[RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Jakub Kicinski]

This series puts the devlink ports fully under the devlink instance
lock's protection. As discussed in the past it implements my preferred
solution of exposing the instance lock to the drivers. This way drivers
which want to support port splitting can lock the devlink instance
themselves on the probe path, and we can take that lock in the core
on the split/unsplit paths.

nfp and mlxsw are converted, with slightly deeper changes done in
nfp since I'm more familiar with that driver.

Now that the devlink port is protected we can pass a pointer to
the drivers, instead of passing a port index and forcing the drivers
to do their own lookups. Both nfp and mlxsw can container_of() to
their own structures.

I'd appreciate some testing, I don't have access to this HW.

Jakub Kicinski (6):
  devlink: expose instance locking and add locked port registering
  eth: nfp: wrap locking assertions in helpers
  eth: nfp: replace driver's "pf" lock with devlink instance lock
  eth: mlxsw: switch to explicit locking for port registration
  devlink: hold the instance lock in port_split / port_unsplit callbacks
  devlink: pass devlink_port to port_split / port_unsplit callbacks

 drivers/net/ethernet/mellanox/mlxsw/core.c    |  36 ++---
 drivers/net/ethernet/mellanox/mlxsw/minimal.c |   6 +
 .../net/ethernet/mellanox/mlxsw/spectrum.c    |   7 +
 .../net/ethernet/netronome/nfp/flower/main.c  |   4 +-
 drivers/net/ethernet/netronome/nfp/nfp_app.c  |   2 +-
 drivers/net/ethernet/netronome/nfp/nfp_app.h  |  12 +-
 .../net/ethernet/netronome/nfp/nfp_devlink.c  |  55 +++----
 drivers/net/ethernet/netronome/nfp/nfp_main.c |  19 +--
 drivers/net/ethernet/netronome/nfp/nfp_main.h |   6 +-
 .../net/ethernet/netronome/nfp/nfp_net_main.c |  34 ++--
 .../net/ethernet/netronome/nfp/nfp_net_repr.c |   4 +-
 drivers/net/ethernet/netronome/nfp/nfp_port.c |  17 --
 drivers/net/ethernet/netronome/nfp/nfp_port.h |   2 -
 include/net/devlink.h                         |  15 +-
 net/core/devlink.c                            | 148 ++++++++++--------
 15 files changed, 196 insertions(+), 171 deletions(-)

-- 
2.34.1

[RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jakub Kicinski]

It should be familiar and beneficial to expose devlink instance
lock to the drivers. This way drivers can block devlink from
calling them during critical sections without breakneck locking.

Add port helpers, port splitting callbacks will be the first
target.

Use 'devl_' prefix for "explicitly locked" API. Initial RFC used
'__devlink' but that's too much typing.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/net/devlink.h | 11 +++++
 net/core/devlink.c    | 99 ++++++++++++++++++++++++++++++++-----------
 2 files changed, 86 insertions(+), 24 deletions(-)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 8d5349d2fb68..9de0d091aee9 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -1479,6 +1479,17 @@ void *devlink_priv(struct devlink *devlink);
 struct devlink *priv_to_devlink(void *priv);
 struct device *devlink_to_dev(const struct devlink *devlink);
 
+/* Devlink instance explicit locking */
+void devl_lock(struct devlink *devlink);
+void devl_unlock(struct devlink *devlink);
+void devl_assert_locked(struct devlink *devlink);
+bool devl_lock_is_held(struct devlink *devlink);
+
+int devl_port_register(struct devlink *devlink,
+		       struct devlink_port *devlink_port,
+		       unsigned int port_index);
+void devl_port_unregister(struct devlink_port *devlink_port);
+
 struct ib_device;
 
 struct net *devlink_net(const struct devlink *devlink);
diff --git a/net/core/devlink.c b/net/core/devlink.c
index fcd9f6d85cf1..c30da1fc023d 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -225,6 +225,37 @@ struct devlink *__must_check devlink_try_get(struct devlink *devlink)
 	return NULL;
 }
 
