[PATCH net 4/4] sfc: don't free_irq()s if they were never requested

[Edward Cree <ecree@solarflare.com>]

If efx_nic_init_interrupt fails, or was never run (e.g. due to an earlier
 failure in ef100_net_open), freeing irqs in efx_nic_fini_interrupt is not
 needed and will cause error messages and stack traces.
So instead, only do this if efx_nic_init_interrupt successfully completed,
 as indicated by the new efx->irqs_hooked flag.

Fixes: 965b549f3c20 ("sfc_ef100: implement ndo_open/close and EVQ probing")
Signed-off-by: Edward Cree <ecree@solarflare.com>
---
 drivers/net/ethernet/sfc/net_driver.h | 2 ++
 drivers/net/ethernet/sfc/nic.c        | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index dcb741d8bd11..062462a13847 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -846,6 +846,7 @@ struct efx_async_filter_insertion {
  * @timer_quantum_ns: Interrupt timer quantum, in nanoseconds
  * @timer_max_ns: Interrupt timer maximum value, in nanoseconds
  * @irq_rx_adaptive: Adaptive IRQ moderation enabled for RX event queues
+ * @irqs_hooked: Channel interrupts are hooked
  * @irq_rx_mod_step_us: Step size for IRQ moderation for RX event queues
  * @irq_rx_moderation_us: IRQ moderation time for RX event queues
  * @msg_enable: Log message enable flags
@@ -1004,6 +1005,7 @@ struct efx_nic {
 	unsigned int timer_quantum_ns;
 	unsigned int timer_max_ns;
 	bool irq_rx_adaptive;
+	bool irqs_hooked;
 	unsigned int irq_mod_step_us;
 	unsigned int irq_rx_moderation_us;
 	u32 msg_enable;
diff --git a/drivers/net/ethernet/sfc/nic.c b/drivers/net/ethernet/sfc/nic.c
index d994d136bb03..d1e908846f5d 100644
--- a/drivers/net/ethernet/sfc/nic.c
+++ b/drivers/net/ethernet/sfc/nic.c
@@ -129,6 +129,7 @@ int efx_nic_init_interrupt(struct efx_nic *efx)
 #endif
 	}
 
+	efx->irqs_hooked = true;
 	return 0;
 
  fail2:
@@ -154,6 +155,8 @@ void efx_nic_fini_interrupt(struct efx_nic *efx)
 	efx->net_dev->rx_cpu_rmap = NULL;
 #endif
 
+	if (!efx->irqs_hooked)
+		return;
 	if (EFX_INT_MODE_USE_MSI(efx)) {
 		/* Disable MSI/MSI-X interrupts */
 		efx_for_each_channel(channel, efx)
@@ -163,6 +166,7 @@ void efx_nic_fini_interrupt(struct efx_nic *efx)
 		/* Disable legacy interrupt */
 		free_irq(efx->legacy_irq, efx);
 	}
+	efx->irqs_hooked = false;
 }
 
 /* Register dump */