git: 7614861463e6 - stable/14 - LinuxKPI: 802.11: adjust locking around lkpi_remove_chanctx()

The branch stable/14 has been updated by bz:

URL: https://cgit.FreeBSD.org/src/commit/?id=7614861463e6c26fdaaa79206b2bb0c79bb23683

commit 7614861463e6c26fdaaa79206b2bb0c79bb23683
Author:     Bjoern A. Zeeb <bz@FreeBSD.org>
AuthorDate: 2025-04-08 16:35:20 +0000
Commit:     Bjoern A. Zeeb <bz@FreeBSD.org>
CommitDate: 2025-04-18 14:36:01 +0000

    LinuxKPI: 802.11: adjust locking around lkpi_remove_chanctx()
    
    With the adjusted locking as a first step and the single code path
    into lkpi_80211_mo_unassign_vif_chanctx() we also move the "setting
    chnactx to NULL" into the caller to simplify the code.
    
    Before we can adjust the other places touching vif->bss_conf.chanctx
    we need to adjust the overall locking in LinuxKPI 802.11.
    
    Sponsored by:   The FreeBSD Foundation
    PR:             280546
    Tested by:      Oleksandr Kryvulia (shuriku shurik.kiev.ua)
    Tested by:      Oleg Nauman (oleg.nauman gmail.com) [rtw88]
    Differential Revision: https://reviews.freebsd.org/D49734
    
    (cherry picked from commit 231168c7e77777f69a323bcd80a7956527d34548)
---
 sys/compat/linuxkpi/common/src/linux_80211.c       | 39 +++++++++++++---------
 sys/compat/linuxkpi/common/src/linux_80211.h       |  2 +-
 .../linuxkpi/common/src/linux_80211_macops.c       | 12 ++++---
 3 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/sys/compat/linuxkpi/common/src/linux_80211.c b/sys/compat/linuxkpi/common/src/linux_80211.c
index 43d5c5dc9deb..edd3b91dcecf 100644
--- a/sys/compat/linuxkpi/common/src/linux_80211.c
+++ b/sys/compat/linuxkpi/common/src/linux_80211.c
@@ -1735,24 +1735,27 @@ lkpi_80211_flush_tx(struct lkpi_hw *lhw, struct lkpi_sta *lsta)
 static void
 lkpi_remove_chanctx(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 {
-	/* Take the chan ctx down. */
-	if (vif->bss_conf.chanctx_conf != NULL) {
-		struct lkpi_chanctx *lchanctx;
-		struct ieee80211_chanctx_conf *chanctx_conf;
+	struct ieee80211_chanctx_conf *chanctx_conf;
+	struct lkpi_chanctx *lchanctx;
 
-		chanctx_conf = vif->bss_conf.chanctx_conf;
-		/* Remove vif context. */
-		lkpi_80211_mo_unassign_vif_chanctx(hw, vif, &vif->bss_conf, &vif->bss_conf.chanctx_conf);
-		/* NB: vif->bss_conf.chanctx_conf is NULL now. */
+	chanctx_conf = rcu_dereference_protected(vif->bss_conf.chanctx_conf,
+	    lockdep_is_held(&hw->wiphy->mtx));
 
-		lkpi_hw_conf_idle(hw, true);
+	if (chanctx_conf == NULL)
+		return;
 
-		/* Remove chan ctx. */
-		lkpi_80211_mo_remove_chanctx(hw, chanctx_conf);
-		vif->bss_conf.chanctx_conf = NULL;
-		lchanctx = CHANCTX_CONF_TO_LCHANCTX(chanctx_conf);
-		free(lchanctx, M_LKPI80211);
-	}
+	/* Remove vif context. */
+	lkpi_80211_mo_unassign_vif_chanctx(hw, vif, &vif->bss_conf, chanctx_conf);
+
+	lkpi_hw_conf_idle(hw, true);
+
+	/* Remove chan ctx. */
+	lkpi_80211_mo_remove_chanctx(hw, chanctx_conf);
+
+	/* Cleanup. */
+	rcu_assign_pointer(vif->bss_conf.chanctx_conf, NULL);
+	lchanctx = CHANCTX_CONF_TO_LCHANCTX(chanctx_conf);
+	free(lchanctx, M_LKPI80211);
 }
 
