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cfg80211: refactor cfg80211_bss_update
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This patch implements minor refactoring for cfg80211_bss_update function.
Code path for updating known BSS is extracted into dedicated
cfg80211_update_known_bss function.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Link: https://lore.kernel.org/r/20190726163922.27509-2-sergey.matyukevich.os@quantenna.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Sergey Matyukevich authored and Johannes Berg committed Jul 29, 2019
1 parent ae6fa4d commit 3ab8227
Showing 1 changed file with 89 additions and 82 deletions.
171 changes: 89 additions & 82 deletions net/wireless/scan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1091,6 +1091,93 @@ struct cfg80211_non_tx_bss {
u8 bssid_index;
};

static bool
cfg80211_update_known_bss(struct cfg80211_registered_device *rdev,
struct cfg80211_internal_bss *known,
struct cfg80211_internal_bss *new,
bool signal_valid)
{
lockdep_assert_held(&rdev->bss_lock);

/* Update IEs */
if (rcu_access_pointer(new->pub.proberesp_ies)) {
const struct cfg80211_bss_ies *old;

old = rcu_access_pointer(known->pub.proberesp_ies);

rcu_assign_pointer(known->pub.proberesp_ies,
new->pub.proberesp_ies);
/* Override possible earlier Beacon frame IEs */
rcu_assign_pointer(known->pub.ies,
new->pub.proberesp_ies);
if (old)
kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
} else if (rcu_access_pointer(new->pub.beacon_ies)) {
const struct cfg80211_bss_ies *old;
struct cfg80211_internal_bss *bss;

if (known->pub.hidden_beacon_bss &&
!list_empty(&known->hidden_list)) {
const struct cfg80211_bss_ies *f;

/* The known BSS struct is one of the probe
* response members of a group, but we're
* receiving a beacon (beacon_ies in the new
* bss is used). This can only mean that the
* AP changed its beacon from not having an
* SSID to showing it, which is confusing so
* drop this information.
*/

f = rcu_access_pointer(new->pub.beacon_ies);
kfree_rcu((struct cfg80211_bss_ies *)f, rcu_head);
return false;
}

old = rcu_access_pointer(known->pub.beacon_ies);

rcu_assign_pointer(known->pub.beacon_ies, new->pub.beacon_ies);

/* Override IEs if they were from a beacon before */
if (old == rcu_access_pointer(known->pub.ies))
rcu_assign_pointer(known->pub.ies, new->pub.beacon_ies);

/* Assign beacon IEs to all sub entries */
list_for_each_entry(bss, &known->hidden_list, hidden_list) {
const struct cfg80211_bss_ies *ies;

ies = rcu_access_pointer(bss->pub.beacon_ies);
WARN_ON(ies != old);

rcu_assign_pointer(bss->pub.beacon_ies,
new->pub.beacon_ies);
}

if (old)
kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
}

known->pub.beacon_interval = new->pub.beacon_interval;

/* don't update the signal if beacon was heard on
* adjacent channel.
*/
if (signal_valid)
known->pub.signal = new->pub.signal;
known->pub.capability = new->pub.capability;
known->ts = new->ts;
known->ts_boottime = new->ts_boottime;
known->parent_tsf = new->parent_tsf;
known->pub.chains = new->pub.chains;
memcpy(known->pub.chain_signal, new->pub.chain_signal,
IEEE80211_MAX_CHAINS);
ether_addr_copy(known->parent_bssid, new->parent_bssid);
known->pub.max_bssid_indicator = new->pub.max_bssid_indicator;
known->pub.bssid_index = new->pub.bssid_index;

return true;
}

/* Returned bss is reference counted and must be cleaned up appropriately. */
struct cfg80211_internal_bss *
cfg80211_bss_update(struct cfg80211_registered_device *rdev,
Expand All @@ -1114,88 +1201,8 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev,
found = rb_find_bss(rdev, tmp, BSS_CMP_REGULAR);

if (found) {
/* Update IEs */
if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
const struct cfg80211_bss_ies *old;

old = rcu_access_pointer(found->pub.proberesp_ies);

rcu_assign_pointer(found->pub.proberesp_ies,
tmp->pub.proberesp_ies);
/* Override possible earlier Beacon frame IEs */
rcu_assign_pointer(found->pub.ies,
tmp->pub.proberesp_ies);
if (old)
kfree_rcu((struct cfg80211_bss_ies *)old,
rcu_head);
} else if (rcu_access_pointer(tmp->pub.beacon_ies)) {
const struct cfg80211_bss_ies *old;
struct cfg80211_internal_bss *bss;

if (found->pub.hidden_beacon_bss &&
!list_empty(&found->hidden_list)) {
const struct cfg80211_bss_ies *f;

/*
* The found BSS struct is one of the probe
* response members of a group, but we're
* receiving a beacon (beacon_ies in the tmp
* bss is used). This can only mean that the
* AP changed its beacon from not having an
* SSID to showing it, which is confusing so
* drop this information.
*/

f = rcu_access_pointer(tmp->pub.beacon_ies);
kfree_rcu((struct cfg80211_bss_ies *)f,
rcu_head);
goto drop;
}

old = rcu_access_pointer(found->pub.beacon_ies);

rcu_assign_pointer(found->pub.beacon_ies,
tmp->pub.beacon_ies);

/* Override IEs if they were from a beacon before */
if (old == rcu_access_pointer(found->pub.ies))
rcu_assign_pointer(found->pub.ies,
tmp->pub.beacon_ies);

/* Assign beacon IEs to all sub entries */
list_for_each_entry(bss, &found->hidden_list,
hidden_list) {
const struct cfg80211_bss_ies *ies;

ies = rcu_access_pointer(bss->pub.beacon_ies);
WARN_ON(ies != old);

rcu_assign_pointer(bss->pub.beacon_ies,
tmp->pub.beacon_ies);
}

if (old)
kfree_rcu((struct cfg80211_bss_ies *)old,
rcu_head);
}

found->pub.beacon_interval = tmp->pub.beacon_interval;
/*
* don't update the signal if beacon was heard on
* adjacent channel.
*/
if (signal_valid)
found->pub.signal = tmp->pub.signal;
found->pub.capability = tmp->pub.capability;
found->ts = tmp->ts;
found->ts_boottime = tmp->ts_boottime;
found->parent_tsf = tmp->parent_tsf;
found->pub.chains = tmp->pub.chains;
memcpy(found->pub.chain_signal, tmp->pub.chain_signal,
IEEE80211_MAX_CHAINS);
ether_addr_copy(found->parent_bssid, tmp->parent_bssid);
found->pub.max_bssid_indicator = tmp->pub.max_bssid_indicator;
found->pub.bssid_index = tmp->pub.bssid_index;
if (!cfg80211_update_known_bss(rdev, found, tmp, signal_valid))
goto drop;
} else {
struct cfg80211_internal_bss *new;
struct cfg80211_internal_bss *hidden;
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