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, 89 insertions, 20 deletions

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 9ab9d3105d5c..7c977d234aba 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_HUGETLB_H
 #define _LINUX_HUGETLB_H
 
+#include <linux/mm.h>
 #include <linux/mm_types.h>
 #include <linux/mmdebug.h>
 #include <linux/fs.h>
@@ -170,11 +171,11 @@ bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
 						vm_flags_t vm_flags);
 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
 						long freed);
-int isolate_hugetlb(struct page *page, struct list_head *list);
-int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison);
+bool isolate_hugetlb(struct folio *folio, struct list_head *list);
+int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison);
 int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 				bool *migratable_cleared);
-void putback_active_hugepage(struct page *page);
+void folio_putback_active_hugetlb(struct folio *folio);
 void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason);
 void free_huge_page(struct page *page);
 void hugetlb_fix_reserve_counts(struct inode *inode);
@@ -193,6 +194,43 @@ extern struct list_head huge_boot_pages;
 
 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
 			unsigned long addr, unsigned long sz);
+/*
+ * huge_pte_offset(): Walk the hugetlb pgtable until the last level PTE.
+ * Returns the pte_t* if found, or NULL if the address is not mapped.
+ *
+ * IMPORTANT: we should normally not directly call this function, instead
+ * this is only a common interface to implement arch-specific
+ * walker. Please use hugetlb_walk() instead, because that will attempt to
+ * verify the locking for you.
+ *
+ * Since this function will walk all the pgtable pages (including not only
+ * high-level pgtable page, but also PUD entry that can be unshared
+ * concurrently for VM_SHARED), the caller of this function should be
+ * responsible of its thread safety.  One can follow this rule:
+ *
+ *  (1) For private mappings: pmd unsharing is not possible, so holding the
+ *      mmap_lock for either read or write is sufficient. Most callers
+ *      already hold the mmap_lock, so normally, no special action is
+ *      required.
+ *
+ *  (2) For shared mappings: pmd unsharing is possible (so the PUD-ranged
+ *      pgtable page can go away from under us!  It can be done by a pmd
+ *      unshare with a follow up munmap() on the other process), then we
+ *      need either:
+ *
+ *     (2.1) hugetlb vma lock read or write held, to make sure pmd unshare
+ *           won't happen upon the range (it also makes sure the pte_t we
+ *           read is the right and stable one), or,
+ *
+ *     (2.2) hugetlb mapping i_mmap_rwsem lock held read or write, to make
+ *           sure even if unshare happened the racy unmap() will wait until
+ *           i_mmap_rwsem is released.
+ *
+ * Option (2.1) is the safest, which guarantees pte stability from pmd
+ * sharing pov, until the vma lock released.  Option (2.2) doesn't protect
+ * a concurrent pmd unshare, but it makes sure the pgtable page is safe to
+ * access.
+ */
 pte_t *huge_pte_offset(struct mm_struct *mm,
 		       unsigned long addr, unsigned long sz);
 unsigned long hugetlb_mask_last_page(struct hstate *h);
@@ -211,7 +249,7 @@ void hugetlb_vma_lock_release(struct kref *kref);
 
 int pmd_huge(pmd_t pmd);
 int pud_huge(pud_t pud);
-unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
+long hugetlb_change_protection(struct vm_area_struct *vma,
 		unsigned long address, unsigned long end, pgprot_t newprot,
 		unsigned long cp_flags);
 
@@ -375,12 +413,12 @@ static inline pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr,
 	return NULL;
 }
 
-static inline int isolate_hugetlb(struct page *page, struct list_head *list)
+static inline bool isolate_hugetlb(struct folio *folio, struct list_head *list)
 {
-	return -EBUSY;
+	return false;
 }
 
-static inline int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison)
+static inline int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison)
 {
 	return 0;
 }
@@ -391,7 +429,7 @@ static inline int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
 	return 0;
 }
 
-static inline void putback_active_hugepage(struct page *page)
+static inline void folio_putback_active_hugetlb(struct folio *folio)
 {
 }
 
