Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
   F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X
   bit.

 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.

 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes

 - Johannes Weiner has a series ("mm: push down lock_page_memcg()")
   which does perform some memcg maintenance and cleanup work.

 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".

   These filters provide users with finer-grained control over DAMOS's
   actions. SeongJae has also done some DAMON cleanup work.

 - Kairui Song adds a series ("Clean up and fixes for swap").

 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".

 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.

 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".

 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".

 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".

 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".

 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series
   "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
   swap PTEs".

 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".

 - Sergey Senozhatsky has improved zsmalloc's memory utilization with
   his series "zsmalloc: make zspage chain size configurable".

 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.

   The previous BPF-based approach had shortcomings. See "mm: In-kernel
   support for memory-deny-write-execute (MDWE)".

 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".

 - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".

 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a
   per-node basis. See the series "Introduce per NUMA node memory error
   statistics".

 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage
   during compaction".

 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".

 - Christoph Hellwig has removed block_device_operations.rw_page() in
   ths series "remove ->rw_page".

 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".

 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier
   functions".

 - Some pagemap cleanup and generalization work in Mike Rapoport's
   series "mm, arch: add generic implementation of pfn_valid() for
   FLATMEM" and "fixups for generic implementation of pfn_valid()"

 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".

 - Jason Gunthorpe rationalized the GUP system's interface to the rest
   of the kernel in the series "Simplify the external interface for
   GUP".

 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface. To support this, we'll temporarily be
   printing warnings when people use the debugfs interface. See the
   series "mm/damon: deprecate DAMON debugfs interface".

 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.

 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".

 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".

* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
  include/linux/migrate.h: remove unneeded externs
  mm/memory_hotplug: cleanup return value handing in do_migrate_range()
  mm/uffd: fix comment in handling pte markers
  mm: change to return bool for isolate_movable_page()
  mm: hugetlb: change to return bool for isolate_hugetlb()
  mm: change to return bool for isolate_lru_page()
  mm: change to return bool for folio_isolate_lru()
  objtool: add UACCESS exceptions for __tsan_volatile_read/write
  kmsan: disable ftrace in kmsan core code
  kasan: mark addr_has_metadata __always_inline
  mm: memcontrol: rename memcg_kmem_enabled()
  sh: initialize max_mapnr
  m68k/nommu: add missing definition of ARCH_PFN_OFFSET
  mm: percpu: fix incorrect size in pcpu_obj_full_size()
  maple_tree: reduce stack usage with gcc-9 and earlier
  mm: page_alloc: call panic() when memoryless node allocation fails
  mm: multi-gen LRU: avoid futile retries
  migrate_pages: move THP/hugetlb migration support check to simplify code
  migrate_pages: batch flushing TLB
  migrate_pages: share more code between _unmap and _move
  ...

