diff mbox series

[net-next,v2,1/5] devlink: Reduce struct devlink exposure

Message ID d21ebe6fde8139d5630ef4ebc9c5eb6ed18b0e3b.1633284302.git.leonro@nvidia.com (mailing list archive)
State Superseded
Headers show
Series devlink reload simplification | expand

Commit Message

Leon Romanovsky Oct. 3, 2021, 6:12 p.m. UTC 
From: Leon Romanovsky <leonro@nvidia.com>

The declaration of struct devlink in general header provokes the
situation where internal fields can be accidentally used by the driver
authors. In order to reduce such possible situations, let's reduce the
namespace exposure of struct devlink.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlxfw/mlxfw.h |  2 +-
 include/net/devlink.h                       | 54 ++--------------
 include/trace/events/devlink.h              | 72 ++++++++++-----------
 net/core/devlink.c                          | 59 +++++++++++++++++
 4 files changed, 100 insertions(+), 87 deletions(-)

Comments

Jakub Kicinski Oct. 4, 2021, 11:38 p.m. UTC | #1 
On Sun,  3 Oct 2021 21:12:02 +0300 Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
> 
> The declaration of struct devlink in general header provokes the
> situation where internal fields can be accidentally used by the driver
> authors. In order to reduce such possible situations, let's reduce the
> namespace exposure of struct devlink.
> 
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

100% subjective but every time I decided to hide a structure definition
like this I came to regret it later. The fact there is only one minor
infraction in drivers poking at members seems to prove this is not in
fact needed.
Leon Romanovsky Oct. 5, 2021, 6:13 a.m. UTC | #2 
On Mon, Oct 04, 2021 at 04:38:08PM -0700, Jakub Kicinski wrote:
> On Sun,  3 Oct 2021 21:12:02 +0300 Leon Romanovsky wrote:
> > From: Leon Romanovsky <leonro@nvidia.com>
> > 
> > The declaration of struct devlink in general header provokes the
> > situation where internal fields can be accidentally used by the driver
> > authors. In order to reduce such possible situations, let's reduce the
> > namespace exposure of struct devlink.
> > 
> > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> 
> 100% subjective but every time I decided to hide a structure definition
> like this I came to regret it later. The fact there is only one minor
> infraction in drivers poking at members seems to prove this is not in
> fact needed.

Yes, it is subjective, my experience is completely opposite :). Every
time the internals were exposed, they were abused.

IMHO, the one user that poked into the struct devlink internals is a pure
luck together with lack of devlink adoption outside of the netdev which
limited number of devlink API users. The more devlink will be used, the
more creative usage will be.

For example, ionic had internal logic based on internal devlink_port state:
 * c2255ff47768 ("ionic: cleanly release devlink instance")
 * d7907a2b1a3b ("devlink: Remove duplicated registration check")

However, this patch was written not because of having right software
abstraction, but because of the next patch, where I needed to have
declaration of "struct devlink_ops" before struct devlink itself.

Without this patch, I would need to heavily reshuffle include/net/devlink.h
to have structs declarations written in different order. So a lot of
churn for something that needs to be fixed anyway (in my opinion).

Thanks
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mellanox/mlxfw/mlxfw.h b/drivers/net/ethernet/mellanox/mlxfw/mlxfw.h
index 7654841a05c2..e6475ea77cd1 100644
--- a/drivers/net/ethernet/mellanox/mlxfw/mlxfw.h
+++ b/drivers/net/ethernet/mellanox/mlxfw/mlxfw.h
@@ -19,7 +19,7 @@  struct mlxfw_dev {
 static inline
 struct device *mlxfw_dev_dev(struct mlxfw_dev *mlxfw_dev)
 {
-	return mlxfw_dev->devlink->dev;
+	return devlink_to_dev(mlxfw_dev->devlink);
 }
 
 #define MLXFW_PRFX "mlxfw: "
diff --git a/include/net/devlink.h b/include/net/devlink.h
index a7852a257bf6..ae03eb1c6cc9 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -21,45 +21,7 @@ 
 #include <linux/xarray.h>
 #include <linux/firmware.h>
 
