From 6b7c93c1439c8833ada9068f612df2de0571fd00 Mon Sep 17 00:00:00 2001 From: Benjamin Berg Date: Fri, 16 Jun 2023 09:53:59 +0300 Subject: [PATCH] wifi: cfg80211: keep bss_lock held when informing It is reasonable to hold bss_lock for a little bit longer after cfg80211_bss_update is done. Right now, this does not make any big difference, but doing so in preparation for the next patch which adds a call to the driver. Signed-off-by: Benjamin Berg Signed-off-by: Gregory Greenman Link: https://lore.kernel.org/r/20230616094948.61701884ff0d.I3358228209eb6766202aff04d1bae0b8fdff611f@changeid Signed-off-by: Johannes Berg --- net/wireless/scan.c | 66 ++++++++++++++++++++++++++++++++++------------------- 1 file changed, 42 insertions(+), 24 deletions(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 19e7014..8984f74 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -1701,10 +1701,10 @@ cfg80211_update_known_bss(struct cfg80211_registered_device *rdev, } /* Returned bss is reference counted and must be cleaned up appropriately. */ -struct cfg80211_internal_bss * -cfg80211_bss_update(struct cfg80211_registered_device *rdev, - struct cfg80211_internal_bss *tmp, - bool signal_valid, unsigned long ts) +static struct cfg80211_internal_bss * +__cfg80211_bss_update(struct cfg80211_registered_device *rdev, + struct cfg80211_internal_bss *tmp, + bool signal_valid, unsigned long ts) { struct cfg80211_internal_bss *found = NULL; @@ -1713,10 +1713,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev, tmp->ts = ts; - spin_lock_bh(&rdev->bss_lock); - if (WARN_ON(!rcu_access_pointer(tmp->pub.ies))) { - spin_unlock_bh(&rdev->bss_lock); return NULL; } @@ -1724,7 +1721,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev, if (found) { if (!cfg80211_update_known_bss(rdev, found, tmp, signal_valid)) - goto drop; + return NULL; } else { struct cfg80211_internal_bss *new; struct cfg80211_internal_bss *hidden; @@ -1744,7 +1741,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev, ies = (void *)rcu_dereference(tmp->pub.proberesp_ies); if (ies) kfree_rcu(ies, rcu_head); - goto drop; + return NULL; } memcpy(new, tmp, sizeof(*new)); new->refcount = 1; @@ -1775,14 +1772,14 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev, */ if (!cfg80211_combine_bsses(rdev, new)) { bss_ref_put(rdev, new); - goto drop; + return NULL; } } if (rdev->bss_entries >= bss_entries_limit && !cfg80211_bss_expire_oldest(rdev)) { bss_ref_put(rdev, new); - goto drop; + return NULL; } /* This must be before the call to bss_ref_get */ @@ -1799,12 +1796,22 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev, rdev->bss_generation++; bss_ref_get(rdev, found); - spin_unlock_bh(&rdev->bss_lock); return found; - drop: +} + +struct cfg80211_internal_bss * +cfg80211_bss_update(struct cfg80211_registered_device *rdev, + struct cfg80211_internal_bss *tmp, + bool signal_valid, unsigned long ts) +{ + struct cfg80211_internal_bss *res; + + spin_lock_bh(&rdev->bss_lock); + res = __cfg80211_bss_update(rdev, tmp, signal_valid, ts); spin_unlock_bh(&rdev->bss_lock); - return NULL; + + return res; } int cfg80211_get_ies_channel_number(const u8 *ie, size_t ielen, @@ -2015,15 +2022,15 @@ cfg80211_inform_single_bss_data(struct wiphy *wiphy, rcu_assign_pointer(tmp.pub.ies, ies); signal_valid = data->chan == channel; - res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid, ts); + spin_lock_bh(&rdev->bss_lock); + res = __cfg80211_bss_update(rdev, &tmp, signal_valid, ts); if (!res) - return NULL; + goto drop; if (non_tx_data) { /* this is a nontransmitting bss, we need to add it to * transmitting bss' list if it is not there */ - spin_lock_bh(&rdev->bss_lock); if (cfg80211_add_nontrans_list(non_tx_data->tx_bss, &res->pub)) { if (__cfg80211_unlink_bss(rdev, res)) { @@ -2031,15 +2038,19 @@ cfg80211_inform_single_bss_data(struct wiphy *wiphy, res = NULL; } } - spin_unlock_bh(&rdev->bss_lock); if (!res) - return NULL; + goto drop; } + spin_unlock_bh(&rdev->bss_lock); trace_cfg80211_return_bss(&res->pub); - /* cfg80211_bss_update gives us a referenced result */ + /* __cfg80211_bss_update gives us a referenced result */ return &res->pub; + +drop: + spin_unlock_bh(&rdev->bss_lock); + return NULL; } static const struct element @@ -2376,6 +2387,7 @@ cfg80211_inform_single_bss_frame_data(struct wiphy *wiphy, struct ieee80211_mgmt *mgmt, size_t len, gfp_t gfp) { + struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy); struct cfg80211_internal_bss tmp = {}, *res; struct cfg80211_bss_ies *ies; struct ieee80211_channel *channel; @@ -2485,14 +2497,20 @@ cfg80211_inform_single_bss_frame_data(struct wiphy *wiphy, ether_addr_copy(tmp.parent_bssid, data->parent_bssid); signal_valid = data->chan == channel; - res = cfg80211_bss_update(wiphy_to_rdev(wiphy), &tmp, signal_valid, - jiffies); + spin_lock_bh(&rdev->bss_lock); + res = __cfg80211_bss_update(rdev, &tmp, signal_valid, jiffies); if (!res) - return NULL; + goto drop; + + spin_unlock_bh(&rdev->bss_lock); trace_cfg80211_return_bss(&res->pub); - /* cfg80211_bss_update gives us a referenced result */ + /* __cfg80211_bss_update gives us a referenced result */ return &res->pub; + +drop: + spin_unlock_bh(&rdev->bss_lock); + return NULL; } struct cfg80211_bss * -- 2.7.4