[PATCH net] gve: defer interrupt enabling until NAPI registration

[Harshitha Ramamurthy <hramamurthy@google.com>]

From: Ankit Garg <nktgrg@google.com>

Currently, interrupts are automatically enabled immediately upon
request. This allows interrupt to fire before the associated NAPI
context is fully initialized and cause failures like below:

[    0.946369] Call Trace:
[    0.946369]  <IRQ>
[    0.946369]  __napi_poll+0x2a/0x1e0
[    0.946369]  net_rx_action+0x2f9/0x3f0
[    0.946369]  handle_softirqs+0xd6/0x2c0
[    0.946369]  ? handle_edge_irq+0xc1/0x1b0
[    0.946369]  __irq_exit_rcu+0xc3/0xe0
[    0.946369]  common_interrupt+0x81/0xa0
[    0.946369]  </IRQ>
[    0.946369]  <TASK>
[    0.946369]  asm_common_interrupt+0x22/0x40
[    0.946369] RIP: 0010:pv_native_safe_halt+0xb/0x10

Use the `IRQF_NO_AUTOEN` flag when requesting interrupts to prevent auto
enablement and explicitly enable the interrupt in NAPI initialization
path (and disable it during NAPI teardown).

This ensures that interrupt lifecycle is strictly coupled with
readiness of NAPI context.

Cc: stable@vger.kernel.org
Fixes: 1dfc2e46117e ("gve: Refactor napi add and remove functions")
Signed-off-by: Ankit Garg <nktgrg@google.com>
Reviewed-by: Jordan Rhee <jordanrhee@google.com>
Reviewed-by: Joshua Washington <joshwash@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
---
 drivers/net/ethernet/google/gve/gve_main.c  | 2 +-
 drivers/net/ethernet/google/gve/gve_utils.c | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c
index 5a74760..96adbbe 100644
--- a/drivers/net/ethernet/google/gve/gve_main.c
+++ b/drivers/net/ethernet/google/gve/gve_main.c
@@ -558,7 +558,7 @@ static int gve_alloc_notify_blocks(struct gve_priv *priv)
 		block->priv = priv;
 		err = request_irq(priv->msix_vectors[msix_idx].vector,
 				  gve_is_gqi(priv) ? gve_intr : gve_intr_dqo,
-				  0, block->name, block);
+				  IRQF_NO_AUTOEN, block->name, block);
 		if (err) {
 			dev_err(&priv->pdev->dev,
 				"Failed to receive msix vector %d\n", i);
diff --git a/drivers/net/ethernet/google/gve/gve_utils.c b/drivers/net/ethernet/google/gve/gve_utils.c
index ace9b86..b53b7fc 100644
--- a/drivers/net/ethernet/google/gve/gve_utils.c
+++ b/drivers/net/ethernet/google/gve/gve_utils.c
@@ -112,11 +112,13 @@ void gve_add_napi(struct gve_priv *priv, int ntfy_idx,
 
 	netif_napi_add_locked(priv->dev, &block->napi, gve_poll);
 	netif_napi_set_irq_locked(&block->napi, block->irq);
+	enable_irq(block->irq);
 }
 
 void gve_remove_napi(struct gve_priv *priv, int ntfy_idx)
 {
 	struct gve_notify_block *block = &priv->ntfy_blocks[ntfy_idx];
 
+	disable_irq(block->irq);
 	netif_napi_del_locked(&block->napi);
 }
-- 
2.52.0.322.g1dd061c0dc-goog