[RFC PATCH 05/14] mm/slub: create folio_set/clear_slab helpers

[Matteo Rizzo]

From: Jann Horn <ja...@google.com>

This is refactoring in preparation for SLAB_VIRTUAL. Extract this code
to separate functions so that it's not duplicated in the code that
allocates and frees page with SLAB_VIRTUAL enabled.

Signed-off-by: Jann Horn <ja...@google.com>
Co-developed-by: Matteo Rizzo <matteori...@google.com>
Signed-off-by: Matteo Rizzo <matteori...@google.com>
---
 mm/slub.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index ad33d9e1601d..9b87afade125 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1849,6 +1849,26 @@ static void *setup_object(struct kmem_cache *s, void 
*object)
 /*
  * Slab allocation and freeing
  */
+
+static void folio_set_slab(struct folio *folio, struct slab *slab)
+{
+       __folio_set_slab(folio);
+       /* Make the flag visible before any changes to folio->mapping */
+       smp_wmb();
+
+       if (folio_is_pfmemalloc(folio))
+               slab_set_pfmemalloc(slab);
+}
+
+static void folio_clear_slab(struct folio *folio, struct slab *slab)
+{
+       __slab_clear_pfmemalloc(slab);
+       folio->mapping = NULL;
+       /* Make the mapping reset visible before clearing the flag */
+       smp_wmb();
+       __folio_clear_slab(folio);
+}
+
 static inline struct slab *alloc_slab_page(gfp_t flags, int node,
                struct kmem_cache_order_objects oo)
 {
@@ -1865,11 +1885,7 @@ static inline struct slab *alloc_slab_page(gfp_t flags, 
int node,
                return NULL;
 
        slab = folio_slab(folio);
-       __folio_set_slab(folio);
-       /* Make the flag visible before any changes to folio->mapping */
-       smp_wmb();
-       if (folio_is_pfmemalloc(folio))
-               slab_set_pfmemalloc(slab);
+       folio_set_slab(folio, slab);
 
        return slab;
 }
@@ -2067,11 +2083,7 @@ static void __free_slab(struct kmem_cache *s, struct 
slab *slab)
        int order = folio_order(folio);
        int pages = 1 << order;
 
-       __slab_clear_pfmemalloc(slab);
-       folio->mapping = NULL;
-       /* Make the mapping reset visible before clearing the flag */
-       smp_wmb();
-       __folio_clear_slab(folio);
+       folio_clear_slab(folio, slab);
        mm_account_reclaimed_pages(pages);
        unaccount_slab(slab, order, s);
        __free_pages(&folio->page, order);
-- 
2.42.0.459.ge4e396fd5e-goog