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| author |   David Hildenbrand <david@redhat.com> | 2021-09-09 18:22:47 +0200 |
|---|---|---|
| committer |   Christian Borntraeger <borntraeger@de.ibm.com> | 2021-10-25 09:20:38 +0200 |
| commit | 7cb70266b0e3996daf4bbef9758b6e27e9ec904d (patch) | |
| tree | 2d5942b4ea4ab50f1a8bb8dac057cf3a971f5a81 /arch/s390/mm/pgtable.c | |
| parent | s390/mm: no need for pte_alloc_map_lock() if we know the pmd is present (diff) | |
| download | linux-dev-7cb70266b0e3996daf4bbef9758b6e27e9ec904d.tar.xz linux-dev-7cb70266b0e3996daf4bbef9758b6e27e9ec904d.zip | |
s390/mm: optimize set_guest_storage_key()
We already optimize get_guest_storage_key() to assume that if we don't have
a PTE table and don't have a huge page mapped that the storage key is 0.
Similarly, optimize set_guest_storage_key() to simply do nothing in case
the key to set is 0.
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20210909162248.14969-9-david@redhat.com
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/pgtable.c')
| -rw-r--r-- | arch/s390/mm/pgtable.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index e74cc59dcd67..1c9aeb361f8d 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -792,13 +792,23 @@ int set_guest_storage_key(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp; pte_t *ptep; - if (pmd_lookup(mm, addr, &pmdp)) + /* + * If we don't have a PTE table and if there is no huge page mapped, + * we can ignore attempts to set the key to 0, because it already is 0. + */ + switch (pmd_lookup(mm, addr, &pmdp)) { + case -ENOENT: + return key ? -EFAULT : 0; + case 0: + break; + default: return -EFAULT; + } ptl = pmd_lock(mm, pmdp); if (!pmd_present(*pmdp)) { spin_unlock(ptl); - return -EFAULT; + return key ? -EFAULT : 0; } if (pmd_large(*pmdp)) { |