mm: introduce pmd_install() helper

Patch series "Do some code cleanups related to mm", v3.

This patch (of 2):

Currently we have three times the same few lines repeated in the code.
Deduplicate them by newly introduced pmd_install() helper.

Link: https://lkml.kernel.org/r/20210901102722.47686-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20210901102722.47686-2-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Mika Penttila <mika.penttila@nextfour.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/filemap.c b/mm/filemap.c
index 938f527..d05f801 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3211,15 +3211,8 @@ static bool filemap_map_pmd(struct vm_fault *vmf, struct page *page)
            }
        }
 
-       if (pmd_none(*vmf->pmd)) {
-               vmf->ptl = pmd_lock(mm, vmf->pmd);
-               if (likely(pmd_none(*vmf->pmd))) {
-                       mm_inc_nr_ptes(mm);
-                       pmd_populate(mm, vmf->pmd, vmf->prealloc_pte);
-                       vmf->prealloc_pte = NULL;
-               }
-               spin_unlock(vmf->ptl);
-       }
+       if (pmd_none(*vmf->pmd))
+               pmd_install(mm, vmf->pmd, &vmf->prealloc_pte);
 
        /* See comment in handle_pte_fault() */
        if (pmd_devmap_trans_unstable(vmf->pmd)) {

diff --git a/mm/internal.h b/mm/internal.h
index cf3cb93..6c3e1a9 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -38,6 +38,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf);
 
 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
                unsigned long floor, unsigned long ceiling);
+void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte);
 
 static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
 {

diff --git a/mm/memory.c b/mm/memory.c
index 48b2e04..38d63f6 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -433,9 +433,20 @@ void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
        }
 }
 
+void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte)
+{
+       spinlock_t *ptl = pmd_lock(mm, pmd);
+
+       if (likely(pmd_none(*pmd))) {   /* Has another populated it ? */
+               mm_inc_nr_ptes(mm);
+               pmd_populate(mm, pmd, *pte);
+               *pte = NULL;
+       }
+       spin_unlock(ptl);
+}
+
 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd)
 {
-       spinlock_t *ptl;
        pgtable_t new = pte_alloc_one(mm);
        if (!new)
                return -ENOMEM;
@@ -455,13 +466,7 @@ int __pte_alloc(struct mm_struct *mm, pmd_t *pmd)
         */
        smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
 
-       ptl = pmd_lock(mm, pmd);
-       if (likely(pmd_none(*pmd))) {   /* Has another populated it ? */
-               mm_inc_nr_ptes(mm);
-               pmd_populate(mm, pmd, new);
-               new = NULL;
-       }
-       spin_unlock(ptl);
+       pmd_install(mm, pmd, &new);
        if (new)
                pte_free(mm, new);
        return 0;
@@ -4024,17 +4029,10 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
                                return ret;
                }
 
-               if (vmf->prealloc_pte) {
-                       vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
-                       if (likely(pmd_none(*vmf->pmd))) {
-                               mm_inc_nr_ptes(vma->vm_mm);
-                               pmd_populate(vma->vm_mm, vmf->pmd, vmf->prealloc_pte);
-                               vmf->prealloc_pte = NULL;
-                       }
-                       spin_unlock(vmf->ptl);
-               } else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) {
+               if (vmf->prealloc_pte)
+                       pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte);
+               else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd)))
                        return VM_FAULT_OOM;
-               }
        }
 
        /* See comment in handle_pte_fault() */