[PATCH net-next v3 3/6] netconsole: add STATE_DEACTIVATED to track targets disabled by low level

[Andre Carvalho <asantostc@gmail.com>]

From: Breno Leitao <leitao@debian.org>

When the low level interface brings a netconsole target down, record this
using a new STATE_DEACTIVATED state. This allows netconsole to distinguish
between targets explicitly disabled by users and those deactivated due to
interface state changes.

It also enables automatic recovery and re-enabling of targets if the
underlying low-level interfaces come back online.

From a code perspective, anything that is not STATE_ENABLED is disabled.
Mark the device that is down due to  NETDEV_UNREGISTER as
STATE_DEACTIVATED, this, should be the same as STATE_DISABLED from
a code perspective.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Andre Carvalho <asantostc@gmail.com>
---
 drivers/net/netconsole.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 2d15f7ab7235..5a374e6d178d 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -120,6 +120,7 @@ enum sysdata_feature {
 enum target_state {
 	STATE_DISABLED,
 	STATE_ENABLED,
+	STATE_DEACTIVATED,
 };
 
 /**
@@ -575,6 +576,14 @@ static ssize_t enabled_store(struct config_item *item,
 	if (ret)
 		goto out_unlock;
 
+	/* When the user explicitly enables or disables a target that is
+	 * currently deactivated, reset its state to disabled. The DEACTIVATED
+	 * state only tracks interface-driven deactivation and should _not_
+	 * persist when the user manually changes the target's enabled state.
+	 */
+	if (nt->state == STATE_DEACTIVATED)
+		nt->state = STATE_DISABLED;
+
 	ret = -EINVAL;
 	current_enabled = nt->state == STATE_ENABLED;
 	if (enabled == current_enabled) {
@@ -1461,7 +1470,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
 			case NETDEV_RELEASE:
 			case NETDEV_JOIN:
 			case NETDEV_UNREGISTER:
-				nt->state = STATE_DISABLED;
+				nt->state = STATE_DEACTIVATED;
 				list_move(&nt->list, &target_cleanup_list);
 				stopped = true;
 			}

-- 
2.51.2