On Thu, 9 Sep 2021 18:22:46 +0200 David Hildenbrand <david@xxxxxxxxxx> wrote: > pte_map_lock() is sufficient. Can you explain the difference and why it is enough? > > Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> > --- > arch/s390/mm/pgtable.c | 15 +++------------ > 1 file changed, 3 insertions(+), 12 deletions(-) > > diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c > index 5fb409ff7842..4e77b8ebdcc5 100644 > --- a/arch/s390/mm/pgtable.c > +++ b/arch/s390/mm/pgtable.c > @@ -814,10 +814,7 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr, > } > spin_unlock(ptl); > > - ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl); > - if (unlikely(!ptep)) > - return -EFAULT; > - > + ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl); > new = old = pgste_get_lock(ptep); > pgste_val(new) &= ~(PGSTE_GR_BIT | PGSTE_GC_BIT | > PGSTE_ACC_BITS | PGSTE_FP_BIT); > @@ -912,10 +909,7 @@ int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr) > } > spin_unlock(ptl); > > - ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl); > - if (unlikely(!ptep)) > - return -EFAULT; > - > + ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl); > new = old = pgste_get_lock(ptep); > /* Reset guest reference bit only */ > pgste_val(new) &= ~PGSTE_GR_BIT; > @@ -977,10 +971,7 @@ int get_guest_storage_key(struct mm_struct *mm, unsigned long addr, > } > spin_unlock(ptl); > > - ptep = pte_alloc_map_lock(mm, pmdp, addr, &ptl); > - if (unlikely(!ptep)) > - return -EFAULT; > - > + ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl); > pgste = pgste_get_lock(ptep); > *key = (pgste_val(pgste) & (PGSTE_ACC_BITS | PGSTE_FP_BIT)) >> 56; > paddr = pte_val(*ptep) & PAGE_MASK;
