mm: simplify follow_invalidate_pte()

The only user (DAX) of range and pmdpp parameters of
follow_invalidate_pte() is gone, it is safe to remove them and make it
static to simlify the code.  This is revertant of the following commits:

  097963959594 ("mm: add follow_pte_pmd()")
  a4d1a8852513 ("dax: update to new mmu_notifier semantic")

There is only one caller of the follow_invalidate_pte().  So just fold it
into follow_pte() and remove it.

Link: https://lkml.kernel.org/r/20220403053957.10770-7-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d446e83..16d6b46 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1845,9 +1845,6 @@ void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
                unsigned long end, unsigned long floor, unsigned long ceiling);
 int
 copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma);
-int follow_invalidate_pte(struct mm_struct *mm, unsigned long address,
-                         struct mmu_notifier_range *range, pte_t **ptepp,
-                         pmd_t **pmdpp, spinlock_t **ptlp);
 int follow_pte(struct mm_struct *mm, unsigned long address,
               pte_t **ptepp, spinlock_t **ptlp);
 int follow_pfn(struct vm_area_struct *vma, unsigned long address,

diff --git a/mm/memory.c b/mm/memory.c
index 76e3af9..8895dd2 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4949,9 +4949,29 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-int follow_invalidate_pte(struct mm_struct *mm, unsigned long address,
-                         struct mmu_notifier_range *range, pte_t **ptepp,
-                         pmd_t **pmdpp, spinlock_t **ptlp)
+/**
+ * follow_pte - look up PTE at a user virtual address
+ * @mm: the mm_struct of the target address space
+ * @address: user virtual address
+ * @ptepp: location to store found PTE
+ * @ptlp: location to store the lock for the PTE
+ *
+ * On a successful return, the pointer to the PTE is stored in @ptepp;
+ * the corresponding lock is taken and its location is stored in @ptlp.
+ * The contents of the PTE are only stable until @ptlp is released;
+ * any further use, if any, must be protected against invalidation
+ * with MMU notifiers.
+ *
+ * Only IO mappings and raw PFN mappings are allowed.  The mmap semaphore
+ * should be taken for read.
+ *
+ * KVM uses this function.  While it is arguably less bad than ``follow_pfn``,
+ * it is not a good general-purpose API.
+ *
+ * Return: zero on success, -ve otherwise.
+ */
+int follow_pte(struct mm_struct *mm, unsigned long address,
+              pte_t **ptepp, spinlock_t **ptlp)
 {
        pgd_t *pgd;
        p4d_t *p4d;
@@ -4974,35 +4994,9 @@ int follow_invalidate_pte(struct mm_struct *mm, unsigned long address,
        pmd = pmd_offset(pud, address);
        VM_BUG_ON(pmd_trans_huge(*pmd));
 
-       if (pmd_huge(*pmd)) {
-               if (!pmdpp)
-                       goto out;
-
-               if (range) {
-                       mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0,
-                                               NULL, mm, address & PMD_MASK,
-                                               (address & PMD_MASK) + PMD_SIZE);
-                       mmu_notifier_invalidate_range_start(range);
-               }
-               *ptlp = pmd_lock(mm, pmd);
-               if (pmd_huge(*pmd)) {
-                       *pmdpp = pmd;
-                       return 0;
-               }
-               spin_unlock(*ptlp);
-               if (range)
-                       mmu_notifier_invalidate_range_end(range);
-       }
-
        if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
                goto out;
 
-       if (range) {
-               mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0, NULL, mm,
-                                       address & PAGE_MASK,
-                                       (address & PAGE_MASK) + PAGE_SIZE);
-               mmu_notifier_invalidate_range_start(range);
-       }
        ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
        if (!pte_present(*ptep))
                goto unlock;
@@ -5010,38 +5004,9 @@ int follow_invalidate_pte(struct mm_struct *mm, unsigned long address,
        return 0;
 unlock:
        pte_unmap_unlock(ptep, *ptlp);
-       if (range)
-               mmu_notifier_invalidate_range_end(range);
 out:
        return -EINVAL;
 }
-
-/**
- * follow_pte - look up PTE at a user virtual address
- * @mm: the mm_struct of the target address space
- * @address: user virtual address
- * @ptepp: location to store found PTE
- * @ptlp: location to store the lock for the PTE
- *
- * On a successful return, the pointer to the PTE is stored in @ptepp;
- * the corresponding lock is taken and its location is stored in @ptlp.
- * The contents of the PTE are only stable until @ptlp is released;
- * any further use, if any, must be protected against invalidation
- * with MMU notifiers.
- *
- * Only IO mappings and raw PFN mappings are allowed.  The mmap semaphore
- * should be taken for read.
- *
- * KVM uses this function.  While it is arguably less bad than ``follow_pfn``,
- * it is not a good general-purpose API.
- *
- * Return: zero on success, -ve otherwise.
- */
-int follow_pte(struct mm_struct *mm, unsigned long address,
-              pte_t **ptepp, spinlock_t **ptlp)
-{
-       return follow_invalidate_pte(mm, address, NULL, ptepp, NULL, ptlp);
-}
 EXPORT_SYMBOL_GPL(follow_pte);
 
 /**