[PATCH 04/22] mm: use mm_is_kernel() in generic page table code
Kevin Brodsky
kevin.brodsky at arm.com
Tue Jul 14 07:03:53 PDT 2026
Generic page-table allocation, constructor and walker code uses
init_mm comparisons to select kernel page table handling. Use
mm_is_kernel() instead so kernel-owned mm's can share that handling
once they are marked with MMF_KERNEL.
No functional change as only init_mm has MMF_KERNEL set for now.
Assisted-by: Codex:GPT-5.5
Signed-off-by: Kevin Brodsky <kevin.brodsky at arm.com>
---
include/asm-generic/pgalloc.h | 16 ++++++++--------
include/linux/mm.h | 4 ++--
mm/memory.c | 6 +++---
mm/page_table_check.c | 14 +++++++-------
mm/pagewalk.c | 4 ++--
5 files changed, 22 insertions(+), 22 deletions(-)
diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h
index 051aa1331051..a283280e3140 100644
--- a/include/asm-generic/pgalloc.h
+++ b/include/asm-generic/pgalloc.h
@@ -138,7 +138,7 @@ static inline pmd_t *pmd_alloc_one_noprof(struct mm_struct *mm, unsigned long ad
struct ptdesc *ptdesc;
gfp_t gfp = GFP_PGTABLE_USER;
- if (mm == &init_mm)
+ if (mm_is_kernel(mm))
gfp = GFP_PGTABLE_KERNEL;
ptdesc = pagetable_alloc_noprof(gfp, 0);
if (!ptdesc)
@@ -148,7 +148,7 @@ static inline pmd_t *pmd_alloc_one_noprof(struct mm_struct *mm, unsigned long ad
return NULL;
}
- if (mm == &init_mm)
+ if (mm_is_kernel(mm))
ptdesc_set_kernel(ptdesc);
return ptdesc_address(ptdesc);
@@ -175,7 +175,7 @@ static inline pud_t *__pud_alloc_one_noprof(struct mm_struct *mm, unsigned long
gfp_t gfp = GFP_PGTABLE_USER;
struct ptdesc *ptdesc;
- if (mm == &init_mm)
+ if (mm_is_kernel(mm))
gfp = GFP_PGTABLE_KERNEL;
ptdesc = pagetable_alloc_noprof(gfp, 0);
@@ -184,7 +184,7 @@ static inline pud_t *__pud_alloc_one_noprof(struct mm_struct *mm, unsigned long
pagetable_pud_ctor(ptdesc);
- if (mm == &init_mm)
+ if (mm_is_kernel(mm))
ptdesc_set_kernel(ptdesc);
return ptdesc_address(ptdesc);
@@ -232,7 +232,7 @@ static inline p4d_t *__p4d_alloc_one_noprof(struct mm_struct *mm, unsigned long
gfp_t gfp = GFP_PGTABLE_USER;
struct ptdesc *ptdesc;
- if (mm == &init_mm)
+ if (mm_is_kernel(mm))
gfp = GFP_PGTABLE_KERNEL;
ptdesc = pagetable_alloc_noprof(gfp, 0);
@@ -241,7 +241,7 @@ static inline p4d_t *__p4d_alloc_one_noprof(struct mm_struct *mm, unsigned long
pagetable_p4d_ctor(ptdesc);
- if (mm == &init_mm)
+ if (mm_is_kernel(mm))
ptdesc_set_kernel(ptdesc);
return ptdesc_address(ptdesc);
@@ -279,7 +279,7 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order
gfp_t gfp = GFP_PGTABLE_USER;
struct ptdesc *ptdesc;
- if (mm == &init_mm)
+ if (mm_is_kernel(mm))
gfp = GFP_PGTABLE_KERNEL;
ptdesc = pagetable_alloc_noprof(gfp, order);
@@ -288,7 +288,7 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order
pagetable_pgd_ctor(ptdesc);
- if (mm == &init_mm)
+ if (mm_is_kernel(mm))
ptdesc_set_kernel(ptdesc);
return ptdesc_address(ptdesc);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7a4b8e7ac8f4..b336eb32faa0 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3818,7 +3818,7 @@ static inline void pagetable_dtor_free(struct ptdesc *ptdesc)
static inline bool pagetable_pte_ctor(struct mm_struct *mm,
struct ptdesc *ptdesc)
{
- if (mm != &init_mm && !ptlock_init(ptdesc))
+ if (!mm_is_kernel(mm) && !ptlock_init(ptdesc))
return false;
__pagetable_ctor(ptdesc);
return true;
@@ -3909,7 +3909,7 @@ static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
static inline bool pagetable_pmd_ctor(struct mm_struct *mm,
struct ptdesc *ptdesc)
{
- if (mm != &init_mm && !pmd_ptlock_init(ptdesc))
+ if (!mm_is_kernel(mm) && !pmd_ptlock_init(ptdesc))
return false;
ptdesc_pmd_pts_init(ptdesc);
__pagetable_ctor(ptdesc);
diff --git a/mm/memory.c b/mm/memory.c
index d5e87624f692..c0244c0b0756 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3394,13 +3394,13 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
spinlock_t *ptl;
if (create) {
- mapped_pte = pte = (mm == &init_mm) ?
