Merge tag 'slab-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab updates from Vlastimil Babka:

 - Separate struct slab from struct page - an offshot of the page folio
   work.

   Struct page fields used by slab allocators are moved from struct page
   to a new struct slab, that uses the same physical storage. Similar to
   struct folio, it always is a head page. This brings better type
   safety, separation of large kmalloc allocations from true slabs, and
   cleanup of related objcg code.

 - A SLAB_MERGE_DEFAULT config optimization.

* tag 'slab-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (33 commits)
  mm/slob: Remove unnecessary page_mapcount_reset() function call
  bootmem: Use page->index instead of page->freelist
  zsmalloc: Stop using slab fields in struct page
  mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled
  mm/slub: Simplify struct slab slabs field definition
  mm/sl*b: Differentiate struct slab fields by sl*b implementations
  mm/kfence: Convert kfence_guarded_alloc() to struct slab
  mm/kasan: Convert to struct folio and struct slab
  mm/slob: Convert SLOB to use struct slab and struct folio
  mm/memcg: Convert slab objcgs from struct page to struct slab
  mm: Convert struct page to struct slab in functions used by other subsystems
  mm/slab: Finish struct page to struct slab conversion
  mm/slab: Convert most struct page to struct slab by spatch
  mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
  mm/slub: Finish struct page to struct slab conversion
  mm/slub: Convert most struct page to struct slab by spatch
  mm/slub: Convert pfmemalloc_match() to take a struct slab
  mm/slub: Convert __free_slab() to use struct slab
  mm/slub: Convert alloc_slab_page() to return a struct slab
  mm/slub: Convert print_page_info() to print_slab_info()
  ...

1 files changed, 7 insertions, 6 deletions

diff --git a/mm/usercopy.c b/mm/usercopy.c
index b3de3c4eefba..d0d268135d96 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -20,6 +20,7 @@
 #include <linux/atomic.h>
 #include <linux/jump_label.h>
 #include <asm/sections.h>
+#include "slab.h"
 
 /*
  * Checks if a given pointer and length is contained by the current
@@ -223,7 +224,7 @@ static inline void check_page_span(const void *ptr, unsigned long n,
 static inline void check_heap_object(const void *ptr, unsigned long n,
 				     bool to_user)
 {
-	struct page *page;
+	struct folio *folio;
 
 	if (!virt_addr_valid(ptr))
 		return;
@@ -231,16 +232,16 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
 	/*
 	 * When CONFIG_HIGHMEM=y, kmap_to_page() will give either the
 	 * highmem page or fallback to virt_to_page(). The following
-	 * is effectively a highmem-aware virt_to_head_page().
+	 * is effectively a highmem-aware virt_to_slab().
 	 */
-	page = compound_head(kmap_to_page((void *)ptr));
+	folio = page_folio(kmap_to_page((void *)ptr));
 
-	if (PageSlab(page)) {
+	if (folio_test_slab(folio)) {
 		/* Check slab allocator for flags and size. */
-		__check_heap_object(ptr, n, page, to_user);
+		__check_heap_object(ptr, n, folio_slab(folio), to_user);
 	} else {
 		/* Verify object does not incorrectly span multiple pages. */
-		check_page_span(ptr, n, page, to_user);
+		check_page_span(ptr, n, folio_page(folio, 0), to_user);
 	}
 }