-#define DEVLINK_RELOAD_STATS_ARRAY_SIZE \
-	(__DEVLINK_RELOAD_LIMIT_MAX * __DEVLINK_RELOAD_ACTION_MAX)
-
-struct devlink_dev_stats {
-	u32 reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
-	u32 remote_reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
-};
-
-struct devlink_ops;
-
-struct devlink {
-	u32 index;
-	struct list_head port_list;
-	struct list_head rate_list;
-	struct list_head sb_list;
-	struct list_head dpipe_table_list;
-	struct list_head resource_list;
-	struct list_head param_list;
-	struct list_head region_list;
-	struct list_head reporter_list;
-	struct mutex reporters_lock; /* protects reporter_list */
-	struct devlink_dpipe_headers *dpipe_headers;
-	struct list_head trap_list;
-	struct list_head trap_group_list;
-	struct list_head trap_policer_list;
-	const struct devlink_ops *ops;
-	struct xarray snapshot_ids;
-	struct devlink_dev_stats stats;
-	struct device *dev;
-	possible_net_t _net;
-	struct mutex lock; /* Serializes access to devlink instance specific objects such as
-			    * port, sb, dpipe, resource, params, region, traps and more.
-			    */
-	u8 reload_failed:1,
-	   reload_enabled:1;
-	refcount_t refcount;
-	struct completion comp;
-	char priv[0] __aligned(NETDEV_ALIGN);
-};
+struct devlink;
 
 struct devlink_port_phys_attrs {
 	u32 port_number; /* Same value as "split group".
@@ -1520,17 +1482,9 @@  struct devlink_ops {
 				    struct netlink_ext_ack *extack);
 };
 
-static inline void *devlink_priv(struct devlink *devlink)
-{
-	BUG_ON(!devlink);
-	return &devlink->priv;
-}
-
-static inline struct devlink *priv_to_devlink(void *priv)
-{
-	BUG_ON(!priv);
-	return container_of(priv, struct devlink, priv);
-}
+void *devlink_priv(struct devlink *devlink);
+struct devlink *priv_to_devlink(void *priv);
+struct device *devlink_to_dev(const struct devlink *devlink);
 
 static inline struct devlink_port *
 netdev_to_devlink_port(struct net_device *dev)
diff --git a/include/trace/events/devlink.h b/include/trace/events/devlink.h
index 44d8e2981065..2814f188d98c 100644
--- a/include/trace/events/devlink.h
+++ b/include/trace/events/devlink.h
@@ -21,9 +21,9 @@  TRACE_EVENT(devlink_hwmsg,
 	TP_ARGS(devlink, incoming, type, buf, len),
 
 	TP_STRUCT__entry(
-		__string(bus_name, devlink->dev->bus->name)
-		__string(dev_name, dev_name(devlink->dev))
-		__string(driver_name, devlink->dev->driver->name)
+		__string(bus_name, devlink_to_dev(devlink)->bus->name)
+		__string(dev_name, dev_name(devlink_to_dev(devlink)))
+		__string(driver_name, devlink_to_dev(devlink)->driver->name)
 		__field(bool, incoming)
 		__field(unsigned long, type)
 		__dynamic_array(u8, buf, len)
@@ -31,9 +31,9 @@  TRACE_EVENT(devlink_hwmsg,
 	),
 
 	TP_fast_assign(
-		__assign_str(bus_name, devlink->dev->bus->name);
-		__assign_str(dev_name, dev_name(devlink->dev));
-		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(bus_name, devlink_to_dev(devlink)->bus->name);
+		__assign_str(dev_name, dev_name(devlink_to_dev(devlink)));
+		__assign_str(driver_name, devlink_to_dev(devlink)->driver->name);
 		__entry->incoming = incoming;
 		__entry->type = type;
 		memcpy(__get_dynamic_array(buf), buf, len);
@@ -55,17 +55,17 @@  TRACE_EVENT(devlink_hwerr,
 	TP_ARGS(devlink, err, msg),
 
