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batman-adv: replace non-atomic packet_size_max with (READ|WRITE)_ONCE

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The maximum packet size of an meshif is only accessed as plain loads/stores
and does not require full atomic_t semantics. Convert to a native integer
and replace its users with READ_ONCE()/WRITE_ONCE() to avoid load/store
tearing.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
This commit is contained in:
Sven Eckelmann 2026-05-12 19:37:05 +02:00
parent 2b2450e326
commit 58020571b5
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GPG Key ID: 4D0F772BD314F5CB
4 changed files with 6 additions and 7 deletions
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3
net/batman-adv/hard-interface.c
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@ -7,7 +7,6 @@
#include "hard-interface.h"
#include "main.h"
#include <linux/atomic.h>
#include <linux/bug.h>
#include <linux/byteorder/generic.h>
#include <linux/compiler.h>
@ -629,7 +628,7 @@ int batadv_hardif_min_mtu(struct net_device *mesh_iface)
* overhead). For example, this value is used by TT to compute the
* maximum local table size
*/
atomic_set(&bat_priv->packet_size_max, min_mtu);
WRITE_ONCE(bat_priv->packet_size_max, min_mtu);
/* the real mesh-interface MTU is computed by removing the payload
* overhead from the maximum amount of bytes that was just computed.

2
net/batman-adv/mesh-interface.c
View File

@ -779,7 +779,7 @@ static int batadv_meshif_init_late(struct net_device *dev)
WRITE_ONCE(bat_priv->log_level, 0);
#endif
WRITE_ONCE(bat_priv->fragmentation, 1);
atomic_set(&bat_priv->packet_size_max, BATADV_MAX_MTU);
WRITE_ONCE(bat_priv->packet_size_max, BATADV_MAX_MTU);
atomic_set(&bat_priv->bcast_queue_left, BATADV_BCAST_QUEUE_LEN);
atomic_set(&bat_priv->batman_queue_left, BATADV_BATMAN_QUEUE_LEN);

6
net/batman-adv/translation-table.c
View File

@ -649,7 +649,7 @@ bool batadv_tt_local_add(struct net_device *mesh_iface, const u8 *addr,
/* Ignore the client if we cannot send it in a full table response. */
table_size = batadv_tt_local_table_transmit_size(bat_priv);
table_size += batadv_tt_len(1);
packet_size_max = atomic_read(&bat_priv->packet_size_max);
packet_size_max = READ_ONCE(bat_priv->packet_size_max);
if (table_size > packet_size_max) {
net_ratelimited_function(batadv_info, mesh_iface,
"Local translation table size (%i) exceeds maximum packet size (%i); Ignoring new local tt entry: %pM\n",
@ -3069,7 +3069,7 @@ static bool batadv_send_other_tt_response(struct batadv_priv *bat_priv,
/* Don't send the response, if larger than fragmented packet. */
tt_len = sizeof(struct batadv_unicast_tvlv_packet) + tvlv_len;
if (tt_len > atomic_read(&bat_priv->packet_size_max)) {
if (tt_len > READ_ONCE(bat_priv->packet_size_max)) {
net_ratelimited_function(batadv_info, bat_priv->mesh_iface,
"Ignoring TT_REQUEST from %pM; Response size exceeds max packet size.\n",
res_dst_orig_node->orig);
@ -3932,7 +3932,7 @@ bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv,
void batadv_tt_local_resize_to_mtu(struct net_device *mesh_iface)
{
struct batadv_priv *bat_priv = netdev_priv(mesh_iface);
int packet_size_max = atomic_read(&bat_priv->packet_size_max);
int packet_size_max = READ_ONCE(bat_priv->packet_size_max);
int table_size, timeout = BATADV_TT_LOCAL_TIMEOUT / 2;
bool reduced = false;

2
net/batman-adv/types.h
View File

@ -1570,7 +1570,7 @@ struct batadv_priv {
* multiple fragmented skbs or a single frame if fragmentation is
* disabled
*/
atomic_t packet_size_max;
int packet_size_max;
/**
* @frag_seqno: incremental counter to identify chains of egress