+void devl_assert_locked(struct devlink *devlink)
+{
+	lockdep_assert_held(&devlink->lock);
+}
+EXPORT_SYMBOL_GPL(devl_assert_locked);
+
+bool devl_lock_is_held(struct devlink *devlink)
+{
+	/* We have to check this at runtime because struct devlink
+	 * is now private. Normally lock_is_held() should be eliminated
+	 * as dead code in the caller and we can depend on the linker error.
+	 */
+	if (!IS_ENABLED(CONFIG_LOCKDEP))
+		return WARN_ON_ONCE(true);
+
+	return lockdep_is_held(&devlink->lock);
+}
+EXPORT_SYMBOL_GPL(devl_lock_is_held);
+
+void devl_lock(struct devlink *devlink)
+{
+	mutex_lock(&devlink->lock);
+}
+EXPORT_SYMBOL_GPL(devl_lock);
+
+void devl_unlock(struct devlink *devlink)
+{
+	mutex_unlock(&devlink->lock);
+}
+EXPORT_SYMBOL_GPL(devl_unlock);
+
 static struct devlink *devlink_get_from_attrs(struct net *net,
 					      struct nlattr **attrs)
 {
@@ -9249,6 +9280,32 @@ static void devlink_port_type_warn_cancel(struct devlink_port *devlink_port)
 	cancel_delayed_work_sync(&devlink_port->type_warn_dw);
 }
 
+int devl_port_register(struct devlink *devlink,
+		       struct devlink_port *devlink_port,
+		       unsigned int port_index)
+{
+	lockdep_assert_held(&devlink->lock);
+
+	if (devlink_port_index_exists(devlink, port_index))
+		return -EEXIST;
+
+	WARN_ON(devlink_port->devlink);
+	devlink_port->devlink = devlink;
+	devlink_port->index = port_index;
+	spin_lock_init(&devlink_port->type_lock);
+	INIT_LIST_HEAD(&devlink_port->reporter_list);
+	mutex_init(&devlink_port->reporters_lock);
+	list_add_tail(&devlink_port->list, &devlink->port_list);
+	INIT_LIST_HEAD(&devlink_port->param_list);
+	INIT_LIST_HEAD(&devlink_port->region_list);
+
+	INIT_DELAYED_WORK(&devlink_port->type_warn_dw, &devlink_port_type_warn);
+	devlink_port_type_warn_schedule(devlink_port);
+	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devl_port_register);
+
 /**
  *	devlink_port_register - Register devlink port
  *
@@ -9266,29 +9323,28 @@ int devlink_port_register(struct devlink *devlink,
 			  struct devlink_port *devlink_port,
 			  unsigned int port_index)
 {
-	mutex_lock(&devlink->lock);
-	if (devlink_port_index_exists(devlink, port_index)) {
-		mutex_unlock(&devlink->lock);
-		return -EEXIST;
-	}
+	int err;
 
-	WARN_ON(devlink_port->devlink);
-	devlink_port->devlink = devlink;
-	devlink_port->index = port_index;
-	spin_lock_init(&devlink_port->type_lock);
-	INIT_LIST_HEAD(&devlink_port->reporter_list);
-	mutex_init(&devlink_port->reporters_lock);
-	list_add_tail(&devlink_port->list, &devlink->port_list);
-	INIT_LIST_HEAD(&devlink_port->param_list);
-	INIT_LIST_HEAD(&devlink_port->region_list);
+	mutex_lock(&devlink->lock);
+	err = devl_port_register(devlink, devlink_port, port_index);
 	mutex_unlock(&devlink->lock);
-	INIT_DELAYED_WORK(&devlink_port->type_warn_dw, &devlink_port_type_warn);
-	devlink_port_type_warn_schedule(devlink_port);
-	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_NEW);
-	return 0;
+	return err;
 }
 EXPORT_SYMBOL_GPL(devlink_port_register);
 
+void devl_port_unregister(struct devlink_port *devlink_port)
+{
+	lockdep_assert_held(&devlink_port->devlink->lock);
+
+	devlink_port_type_warn_cancel(devlink_port);
+	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_DEL);
+	list_del(&devlink_port->list);
+	WARN_ON(!list_empty(&devlink_port->reporter_list));
+	WARN_ON(!list_empty(&devlink_port->region_list));
+	mutex_destroy(&devlink_port->reporters_lock);
+}
+EXPORT_SYMBOL_GPL(devl_port_unregister);
+
 /**
  *	devlink_port_unregister - Unregister devlink port
  *
@@ -9298,14 +9354,9 @@ void devlink_port_unregister(struct devlink_port *devlink_port)
 {
 	struct devlink *devlink = devlink_port->devlink;
 
