mac80211_hwsim: add hashtable with mac address keys for faster lookup

This patch adds a rhastable for mac address lookup of hwsim radios. This
especially improve the speed on reception of a netlink message with a new
frame. Although redundant, we keep holding a normal list for all radios,
since the rhashtable_walk interface adds a lot of overhead for iterating
over all radios and the doc of rhashtable recommend a redundant structure
for stable walks in such situations.

Since rhashtable is rcu protected we do not need a lock for delivering
frames and thus improving this scenario.

Signed-off-by: Benjamin Beichler <benjamin.beichler@uni-rostock.de>
[remove hash function, it would cause alignment issues]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 78367373185f3ce7ec6a90b4205c41b04304132e..9339615a46d338e02f831cce1cc5719f4cd492be 100644 (file)
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -32,6 +32,7 @@
 #include <net/genetlink.h>
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
+#include <linux/rhashtable.h>
 #include "mac80211_hwsim.h"
 
 #define WARN_QUEUE 100
@@ -489,6 +490,7 @@ static const struct ieee80211_iface_combination hwsim_if_comb_p2p_dev[] = {
 
 static spinlock_t hwsim_radio_lock;
 static LIST_HEAD(hwsim_radios);
+static struct rhashtable hwsim_radios_rht;
 static int hwsim_radio_idx;
 
 static struct platform_driver mac80211_hwsim_driver = {
@@ -499,6 +501,7 @@ static struct platform_driver mac80211_hwsim_driver = {
 
 struct mac80211_hwsim_data {
        struct list_head list;
+       struct rhash_head rht;
        struct ieee80211_hw *hw;
        struct device *dev;
        struct ieee80211_supported_band bands[NUM_NL80211_BANDS];
@@ -573,6 +576,13 @@ struct mac80211_hwsim_data {
        u64 tx_failed;
 };
 
+static const struct rhashtable_params hwsim_rht_params = {
+       .nelem_hint = 2,
+       .automatic_shrinking = true,
+       .key_len = ETH_ALEN,
+       .key_offset = offsetof(struct mac80211_hwsim_data, addresses[1]),
+       .head_offset = offsetof(struct mac80211_hwsim_data, rht),
+};
 
 struct hwsim_radiotap_hdr {
        struct ieee80211_radiotap_header hdr;
@@ -2731,6 +2741,15 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
                             CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 
        spin_lock_bh(&hwsim_radio_lock);
+       err = rhashtable_insert_fast(&hwsim_radios_rht, &data->rht,
+                                    hwsim_rht_params);
+       if (err < 0) {
+               pr_debug("mac80211_hwsim: radio index %d already present\n",
+                        idx);
+               spin_unlock_bh(&hwsim_radio_lock);
+               goto failed_final_insert;
+       }
+
        list_add_tail(&data->list, &hwsim_radios);
        spin_unlock_bh(&hwsim_radio_lock);
 
@@ -2739,6 +2758,9 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
 
        return idx;
 
+failed_final_insert:
+       debugfs_remove_recursive(data->debugfs);
+       ieee80211_unregister_hw(data->hw);
 failed_hw:
        device_release_driver(data->dev);
 failed_bind:
@@ -2874,22 +2896,9 @@ static void hwsim_mon_setup(struct net_device *dev)
 
 static struct mac80211_hwsim_data *get_hwsim_data_ref_from_addr(const u8 *addr)
 {
-       struct mac80211_hwsim_data *data;
-       bool _found = false;
-
-       spin_lock_bh(&hwsim_radio_lock);
-       list_for_each_entry(data, &hwsim_radios, list) {
-               if (memcmp(data->addresses[1].addr, addr, ETH_ALEN) == 0) {
-                       _found = true;
-                       break;
-               }
-       }
-       spin_unlock_bh(&hwsim_radio_lock);
-
-       if (!_found)
-               return NULL;
-
-       return data;
+       return rhashtable_lookup_fast(&hwsim_radios_rht,
+                                     addr,
+                                     hwsim_rht_params);
 }
 
 static void hwsim_register_wmediumd(struct net *net, u32 portid)
@@ -3191,6 +3200,8 @@ static int hwsim_del_radio_nl(struct sk_buff *msg, struct genl_info *info)
                        continue;
 
                list_del(&data->list);
+               rhashtable_remove_fast(&hwsim_radios_rht, &data->rht,
+                                      hwsim_rht_params);
                spin_unlock_bh(&hwsim_radio_lock);
                mac80211_hwsim_del_radio(data, wiphy_name(data->hw->wiphy),
                                         info);
@@ -3346,6 +3357,8 @@ static void remove_user_radios(u32 portid)
        list_for_each_entry_safe(entry, tmp, &hwsim_radios, list) {
                if (entry->destroy_on_close && entry->portid == portid) {
                        list_del(&entry->list);
+                       rhashtable_remove_fast(&hwsim_radios_rht, &entry->rht,
+                                              hwsim_rht_params);
                        INIT_WORK(&entry->destroy_work, destroy_radio);
                        schedule_work(&entry->destroy_work);
                }
@@ -3421,6 +3434,8 @@ static void __net_exit hwsim_exit_net(struct net *net)
                        continue;
 
                list_del(&data->list);
+               rhashtable_remove_fast(&hwsim_radios_rht, &data->rht,
+                                      hwsim_rht_params);
                INIT_WORK(&data->destroy_work, destroy_radio);
                schedule_work(&data->destroy_work);
        }
@@ -3454,6 +3469,8 @@ static int __init init_mac80211_hwsim(void)
 
        spin_lock_init(&hwsim_radio_lock);
 
+       rhashtable_init(&hwsim_radios_rht, &hwsim_rht_params);
+
        err = register_pernet_device(&hwsim_net_ops);
        if (err)
                return err;
@@ -3592,6 +3609,7 @@ static void __exit exit_mac80211_hwsim(void)
        hwsim_exit_netlink();
 
        mac80211_hwsim_free();
+       rhashtable_destroy(&hwsim_radios_rht);
        unregister_netdev(hwsim_mon);
        platform_driver_unregister(&mac80211_hwsim_driver);
        unregister_pernet_device(&hwsim_net_ops);