[PATCH net-next] net: dsa: lan9303: Protect ALR operations with mutex

[Egil Hjelmeland]

ALR table operations are a sequence of related register operations which
should be protected from concurrent access. The alr_cache should also be
protected. Add alr_mutex doing that.

Signed-off-by: Egil Hjelmeland <pri...@egil-hjelmeland.no>
---
 drivers/net/dsa/lan9303-core.c | 14 ++++++++++++--
 include/linux/dsa/lan9303.h    |  1 +
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/lan9303-core.c b/drivers/net/dsa/lan9303-core.c
index ea59dadefb33..c1b004fa64d9 100644
--- a/drivers/net/dsa/lan9303-core.c
+++ b/drivers/net/dsa/lan9303-core.c
@@ -583,6 +583,7 @@ static void lan9303_alr_loop(struct lan9303 *chip, 
alr_loop_cb_t *cb, void *ctx)
 {
        int i;
 
+       mutex_lock(&chip->alr_mutex);
        lan9303_write_switch_reg(chip, LAN9303_SWE_ALR_CMD,
                                 LAN9303_ALR_CMD_GET_FIRST);
        lan9303_write_switch_reg(chip, LAN9303_SWE_ALR_CMD, 0);
@@ -606,6 +607,7 @@ static void lan9303_alr_loop(struct lan9303 *chip, 
alr_loop_cb_t *cb, void *ctx)
                                         LAN9303_ALR_CMD_GET_NEXT);
                lan9303_write_switch_reg(chip, LAN9303_SWE_ALR_CMD, 0);
        }
+       mutex_unlock(&chip->alr_mutex);
 }
 
 static void alr_reg_to_mac(u32 dat0, u32 dat1, u8 mac[6])
@@ -694,16 +696,20 @@ static int lan9303_alr_add_port(struct lan9303 *chip, 
const u8 *mac, int port,
 {
        struct lan9303_alr_cache_entry *entr;
 
+       mutex_lock(&chip->alr_mutex);
        entr = lan9303_alr_cache_find_mac(chip, mac);
        if (!entr) { /*New entry */
                entr = lan9303_alr_cache_find_free(chip);
-               if (!entr)
+               if (!entr) {
+                       mutex_unlock(&chip->alr_mutex);
                        return -ENOSPC;
+               }
                ether_addr_copy(entr->mac_addr, mac);
        }
        entr->port_map |= BIT(port);
        entr->stp_override = stp_override;
        lan9303_alr_set_entry(chip, mac, entr->port_map, stp_override);
+       mutex_unlock(&chip->alr_mutex);
 
        return 0;
 }
@@ -713,15 +719,18 @@ static int lan9303_alr_del_port(struct lan9303 *chip, 
const u8 *mac, int port)
 {
        struct lan9303_alr_cache_entry *entr;
 
+       mutex_lock(&chip->alr_mutex);
        entr = lan9303_alr_cache_find_mac(chip, mac);
        if (!entr)
-               return 0;  /* no static entry found */
+               goto out;  /* no static entry found */
 
        entr->port_map &= ~BIT(port);
        if (entr->port_map == 0) /* zero means its free again */
                eth_zero_addr(entr->mac_addr);
        lan9303_alr_set_entry(chip, mac, entr->port_map, entr->stp_override);
 
+out:
+       mutex_unlock(&chip->alr_mutex);
        return 0;
 }
 
@@ -1323,6 +1332,7 @@ int lan9303_probe(struct lan9303 *chip, struct 
device_node *np)
        int ret;
 
        mutex_init(&chip->indirect_mutex);
+       mutex_init(&chip->alr_mutex);
 
        lan9303_probe_reset_gpio(chip, np);
 
diff --git a/include/linux/dsa/lan9303.h b/include/linux/dsa/lan9303.h
index f48a85c377de..b6514c29563f 100644
--- a/include/linux/dsa/lan9303.h
+++ b/include/linux/dsa/lan9303.h
@@ -26,6 +26,7 @@ struct lan9303 {
        bool phy_addr_sel_strap;
        struct dsa_switch *ds;
        struct mutex indirect_mutex; /* protect indexed register access */
+       struct mutex alr_mutex; /* protect ALR access */
        const struct lan9303_phy_ops *ops;
        bool is_bridged; /* true if port 1 and 2 are bridged */
 
-- 
2.14.1