-	devlink_port_type_warn_cancel(devlink_port);
-	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_DEL);
 	mutex_lock(&devlink->lock);
-	list_del(&devlink_port->list);
+	devl_port_unregister(devlink_port);
 	mutex_unlock(&devlink->lock);
-	WARN_ON(!list_empty(&devlink_port->reporter_list));
-	WARN_ON(!list_empty(&devlink_port->region_list));
-	mutex_destroy(&devlink_port->reporters_lock);
 }
 EXPORT_SYMBOL_GPL(devlink_port_unregister);
 
-- 
2.34.1

[RFT net-next 2/6] eth: nfp: wrap locking assertions in helpers

[Jakub Kicinski]

We can replace the PF lock with devlink instance lock in subsequent
changes. To make the patches easier to comprehend and limit line
lengths - factor out the existing locking assertions.

No functional changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/netronome/nfp/flower/main.c  | 4 ++--
 drivers/net/ethernet/netronome/nfp/nfp_app.c      | 2 +-
 drivers/net/ethernet/netronome/nfp/nfp_app.h      | 9 +++++++++
 drivers/net/ethernet/netronome/nfp/nfp_net_repr.c | 4 ++--
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/flower/main.c b/drivers/net/ethernet/netronome/nfp/flower/main.c
index ac1dcfa1d179..4d960a9641b3 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/main.c
+++ b/drivers/net/ethernet/netronome/nfp/flower/main.c
@@ -266,7 +266,7 @@ nfp_flower_reprs_reify(struct nfp_app *app, enum nfp_repr_type type,
 	int i, err, count = 0;
 
 	reprs = rcu_dereference_protected(app->reprs[type],
-					  lockdep_is_held(&app->pf->lock));
+					  nfp_app_is_locked(app));
 	if (!reprs)
 		return 0;
 
@@ -295,7 +295,7 @@ nfp_flower_wait_repr_reify(struct nfp_app *app, atomic_t *replies, int tot_repl)
 	if (!tot_repl)
 		return 0;
 
-	lockdep_assert_held(&app->pf->lock);
+	assert_nfp_app_locked(app);
 	if (!wait_event_timeout(priv->reify_wait_queue,
 				atomic_read(replies) >= tot_repl,
 				NFP_FL_REPLY_TIMEOUT)) {
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_app.c b/drivers/net/ethernet/netronome/nfp/nfp_app.c
index 3a973282b2bb..09f250e74dfa 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_app.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.c
@@ -121,7 +121,7 @@ struct nfp_reprs *
 nfp_reprs_get_locked(struct nfp_app *app, enum nfp_repr_type type)
 {
 	return rcu_dereference_protected(app->reprs[type],
-					 lockdep_is_held(&app->pf->lock));
+					 nfp_app_is_locked(app));
 }
 
 struct nfp_reprs *
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_app.h b/drivers/net/ethernet/netronome/nfp/nfp_app.h
index 3e9baff07100..60cb8a71e02d 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_app.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.h
@@ -4,10 +4,12 @@
 #ifndef _NFP_APP_H
 #define _NFP_APP_H 1
 
+#include <linux/lockdep.h>
 #include <net/devlink.h>
 
 #include <trace/events/devlink.h>
 
+#include "nfp_main.h"
 #include "nfp_net_repr.h"
 
 #define NFP_APP_CTRL_MTU_MAX	U32_MAX
@@ -174,6 +176,13 @@ struct nfp_app {
 	void *priv;
 };
 
+static inline void assert_nfp_app_locked(struct nfp_app *app)
+{
+	lockdep_assert_held(&app->pf->lock);
+}
+
+#define nfp_app_is_locked(app)	lockdep_is_held(&(app)->pf->lock)
+
 void nfp_check_rhashtable_empty(void *ptr, void *arg);
 bool __nfp_ctrl_tx(struct nfp_net *nn, struct sk_buff *skb);
 bool nfp_ctrl_tx(struct nfp_net *nn, struct sk_buff *skb);
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
index 181ac8e789a3..ba3fa7eac98d 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
@@ -20,7 +20,7 @@ struct net_device *
 nfp_repr_get_locked(struct nfp_app *app, struct nfp_reprs *set, unsigned int id)
 {
 	return rcu_dereference_protected(set->reprs[id],
-					 lockdep_is_held(&app->pf->lock));
+					 nfp_app_is_locked(app));
 }
 
 static void
@@ -476,7 +476,7 @@ nfp_reprs_clean_and_free_by_type(struct nfp_app *app, enum nfp_repr_type type)
 	int i;
 
 	reprs = rcu_dereference_protected(app->reprs[type],
-					  lockdep_is_held(&app->pf->lock));
+					  nfp_app_is_locked(app));
 	if (!reprs)
 		return;
 
