powerpc/pseries/mm: factorize PTE slot computation

This part of code will be called also when dealing with H_BLOCK_REMOVE.

Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/pseries/lpar.c

@@ -546,6 +546,24 @@ static int pSeries_lpar_hpte_removebolted(unsigned long ea,
 	return 0;
 }
 
+
+static inline unsigned long compute_slot(real_pte_t pte,
+					 unsigned long vpn,
+					 unsigned long index,
+					 unsigned long shift,
+					 int ssize)
+{
+	unsigned long slot, hash, hidx;
+
+	hash = hpt_hash(vpn, shift, ssize);
+	hidx = __rpte_to_hidx(pte, index);
+	if (hidx & _PTEIDX_SECONDARY)
+		hash = ~hash;
+	slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+	slot += hidx & _PTEIDX_GROUP_IX;
+	return slot;
+}
+
 /*
  * Take a spinlock around flushes to avoid bouncing the hypervisor tlbie
  * lock.
@@ -558,7 +576,7 @@ static void pSeries_lpar_flush_hash_range(unsigned long number, int local)
 	struct ppc64_tlb_batch *batch = this_cpu_ptr(&ppc64_tlb_batch);
 	int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
 	unsigned long param[PLPAR_HCALL9_BUFSIZE];
-	unsigned long hash, index, shift, hidx, slot;
+	unsigned long index, shift, slot;
 	real_pte_t pte;
 	int psize, ssize;
 
@@ -572,12 +590,7 @@ static void pSeries_lpar_flush_hash_range(unsigned long number, int local)
 		vpn = batch->vpn[i];
 		pte = batch->pte[i];
 		pte_iterate_hashed_subpages(pte, psize, vpn, index, shift) {
-			hash = hpt_hash(vpn, shift, ssize);
-			hidx = __rpte_to_hidx(pte, index);
-			if (hidx & _PTEIDX_SECONDARY)
-				hash = ~hash;
-			slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
-			slot += hidx & _PTEIDX_GROUP_IX;
+			slot = compute_slot(pte, vpn, index, shift, ssize);
 			if (!firmware_has_feature(FW_FEATURE_BULK_REMOVE)) {
 				/*
 				 * lpar doesn't use the passed actual page size