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Merge branch 'net-lan966x-fix-issues-with-mac-table'
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Horatiu Vultur says:

====================
net: lan966x: Fix issues with MAC table

The patch series fixes 2 issues:
- when an entry was forgotten the irq thread was holding a spin lock and then
  was talking also rtnl_lock.
- the access to the HW MAC table is indirect, so the access to the HW MAC
  table was not synchronized, which means that there could be race conditions.
====================

Link: https://lore.kernel.org/r/20220714194040.231651-1-horatiu.vultur@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Jakub Kicinski committed Jul 19, 2022
2 parents c32349f + 675c807 commit b6224a3
Showing 1 changed file with 80 additions and 32 deletions.
112 changes: 80 additions & 32 deletions drivers/net/ethernet/microchip/lan966x/lan966x_mac.c
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Original file line number Diff line number Diff line change
Expand Up @@ -75,6 +75,9 @@ static int __lan966x_mac_learn(struct lan966x *lan966x, int pgid,
unsigned int vid,
enum macaccess_entry_type type)
{
int ret;

spin_lock(&lan966x->mac_lock);
lan966x_mac_select(lan966x, mac, vid);

/* Issue a write command */
Expand All @@ -86,7 +89,10 @@ static int __lan966x_mac_learn(struct lan966x *lan966x, int pgid,
ANA_MACACCESS_MAC_TABLE_CMD_SET(MACACCESS_CMD_LEARN),
lan966x, ANA_MACACCESS);

return lan966x_mac_wait_for_completion(lan966x);
ret = lan966x_mac_wait_for_completion(lan966x);
spin_unlock(&lan966x->mac_lock);

return ret;
}

/* The mask of the front ports is encoded inside the mac parameter via a call
Expand All @@ -113,11 +119,13 @@ int lan966x_mac_learn(struct lan966x *lan966x, int port,
return __lan966x_mac_learn(lan966x, port, false, mac, vid, type);
}

int lan966x_mac_forget(struct lan966x *lan966x,
const unsigned char mac[ETH_ALEN],
unsigned int vid,
enum macaccess_entry_type type)
static int lan966x_mac_forget_locked(struct lan966x *lan966x,
const unsigned char mac[ETH_ALEN],
unsigned int vid,
enum macaccess_entry_type type)
{
lockdep_assert_held(&lan966x->mac_lock);

lan966x_mac_select(lan966x, mac, vid);

/* Issue a forget command */
Expand All @@ -128,6 +136,20 @@ int lan966x_mac_forget(struct lan966x *lan966x,
return lan966x_mac_wait_for_completion(lan966x);
}

int lan966x_mac_forget(struct lan966x *lan966x,
const unsigned char mac[ETH_ALEN],
unsigned int vid,
enum macaccess_entry_type type)
{
int ret;

spin_lock(&lan966x->mac_lock);
ret = lan966x_mac_forget_locked(lan966x, mac, vid, type);
spin_unlock(&lan966x->mac_lock);

return ret;
}

int lan966x_mac_cpu_learn(struct lan966x *lan966x, const char *addr, u16 vid)
{
return lan966x_mac_learn(lan966x, PGID_CPU, addr, vid, ENTRYTYPE_LOCKED);
Expand Down Expand Up @@ -161,7 +183,7 @@ static struct lan966x_mac_entry *lan966x_mac_alloc_entry(const unsigned char *ma
{
struct lan966x_mac_entry *mac_entry;

mac_entry = kzalloc(sizeof(*mac_entry), GFP_KERNEL);
mac_entry = kzalloc(sizeof(*mac_entry), GFP_ATOMIC);
if (!mac_entry)
return NULL;

Expand All @@ -179,7 +201,6 @@ static struct lan966x_mac_entry *lan966x_mac_find_entry(struct lan966x *lan966x,
struct lan966x_mac_entry *res = NULL;
struct lan966x_mac_entry *mac_entry;

spin_lock(&lan966x->mac_lock);
list_for_each_entry(mac_entry, &lan966x->mac_entries, list) {
if (mac_entry->vid == vid &&
ether_addr_equal(mac, mac_entry->mac) &&
Expand All @@ -188,7 +209,6 @@ static struct lan966x_mac_entry *lan966x_mac_find_entry(struct lan966x *lan966x,
break;
}
}
spin_unlock(&lan966x->mac_lock);

return res;
}
Expand Down Expand Up @@ -231,8 +251,11 @@ int lan966x_mac_add_entry(struct lan966x *lan966x, struct lan966x_port *port,
{
struct lan966x_mac_entry *mac_entry;

if (lan966x_mac_lookup(lan966x, addr, vid, ENTRYTYPE_NORMAL))
spin_lock(&lan966x->mac_lock);
if (lan966x_mac_lookup(lan966x, addr, vid, ENTRYTYPE_NORMAL)) {
spin_unlock(&lan966x->mac_lock);
return 0;
}

/* In case the entry already exists, don't add it again to SW,
* just update HW, but we need to look in the actual HW because
Expand All @@ -241,21 +264,25 @@ int lan966x_mac_add_entry(struct lan966x *lan966x, struct lan966x_port *port,
* add the entry but without the extern_learn flag.
*/
mac_entry = lan966x_mac_find_entry(lan966x, addr, vid, port->chip_port);
if (mac_entry)
return lan966x_mac_learn(lan966x, port->chip_port,
addr, vid, ENTRYTYPE_LOCKED);
if (mac_entry) {
spin_unlock(&lan966x->mac_lock);
goto mac_learn;
}

mac_entry = lan966x_mac_alloc_entry(addr, vid, port->chip_port);
if (!mac_entry)
if (!mac_entry) {
spin_unlock(&lan966x->mac_lock);
return -ENOMEM;
}

