tls: use fixed size for tls_offload_context_{tx,rx}.driver_state

driver_state is a flex array, but is always allocated by the tls core
to a fixed size (TLS_DRIVER_STATE_SIZE_{TX,RX}). Simplify the code by
making that size explicit so that sizeof(struct
tls_offload_context_{tx,rx}) works.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tls.h

@@ -150,6 +150,7 @@ struct tls_record_info {
 	skb_frag_t frags[MAX_SKB_FRAGS];
 };
 
+#define TLS_DRIVER_STATE_SIZE_TX	16
 struct tls_offload_context_tx {
 	struct crypto_aead *aead_send;
 	spinlock_t lock;	/* protects records list */
@@ -163,17 +164,13 @@ struct tls_offload_context_tx {
 	void (*sk_destruct)(struct sock *sk);
 	struct work_struct destruct_work;
 	struct tls_context *ctx;
-	u8 driver_state[] __aligned(8);
 	/* The TLS layer reserves room for driver specific state
 	 * Currently the belief is that there is not enough
 	 * driver specific state to justify another layer of indirection
 	 */
-#define TLS_DRIVER_STATE_SIZE_TX	16
+	u8 driver_state[TLS_DRIVER_STATE_SIZE_TX] __aligned(8);
 };
 
-#define TLS_OFFLOAD_CONTEXT_SIZE_TX                                            \
-	(sizeof(struct tls_offload_context_tx) + TLS_DRIVER_STATE_SIZE_TX)
-
 enum tls_context_flags {
 	/* tls_device_down was called after the netdev went down, device state
 	 * was released, and kTLS works in software, even though rx_conf is
@@ -303,6 +300,7 @@ struct tls_offload_resync_async {
 	u32 log[TLS_DEVICE_RESYNC_ASYNC_LOGMAX];
 };
 
+#define TLS_DRIVER_STATE_SIZE_RX	8
 struct tls_offload_context_rx {
 	/* sw must be the first member of tls_offload_context_rx */
 	struct tls_sw_context_rx sw;
@@ -326,17 +324,13 @@ struct tls_offload_context_rx {
 			struct tls_offload_resync_async *resync_async;
 		};
 	};
-	u8 driver_state[] __aligned(8);
 	/* The TLS layer reserves room for driver specific state
 	 * Currently the belief is that there is not enough
 	 * driver specific state to justify another layer of indirection
 	 */
-#define TLS_DRIVER_STATE_SIZE_RX	8
+	u8 driver_state[TLS_DRIVER_STATE_SIZE_RX] __aligned(8);
 };
 
-#define TLS_OFFLOAD_CONTEXT_SIZE_RX					\
-	(sizeof(struct tls_offload_context_rx) + TLS_DRIVER_STATE_SIZE_RX)
-
 struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
 				       u32 seq, u64 *p_record_sn);
 

net/tls/tls_device.c

@@ -1038,7 +1038,7 @@ static struct tls_offload_context_tx *alloc_offload_ctx_tx(struct tls_context *c
 	struct tls_offload_context_tx *offload_ctx;
 	__be64 rcd_sn;
 
-	offload_ctx = kzalloc(TLS_OFFLOAD_CONTEXT_SIZE_TX, GFP_KERNEL);
+	offload_ctx = kzalloc(sizeof(*offload_ctx), GFP_KERNEL);
 	if (!offload_ctx)
 		return NULL;
 
@@ -1225,7 +1225,7 @@ int tls_set_device_offload_rx(struct sock *sk, struct tls_context *ctx)
 		goto release_lock;
 	}
 
-	context = kzalloc(TLS_OFFLOAD_CONTEXT_SIZE_RX, GFP_KERNEL);
+	context = kzalloc(sizeof(*context), GFP_KERNEL);
 	if (!context) {
 		rc = -ENOMEM;
 		goto release_lock;