igb: Add macro for size of RETA indirection table

RETA indirection table is used to assign the received data to a CPU
in order to maintain an efficient distribution of network receive
processing across multiple CPUs.

This patch removes the hard-coded value for the size of the indirection
table and defines a new macro.

Signed-off-by: Laura Mihaela Vasilescu <laura.vasilescu@rosedu.org>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/igb.h

@@ -343,6 +343,8 @@ struct hwmon_buff {
 	};
 #endif
 
+#define IGB_RETA_SIZE	128
+
 /* board specific private data structure */
 struct igb_adapter {
 	unsigned long active_vlans[BITS_TO_LONGS(VLAN_N_VID)];

drivers/net/ethernet/intel/igb/igb_main.c

@@ -3157,7 +3157,7 @@ static void igb_setup_mrqc(struct igb_adapter *adapter)
 	 * we are generating the results for n and n+2 and then interleaving
 	 * those with the results with n+1 and n+3.
 	 */
-	for (j = 0; j < 32; j++) {
+	for (j = 0; j < IGB_RETA_SIZE / 4; j++) {
 		/* first pass generates n and n+2 */
 		u32 base = ((j * 0x00040004) + 0x00020000) * num_rx_queues;
 		u32 reta = (base & 0x07800780) >> (7 - shift);