 	TP_STRUCT__entry(
-		__string(bus_name, devlink->dev->bus->name)
-		__string(dev_name, dev_name(devlink->dev))
-		__string(driver_name, devlink->dev->driver->name)
+		__string(bus_name, devlink_to_dev(devlink)->bus->name)
+		__string(dev_name, dev_name(devlink_to_dev(devlink)))
+		__string(driver_name, devlink_to_dev(devlink)->driver->name)
 		__field(int, err)
 		__string(msg, msg)
 		),
 
 	TP_fast_assign(
-		__assign_str(bus_name, devlink->dev->bus->name);
-		__assign_str(dev_name, dev_name(devlink->dev));
-		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(bus_name, devlink_to_dev(devlink)->bus->name);
+		__assign_str(dev_name, dev_name(devlink_to_dev(devlink)));
+		__assign_str(driver_name, devlink_to_dev(devlink)->driver->name);
 		__entry->err = err;
 		__assign_str(msg, msg);
 		),
@@ -85,17 +85,17 @@  TRACE_EVENT(devlink_health_report,
 	TP_ARGS(devlink, reporter_name, msg),
 
 	TP_STRUCT__entry(
-		__string(bus_name, devlink->dev->bus->name)
-		__string(dev_name, dev_name(devlink->dev))
-		__string(driver_name, devlink->dev->driver->name)
+		__string(bus_name, devlink_to_dev(devlink)->bus->name)
+		__string(dev_name, dev_name(devlink_to_dev(devlink)))
+		__string(driver_name, devlink_to_dev(devlink)->driver->name)
 		__string(reporter_name, msg)
 		__string(msg, msg)
 	),
 
 	TP_fast_assign(
-		__assign_str(bus_name, devlink->dev->bus->name);
-		__assign_str(dev_name, dev_name(devlink->dev));
-		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(bus_name, devlink_to_dev(devlink)->bus->name);
+		__assign_str(dev_name, dev_name(devlink_to_dev(devlink)));
+		__assign_str(driver_name, devlink_to_dev(devlink)->driver->name);
 		__assign_str(reporter_name, reporter_name);
 		__assign_str(msg, msg);
 	),
@@ -116,18 +116,18 @@  TRACE_EVENT(devlink_health_recover_aborted,
 	TP_ARGS(devlink, reporter_name, health_state, time_since_last_recover),
 
 	TP_STRUCT__entry(
-		__string(bus_name, devlink->dev->bus->name)
-		__string(dev_name, dev_name(devlink->dev))
-		__string(driver_name, devlink->dev->driver->name)
+		__string(bus_name, devlink_to_dev(devlink)->bus->name)
+		__string(dev_name, dev_name(devlink_to_dev(devlink)))
+		__string(driver_name, devlink_to_dev(devlink)->driver->name)
 		__string(reporter_name, reporter_name)
 		__field(bool, health_state)
 		__field(u64, time_since_last_recover)
 	),
 
 	TP_fast_assign(
-		__assign_str(bus_name, devlink->dev->bus->name);
-		__assign_str(dev_name, dev_name(devlink->dev));
-		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(bus_name, devlink_to_dev(devlink)->bus->name);
+		__assign_str(dev_name, dev_name(devlink_to_dev(devlink)));
+		__assign_str(driver_name, devlink_to_dev(devlink)->driver->name);
 		__assign_str(reporter_name, reporter_name);
 		__entry->health_state = health_state;
 		__entry->time_since_last_recover = time_since_last_recover;
@@ -150,17 +150,17 @@  TRACE_EVENT(devlink_health_reporter_state_update,
 	TP_ARGS(devlink, reporter_name, new_state),
 
 	TP_STRUCT__entry(
-		__string(bus_name, devlink->dev->bus->name)
-		__string(dev_name, dev_name(devlink->dev))
-		__string(driver_name, devlink->dev->driver->name)
+		__string(bus_name, devlink_to_dev(devlink)->bus->name)
+		__string(dev_name, dev_name(devlink_to_dev(devlink)))
+		__string(driver_name, devlink_to_dev(devlink)->driver->name)
 		__string(reporter_name, reporter_name)
 		__field(u8, new_state)
 	),
 
