[PATCH -next 01/10] wifi: cfg80211: pre-assign cookie for remain_on_channel, mgmt_tx, probe_peer and tx_control_port

Having a single place for cookie assignment and keeping that
responsibility in the cfg80211 subsystem is a logical choice as it
handles the userspace nl80211 API. add_nan_func already does this:
cfg80211 calls cfg80211_assign_cookie() before invoking the driver.
Apply the same pattern to remain_on_channel, mgmt_tx, probe_peer and
tx_control_port by pre-assigning the cookie in the nl80211 command
handlers before the rdev_* call. For tx_control_port the cookie is
only pre-assigned when the caller requests an ack (cookie pointer
non-NULL).

Drivers may still overwrite the value for now; subsequent patches will
remove per-driver cookie generation. Update the cfg80211_ops kerneldoc
to note that the cookie is pre-assigned and drivers must not modify it.

Assisted-by: Claude:claude-sonnet-4-6
---
 include/net/cfg80211.h | 12 ++++++++----
 net/wireless/nl80211.c |  5 +++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 15c08b24502f..a30550f356ab 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -5048,11 +5048,13 @@ struct mgmt_frame_regs {
  *	channel for the specified duration to complete an off-channel
  *	operation (e.g., public action frame exchange). When the driver is
  *	ready on the requested channel, it must indicate this with an event
- *	notification by calling cfg80211_ready_on_channel().
+ *	notification by calling cfg80211_ready_on_channel(). The @cookie is
+ *	pre-assigned by cfg80211; drivers must not modify it.
  * @cancel_remain_on_channel: Cancel an on-going remain-on-channel operation.
  *	This allows the operation to be terminated prior to timeout based on
  *	the duration value.
- * @mgmt_tx: Transmit a management frame.
+ * @mgmt_tx: Transmit a management frame. The @cookie is pre-assigned by
+ *	cfg80211; drivers must not modify it.
  * @mgmt_tx_cancel_wait: Cancel the wait time from transmitting a management
  *	frame on another channel
  *
@@ -5107,7 +5109,8 @@ struct mgmt_frame_regs {
  * @tdls_oper: Perform a high-level TDLS operation (e.g. TDLS link setup).
  *
  * @probe_peer: probe a connected peer (AP: STA MAC required; STA: no MAC),
- *	must return a cookie that is later passed to cfg80211_probe_status().
+ *	uses the @cookie pre-assigned by cfg80211 (drivers must not modify it)
+ *	which is later passed to cfg80211_probe_status().
  *
  * @set_noack_map: Set the NoAck Map for the TIDs.
  *
@@ -5218,7 +5221,8 @@ struct mgmt_frame_regs {
  *     user space
  *
  * @tx_control_port: TX a control port frame (EAPoL).  The noencrypt parameter
- *	tells the driver that the frame should not be encrypted.
+ *	tells the driver that the frame should not be encrypted. When @cookie is
+ *	non-NULL it is pre-assigned by cfg80211; drivers must not modify it.
  *
  * @get_ftm_responder_stats: Retrieve FTM responder statistics, if available.
  *	Statistics should be cumulative, currently no way to reset is provided.
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index ac0c0da45241..bfb3005c23a7 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -14630,6 +14630,7 @@ static int nl80211_remain_on_channel(struct sk_buff *skb,
 		goto free_msg;
 	}
 
+	cookie = cfg80211_assign_cookie(rdev);
 	err = rdev_remain_on_channel(rdev, wdev, chandef.chan,
 				     duration, &cookie, rx_addr);
 
@@ -14871,6 +14872,7 @@ static int nl80211_tx_mgmt(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	params.chan = chandef.chan;
+	cookie = cfg80211_assign_cookie(rdev);
 	err = cfg80211_mlme_mgmt_tx(rdev, wdev, &params, &cookie);
 	if (err)
 		goto free_msg;
@@ -16359,6 +16361,7 @@ static int nl80211_probe_peer(struct sk_buff *skb, struct genl_info *info)
 		goto free_msg;
 	}
 
+	cookie = cfg80211_assign_cookie(rdev);
 	err = rdev_probe_peer(rdev, dev, addr, &cookie);
 	if (err)
 		goto free_msg;
@@ -18574,6 +18577,8 @@ static int nl80211_tx_control_port(struct sk_buff *skb, struct genl_info *info)
 
 	link_id = nl80211_link_id_or_invalid(info->attrs);
 
+	if (!dont_wait_for_ack)
+		cookie = cfg80211_assign_cookie(rdev);
 	err = rdev_tx_control_port(rdev, dev, buf, len,
 				   dest, cpu_to_be16(proto), noencrypt, link_id,
 				   dont_wait_for_ack ? NULL : &cookie);
-- 
2.54.0