@@ -400,7 +438,7 @@ static inline void move_hugetlb_state(struct folio *old_folio,
 {
 }
 
-static inline unsigned long hugetlb_change_protection(
+static inline long hugetlb_change_protection(
 			struct vm_area_struct *vma, unsigned long address,
 			unsigned long end, pgprot_t newprot,
 			unsigned long cp_flags)
@@ -679,16 +717,16 @@ struct huge_bootmem_page {
 };
 
 int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list);
-struct page *alloc_huge_page(struct vm_area_struct *vma,
+struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
 				unsigned long addr, int avoid_reserve);
-struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
+struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid,
 				nodemask_t *nmask, gfp_t gfp_mask);
-struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
+struct folio *alloc_hugetlb_folio_vma(struct hstate *h, struct vm_area_struct *vma,
 				unsigned long address);
-int hugetlb_add_to_page_cache(struct page *page, struct address_space *mapping,
+int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping,
 			pgoff_t idx);
 void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
-				unsigned long address, struct page *page);
+				unsigned long address, struct folio *folio);
 
 /* arch callback */
 int __init __alloc_bootmem_huge_page(struct hstate *h, int nid);
@@ -843,9 +881,9 @@ extern int dissolve_free_huge_pages(unsigned long start_pfn,
 				    unsigned long end_pfn);
 
 #ifdef CONFIG_MEMORY_FAILURE
-extern void hugetlb_clear_page_hwpoison(struct page *hpage);
+extern void folio_clear_hugetlb_hwpoison(struct folio *folio);
 #else
-static inline void hugetlb_clear_page_hwpoison(struct page *hpage)
+static inline void folio_clear_hugetlb_hwpoison(struct folio *folio)
 {
 }
 #endif
@@ -998,21 +1036,21 @@ static inline int isolate_or_dissolve_huge_page(struct page *page,
 	return -ENOMEM;
 }
 
-static inline struct page *alloc_huge_page(struct vm_area_struct *vma,
+static inline struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma,
 					   unsigned long addr,
 					   int avoid_reserve)
 {
 	return NULL;
 }
 
-static inline struct page *
-alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
+static inline struct folio *
+alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid,
 			nodemask_t *nmask, gfp_t gfp_mask)
 {
 	return NULL;
 }
 
-static inline struct page *alloc_huge_page_vma(struct hstate *h,
+static inline struct folio *alloc_hugetlb_folio_vma(struct hstate *h,
 					       struct vm_area_struct *vma,
 					       unsigned long address)
 {
@@ -1213,4 +1251,35 @@ bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr);
 #define flush_hugetlb_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
 #endif
 
+static inline bool __vma_shareable_lock(struct vm_area_struct *vma)
+{
+	return (vma->vm_flags & VM_MAYSHARE) && vma->vm_private_data;
+}
+
+/*
+ * Safe version of huge_pte_offset() to check the locks.  See comments
+ * above huge_pte_offset().
+ */
+static inline pte_t *
+hugetlb_walk(struct vm_area_struct *vma, unsigned long addr, unsigned long sz)
+{
+#if defined(CONFIG_HUGETLB_PAGE) && \
+	defined(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) && defined(CONFIG_LOCKDEP)
+	struct hugetlb_vma_lock *vma_lock = vma->vm_private_data;
+
+	/*
+	 * If pmd sharing possible, locking needed to safely walk the
+	 * hugetlb pgtables.  More information can be found at the comment
+	 * above huge_pte_offset() in the same file.
+	 *
+	 * NOTE: lockdep_is_held() is only defined with CONFIG_LOCKDEP.
+	 */
+	if (__vma_shareable_lock(vma))
+		WARN_ON_ONCE(!lockdep_is_held(&vma_lock->rw_sema) &&
+			     !lockdep_is_held(
+				 &vma->vm_file->f_mapping->i_mmap_rwsem));
+#endif
+	return huge_pte_offset(vma->vm_mm, addr, sz);
+}
+
 #endif /* _LINUX_HUGETLB_H */