 	TP_fast_assign(
-		__assign_str(bus_name, devlink->dev->bus->name);
-		__assign_str(dev_name, dev_name(devlink->dev));
-		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(bus_name, devlink_to_dev(devlink)->bus->name);
+		__assign_str(dev_name, dev_name(devlink_to_dev(devlink)));
+		__assign_str(driver_name, devlink_to_dev(devlink)->driver->name);
 		__assign_str(reporter_name, reporter_name);
 		__entry->new_state = new_state;
 	),
@@ -181,9 +181,9 @@  TRACE_EVENT(devlink_trap_report,
 	TP_ARGS(devlink, skb, metadata),
 
 	TP_STRUCT__entry(
-		__string(bus_name, devlink->dev->bus->name)
-		__string(dev_name, dev_name(devlink->dev))
-		__string(driver_name, devlink->dev->driver->name)
+		__string(bus_name, devlink_to_dev(devlink)->bus->name)
+		__string(dev_name, dev_name(devlink_to_dev(devlink)))
+		__string(driver_name, devlink_to_dev(devlink)->driver->name)
 		__string(trap_name, metadata->trap_name)
 		__string(trap_group_name, metadata->trap_group_name)
 		__dynamic_array(char, input_dev_name, IFNAMSIZ)
@@ -192,9 +192,9 @@  TRACE_EVENT(devlink_trap_report,
 	TP_fast_assign(
 		struct net_device *input_dev = metadata->input_dev;
 
-		__assign_str(bus_name, devlink->dev->bus->name);
-		__assign_str(dev_name, dev_name(devlink->dev));
-		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(bus_name, devlink_to_dev(devlink)->bus->name);
+		__assign_str(dev_name, dev_name(devlink_to_dev(devlink)));
+		__assign_str(driver_name, devlink_to_dev(devlink)->driver->name);
 		__assign_str(trap_name, metadata->trap_name);
 		__assign_str(trap_group_name, metadata->trap_group_name);
 		__assign_str(input_dev_name,
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 4917112406a0..9642429cec65 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -30,6 +30,65 @@ 
 #define CREATE_TRACE_POINTS
 #include <trace/events/devlink.h>
 
+#define DEVLINK_RELOAD_STATS_ARRAY_SIZE \
+	(__DEVLINK_RELOAD_LIMIT_MAX * __DEVLINK_RELOAD_ACTION_MAX)
+
+struct devlink_dev_stats {
+	u32 reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
+	u32 remote_reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
+};
+
+struct devlink {
+	u32 index;
+	struct list_head port_list;
+	struct list_head rate_list;
+	struct list_head sb_list;
+	struct list_head dpipe_table_list;
+	struct list_head resource_list;
+	struct list_head param_list;
+	struct list_head region_list;
+	struct list_head reporter_list;
+	struct mutex reporters_lock; /* protects reporter_list */
+	struct devlink_dpipe_headers *dpipe_headers;
+	struct list_head trap_list;
+	struct list_head trap_group_list;
+	struct list_head trap_policer_list;
+	const struct devlink_ops *ops;
+	struct xarray snapshot_ids;
+	struct devlink_dev_stats stats;
+	struct device *dev;
+	possible_net_t _net;
+	/* Serializes access to devlink instance specific objects such as
+	 * port, sb, dpipe, resource, params, region, traps and more.
+	 */
+	struct mutex lock;
+	u8 reload_failed:1,
+	   reload_enabled:1;
+	refcount_t refcount;
+	struct completion comp;
+	char priv[0] __aligned(NETDEV_ALIGN);
+};
+
+void *devlink_priv(struct devlink *devlink)
+{
+	BUG_ON(!devlink);
+	return &devlink->priv;
+}
+EXPORT_SYMBOL_GPL(devlink_priv);
+
+struct devlink *priv_to_devlink(void *priv)
+{
+	BUG_ON(!priv);
+	return container_of(priv, struct devlink, priv);
+}
+EXPORT_SYMBOL_GPL(priv_to_devlink);
+
+struct device *devlink_to_dev(const struct devlink *devlink)
+{
+	return devlink->dev;
+}
+EXPORT_SYMBOL_GPL(devlink_to_dev);
+
 static struct devlink_dpipe_field devlink_dpipe_fields_ethernet[] = {
 	{
 		.name = "destination mac",