+ mapped_pte = pte = mm_is_kernel(mm) ?
pte_alloc_kernel_track(pmd, addr, mask) :
pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
} else {
- mapped_pte = pte = (mm == &init_mm) ?
+ mapped_pte = pte = mm_is_kernel(mm) ?
pte_offset_kernel(pmd, addr) :
pte_offset_map_lock(mm, pmd, addr, &ptl);
if (!pte)
@@ -3422,7 +3422,7 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
lazy_mmu_mode_disable();
- if (mm != &init_mm)
+ if (!mm_is_kernel(mm))
pte_unmap_unlock(mapped_pte, ptl);
return err;
}
diff --git a/mm/page_table_check.c b/mm/page_table_check.c
index 3fb995e5d40d..a5382c245b32 100644
--- a/mm/page_table_check.c
+++ b/mm/page_table_check.c
@@ -148,7 +148,7 @@ void __page_table_check_zero(struct page *page, unsigned int order)
void __page_table_check_pte_clear(struct mm_struct *mm, unsigned long addr,
pte_t pte)
{
- if (&init_mm == mm)
+ if (mm_is_kernel(mm))
return;
if (pte_user_accessible_page(mm, addr, pte))
@@ -159,7 +159,7 @@ EXPORT_SYMBOL(__page_table_check_pte_clear);
void __page_table_check_pmd_clear(struct mm_struct *mm, unsigned long addr,
pmd_t pmd)
{
- if (&init_mm == mm)
+ if (mm_is_kernel(mm))
return;
if (pmd_user_accessible_page(mm, addr, pmd))
@@ -170,7 +170,7 @@ EXPORT_SYMBOL(__page_table_check_pmd_clear);
void __page_table_check_pud_clear(struct mm_struct *mm, unsigned long addr,
pud_t pud)
{
- if (&init_mm == mm)
+ if (mm_is_kernel(mm))
return;
if (pud_user_accessible_page(mm, addr, pud))
@@ -201,7 +201,7 @@ void __page_table_check_ptes_set(struct mm_struct *mm, unsigned long addr,
{
unsigned int i;
- if (&init_mm == mm)
+ if (mm_is_kernel(mm))
return;
page_table_check_pte_flags(pte);
@@ -231,7 +231,7 @@ void __page_table_check_pmds_set(struct mm_struct *mm, unsigned long addr,
unsigned long stride = PMD_SIZE >> PAGE_SHIFT;
unsigned int i;
- if (&init_mm == mm)
+ if (mm_is_kernel(mm))
return;
page_table_check_pmd_flags(pmd);
@@ -249,7 +249,7 @@ void __page_table_check_puds_set(struct mm_struct *mm, unsigned long addr,
unsigned long stride = PUD_SIZE >> PAGE_SHIFT;
unsigned int i;
- if (&init_mm == mm)
+ if (mm_is_kernel(mm))
return;
for (i = 0; i < nr; i++)
@@ -263,7 +263,7 @@ void __page_table_check_pte_clear_range(struct mm_struct *mm,
unsigned long addr,
pmd_t pmd)
{
- if (&init_mm == mm)
+ if (mm_is_kernel(mm))
return;
if (!pmd_bad(pmd) && !pmd_leaf(pmd)) {
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index ed4860c01936..a3f47d1de3c5 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -72,13 +72,13 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
* fit its pmd_bad() check (_PAGE_NX set and _PAGE_RW clear),
* and CONFIG_EFI_PGT_DUMP efi_mm goes so far as to walk them.
*/
- if (walk->mm == &init_mm || addr >= TASK_SIZE)
+ if (mm_is_kernel(walk->mm) || addr >= TASK_SIZE)
pte = pte_offset_kernel(pmd, addr);
else
pte = pte_offset_map(pmd, addr);
if (pte) {
err = walk_pte_range_inner(pte, addr, end, walk);
- if (walk->mm != &init_mm && addr < TASK_SIZE)
+ if (!mm_is_kernel(walk->mm) && addr < TASK_SIZE)
pte_unmap(pte);
}
} else {
--
2.51.2
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