 
@@ -2183,7 +2186,9 @@ lkpi_sta_auth_to_scan(struct ieee80211vap *vap, enum ieee80211_state nstate, int
 
 	/* conf_tx */
 
+	wiphy_lock(hw->wiphy);
 	lkpi_remove_chanctx(hw, vif);
+	wiphy_unlock(hw->wiphy);
 
 out:
 	LKPI_80211_LHW_UNLOCK(lhw);
@@ -2511,7 +2516,9 @@ _lkpi_sta_assoc_to_down(struct ieee80211vap *vap, enum ieee80211_state nstate, i
 
 	/* conf_tx */
 
+	wiphy_lock(hw->wiphy);
 	lkpi_remove_chanctx(hw, vif);
+	wiphy_unlock(hw->wiphy);
 
 	error = EALREADY;
 out:
@@ -3111,7 +3118,9 @@ lkpi_sta_run_to_init(struct ieee80211vap *vap, enum ieee80211_state nstate, int
 
 	/* conf_tx */
 
+	wiphy_lock(hw->wiphy);
 	lkpi_remove_chanctx(hw, vif);
+	wiphy_unlock(hw->wiphy);
 
 	error = EALREADY;
 out:
diff --git a/sys/compat/linuxkpi/common/src/linux_80211.h b/sys/compat/linuxkpi/common/src/linux_80211.h
index c2d29b2dcc4b..c01a6cb0cd7c 100644
--- a/sys/compat/linuxkpi/common/src/linux_80211.h
+++ b/sys/compat/linuxkpi/common/src/linux_80211.h
@@ -425,7 +425,7 @@ int lkpi_80211_mo_config(struct ieee80211_hw *, uint32_t);
 int lkpi_80211_mo_assign_vif_chanctx(struct ieee80211_hw *, struct ieee80211_vif *,
     struct ieee80211_bss_conf *, struct ieee80211_chanctx_conf *);
 void lkpi_80211_mo_unassign_vif_chanctx(struct ieee80211_hw *, struct ieee80211_vif *,
-    struct ieee80211_bss_conf *, struct ieee80211_chanctx_conf **);
+    struct ieee80211_bss_conf *, struct ieee80211_chanctx_conf *);
 int lkpi_80211_mo_add_chanctx(struct ieee80211_hw *, struct ieee80211_chanctx_conf *);
 void lkpi_80211_mo_change_chanctx(struct ieee80211_hw *,
     struct ieee80211_chanctx_conf *, uint32_t);
diff --git a/sys/compat/linuxkpi/common/src/linux_80211_macops.c b/sys/compat/linuxkpi/common/src/linux_80211_macops.c
index e9f97914a4b1..ff3959340af7 100644
--- a/sys/compat/linuxkpi/common/src/linux_80211_macops.c
+++ b/sys/compat/linuxkpi/common/src/linux_80211_macops.c
@@ -467,21 +467,23 @@ out:
 
 void
 lkpi_80211_mo_unassign_vif_chanctx(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
-    struct ieee80211_bss_conf *conf, struct ieee80211_chanctx_conf **chanctx_conf)
+    struct ieee80211_bss_conf *conf, struct ieee80211_chanctx_conf *chanctx_conf)
 {
 	struct lkpi_hw *lhw;
 
+	might_sleep();
+	lockdep_assert_wiphy(hw->wiphy);
+
 	lhw = HW_TO_LHW(hw);
 	if (lhw->ops->unassign_vif_chanctx == NULL)
 		return;
 
-	if (*chanctx_conf == NULL)
+	if (chanctx_conf == NULL)
 		return;
 
 	LKPI_80211_TRACE_MO("hw %p vif %p bss_conf %p chanctx_conf %p",
-	    hw, vif, conf, *chanctx_conf);
-	lhw->ops->unassign_vif_chanctx(hw, vif, conf, *chanctx_conf);
-	*chanctx_conf = NULL;
+	    hw, vif, conf, chanctx_conf);
+	lhw->ops->unassign_vif_chanctx(hw, vif, conf, chanctx_conf);
 }