1 files changed, 110 insertions, 76 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index af8119776ab1..0722859c3647 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -140,30 +140,6 @@ struct page {
 		};
 		struct {	/* Tail pages of compound page */
 			unsigned long compound_head;	/* Bit zero is set */
-
-			/* First tail page only */
-			unsigned char compound_dtor;
-			unsigned char compound_order;
-			atomic_t compound_mapcount;
-			atomic_t subpages_mapcount;
-			atomic_t compound_pincount;
-#ifdef CONFIG_64BIT
-			unsigned int compound_nr; /* 1 << compound_order */
-#endif
-		};
-		struct {	/* Second tail page of transparent huge page */
-			unsigned long _compound_pad_1;	/* compound_head */
-			unsigned long _compound_pad_2;
-			/* For both global and memcg */
-			struct list_head deferred_list;
-		};
-		struct {	/* Second tail page of hugetlb page */
-			unsigned long _hugetlb_pad_1;	/* compound_head */
-			void *hugetlb_subpool;
-			void *hugetlb_cgroup;
-			void *hugetlb_cgroup_rsvd;
-			void *hugetlb_hwpoison;
-			/* No more space on 32-bit: use third tail if more */
 		};
 		struct {	/* Page table pages */
 			unsigned long _pt_pad_1;	/* compound_head */
@@ -302,20 +278,17 @@ static inline struct page *encoded_page_ptr(struct encoded_page *page)
  * @_refcount: Do not access this member directly.  Use folio_ref_count()
  *    to find how many references there are to this folio.
  * @memcg_data: Memory Control Group data.
- * @_flags_1: For large folios, additional page flags.
- * @_head_1: Points to the folio.  Do not use.
  * @_folio_dtor: Which destructor to use for this folio.
  * @_folio_order: Do not use directly, call folio_order().
- * @_compound_mapcount: Do not use directly, call folio_entire_mapcount().
- * @_subpages_mapcount: Do not use directly, call folio_mapcount().
+ * @_entire_mapcount: Do not use directly, call folio_entire_mapcount().
+ * @_nr_pages_mapped: Do not use directly, call folio_mapcount().
  * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
  * @_folio_nr_pages: Do not use directly, call folio_nr_pages().
- * @_flags_2: For alignment.  Do not use.
- * @_head_2: Points to the folio.  Do not use.
  * @_hugetlb_subpool: Do not use directly, use accessor in hugetlb.h.
  * @_hugetlb_cgroup: Do not use directly, use accessor in hugetlb_cgroup.h.
  * @_hugetlb_cgroup_rsvd: Do not use directly, use accessor in hugetlb_cgroup.h.
  * @_hugetlb_hwpoison: Do not use directly, call raw_hwp_list_head().
+ * @_deferred_list: Folios to be split under memory pressure.
  *
  * A folio is a physically, virtually and logically contiguous set
  * of bytes.  It is a power-of-two in size, and it is aligned to that
@@ -358,14 +331,16 @@ struct folio {
 		struct {
 			unsigned long _flags_1;
 			unsigned long _head_1;
+	/* public: */
 			unsigned char _folio_dtor;
 			unsigned char _folio_order;
-			atomic_t _compound_mapcount;
-			atomic_t _subpages_mapcount;
+			atomic_t _entire_mapcount;
+			atomic_t _nr_pages_mapped;
 			atomic_t _pincount;
 #ifdef CONFIG_64BIT
 			unsigned int _folio_nr_pages;
 #endif
+	/* private: the union with struct page is transitional */
 		};
 		struct page __page_1;
 	};
@@ -373,10 +348,19 @@ struct folio {
 		struct {
 			unsigned long _flags_2;
 			unsigned long _head_2;
+	/* public: */
 			void *_hugetlb_subpool;
 			void *_hugetlb_cgroup;
 			void *_hugetlb_cgroup_rsvd;
 			void *_hugetlb_hwpoison;
+	/* private: the union with struct page is transitional */
+		};
+		struct {
+			unsigned long _flags_2a;
+			unsigned long _head_2a;
+	/* public: */
+			struct list_head _deferred_list;
+	/* private: the union with struct page is transitional */
 		};
 		struct page __page_2;
 	};
@@ -401,53 +385,14 @@ FOLIO_MATCH(memcg_data, memcg_data);
 			offsetof(struct page, pg) + sizeof(struct page))
 FOLIO_MATCH(flags, _flags_1);
 FOLIO_MATCH(compound_head, _head_1);
-FOLIO_MATCH(compound_dtor, _folio_dtor);
-FOLIO_MATCH(compound_order, _folio_order);
-FOLIO_MATCH(compound_mapcount, _compound_mapcount);
-FOLIO_MATCH(subpages_mapcount, _subpages_mapcount);
-FOLIO_MATCH(compound_pincount, _pincount);
-#ifdef CONFIG_64BIT
-FOLIO_MATCH(compound_nr, _folio_nr_pages);
-#endif
 #undef FOLIO_MATCH
 #define FOLIO_MATCH(pg, fl)						\
 	static_assert(offsetof(struct folio, fl) ==			\
 			offsetof(struct page, pg) + 2 * sizeof(struct page))
 FOLIO_MATCH(flags, _flags_2);
 FOLIO_MATCH(compound_head, _head_2);
-FOLIO_MATCH(hugetlb_subpool, _hugetlb_subpool);
-FOLIO_MATCH(hugetlb_cgroup, _hugetlb_cgroup);
-FOLIO_MATCH(hugetlb_cgroup_rsvd, _hugetlb_cgroup_rsvd);
-FOLIO_MATCH(hugetlb_hwpoison, _hugetlb_hwpoison);
 #undef FOLIO_MATCH
 
-static inline atomic_t *folio_mapcount_ptr(struct folio *folio)
-{
-	struct page *tail = &folio->page + 1;
-	return &tail->compound_mapcount;
-}
-
-static inline atomic_t *folio_subpages_mapcount_ptr(struct folio *folio)
-{
-	struct page *tail = &folio->page + 1;
-	return &tail->subpages_mapcount;
-}
-
-static inline atomic_t *compound_mapcount_ptr(struct page *page)
-{
-	return &page[1].compound_mapcount;
-}
-
-static inline atomic_t *subpages_mapcount_ptr(struct page *page)
-{
-	return &page[1].subpages_mapcount;
-}
-
-static inline atomic_t *compound_pincount_ptr(struct page *page)
-{
-	return &page[1].compound_pincount;
-}
-
 /*
  * Used for sizing the vmemmap region on some architectures
  */
@@ -546,7 +491,15 @@ struct vm_area_struct {
 	 * See vmf_insert_mixed_prot() for discussion.
 	 */
 	pgprot_t vm_page_prot;
-	unsigned long vm_flags;		/* Flags, see mm.h. */
+
+	/*
+	 * Flags, see mm.h.
+	 * To modify use vm_flags_{init|reset|set|clear|mod} functions.
+	 */
+	union {
+		const vm_flags_t vm_flags;
+		vm_flags_t __private __vm_flags;
+	};
 
