github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

batman-adv: tt: remove only the entry which was looked up from the hash

Browse Source 
batadv_hash_remove() searches a bucket with a compare callback and unlinks
the first matching entry. batadv_compare_tt() matches any entry for the
same MAC address and VLAN, not the object which was passed in, and the
callers in batadv_tt_local_remove() and batadv_tt_global_free() are not
serialized against the rest of the translation table in any way.

So when the looked up entry was already unlinked by another context and a
new entry for the same client was added in the meantime, these two
functions unlink that new entry instead.

Add batadv_compare_tt_entry(), which matches the very object which is
searched for, and use it for both removals. Nothing is unlinked when the
entry is gone already, batadv_hash_remove() then simply returns NULL and
only the reference of the calling context is dropped.

As a side effect the returned hlist_node can no longer belong to a
different object, so both functions can operate on the entry they were
given.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
This commit is contained in:
Sven Eckelmann 2026-08-30 17:21:38 +02:00
parent d9304a90ec
commit bbfb0d2cf0
No known key found for this signature in database
GPG Key ID: 4D0F772BD314F5CB
1 changed files with 26 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
net/batman-adv/translation-table.c
View File

@ -95,6 +95,26 @@ static bool batadv_compare_tt(const struct hlist_node *node, const void *data2)
return (tt1->vid == tt2->vid) && batadv_compare_eth(data1, data2);
}
/**
* batadv_compare_tt_entry() - check if a hash node is a specific TT entry
* @node: the list element pointer of the TT entry stored in the bucket
* @data2: pointer to the tt_common_entry which is looked for
*
* Unlike batadv_compare_tt(), this only matches the very object which is
* passed as @data2 and not just any entry for the same TT client. It is meant
* for batadv_hash_remove() callers which must not unlink an entry they did not
* look up themselves.
*
* Return: true if @node belongs to @data2, false otherwise
*/
static bool batadv_compare_tt_entry(const struct hlist_node *node,
const void *data2)
{
const struct batadv_tt_common_entry *tt = data2;
return node == &tt->hash_entry;
}
/**
* batadv_choose_tt() - return the index of the tt entry in the hash table
* @data: pointer to the tt_common_entry object to map
@ -575,7 +595,6 @@ static void batadv_tt_global_free(struct batadv_priv *bat_priv,
struct batadv_tt_global_entry *tt_global,
const char *message)
{
struct batadv_tt_global_entry *tt_removed_entry;
struct hlist_node *tt_removed_node;
batadv_dbg(BATADV_DBG_TT, bat_priv,
@ -583,18 +602,16 @@ static void batadv_tt_global_free(struct batadv_priv *bat_priv,
tt_global->common.addr,
batadv_print_vid(tt_global->common.vid), message);
/* remove exactly this object when still present in hash */
tt_removed_node = batadv_hash_remove(bat_priv->tt.global_hash,
batadv_compare_tt,
batadv_compare_tt_entry,
batadv_choose_tt,
&tt_global->common);
if (!tt_removed_node)
return;
/* drop reference of remove hash entry */
tt_removed_entry = hlist_entry(tt_removed_node,
struct batadv_tt_global_entry,
common.hash_entry);
batadv_tt_global_entry_put(tt_removed_entry);
batadv_tt_global_entry_put(tt_global);
}
/**
@ -1292,7 +1309,6 @@ u16 batadv_tt_local_remove(struct batadv_priv *bat_priv, const u8 *addr,
unsigned short vid, const char *message,
bool roaming)
{
struct batadv_tt_local_entry *tt_removed_entry;
struct batadv_tt_local_entry *tt_local_entry;
struct hlist_node *tt_removed_node;
u16 curr_flags = BATADV_NO_FLAGS;
@ -1325,18 +1341,16 @@ u16 batadv_tt_local_remove(struct batadv_priv *bat_priv, const u8 *addr,
*/
batadv_tt_local_event(bat_priv, tt_local_entry, BATADV_TT_CLIENT_DEL);
/* remove exactly this object when still present in hash */
tt_removed_node = batadv_hash_remove(bat_priv->tt.local_hash,
batadv_compare_tt,
batadv_compare_tt_entry,
batadv_choose_tt,
&tt_local_entry->common);
if (!tt_removed_node)
goto out;
/* drop reference of remove hash entry */
tt_removed_entry = hlist_entry(tt_removed_node,
struct batadv_tt_local_entry,
common.hash_entry);
batadv_tt_local_entry_put(tt_removed_entry);
batadv_tt_local_entry_put(tt_local_entry);
out:
batadv_tt_local_entry_put(tt_local_entry);