-- 
2.34.1

[RFT net-next 3/6] eth: nfp: replace driver's "pf" lock with devlink instance lock

[Jakub Kicinski]

The whole reason for existence of the pf mutex is that we could
not lock the devlink instance around port splitting. There are
more types of reconfig which can make ports appear or disappear.
Now that the devlink instance lock is exposed to drivers and
"locked" helpers exist we can switch to using the devlink lock
directly.

Next patches will move the locking inside .port_(un)split to
the core.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/netronome/nfp/nfp_app.h  | 11 +++---
 .../net/ethernet/netronome/nfp/nfp_devlink.c  | 16 ++++-----
 drivers/net/ethernet/netronome/nfp/nfp_main.c | 19 ++++++-----
 drivers/net/ethernet/netronome/nfp/nfp_main.h |  6 ++--
 .../net/ethernet/netronome/nfp/nfp_net_main.c | 34 +++++++++++--------
 drivers/net/ethernet/netronome/nfp/nfp_port.c |  3 +-
 6 files changed, 48 insertions(+), 41 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_app.h b/drivers/net/ethernet/netronome/nfp/nfp_app.h
index 60cb8a71e02d..dd56207df246 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_app.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_app.h
@@ -4,12 +4,10 @@
 #ifndef _NFP_APP_H
 #define _NFP_APP_H 1
 
-#include <linux/lockdep.h>
 #include <net/devlink.h>
 
 #include <trace/events/devlink.h>
 
-#include "nfp_main.h"
 #include "nfp_net_repr.h"
 
 #define NFP_APP_CTRL_MTU_MAX	U32_MAX
@@ -77,7 +75,7 @@ extern const struct nfp_app_type app_abm;
  * @bpf:	BPF ndo offload-related calls
  * @xdp_offload:    offload an XDP program
  * @eswitch_mode_get:    get SR-IOV eswitch mode
- * @eswitch_mode_set:    set SR-IOV eswitch mode (under pf->lock)
+ * @eswitch_mode_set:    set SR-IOV eswitch mode
  * @sriov_enable: app-specific sriov initialisation
  * @sriov_disable: app-specific sriov clean-up
  * @dev_get:	get representor or internal port representing netdev
@@ -178,10 +176,13 @@ struct nfp_app {
 
 static inline void assert_nfp_app_locked(struct nfp_app *app)
 {
-	lockdep_assert_held(&app->pf->lock);
+	devl_assert_locked(priv_to_devlink(app->pf));
 }
 
-#define nfp_app_is_locked(app)	lockdep_is_held(&(app)->pf->lock)
+static inline bool nfp_app_is_locked(struct nfp_app *app)
+{
+	return devl_lock_is_held(priv_to_devlink(app->pf));
+}
 
 void nfp_check_rhashtable_empty(void *ptr, void *arg);
 bool __nfp_ctrl_tx(struct nfp_net *nn, struct sk_buff *skb);
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
index bea978df7713..865f62958a72 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
@@ -70,7 +70,7 @@ nfp_devlink_port_split(struct devlink *devlink, unsigned int port_index,
 	unsigned int lanes;
 	int ret;
 
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 
 	rtnl_lock();
 	ret = nfp_devlink_fill_eth_port_from_id(pf, port_index, &eth_port);
@@ -90,7 +90,7 @@ nfp_devlink_port_split(struct devlink *devlink, unsigned int port_index,
 
 	ret = nfp_devlink_set_lanes(pf, eth_port.index, lanes);
 out:
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 
 	return ret;
 }
@@ -104,7 +104,7 @@ nfp_devlink_port_unsplit(struct devlink *devlink, unsigned int port_index,
 	unsigned int lanes;
 	int ret;
 
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 
 	rtnl_lock();
 	ret = nfp_devlink_fill_eth_port_from_id(pf, port_index, &eth_port);
@@ -124,7 +124,7 @@ nfp_devlink_port_unsplit(struct devlink *devlink, unsigned int port_index,
 
 	ret = nfp_devlink_set_lanes(pf, eth_port.index, lanes);
 out:
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 
 	return ret;
 }
@@ -163,9 +163,9 @@ static int nfp_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
 	struct nfp_pf *pf = devlink_priv(devlink);
 	int ret;
 
