@@ -27,6 +27,7 @@
*/
#include <linux/bitops.h>
+#include <linux/cleanup.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/fwnode.h>
@@ -467,6 +468,8 @@ struct ub960_rxport {
};
} eq;
+ /* lock for aliased_addrs and associated registers */
+ struct mutex aliased_addrs_lock;
u16 aliased_addrs[UB960_MAX_PORT_ALIASES];
};
@@ -1031,6 +1034,8 @@ static int ub960_atr_attach_client(struct i2c_atr *atr, u32 chan_id,
struct device *dev = &priv->client->dev;
unsigned int reg_idx;
+ guard(mutex)(&rxport->aliased_addrs_lock);
+
for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_addrs); reg_idx++) {
if (!rxport->aliased_addrs[reg_idx])
break;
@@ -1062,6 +1067,8 @@ static void ub960_atr_detach_client(struct i2c_atr *atr, u32 chan_id,
struct device *dev = &priv->client->dev;
unsigned int reg_idx;
+ guard(mutex)(&rxport->aliased_addrs_lock);
+
for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_addrs); reg_idx++) {
if (rxport->aliased_addrs[reg_idx] == client->addr)
break;
@@ -3181,6 +3188,8 @@ static void ub960_rxport_free_ports(struct ub960_data *priv)
fwnode_handle_put(rxport->source.ep_fwnode);
fwnode_handle_put(rxport->ser.fwnode);
+ mutex_destroy(&rxport->aliased_addrs_lock);
+
kfree(rxport);
priv->rxports[nport] = NULL;
}
@@ -3401,6 +3410,8 @@ static int ub960_parse_dt_rxport(struct ub960_data *priv, unsigned int nport,
if (ret)
goto err_put_remote_fwnode;
+ mutex_init(&rxport->aliased_addrs_lock);
+
return 0;
err_put_remote_fwnode:
The aliased_addrs list represents the occupation of an RX port's hardware alias table. This list and the underlying hardware table are only accessed in the attach/detach_client() callbacks. These functions are only called from a bus notifier handler in i2c-atr.c, which is always called with the notifier chain's semaphore held. This indirectly prevents concurrent access to the aliased_addrs list. However, more explicit and direct locking is preferable. Moreover, with the introduction of dynamic address translation in a future patch, the attach/detach_client() callbacks will be called from outside of the notifier chain's read section. Introduce a mutex to protect access to the aliased_addrs list and its underlying hardware table. Signed-off-by: Romain Gantois <romain.gantois@bootlin.com> --- drivers/media/i2c/ds90ub960.c | 11 +++++++++++ 1 file changed, 11 insertions(+)