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s390/mm: take the mmap_sem in kvm_s390_shadow_fault() 

Instead of doing it in the caller, let's just take the mmap_sem
in kvm_s390_shadow_fault(). By taking it as read, we allow parallel
faulting on shadow page tables, gmap shadow code is prepared for that.

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
David Hildenbrand 2016-02-02 12:26:00 +01:00 committed by Christian Borntraeger
parent 0f7f848915
commit e52f8b6112
1 changed files with 15 additions and 17 deletions
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32
arch/s390/kvm/gaccess.c
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@ -1091,26 +1091,24 @@ int kvm_s390_shadow_fault(struct gmap *sg, unsigned long saddr, int write)
int dat_protection;
int rc;
down_read(&sg->mm->mmap_sem);
rc = gmap_shadow_pgt_lookup(sg, saddr, &pgt, &dat_protection);
if (rc) {
if (rc)
rc = kvm_s390_shadow_tables(sg, saddr, &pgt, &dat_protection);
if (rc)
return rc;
}
vaddr.addr = saddr;
rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val);
if (rc)
return rc;
if (pte.i)
return PGM_PAGE_TRANSLATION;
if (pte.z || pte.co)
return PGM_TRANSLATION_SPEC;
if (!rc)
rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val);
if (!rc && pte.i)
rc = PGM_PAGE_TRANSLATION;
if (!rc && (pte.z || pte.co))
rc = PGM_TRANSLATION_SPEC;
dat_protection |= pte.p;
if (write && dat_protection)
return PGM_PROTECTION;
rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
if (rc)
return rc;
return 0;
if (!rc && write && dat_protection)
rc = PGM_PROTECTION;
if (!rc)
rc = gmap_shadow_page(sg, saddr, __pte(pte.val));
up_read(&sg->mm->mmap_sem);
return rc;
}