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>

4 files changed, 10 insertions, 22 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index 23b724c746e9..ce5610aa124c 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -281,11 +281,9 @@ static inline int hpte_cache_flags_ok(unsigned long ptel, unsigned long io_type)
 
 /*
  * If it's present and writable, atomically set dirty and referenced bits and
- * return the PTE, otherwise return 0. If we find a transparent hugepage
- * and if it is marked splitting we return 0;
+ * return the PTE, otherwise return 0.
  */
-static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing,
-                                                 unsigned int hugepage)
+static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing)
 {
         pte_t old_pte, new_pte = __pte(0);
 
@@ -301,12 +299,6 @@ static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing,
                         cpu_relax();
                         continue;
                 }
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-                /* If hugepage and is trans splitting return None */
-                if (unlikely(hugepage &&
-                             pmd_trans_splitting(pte_pmd(old_pte))))
-                        return __pte(0);
-#endif
                 /* If pte is not present return None */
                 if (unlikely(!(pte_val(old_pte) & _PAGE_PRESENT)))
                         return __pte(0);
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 26df3864d85a..0fe9c92e78ed 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/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;
                         }
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index f559b25de173..d839f08cb903 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/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 */
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index a9dbb27ca887..0ce968b00b7c 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -1014,12 +1014,11 @@ pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
                          * A hugepage collapse is captured by pmd_none, because
                          * it mark the pmd none and do a hpte invalidate.
                          *
-                         * A hugepage split is captured by pmd_trans_splitting
-                         * because we mark the pmd trans splitting and do a
-                         * hpte invalidate
-                         *
+                         * We don't worry about pmd_trans_splitting here, The
+                         * caller if it needs to handle the splitting case
+                         * should check for that.
                          */
-                        if (pmd_none(pmd) || pmd_trans_splitting(pmd))
+                        if (pmd_none(pmd))
                                 return NULL;
 
                         if (pmd_huge(pmd) || pmd_large(pmd)) {