spin_lock(&lan966x->mac_lock);
list_add_tail(&mac_entry->list, &lan966x->mac_entries);
spin_unlock(&lan966x->mac_lock);

lan966x_mac_learn(lan966x, port->chip_port, addr, vid, ENTRYTYPE_LOCKED);
lan966x_fdb_call_notifiers(SWITCHDEV_FDB_OFFLOADED, addr, vid, port->dev);

mac_learn:
lan966x_mac_learn(lan966x, port->chip_port, addr, vid, ENTRYTYPE_LOCKED);

return 0;
}

Expand All @@ -269,8 +296,9 @@ int lan966x_mac_del_entry(struct lan966x *lan966x, const unsigned char *addr,
list) {
if (mac_entry->vid == vid &&
ether_addr_equal(addr, mac_entry->mac)) {
lan966x_mac_forget(lan966x, mac_entry->mac, mac_entry->vid,
ENTRYTYPE_LOCKED);
lan966x_mac_forget_locked(lan966x, mac_entry->mac,
mac_entry->vid,
ENTRYTYPE_LOCKED);

list_del(&mac_entry->list);
kfree(mac_entry);
Expand All @@ -288,8 +316,8 @@ void lan966x_mac_purge_entries(struct lan966x *lan966x)
spin_lock(&lan966x->mac_lock);
list_for_each_entry_safe(mac_entry, tmp, &lan966x->mac_entries,
list) {
lan966x_mac_forget(lan966x, mac_entry->mac, mac_entry->vid,
ENTRYTYPE_LOCKED);
lan966x_mac_forget_locked(lan966x, mac_entry->mac,
mac_entry->vid, ENTRYTYPE_LOCKED);

list_del(&mac_entry->list);
kfree(mac_entry);
Expand Down Expand Up @@ -325,10 +353,13 @@ static void lan966x_mac_irq_process(struct lan966x *lan966x, u32 row,
{
struct lan966x_mac_entry *mac_entry, *tmp;
unsigned char mac[ETH_ALEN] __aligned(2);
struct list_head mac_deleted_entries;
u32 dest_idx;
u32 column;
u16 vid;

INIT_LIST_HEAD(&mac_deleted_entries);

spin_lock(&lan966x->mac_lock);
list_for_each_entry_safe(mac_entry, tmp, &lan966x->mac_entries, list) {
bool found = false;
Expand Down Expand Up @@ -362,20 +393,26 @@ static void lan966x_mac_irq_process(struct lan966x *lan966x, u32 row,
}

if (!found) {
/* Notify the bridge that the entry doesn't exist
* anymore in the HW and remove the entry from the SW
* list
*/
lan966x_mac_notifiers(SWITCHDEV_FDB_DEL_TO_BRIDGE,
mac_entry->mac, mac_entry->vid,
lan966x->ports[mac_entry->port_index]->dev);

list_del(&mac_entry->list);
kfree(mac_entry);
/* Move the entry from SW list to a tmp list such that
* it would be deleted later
*/
list_add_tail(&mac_entry->list, &mac_deleted_entries);
}
}
spin_unlock(&lan966x->mac_lock);

list_for_each_entry_safe(mac_entry, tmp, &mac_deleted_entries, list) {
/* Notify the bridge that the entry doesn't exist
* anymore in the HW
*/
lan966x_mac_notifiers(SWITCHDEV_FDB_DEL_TO_BRIDGE,
mac_entry->mac, mac_entry->vid,
lan966x->ports[mac_entry->port_index]->dev);
list_del(&mac_entry->list);
kfree(mac_entry);
}

/* Now go to the list of columns and see if any entry was not in the SW
* list, then that means that the entry is new so it needs to notify the
* bridge.
Expand All @@ -396,13 +433,20 @@ static void lan966x_mac_irq_process(struct lan966x *lan966x, u32 row,
if (WARN_ON(dest_idx >= lan966x->num_phys_ports))
continue;

spin_lock(&lan966x->mac_lock);
mac_entry = lan966x_mac_find_entry(lan966x, mac, vid, dest_idx);
if (mac_entry) {
spin_unlock(&lan966x->mac_lock);
continue;
}

mac_entry = lan966x_mac_alloc_entry(mac, vid, dest_idx);
if (!mac_entry)
if (!mac_entry) {
spin_unlock(&lan966x->mac_lock);
return;
}

mac_entry->row = row;

spin_lock(&lan966x->mac_lock);
list_add_tail(&mac_entry->list, &lan966x->mac_entries);
spin_unlock(&lan966x->mac_lock);

Expand All @@ -424,6 +468,7 @@ irqreturn_t lan966x_mac_irq_handler(struct lan966x *lan966x)
lan966x, ANA_MACTINDX);

while (1) {
spin_lock(&lan966x->mac_lock);
lan_rmw(ANA_MACACCESS_MAC_TABLE_CMD_SET(MACACCESS_CMD_SYNC_GET_NEXT),
ANA_MACACCESS_MAC_TABLE_CMD,
lan966x, ANA_MACACCESS);
Expand All @@ -447,12 +492,15 @@ irqreturn_t lan966x_mac_irq_handler(struct lan966x *lan966x)
stop = false;

if (column == LAN966X_MAC_COLUMNS - 1 &&
index == 0 && stop)
index == 0 && stop) {
spin_unlock(&lan966x->mac_lock);
break;
}

entry[column].mach = lan_rd(lan966x, ANA_MACHDATA);
entry[column].macl = lan_rd(lan966x, ANA_MACLDATA);
entry[column].maca = lan_rd(lan966x, ANA_MACACCESS);
spin_unlock(&lan966x->mac_lock);

/* Once all the columns are read process them */
if (column == LAN966X_MAC_COLUMNS - 1) {
Expand Down

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