Merge branch 'hsr-fix-lock-warnings'

Hangbin Liu says:

====================
hsr: fix lock warnings

hsr_for_each_port is called in many places without holding the RCU read
lock, this may trigger warnings on debug kernels like:

  [   40.457015] [  T201] WARNING: suspicious RCU usage
  [   40.457020] [  T201] 6.17.0-rc2-virtme #1 Not tainted
  [   40.457025] [  T201] -----------------------------
  [   40.457029] [  T201] net/hsr/hsr_main.c:137 RCU-list traversed in non-reader section!!
  [   40.457036] [  T201]
                          other info that might help us debug this:

  [   40.457040] [  T201]
                          rcu_scheduler_active = 2, debug_locks = 1
  [   40.457045] [  T201] 2 locks held by ip/201:
  [   40.457050] [  T201]  #0: ffffffff93040a40 (&ops->srcu){.+.+}-{0:0}, at: rtnl_link_ops_get+0xf2/0x280
  [   40.457080] [  T201]  #1: ffffffff92e7f968 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x5e1/0xb20
  [   40.457102] [  T201]
                          stack backtrace:
  [   40.457108] [  T201] CPU: 2 UID: 0 PID: 201 Comm: ip Not tainted 6.17.0-rc2-virtme #1 PREEMPT(full)
  [   40.457114] [  T201] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  [   40.457117] [  T201] Call Trace:
  [   40.457120] [  T201]  <TASK>
  [   40.457126] [  T201]  dump_stack_lvl+0x6f/0xb0
  [   40.457136] [  T201]  lockdep_rcu_suspicious.cold+0x4f/0xb1
  [   40.457148] [  T201]  hsr_port_get_hsr+0xfe/0x140
  [   40.457158] [  T201]  hsr_add_port+0x192/0x940
  [   40.457167] [  T201]  ? __pfx_hsr_add_port+0x10/0x10
  [   40.457176] [  T201]  ? lockdep_init_map_type+0x5c/0x270
  [   40.457189] [  T201]  hsr_dev_finalize+0x4bc/0xbf0
  [   40.457204] [  T201]  hsr_newlink+0x3c3/0x8f0
  [   40.457212] [  T201]  ? __pfx_hsr_newlink+0x10/0x10
  [   40.457222] [  T201]  ? rtnl_create_link+0x173/0xe40
  [   40.457233] [  T201]  rtnl_newlink_create+0x2cf/0x750
  [   40.457243] [  T201]  ? __pfx_rtnl_newlink_create+0x10/0x10
  [   40.457247] [  T201]  ? __dev_get_by_name+0x12/0x50
  [   40.457252] [  T201]  ? rtnl_dev_get+0xac/0x140
  [   40.457259] [  T201]  ? __pfx_rtnl_dev_get+0x10/0x10
  [   40.457285] [  T201]  __rtnl_newlink+0x22c/0xa50
  [   40.457305] [  T201]  rtnl_newlink+0x637/0xb20

Adding rcu_read_lock() for all hsr_for_each_port() looks confusing.

Introduce a new helper, hsr_for_each_port_rtnl(), that assumes the
RTNL lock is held. This allows callers in suitable contexts to iterate
ports safely without explicit RCU locking.

Other code paths that rely on RCU protection continue to use
hsr_for_each_port() with rcu_read_lock().
====================

Link: https://patch.msgid.link/20250905091533.377443-1-liuhangbin@gmail.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>