mm: introduce mm_find_pmd()
Several place need to find the pmd by(mm_struct, address), so introduce a
function to simplify it.
[akpm@linux-foundation.org: fix warning]
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Ni zhan Chen <nizhan.chen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6f022f5..9ae9724 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1146,22 +1146,14 @@
unsigned long address,
enum page_check_address_pmd_flag flag)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd, *ret = NULL;
if (address & ~HPAGE_PMD_MASK)
goto out;
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
+ pmd = mm_find_pmd(mm, address);
+ if (!pmd)
goto out;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- goto out;
-
- pmd = pmd_offset(pud, address);
if (pmd_none(*pmd))
goto out;
if (pmd_page(*pmd) != page)
@@ -1908,8 +1900,6 @@
struct vm_area_struct *vma,
int node)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd, _pmd;
pte_t *pte;
pgtable_t pgtable;
@@ -1955,17 +1945,10 @@
goto out;
VM_BUG_ON(vma->vm_flags & VM_NO_THP);
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
+ pmd = mm_find_pmd(mm, address);
+ if (!pmd)
goto out;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- goto out;
-
- pmd = pmd_offset(pud, address);
- /* pmd can't go away or become huge under us */
- if (!pmd_present(*pmd) || pmd_trans_huge(*pmd))
+ if (pmd_trans_huge(*pmd))
goto out;
anon_vma_lock(vma->anon_vma);
@@ -2048,8 +2031,6 @@
unsigned long address,
struct page **hpage)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *pte, *_pte;
int ret = 0, referenced = 0, none = 0;
@@ -2060,16 +2041,10 @@
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
+ pmd = mm_find_pmd(mm, address);
+ if (!pmd)
goto out;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- goto out;
-
- pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd) || pmd_trans_huge(*pmd))
+ if (pmd_trans_huge(*pmd))
goto out;
pte = pte_offset_map_lock(mm, pmd, address, &ptl);
@@ -2363,22 +2338,12 @@
static void split_huge_page_address(struct mm_struct *mm,
unsigned long address)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
VM_BUG_ON(!(address & ~HPAGE_PMD_MASK));
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
- return;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- return;
-
- pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd))
+ pmd = mm_find_pmd(mm, address);
+ if (!pmd)
return;
/*
* Caller holds the mmap_sem write mode, so a huge pmd cannot
diff --git a/mm/internal.h b/mm/internal.h
index a4fa284..52d1fa9 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -92,6 +92,11 @@
extern void putback_lru_page(struct page *page);
/*
+ * in mm/rmap.c:
+ */
+extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
+
+/*
* in mm/page_alloc.c
*/
extern void __free_pages_bootmem(struct page *page, unsigned int order);
diff --git a/mm/ksm.c b/mm/ksm.c
index ae539f0..31ae5ea 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -778,8 +778,6 @@
struct page *kpage, pte_t orig_pte)
{
struct mm_struct *mm = vma->vm_mm;
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *ptep;
spinlock_t *ptl;
@@ -792,18 +790,10 @@
if (addr == -EFAULT)
goto out;
- pgd = pgd_offset(mm, addr);
- if (!pgd_present(*pgd))
+ pmd = mm_find_pmd(mm, addr);
+ if (!pmd)
goto out;
-
- pud = pud_offset(pgd, addr);
- if (!pud_present(*pud))
- goto out;
-
- pmd = pmd_offset(pud, addr);
BUG_ON(pmd_trans_huge(*pmd));
- if (!pmd_present(*pmd))
- goto out;
mmun_start = addr;
mmun_end = addr + PAGE_SIZE;
diff --git a/mm/migrate.c b/mm/migrate.c
index 77ed2d7..1dc4598 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -91,8 +91,6 @@
{
struct mm_struct *mm = vma->vm_mm;
swp_entry_t entry;
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *ptep, pte;
spinlock_t *ptl;
@@ -103,19 +101,11 @@
goto out;
ptl = &mm->page_table_lock;
} else {
- pgd = pgd_offset(mm, addr);
- if (!pgd_present(*pgd))
+ pmd = mm_find_pmd(mm, addr);
+ if (!pmd)
goto out;
-
- pud = pud_offset(pgd, addr);
- if (!pud_present(*pud))
- goto out;
-
- pmd = pmd_offset(pud, addr);
if (pmd_trans_huge(*pmd))
goto out;
- if (!pmd_present(*pmd))
- goto out;
ptep = pte_offset_map(pmd, addr);
diff --git a/mm/rmap.c b/mm/rmap.c
index 2ee1ef0..46823fb 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -562,6 +562,27 @@
return address;
}
+pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd = NULL;
+
+ pgd = pgd_offset(mm, address);
+ if (!pgd_present(*pgd))
+ goto out;
+
+ pud = pud_offset(pgd, address);
+ if (!pud_present(*pud))
+ goto out;
+
+ pmd = pmd_offset(pud, address);
+ if (!pmd_present(*pmd))
+ pmd = NULL;
+out:
+ return pmd;
+}
+
/*
* Check that @page is mapped at @address into @mm.
*
@@ -574,8 +595,6 @@
pte_t *__page_check_address(struct page *page, struct mm_struct *mm,
unsigned long address, spinlock_t **ptlp, int sync)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *pte;
spinlock_t *ptl;
@@ -586,17 +605,10 @@
goto check;
}
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
+ pmd = mm_find_pmd(mm, address);
+ if (!pmd)
return NULL;
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- return NULL;
-
- pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd))
- return NULL;
if (pmd_trans_huge(*pmd))
return NULL;
@@ -1345,8 +1357,6 @@
struct vm_area_struct *vma, struct page *check_page)
{
struct mm_struct *mm = vma->vm_mm;
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pte_t pteval;
@@ -1366,16 +1376,8 @@
if (end > vma->vm_end)
end = vma->vm_end;
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
- return ret;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- return ret;
-
- pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd))
+ pmd = mm_find_pmd(mm, address);
+ if (!pmd)
return ret;
mmun_start = address;