[PATCH v2 0/3] Bluetooth: Advertising sets on a single-set controller

[Weihong Guan <weihong.guan@gmail.com>]

When the controller supports a single advertising set,
hci_add_adv_instance() gives instance 1 handle 0x00, the handle Global
Advertising uses too. The parameters, data and enable commands already
use adv->handle; these patches cover what still takes the instance
number for the handle: setting the set's random address, removing the
set, and the Advertising Set Terminated event.

Changes in v2, addressing the review at
https://sashiko.dev/#/patchset/20261023132421.1889022-1-weihong.guan%40gmail.com
(I hadn't seen it, sorry):

 - The instance is looked up, and adv->handle read, with hdev->lock held.
 - Patch 1: hci_cc_le_set_adv_set_random_addr() records the address of
   the instance numbered as the handle and leaves handle 0x00 alone, so
   instance 1's address on handle 0x00 went unrecorded. It is now
   recorded in hci_set_adv_set_random_addr_sync() when the instance and
   its handle differ.
 - Patch 2: hci_cc_le_remove_adv_set() looked up instance 0 for handle
   0x00 and left instance 1 in hdev->adv_instances. The completion can't
   tell instance 1 from instance 0, which MGMT's Set Advertising also
   removes on handle 0x00, so instance 1 is removed in
   hci_remove_ext_adv_instance_sync() once the command succeeds.
 - Patch 2: while Global Advertising is on it owns handle 0x00, and the
   controller would refuse to remove an enabled set, so only the instance
   is removed then.
 - Patch 3 (new): the Advertising Set Terminated event finds the instance
   owning handle 0x00, the one enabled on it as hci_le_ext_adv_set_enabled()
   tracks, for the connection's responder address (which SMP checks), the
   instance re-enabled after the disconnection, and the removal on an
   error.

Tested on a Raspberry Pi 5 (rpi-7.4.y, 7.4-rc2, with net/bluetooth and
include/net/bluetooth from bluetooth-next and these patches) with a
controller reporting one advertising set (LE Read Number of Supported
Advertising Sets = 1), btmgmt and btmon:

  - A non-connectable instance (a random address) starts: its address
    goes to handle 0x00 and the set advertises from it.
  - Removing it sends LE Remove Advertising Set for handle 0x00; the
    instance leaves the list (Read Advertising Features: none) and
    Advertising Removed goes out.
  - With Global Advertising on, removing instance 1 sends no LE Remove
    Advertising Set, the instance still leaves the list, and the set
    keeps advertising for Global Advertising.
  - A connectable instance from a random static address
    (force_static_address) on handle 0x00: Advertising Set Terminated
    for handle 0x00, LE Secure Connections pairing completes (DHKey
    Check both ways, so the responder address is the one advertised),
    and after the disconnection instance 1 advertises again.

Built with W=1; checkpatch clean but for the Assisted-by tag.

v1: https://lore.kernel.org/linux-bluetooth/20261023132421.1889022-1-weihong.guan@gmail.com/

Weihong Guan (3):
  Bluetooth: hci_sync: Set an advertising set's random address on its
    handle
  Bluetooth: hci_sync: Remove an advertising set by its handle
  Bluetooth: hci_event: Find the instance owning a terminated
    advertising set

 net/bluetooth/hci_event.c | 42 ++++++++++++-----
 net/bluetooth/hci_sync.c  | 94 +++++++++++++++++++++++++++++++++++----
 2 files changed, 116 insertions(+), 20 deletions(-)

-- 
2.47.3