[PATCH] adapter: Fix Discovering staying true after a rejected stop

[Kevin Dewald <kevin@simpleble.org>]

The kernel rejects Stop Discovery when no discovery is active by the
time it processes the command, because the discovery ended or another
mgmt client stopped it just before. stop_discovery_complete() then
removes the client but keeps the discovery state, so Discovering stays
true with no client left, and the next StartDiscovery with the same
filter returns without starting a discovery. The client that called
StopDiscovery also gets an InProgress error, and "No discovery started"
if it tries again.

Treat MGMT_STATUS_REJECTED as the discovery being stopped, as
stop_passive_scanning_complete() already does.

Closes: https://github.com/bluez/bluez/issues/2547
Link: https://github.com/bluez/bluez/issues/807
Fixes: c1226f79ec97 ("adapter: Fix not checking status of stop discovery command")
Assisted-by: Claude:claude-opus-5.5
---
Reproduced with a functional test that holds the emulated controller
while a second mgmt client stops the discovery, so the kernel rejects
the Stop Discovery bluetoothd sends for StopDiscovery: on master the
call fails with InProgress and Discovering stays true (3 of 3 runs);
with this patch it succeeds and Discovering goes false (5 of 5). I can
send the test as well if you want it.

 src/adapter.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/adapter.c b/src/adapter.c
index 1561ea3bf..4d753028a 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -2194,6 +2194,14 @@ static void stop_discovery_complete(uint8_t status, uint16_t length,
 
 	DBG("status 0x%02x", status);
 
+	/*
+	 * MGMT_STATUS_REJECTED is returned from kernel when no discovery is
+	 * active, e.g. because it ended or another mgmt client stopped it
+	 * just before this command, so treat it as stopped as well.
+	 */
+	if (status == MGMT_STATUS_REJECTED)
+		status = MGMT_STATUS_SUCCESS;
+
 	client = discovery_complete(adapter, status);
 	if (client)
 		discovery_remove(client);

base-commit: b0bf49270d445da0852851f393cd67a0a1e5f05e
-- 
2.54.0 (Apple Git-157)