[PATCH v1 2/4] mm: Cleanup apply_to_pte_range() routine

Alexander Gordeev
2025-04-07T15:12:17Z

Reverse 'create' vs 'mm == &init_mm' conditions and move
page table mask modification out of the atomic context.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
---
mm/memory.c | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 2d8c265fc7d6..f0201c8ec1ce 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2915,24 +2915,28 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
pte_fn_t fn, void *data, bool create,
pgtbl_mod_mask *mask)
{
+ int err = create ? -ENOMEM : -EINVAL;
pte_t *pte, *mapped_pte;
- int err = 0;
spinlock_t *ptl;

- if (create) {
- mapped_pte = pte = (mm == &init_mm) ?
- pte_alloc_kernel_track(pmd, addr, mask) :
- pte_alloc_map_lock(mm, pmd, addr, &ptl);
+ if (mm == &init_mm) {
+ if (create)
+ pte = pte_alloc_kernel_track(pmd, addr, mask);
+ else
+ pte = pte_offset_kernel(pmd, addr);
if (!pte)
- return -ENOMEM;
+ return err;
} else {
- mapped_pte = pte = (mm == &init_mm) ?
- pte_offset_kernel(pmd, addr) :
- pte_offset_map_lock(mm, pmd, addr, &ptl);
+ if (create)
+ pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
+ else
+ pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
if (!pte)
- return -EINVAL;
+ return err;
+ mapped_pte = pte;
}

+ err = 0;
arch_enter_lazy_mmu_mode();

if (fn) {
@@ -2944,12 +2948,14 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
}
} while (addr += PAGE_SIZE, addr != end);
}
- *mask |= PGTBL_PTE_MODIFIED;

arch_leave_lazy_mmu_mode();

if (mm != &init_mm)
pte_unmap_unlock(mapped_pte, ptl);
+
+ *mask |= PGTBL_PTE_MODIFIED;
+
return err;
}

--
2.45.2