This is a note to let you know that I've just added the patch titled
mm: introduce pmd_install() helper
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-introduce-pmd_install-helper.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ff6322441eedbfaa12d55c7d7024199b50945513
Author: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Date: Fri Nov 5 13:38:38 2021 -0700
mm: introduce pmd_install() helper
[ Upstream commit 03c4f20454e0231d2cdec4373841a3a25cf4efed ]
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@xxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20210901102722.47686-2-zhengqi.arch@xxxxxxxxxxxxx
Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Mika Penttila <mika.penttila@xxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Stable-dep-of: 9aa1345d66b8 ("mm: fix oops when filemap_map_pmd() without prealloc_pte")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/mm/filemap.c b/mm/filemap.c
index 81e28722edfaf..179eb8066c9b3 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3209,15 +3209,8 @@ 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 cf3cb933eba3f..6c3e1a9f8c5a6 100644
--- 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 1bb01b12db532..46fcc91604814 100644
--- 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;
@@ -4085,17 +4090,10 @@ 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;
- }
}
/*
