From cb98c439d66c303353a9f4abbbe9ddb51559c638 Mon Sep 17 00:00:00 2001
From: Artur Rojek <ar@semihalf.com>
Date: Thu, 12 Aug 2021 10:34:26 +0200
Subject: [PATCH] ena: Add locking assertions

ENA silently assumed that ena_up, ena_down and ena_start_xmit routines
should be called within locked context. Driver's logic heavily assumes
on concurrent access to those routines, so for safety and better
documentation about this assumption, the locking assertions were added
to the above functions.

The assertion was added only for the main steps (skipping the helper
functions) which can be called from multiple places including the kernel
and the driver itself.

Obtained from: Semihalf
MFC after: 2 weeks
Sponsored by: Amazon, Inc.
---
 sys/dev/ena/ena.c          | 4 ++++
 sys/dev/ena/ena.h          | 4 ++++
 sys/dev/ena/ena_datapath.c | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/sys/dev/ena/ena.c b/sys/dev/ena/ena.c
index dbe5b9f785a9..faa1278c6d81 100644
--- a/sys/dev/ena/ena.c
+++ b/sys/dev/ena/ena.c
@@ -2092,6 +2092,8 @@ ena_up(struct ena_adapter *adapter)
 {
 	int rc = 0;
 
+	ENA_LOCK_ASSERT(adapter);
+
 	if (unlikely(device_is_attached(adapter->pdev) == 0)) {
 		ena_log(adapter->pdev, ERR, "device is not attached!\n");
 		return (ENXIO);
@@ -2465,6 +2467,8 @@ ena_down(struct ena_adapter *adapter)
 {
 	int rc;
 
+	ENA_LOCK_ASSERT(adapter);
+
 	if (!ENA_FLAG_ISSET(ENA_FLAG_DEV_UP, adapter))
 		return;
 
diff --git a/sys/dev/ena/ena.h b/sys/dev/ena/ena.h
index 1d06a3cb56de..f05c2d69fbe4 100644
--- a/sys/dev/ena/ena.h
+++ b/sys/dev/ena/ena.h
@@ -480,12 +480,16 @@ struct ena_adapter {
 #define	ENA_RING_MTX_LOCK(_ring)		mtx_lock(&(_ring)->ring_mtx)
 #define	ENA_RING_MTX_TRYLOCK(_ring)		mtx_trylock(&(_ring)->ring_mtx)
 #define	ENA_RING_MTX_UNLOCK(_ring)		mtx_unlock(&(_ring)->ring_mtx)
+#define ENA_RING_MTX_ASSERT(_ring)		\
+	mtx_assert(&(_ring)->ring_mtx, MA_OWNED)
 
 #define ENA_LOCK_INIT(adapter)			\
 	sx_init(&(adapter)->global_lock, "ENA global lock")
 #define ENA_LOCK_DESTROY(adapter)	sx_destroy(&(adapter)->global_lock)
 #define ENA_LOCK_LOCK(adapter)		sx_xlock(&(adapter)->global_lock)
 #define ENA_LOCK_UNLOCK(adapter)	sx_unlock(&(adapter)->global_lock)
+#define ENA_LOCK_ASSERT(adapter)		\
+	sx_assert(&(adapter)->global_lock, SA_XLOCKED)
 
 #define clamp_t(type, _x, min, max)	min_t(type, max_t(type, _x, min), max)
 #define clamp_val(val, lo, hi)		clamp_t(__typeof(val), val, lo, hi)
diff --git a/sys/dev/ena/ena_datapath.c b/sys/dev/ena/ena_datapath.c
index e6286ebfc25f..6506c808e4cb 100644
--- a/sys/dev/ena/ena_datapath.c
+++ b/sys/dev/ena/ena_datapath.c
@@ -1075,6 +1075,8 @@ ena_start_xmit(struct ena_ring *tx_ring)
 	int ena_qid;
 	int ret = 0;
 
+	ENA_RING_MTX_ASSERT(tx_ring);
+
 	if (unlikely((if_getdrvflags(adapter->ifp) & IFF_DRV_RUNNING) == 0))
 		return;