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 	ret = nfp_app_eswitch_mode_set(pf->app, mode);
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 
 	return ret;
 }
@@ -375,12 +375,12 @@ int nfp_devlink_port_register(struct nfp_app *app, struct nfp_port *port)
 
 	devlink = priv_to_devlink(app->pf);
 
-	return devlink_port_register(devlink, &port->dl_port, port->eth_id);
+	return devl_port_register(devlink, &port->dl_port, port->eth_id);
 }
 
 void nfp_devlink_port_unregister(struct nfp_port *port)
 {
-	devlink_port_unregister(&port->dl_port);
+	devl_port_unregister(&port->dl_port);
 }
 
 void nfp_devlink_port_type_eth_set(struct nfp_port *port)
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_main.c b/drivers/net/ethernet/netronome/nfp/nfp_main.c
index bb3b8a7f6c5d..a42068d706cb 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_main.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_main.c
@@ -222,6 +222,7 @@ static int nfp_pcie_sriov_enable(struct pci_dev *pdev, int num_vfs)
 {
 #ifdef CONFIG_PCI_IOV
 	struct nfp_pf *pf = pci_get_drvdata(pdev);
+	struct devlink *devlink;
 	int err;
 
 	if (num_vfs > pf->limit_vfs) {
@@ -236,7 +237,8 @@ static int nfp_pcie_sriov_enable(struct pci_dev *pdev, int num_vfs)
 		return err;
 	}
 
-	mutex_lock(&pf->lock);
+	devlink = priv_to_devlink(pf);
+	devl_lock(devlink);
 
 	err = nfp_app_sriov_enable(pf->app, num_vfs);
 	if (err) {
@@ -250,11 +252,11 @@ static int nfp_pcie_sriov_enable(struct pci_dev *pdev, int num_vfs)
 
 	dev_dbg(&pdev->dev, "Created %d VFs.\n", pf->num_vfs);
 
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 	return num_vfs;
 
 err_sriov_disable:
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 	pci_disable_sriov(pdev);
 	return err;
 #endif
@@ -265,8 +267,10 @@ static int nfp_pcie_sriov_disable(struct pci_dev *pdev)
 {
 #ifdef CONFIG_PCI_IOV
 	struct nfp_pf *pf = pci_get_drvdata(pdev);
+	struct devlink *devlink;
 
-	mutex_lock(&pf->lock);
+	devlink = priv_to_devlink(pf);
+	devl_lock(devlink);
 
 	/* If the VFs are assigned we cannot shut down SR-IOV without
 	 * causing issues, so just leave the hardware available but
@@ -274,7 +278,7 @@ static int nfp_pcie_sriov_disable(struct pci_dev *pdev)
 	 */
 	if (pci_vfs_assigned(pdev)) {
 		dev_warn(&pdev->dev, "Disabling while VFs assigned - VFs will not be deallocated\n");
-		mutex_unlock(&pf->lock);
+		devl_unlock(devlink);
 		return -EPERM;
 	}
 
@@ -282,7 +286,7 @@ static int nfp_pcie_sriov_disable(struct pci_dev *pdev)
 
 	pf->num_vfs = 0;
 
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 
 	pci_disable_sriov(pdev);
 	dev_dbg(&pdev->dev, "Removed VFs.\n");
@@ -700,7 +704,6 @@ static int nfp_pci_probe(struct pci_dev *pdev,
 	pf = devlink_priv(devlink);
 	INIT_LIST_HEAD(&pf->vnics);
 	INIT_LIST_HEAD(&pf->ports);
-	mutex_init(&pf->lock);
 	pci_set_drvdata(pdev, pf);
 	pf->pdev = pdev;
 