 	/*
 	 * For areas with an address space and backing store,
@@ -658,7 +611,7 @@ struct mm_struct {
 		raw_spinlock_t cid_lock;
 #endif
 #ifdef CONFIG_MMU
-		atomic_long_t pgtables_bytes;	/* PTE page table pages */
+		atomic_long_t pgtables_bytes;	/* size of all page tables */
 #endif
 		int map_count;			/* number of VMAs */
 
@@ -915,9 +868,7 @@ struct vma_iterator {
 static inline void vma_iter_init(struct vma_iterator *vmi,
 		struct mm_struct *mm, unsigned long addr)
 {
-	vmi->mas.tree = &mm->mm_mt;
-	vmi->mas.index = addr;
-	vmi->mas.node = MAS_START;
+	mas_init(&vmi->mas, &mm->mm_mt, addr);
 }
 
 #ifdef CONFIG_SCHED_MM_CID
@@ -1126,4 +1077,87 @@ enum fault_flag {
 
 typedef unsigned int __bitwise zap_flags_t;
 
+/*
+ * FOLL_PIN and FOLL_LONGTERM may be used in various combinations with each
+ * other. Here is what they mean, and how to use them:
+ *
+ *
+ * FIXME: For pages which are part of a filesystem, mappings are subject to the
+ * lifetime enforced by the filesystem and we need guarantees that longterm
+ * users like RDMA and V4L2 only establish mappings which coordinate usage with
+ * the filesystem.  Ideas for this coordination include revoking the longterm
+ * pin, delaying writeback, bounce buffer page writeback, etc.  As FS DAX was
+ * added after the problem with filesystems was found FS DAX VMAs are
+ * specifically failed.  Filesystem pages are still subject to bugs and use of
+ * FOLL_LONGTERM should be avoided on those pages.
+ *
+ * In the CMA case: long term pins in a CMA region would unnecessarily fragment
+ * that region.  And so, CMA attempts to migrate the page before pinning, when
+ * FOLL_LONGTERM is specified.
+ *
+ * FOLL_PIN indicates that a special kind of tracking (not just page->_refcount,
+ * but an additional pin counting system) will be invoked. This is intended for
+ * anything that gets a page reference and then touches page data (for example,
+ * Direct IO). This lets the filesystem know that some non-file-system entity is
+ * potentially changing the pages' data. In contrast to FOLL_GET (whose pages
+ * are released via put_page()), FOLL_PIN pages must be released, ultimately, by
+ * a call to unpin_user_page().
+ *
+ * FOLL_PIN is similar to FOLL_GET: both of these pin pages. They use different
+ * and separate refcounting mechanisms, however, and that means that each has
+ * its own acquire and release mechanisms:
+ *
+ *     FOLL_GET: get_user_pages*() to acquire, and put_page() to release.
+ *
+ *     FOLL_PIN: pin_user_pages*() to acquire, and unpin_user_pages to release.
+ *
+ * FOLL_PIN and FOLL_GET are mutually exclusive for a given function call.
+ * (The underlying pages may experience both FOLL_GET-based and FOLL_PIN-based
+ * calls applied to them, and that's perfectly OK. This is a constraint on the
+ * callers, not on the pages.)
+ *
+ * FOLL_PIN should be set internally by the pin_user_pages*() APIs, never
+ * directly by the caller. That's in order to help avoid mismatches when
+ * releasing pages: get_user_pages*() pages must be released via put_page(),
+ * while pin_user_pages*() pages must be released via unpin_user_page().
+ *
+ * Please see Documentation/core-api/pin_user_pages.rst for more information.
+ */
+
+enum {
+	/* check pte is writable */
+	FOLL_WRITE = 1 << 0,
+	/* do get_page on page */
+	FOLL_GET = 1 << 1,
+	/* give error on hole if it would be zero */
+	FOLL_DUMP = 1 << 2,
+	/* get_user_pages read/write w/o permission */
+	FOLL_FORCE = 1 << 3,
+	/*
+	 * if a disk transfer is needed, start the IO and return without waiting
+	 * upon it
+	 */
+	FOLL_NOWAIT = 1 << 4,
+	/* do not fault in pages */
+	FOLL_NOFAULT = 1 << 5,
+	/* check page is hwpoisoned */
+	FOLL_HWPOISON = 1 << 6,
+	/* don't do file mappings */
+	FOLL_ANON = 1 << 7,
+	/*
+	 * FOLL_LONGTERM indicates that the page will be held for an indefinite
+	 * time period _often_ under userspace control.  This is in contrast to
+	 * iov_iter_get_pages(), whose usages are transient.
+	 */
+	FOLL_LONGTERM = 1 << 8,
+	/* split huge pmd before returning */
+	FOLL_SPLIT_PMD = 1 << 9,
+	/* allow returning PCI P2PDMA pages */
+	FOLL_PCI_P2PDMA = 1 << 10,
+	/* allow interrupts from generic signals */
+	FOLL_INTERRUPTIBLE = 1 << 11,
+
+	/* See also internal only FOLL flags in mm/internal.h */
+};
+
 #endif /* _LINUX_MM_TYPES_H */