powerpc/mm/thp: Return pte address if we find trans_splitting.

For THP that is marked trans splitting, we return the pte.
This require the callers to handle the pmd_trans_splitting scenario,
if they care. All the current callers are either looking at pfn or
write_ok, hence we don't need to update them.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kvm/book3s_64_mmu_hv.c

@@ -537,20 +537,17 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		}
 		/* if the guest wants write access, see if that is OK */
 		if (!writing && hpte_is_writable(r)) {
-			unsigned int hugepage_shift;
 			pte_t *ptep, pte;
 			unsigned long flags;
-
 			/*
 			 * We need to protect against page table destruction
-			 * while looking up and updating the pte.
+			 * hugepage split and collapse.
 			 */
 			local_irq_save(flags);
 			ptep = find_linux_pte_or_hugepte(current->mm->pgd,
-							 hva, &hugepage_shift);
+							 hva, NULL);
 			if (ptep) {
-				pte = kvmppc_read_update_linux_pte(ptep, 1,
-							   hugepage_shift);
+				pte = kvmppc_read_update_linux_pte(ptep, 1);
 				if (pte_write(pte))
 					write_ok = 1;
 			}

arch/powerpc/kvm/book3s_hv_rm_mmu.c

@@ -219,7 +219,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
 				local_irq_restore(flags);
 			return H_PARAMETER;
 		}
-		pte = kvmppc_read_update_linux_pte(ptep, writing, hpage_shift);
+		pte = kvmppc_read_update_linux_pte(ptep, writing);
 		if (pte_present(pte) && !pte_protnone(pte)) {
 			if (writing && !pte_write(pte))
 				/* make the actual HPTE be read-only */