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From:   Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
To:     marcel@holtmann.org, linux-bluetooth@vger.kernel.org
Cc:     chromeos-bluetooth-upstreaming@chromium.org,
        Abhishek Pandit-Subedi <abhishekpandit@chromium.org>,
        "David S. Miller" <davem@davemloft.net>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jakub Kicinski <kuba@kernel.org>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Subject: [PATCH] Bluetooth: Pause service discovery for suspend
Date:   Thu, 17 Dec 2020 15:04:08 -0800
Message-Id: <20201217150346.1.If6feff48e17a881af9cb55526db7f53bf0db40f1@changeid>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Just like MGMT_OP_START_DISCOVERY, we should reject
MGMT_OP_START_SERVICE_DISCOVERY with MGMT_STATUS_BUSY when we are paused
for suspend.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
---
On ChromeOS, we started getting reports of scanning failing after
resuming from suspend. The root cause was that Start Service Discovery
was being called while discovery was supposed to be paused for suspend
and it was screwing up some internal state. Adding this check
immediately fixed it.

The fix was tested by doing the following:
* Set Discovery Filter ({'transport': 'auto'})
* Start Discovery
* Suspend
* Resume
* Check the Discovering property

Without the fix, this test failed when checking the Discovering
property above.

 net/bluetooth/mgmt.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index fa0f7a4a1d2fc8a..608dda5403b7327 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -4798,6 +4798,14 @@ static int start_service_discovery(struct sock *sk, struct hci_dev *hdev,
 		goto failed;
 	}
 
+	if (hdev->discovery_paused) {
+		err = mgmt_cmd_complete(sk, hdev->id,
+					MGMT_OP_START_SERVICE_DISCOVERY,
+					MGMT_STATUS_BUSY, &cp->type,
+					sizeof(cp->type));
+		goto failed;
+	}
+
 	uuid_count = __le16_to_cpu(cp->uuid_count);
 	if (uuid_count > max_uuid_count) {
 		bt_dev_err(hdev, "service_discovery: too big uuid_count value %u",
-- 
2.29.2.729.g45daf8777d-goog