net/ena/base: restructure interrupt handling

[ upstream commit 553653ccc18c1ed9fb0406e1b0130e945d5ab30f ]

When invoking an admin command, in interrupt mode, if the interrupt
is received after timeout and also after the calling function finished
running, the response will be written into a memory that is no longer
valid.

Fixes: 99ecfbf ("ena: import communication layer")

Signed-off-by: Shai Brandes <shaibran@amazon.com>
Reviewed-by: Amit Bernstein <amitbern@amazon.com>

drivers/net/ena/base/ena_com.c

@@ -173,6 +173,7 @@ static int ena_com_admin_init_aenq(struct ena_com_dev *ena_dev,
 static void comp_ctxt_release(struct ena_com_admin_queue *queue,
 				     struct ena_comp_ctx *comp_ctx)
 {
+	comp_ctx->user_cqe = NULL;
 	comp_ctx->occupied = false;
 	ATOMIC32_DEC(&queue->outstanding_cmds);
 }
@@ -466,6 +467,9 @@ static void ena_com_handle_single_admin_completion(struct ena_com_admin_queue *a
 		return;
 	}
 
+	if (!comp_ctx->occupied)
+		return;
+
 	comp_ctx->status = ENA_CMD_COMPLETED;
 	comp_ctx->comp_status = cqe->acq_common_descriptor.status;