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mac80211: split sta_info_add

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sta_info_add() has two functions: allocating a station info
structure and inserting it into the hash table/list. Splitting
these two functions allows allocating with GFP_KERNEL in many
places instead of GFP_ATOMIC which is now required by the RCU
protection. Additionally, in many places RCU protection is now
no longer needed at all because between sta_info_alloc() and
sta_info_insert() the caller owns the structure.

This fixes a few race conditions with setting initial flags
and similar, but not all (see comments in ieee80211_sta.c and
cfg.c). More documentation on the existing races will be in
a follow-up patch.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg
2008-02-25 16:27:47 +01:00
committed by John W. Linville
parent d0709a6518
commit 73651ee639
7 changed files with 166 additions and 74 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
net/mac80211/mesh_plink.c
View File

@@ -89,44 +89,41 @@ static inline void mesh_plink_fsm_restart(struct sta_info *sta)
}
/**
* mesh_plink_add - allocate and add a new mesh peer link
* mesh_plink_alloc - allocate a new mesh peer link
*
* @sdata: local mesh interface
* @hw_addr: hardware address (ETH_ALEN length)
* @rates: rates the mesh peer supports
* @dev: local mesh interface
*
* The initial state of the new plink is set to LISTEN
*
* Returns: non-NULL on success, ERR_PTR() on error.
* Returns: NULL on error.
*/
struct sta_info *mesh_plink_add(u8 *hw_addr, u64 rates,
struct ieee80211_sub_if_data *sdata)
struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
u8 *hw_addr, u64 rates, gfp_t gfp)
{
struct ieee80211_local *local = sdata->local;
struct sta_info *sta;
if (compare_ether_addr(hw_addr, sdata->dev->dev_addr) == 0)
/* never add ourselves as neighbours */
return ERR_PTR(-EINVAL);
return NULL;
if (is_multicast_ether_addr(hw_addr))
return ERR_PTR(-EINVAL);
return NULL;
if (local->num_sta >= MESH_MAX_PLINKS)
return ERR_PTR(-ENOSPC);
return NULL;
sta = sta_info_add(sdata, hw_addr);
if (IS_ERR(sta))
return sta;
sta = sta_info_alloc(sdata, hw_addr, gfp);
if (!sta)
return NULL;
sta->plink_state = LISTEN;
spin_lock_init(&sta->plink_lock);
init_timer(&sta->plink_timer);
sta->flags |= WLAN_STA_AUTHORIZED;
sta->supp_rates[local->hw.conf.channel->band] = rates;
rate_control_rate_init(sta, local);
mesh_accept_plinks_update(sdata);
return sta;
}
@@ -252,8 +249,13 @@ void mesh_neighbour_update(u8 *hw_addr, u64 rates, struct net_device *dev,
sta = sta_info_get(local, hw_addr);
if (!sta) {
sta = mesh_plink_add(hw_addr, rates, sdata);
if (IS_ERR(sta)) {
sta = mesh_plink_alloc(sdata, hw_addr, rates, GFP_ATOMIC);
if (!sta) {
rcu_read_unlock();
return;
}
if (sta_info_insert(sta)) {
sta_info_destroy(sta);
rcu_read_unlock();
return;
}
@@ -516,12 +518,17 @@ void mesh_rx_plink_frame(struct net_device *dev, struct ieee80211_mgmt *mgmt,
}
rates = ieee80211_sta_get_rates(local, &elems, rx_status->band);
sta = mesh_plink_add(mgmt->sa, rates, sdata);
if (IS_ERR(sta)) {
sta = mesh_plink_alloc(sdata, mgmt->sa, rates, GFP_ATOMIC);
if (!sta) {
mpl_dbg("Mesh plink error: plink table full\n");
rcu_read_unlock();
return;
}
if (sta_info_insert(sta)) {
sta_info_destroy(sta);
rcu_read_unlock();
return;
}
event = OPN_ACPT;
spin_lock_bh(&sta->plink_lock);
} else {