drbd: Get rid of P_MAX_CMD

Instead of artificially enlarging the command decoding arrays to
P_MAX_CMD entries, check if an index is within the valid range using the
ARRAY_SIZE() macro.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_int.h

@@ -225,7 +225,6 @@ enum drbd_packet {
 	P_CONN_ST_CHG_REPLY   = 0x2b, /* meta sock: Connection side state req reply */
 	P_RETRY_WRITE	      = 0x2c, /* Protocol C: retry conflicting write request */
 
-	P_MAX_CMD	      = 0x2d,
 	P_MAY_IGNORE	      = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */
 	P_MAX_OPT_CMD	      = 0x101,
 

drivers/block/drbd/drbd_main.c

@@ -3019,7 +3019,6 @@ const char *cmdname(enum drbd_packet cmd)
 		[P_DELAY_PROBE]         = "DelayProbe",
 		[P_OUT_OF_SYNC]		= "OutOfSync",
 		[P_RETRY_WRITE]		= "RetryWrite",
-		[P_MAX_CMD]	        = NULL,
 	};
 
 	if (cmd == P_HAND_SHAKE_M)
@@ -3028,7 +3027,7 @@ const char *cmdname(enum drbd_packet cmd)
 		return "HandShakeS";
 	if (cmd == P_HAND_SHAKE)
 		return "HandShake";
-	if (cmd >= P_MAX_CMD)
+	if (cmd >= ARRAY_SIZE(cmdnames))
 		return "Unknown";
 	return cmdnames[cmd];
 }

drivers/block/drbd/drbd_receiver.c

@@ -3875,9 +3875,6 @@ static struct data_cmd drbd_cmd_handler[] = {
 	[P_DELAY_PROBE]     = { 0, sizeof(struct p_delay_probe93), receive_skip },
 	[P_OUT_OF_SYNC]     = { 0, sizeof(struct p_block_desc), receive_out_of_sync },
 	[P_CONN_ST_CHG_REQ] = { 0, sizeof(struct p_req_state), receive_req_state },
-	/* anything missing from this table is in
-	 * the asender_tbl, see get_asender_cmd */
-	[P_MAX_CMD]	    = { 0, 0, NULL },
 };
 
 /* All handler functions that expect a sub-header get that sub-heder in
@@ -3899,7 +3896,8 @@ static void drbdd(struct drbd_tconn *tconn)
 		if (!drbd_recv_header(tconn, &pi))
 			goto err_out;
 
-		if (unlikely(pi.cmd >= P_MAX_CMD || !drbd_cmd_handler[pi.cmd].function)) {
+		if (unlikely(pi.cmd >= ARRAY_SIZE(drbd_cmd_handler) ||
+		    !drbd_cmd_handler[pi.cmd].function)) {
 			conn_err(tconn, "unknown packet type %d, l: %d!\n", pi.cmd, pi.size);
 			goto err_out;
 		}
@@ -4678,9 +4676,9 @@ static struct asender_cmd *get_asender_cmd(int cmd)
 	[P_RS_CANCEL]       = { sizeof(struct p_block_ack), got_NegRSDReply},
 	[P_CONN_ST_CHG_REPLY]={ sizeof(struct p_req_state_reply), got_RqSReply },
 	[P_RETRY_WRITE]	    = { sizeof(struct p_block_ack), got_BlockAck },
-	[P_MAX_CMD]	    = { 0, NULL },
 	};
-	if (cmd > P_MAX_CMD || asender_tbl[cmd].process == NULL)
+
+	if (cmd >= ARRAY_SIZE(asender_tbl) || !asender_tbl[cmd].process)
 		return NULL;
 	return &asender_tbl[cmd];
 }