793318 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -265,7 +265,7 @@ static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
  * @size: size of the area to populate in bytes
  *
  * For each cpu, populate and map pages [@page_start,@page_end) into
- * @chunk.  The area is cleared on return.
+ * @chunk.
  *
  * CONTEXT:
  * pcpu_alloc_mutex, does GFP_KERNEL allocation.
@@ -276,18 +276,8 @@ static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
         int page_end = PFN_UP(off + size);
         int free_end = page_start, unmap_end = page_start;
         struct page **pages;
-        unsigned int cpu;
         int rs, re, rc;
 
-        /* quick path, check whether all pages are already there */
-        rs = page_start;
-        pcpu_next_pop(chunk, &rs, &re, page_end);
-        if (rs == page_start && re == page_end)
-                goto clear;
-
-        /* need to allocate and map pages, this chunk can't be immutable */
-        WARN_ON(chunk->immutable);
-
         pages = pcpu_get_pages(chunk);
         if (!pages)
                 return -ENOMEM;
@@ -308,10 +298,6 @@ static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
         }
         pcpu_post_map_flush(chunk, page_start, page_end);
 
-        bitmap_set(chunk->populated, page_start, page_end - page_start);
-clear:
-        for_each_possible_cpu(cpu)
-                memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
         return 0;
 
 err_unmap:
@@ -345,15 +331,6 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
         struct page **pages;
         int rs, re;
 
-        /* quick path, check whether it's empty already */
-        rs = page_start;
-        pcpu_next_unpop(chunk, &rs, &re, page_end);
-        if (rs == page_start && re == page_end)
-                return;
-
-        /* immutable chunks can't be depopulated */
-        WARN_ON(chunk->immutable);
-
         /*
          * If control reaches here, there must have been at least one
          * successful population attempt so the temp pages array must
@@ -372,8 +349,6 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
 
         pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
                 pcpu_free_pages(chunk, pages, rs, re);
-
-        bitmap_clear(chunk->populated, page_start, page_end - page_start);
 }
 
 static struct pcpu_chunk *pcpu_create_chunk(void)