wifi: ath12k: Fix the assignment of logical link index

Per-link logical index is assigned from the global counter,
ahsta->num_peer. This logical index is sent to firmware during peer
association. If there is a failure in creating a link station,
ath12k_mac_free_unassign_link_sta() clears the link, but does not decrement
the logical link index. This will result in a higher logical link index for
the next link station created. Also, if there is a leak in logical link
index as we assign the incremented num_peer, then the index can exceed the
maximum valid value of 15.

As an example, let's say we have a 2 GHz + 5 GHz + 6 GHz MLO setup. So the
logical link indices that they have are 0, 1 and 2, respectively. If the
5 GHz link is removed, logical link index 1 becomes available, and num_peer
is not reduced to 2 and still remains at 3. If a new 5 GHz link is added
later, it gets the index 3, instead of reusing link index 1. Also,
num_peer is increased to 4, though only 3 links are present.

To resolve these, create a bitmap, free_logical_link_idx, that tracks the
available logical link indices. When a link station is created, select the
first free logical index and when a link station is removed, mark its
logical link index as available by setting the bit.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.6-01181-QCAHKSWPL_SILICONZ-1

Signed-off-by: Manish Dharanenthiran <manish.dharanenthiran@oss.qualcomm.com>
Signed-off-by: Roopni Devanathan <roopni.devanathan@oss.qualcomm.com>
Reviewed-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20260226041911.2434999-1-roopni.devanathan@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>

diff --git a/drivers/net/wireless/ath/ath12k/core.h b/drivers/net/wireless/ath/ath12k/core.h
index 760c76d6f0f4a778f1f85610edb6ba4dcd3fe57c..59c193b247646e712516fd533e69c4802c7882cf 100644 (file)
--- a/drivers/net/wireless/ath/ath12k/core.h
+++ b/drivers/net/wireless/ath/ath12k/core.h
@@ -523,7 +523,7 @@ struct ath12k_sta {
        u16 links_map;
        u8 assoc_link_id;
        u16 ml_peer_id;
-       u8 num_peer;
+       u16 free_logical_link_idx_map;
 
        enum ieee80211_sta_state state;
 };

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index 05268d425d6ae6e646a23c9dfab335e53bbd6d54..41fa85f89f0ebfc2e6e927581f364be12a28f905 100644 (file)
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -6786,6 +6786,8 @@ static void ath12k_mac_free_unassign_link_sta(struct ath12k_hw *ah,
                return;
 
        ahsta->links_map &= ~BIT(link_id);
+       ahsta->free_logical_link_idx_map |= BIT(arsta->link_idx);
+
        rcu_assign_pointer(ahsta->link[link_id], NULL);
        synchronize_rcu();
 
@@ -7104,6 +7106,7 @@ static int ath12k_mac_assign_link_sta(struct ath12k_hw *ah,
        struct ieee80211_sta *sta = ath12k_ahsta_to_sta(ahsta);
        struct ieee80211_link_sta *link_sta;
        struct ath12k_link_vif *arvif;
+       int link_idx;
 
        lockdep_assert_wiphy(ah->hw->wiphy);
 
@@ -7122,8 +7125,16 @@ static int ath12k_mac_assign_link_sta(struct ath12k_hw *ah,
 
        ether_addr_copy(arsta->addr, link_sta->addr);
 
-       /* logical index of the link sta in order of creation */
-       arsta->link_idx = ahsta->num_peer++;
+       if (!ahsta->free_logical_link_idx_map)
+               return -ENOSPC;
+
+       /*
+        * Allocate a logical link index by selecting the first available bit
+        * from the free logical index map
+        */
+       link_idx = __ffs(ahsta->free_logical_link_idx_map);
+       ahsta->free_logical_link_idx_map &= ~BIT(link_idx);
+       arsta->link_idx = link_idx;
 
        arsta->link_id = link_id;
        ahsta->links_map |= BIT(arsta->link_id);
@@ -7632,6 +7643,7 @@ int ath12k_mac_op_sta_state(struct ieee80211_hw *hw,
        if (old_state == IEEE80211_STA_NOTEXIST &&
            new_state == IEEE80211_STA_NONE) {
                memset(ahsta, 0, sizeof(*ahsta));
+               ahsta->free_logical_link_idx_map = U16_MAX;
 
                arsta = &ahsta->deflink;