sfc: Do not assume efx_nic_type::ev_fini is idempotent

efx_fini_eventq() needs to be idempotent but EF10 firmware is
picky about queue states.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

drivers/net/ethernet/sfc/efx.c

@@ -339,6 +339,7 @@ static void efx_init_eventq(struct efx_channel *channel)
 	channel->eventq_read_ptr = 0;
 
 	efx_nic_init_eventq(channel);
+	channel->eventq_init = true;
 }
 
 /* Enable event queue processing and NAPI */
@@ -367,10 +368,14 @@ static void efx_stop_eventq(struct efx_channel *channel)
 
 static void efx_fini_eventq(struct efx_channel *channel)
 {
+	if (!channel->eventq_init)
+		return;
+
 	netif_dbg(channel->efx, drv, channel->efx->net_dev,
 		  "chan %d fini event queue\n", channel->channel);
 
 	efx_nic_fini_eventq(channel);
+	channel->eventq_init = false;
 }
 
 static void efx_remove_eventq(struct efx_channel *channel)

drivers/net/ethernet/sfc/net_driver.h

@@ -356,6 +356,7 @@ enum efx_rx_alloc_method {
  * @efx: Associated Efx NIC
  * @channel: Channel instance number
  * @type: Channel type definition
+ * @eventq_init: Event queue initialised flag
  * @enabled: Channel enabled indicator
  * @irq: IRQ number (MSI and MSI-X only)
  * @irq_moderation: IRQ moderation value (in hardware ticks)
@@ -387,6 +388,7 @@ struct efx_channel {
 	struct efx_nic *efx;
 	int channel;
 	const struct efx_channel_type *type;
+	bool eventq_init;
 	bool enabled;
 	int irq;
 	unsigned int irq_moderation;