ppc64: allow pSeries LPAR insert_pte to fail

arch/ppc64/kernel/htab.c

@@ -349,6 +349,9 @@ int __hash_page(unsigned long ea, unsigned long access, unsigned long vsid,
                         }
 		}
 
+		if (unlikely(slot == -2))
+			panic("hash_page: pte_insert failed\n");
+
 		pte_val(new_pte) |= (slot<<12) & _PAGE_GROUP_IX;
 
 		/* 

arch/ppc64/kernel/pSeries_lpar.c

@@ -460,8 +460,13 @@ long pSeries_lpar_hpte_insert(unsigned long hpte_group,
 	if (lpar_rc == H_PTEG_Full)
 		return -1;
 
+	/*
+	 * Since we try and ioremap PHBs we dont own, the pte insert
+	 * will fail. However we must catch the failure in hash_page
+	 * or we will loop forever, so return -2 in this case.
+	 */
 	if (lpar_rc != H_Success)
-		panic("Bad return code from pte enter rc = %lx\n", lpar_rc);
+		return -2;
 
 	return slot;
 }

arch/ppc64/mm/init.c

@@ -233,6 +233,7 @@ static void map_io_page(unsigned long ea, unsigned long pa, int flags)
 
 		hpteg = ((hash & htab_data.htab_hash_mask)*HPTES_PER_GROUP);
 
+		/* Panic if a pte grpup is full */
 		if (ppc_md.hpte_insert(hpteg, va, pa >> PAGE_SHIFT, 0,
 				       _PAGE_NO_CACHE|_PAGE_GUARDED|PP_RWXX,
 				       1, 0) == -1) {