devlink: convert occ_get op to separate registration

This resolves race during initialization where the resources with
ops are registered before driver and the structures used by occ_get
op is initialized. So keep occ_get callbacks registered only when
all structs are initialized.

The example flows, as it is in mlxsw:
1) driver load/asic probe:
   mlxsw_core
      -> mlxsw_sp_resources_register
        -> mlxsw_sp_kvdl_resources_register
          -> devlink_resource_register IDX
   mlxsw_spectrum
      -> mlxsw_sp_kvdl_init
        -> mlxsw_sp_kvdl_parts_init
          -> mlxsw_sp_kvdl_part_init
            -> devlink_resource_size_get IDX (to get the current setup
                                              size from devlink)
        -> devlink_resource_occ_get_register IDX (register current
                                                  occupancy getter)
2) reload triggered by devlink command:
  -> mlxsw_devlink_core_bus_device_reload
    -> mlxsw_sp_fini
      -> mlxsw_sp_kvdl_fini
	-> devlink_resource_occ_get_unregister IDX
    (struct mlxsw_sp *mlxsw_sp is freed at this point, call to occ get
     which is using mlxsw_sp would cause use-after free)
    -> mlxsw_sp_init
      -> mlxsw_sp_kvdl_init
        -> mlxsw_sp_kvdl_parts_init
          -> mlxsw_sp_kvdl_part_init
            -> devlink_resource_size_get IDX (to get the current setup
                                              size from devlink)
        -> devlink_resource_occ_get_register IDX (register current
                                                  occupancy getter)

Fixes: d9f9b9a4d05f ("devlink: Add support for resource abstraction")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 34 deletions

diff --git a/drivers/net/netdevsim/devlink.c b/drivers/net/netdevsim/devlink.c
index 1dba47936456..bef7db5d129a 100644
--- a/drivers/net/netdevsim/devlink.c
+++ b/drivers/net/netdevsim/devlink.c
@@ -30,52 +30,36 @@ static struct net *nsim_devlink_net(struct devlink *devlink)
 
 /* IPv4
  */
-static u64 nsim_ipv4_fib_resource_occ_get(struct devlink *devlink)
+static u64 nsim_ipv4_fib_resource_occ_get(void *priv)
 {
-	struct net *net = nsim_devlink_net(devlink);
+	struct net *net = priv;
 
 	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB, false);
 }
 
-static struct devlink_resource_ops nsim_ipv4_fib_res_ops = {
-	.occ_get = nsim_ipv4_fib_resource_occ_get,
-};
-
-static u64 nsim_ipv4_fib_rules_res_occ_get(struct devlink *devlink)
+static u64 nsim_ipv4_fib_rules_res_occ_get(void *priv)
 {
-	struct net *net = nsim_devlink_net(devlink);
+	struct net *net = priv;
 
 	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB_RULES, false);
 }
 
-static struct devlink_resource_ops nsim_ipv4_fib_rules_res_ops = {
-	.occ_get = nsim_ipv4_fib_rules_res_occ_get,
-};
-
 /* IPv6
  */
-static u64 nsim_ipv6_fib_resource_occ_get(struct devlink *devlink)
+static u64 nsim_ipv6_fib_resource_occ_get(void *priv)
 {
-	struct net *net = nsim_devlink_net(devlink);
+	struct net *net = priv;
 
 	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB, false);
 }
 
-static struct devlink_resource_ops nsim_ipv6_fib_res_ops = {
-	.occ_get = nsim_ipv6_fib_resource_occ_get,
-};
-
-static u64 nsim_ipv6_fib_rules_res_occ_get(struct devlink *devlink)
+static u64 nsim_ipv6_fib_rules_res_occ_get(void *priv)
 {
-	struct net *net = nsim_devlink_net(devlink);
+	struct net *net = priv;
 
 	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB_RULES, false);
 }
 
-static struct devlink_resource_ops nsim_ipv6_fib_rules_res_ops = {
-	.occ_get = nsim_ipv6_fib_rules_res_occ_get,
-};
-
 static int devlink_resources_register(struct devlink *devlink)
 {
 	struct devlink_resource_size_params params = {
@@ -91,7 +75,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	err = devlink_resource_register(devlink, "IPv4", (u64)-1,
 					NSIM_RESOURCE_IPV4,
 					DEVLINK_RESOURCE_ID_PARENT_TOP,
-					&params, NULL);
+					&params);
 	if (err) {
 		pr_err("Failed to register IPv4 top resource\n");
 		goto out;
@@ -100,8 +84,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB, true);
 	err = devlink_resource_register(devlink, "fib", n,
 					NSIM_RESOURCE_IPV4_FIB,
-					NSIM_RESOURCE_IPV4,
-					&params, &nsim_ipv4_fib_res_ops);
+					NSIM_RESOURCE_IPV4, &params);
 	if (err) {
 		pr_err("Failed to register IPv4 FIB resource\n");
 		return err;
@@ -110,8 +93,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB_RULES, true);
 	err = devlink_resource_register(devlink, "fib-rules", n,
 					NSIM_RESOURCE_IPV4_FIB_RULES,
-					NSIM_RESOURCE_IPV4,
-					&params, &nsim_ipv4_fib_rules_res_ops);
+					NSIM_RESOURCE_IPV4, &params);
 	if (err) {
 		pr_err("Failed to register IPv4 FIB rules resource\n");
 		return err;
@@ -121,7 +103,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	err = devlink_resource_register(devlink, "IPv6", (u64)-1,
 					NSIM_RESOURCE_IPV6,
 					DEVLINK_RESOURCE_ID_PARENT_TOP,
-					&params, NULL);
+					&params);
 	if (err) {
 		pr_err("Failed to register IPv6 top resource\n");
 		goto out;
@@ -130,8 +112,7 @@ static int devlink_resources_register(struct devlink *devlink)
 	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB, true);
 	err = devlink_resource_register(devlink, "fib", n,
 					NSIM_RESOURCE_IPV6_FIB,
-					NSIM_RESOURCE_IPV6,
-					&params, &nsim_ipv6_fib_res_ops);
+					NSIM_RESOURCE_IPV6, &params);
 	if (err) {
 		pr_err("Failed to register IPv6 FIB resource\n");
 		return err;
@@ -140,12 +121,28 @@ static int devlink_resources_register(struct devlink *devlink)
 	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB_RULES, true);
 	err = devlink_resource_register(devlink, "fib-rules", n,
 					NSIM_RESOURCE_IPV6_FIB_RULES,
-					NSIM_RESOURCE_IPV6,
-					&params, &nsim_ipv6_fib_rules_res_ops);
+					NSIM_RESOURCE_IPV6, &params);
 	if (err) {
 		pr_err("Failed to register IPv6 FIB rules resource\n");
 		return err;
 	}
+
+	devlink_resource_occ_get_register(devlink,
+					  NSIM_RESOURCE_IPV4_FIB,
+					  nsim_ipv4_fib_resource_occ_get,
+					  net);
+	devlink_resource_occ_get_register(devlink,
+					  NSIM_RESOURCE_IPV4_FIB_RULES,
+					  nsim_ipv4_fib_rules_res_occ_get,
+					  net);
+	devlink_resource_occ_get_register(devlink,
+					  NSIM_RESOURCE_IPV6_FIB,
+					  nsim_ipv6_fib_resource_occ_get,
+					  net);
+	devlink_resource_occ_get_register(devlink,
+					  NSIM_RESOURCE_IPV6_FIB_RULES,
+					  nsim_ipv6_fib_rules_res_occ_get,
+					  net);
 out:
 	return err;
 }