RDMA/core: Allocate the pkey cache only if the pkey_tbl_len is set

Allocate the pkey cache only if the pkey_tbl_len is set by the provider,
also add checks to avoid accessing the pkey cache when it not initialized.

Link: https://lore.kernel.org/r/20200714183414.61069-3-kamalheib1@gmail.comSigned-off-by: Kamal Heib <kamalheib1@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/core/cache.c

@@ -1054,7 +1054,7 @@ int ib_get_cached_pkey(struct ib_device *device,
 
 	cache = device->port_data[port_num].cache.pkey;
 
-	if (index < 0 || index >= cache->table_len)
+	if (!cache || index < 0 || index >= cache->table_len)
 		ret = -EINVAL;
 	else
 		*pkey = cache->table[index];
@@ -1099,6 +1099,10 @@ int ib_find_cached_pkey(struct ib_device *device,
 	read_lock_irqsave(&device->cache_lock, flags);
 
 	cache = device->port_data[port_num].cache.pkey;
+	if (!cache) {
+		ret = -EINVAL;
+		goto err;
+	}
 
 	*index = -1;
 
@@ -1117,6 +1121,7 @@ int ib_find_cached_pkey(struct ib_device *device,
 		ret = 0;
 	}
 
+err:
 	read_unlock_irqrestore(&device->cache_lock, flags);
 
 	return ret;
@@ -1139,6 +1144,10 @@ int ib_find_exact_cached_pkey(struct ib_device *device,
 	read_lock_irqsave(&device->cache_lock, flags);
 
 	cache = device->port_data[port_num].cache.pkey;
+	if (!cache) {
+		ret = -EINVAL;
+		goto err;
+	}
 
 	*index = -1;
 
@@ -1149,6 +1158,7 @@ int ib_find_exact_cached_pkey(struct ib_device *device,
 			break;
 		}
 
+err:
 	read_unlock_irqrestore(&device->cache_lock, flags);
 
 	return ret;
@@ -1425,23 +1435,26 @@ ib_cache_update(struct ib_device *device, u8 port, bool enforce_security)
 			goto err;
 	}
 
-	pkey_cache = kmalloc(struct_size(pkey_cache, table,
-					 tprops->pkey_tbl_len),
-			     GFP_KERNEL);
-	if (!pkey_cache) {
-		ret = -ENOMEM;
-		goto err;
-	}
+	if (tprops->pkey_tbl_len) {
+		pkey_cache = kmalloc(struct_size(pkey_cache, table,
+						 tprops->pkey_tbl_len),
+				     GFP_KERNEL);
+		if (!pkey_cache) {
+			ret = -ENOMEM;
+			goto err;
+		}
 
-	pkey_cache->table_len = tprops->pkey_tbl_len;
+		pkey_cache->table_len = tprops->pkey_tbl_len;
 
-	for (i = 0; i < pkey_cache->table_len; ++i) {
-		ret = ib_query_pkey(device, port, i, pkey_cache->table + i);
-		if (ret) {
-			dev_warn(&device->dev,
-				 "ib_query_pkey failed (%d) for index %d\n",
-				 ret, i);
-			goto err;
+		for (i = 0; i < pkey_cache->table_len; ++i) {
+			ret = ib_query_pkey(device, port, i,
+					    pkey_cache->table + i);
+			if (ret) {
+				dev_warn(&device->dev,
+					 "ib_query_pkey failed (%d) for index %d\n",
+					 ret, i);
+				goto err;
+			}
 		}
 	}