@@ -790,7 +793,6 @@ static int nfp_pci_probe(struct pci_dev *pdev,
 	destroy_workqueue(pf->wq);
 err_pci_priv_unset:
 	pci_set_drvdata(pdev, NULL);
-	mutex_destroy(&pf->lock);
 	devlink_free(devlink);
 err_rel_regions:
 	pci_release_regions(pdev);
@@ -827,7 +829,6 @@ static void __nfp_pci_shutdown(struct pci_dev *pdev, bool unload_fw)
 
 	kfree(pf->eth_tbl);
 	kfree(pf->nspi);
-	mutex_destroy(&pf->lock);
 	devlink_free(priv_to_devlink(pf));
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_main.h b/drivers/net/ethernet/netronome/nfp/nfp_main.h
index a7dede946a33..20129a6aaea0 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_main.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_main.h
@@ -13,7 +13,6 @@
 #include <linux/list.h>
 #include <linux/types.h>
 #include <linux/msi.h>
-#include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/workqueue.h>
 #include <net/devlink.h>
@@ -84,7 +83,8 @@ struct nfp_dumpspec {
  * @port_refresh_work:	Work entry for taking netdevs out
  * @shared_bufs:	Array of shared buffer structures if FW has any SBs
  * @num_shared_bufs:	Number of elements in @shared_bufs
- * @lock:		Protects all fields which may change after probe
+ *
+ * Fields which may change after proble are protected by devlink instance lock.
  */
 struct nfp_pf {
 	struct pci_dev *pdev;
@@ -139,8 +139,6 @@ struct nfp_pf {
 
 	struct nfp_shared_buf *shared_bufs;
 	unsigned int num_shared_bufs;
-
-	struct mutex lock;
 };
 
 extern struct pci_driver nfp_netvf_pci_driver;
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_main.c b/drivers/net/ethernet/netronome/nfp/nfp_net_main.c
index 751f76cd4f79..efcc76a06a9a 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_main.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_main.c
@@ -307,6 +307,7 @@ static int nfp_net_pf_init_vnics(struct nfp_pf *pf)
 static int
 nfp_net_pf_app_init(struct nfp_pf *pf, u8 __iomem *qc_bar, unsigned int stride)
 {
+	struct devlink *devlink = priv_to_devlink(pf);
 	u8 __iomem *ctrl_bar;
 	int err;
 
@@ -314,9 +315,9 @@ nfp_net_pf_app_init(struct nfp_pf *pf, u8 __iomem *qc_bar, unsigned int stride)
 	if (IS_ERR(pf->app))
 		return PTR_ERR(pf->app);
 
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 	err = nfp_app_init(pf->app);
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 	if (err)
 		goto err_free;
 
@@ -343,9 +344,9 @@ nfp_net_pf_app_init(struct nfp_pf *pf, u8 __iomem *qc_bar, unsigned int stride)
 err_unmap:
 	nfp_cpp_area_release_free(pf->ctrl_vnic_bar);
 err_app_clean:
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 	nfp_app_clean(pf->app);
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 err_free:
 	nfp_app_free(pf->app);
 	pf->app = NULL;
@@ -354,14 +355,16 @@ nfp_net_pf_app_init(struct nfp_pf *pf, u8 __iomem *qc_bar, unsigned int stride)
 
 static void nfp_net_pf_app_clean(struct nfp_pf *pf)
 {
+	struct devlink *devlink = priv_to_devlink(pf);
+
 	if (pf->ctrl_vnic) {
 		nfp_net_pf_free_vnic(pf, pf->ctrl_vnic);
 		nfp_cpp_area_release_free(pf->ctrl_vnic_bar);
 	}
 
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 	nfp_app_clean(pf->app);
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 
 	nfp_app_free(pf->app);
 	pf->app = NULL;
@@ -546,12 +549,13 @@ nfp_net_eth_port_update(struct nfp_cpp *cpp, struct nfp_port *port,
 
 int nfp_net_refresh_port_table_sync(struct nfp_pf *pf)
 {
+	struct devlink *devlink = priv_to_devlink(pf);
 	struct nfp_eth_table *eth_table;
 	struct nfp_net *nn, *next;
 	struct nfp_port *port;
 	int err;
 
-	lockdep_assert_held(&pf->lock);
+	devl_assert_locked(devlink);
 
 	/* Check for nfp_net_pci_remove() racing against us */
 	if (list_empty(&pf->vnics))
@@ -600,10 +604,11 @@ static void nfp_net_refresh_vnics(struct work_struct *work)
 {
 	struct nfp_pf *pf = container_of(work, struct nfp_pf,
 					 port_refresh_work);
+	struct devlink *devlink = priv_to_devlink(pf);
 
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 	nfp_net_refresh_port_table_sync(pf);
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 }
 
 void nfp_net_refresh_port_table(struct nfp_port *port)
@@ -709,7 +714,7 @@ int nfp_net_pci_probe(struct nfp_pf *pf)
 	if (err)
 		goto err_shared_buf_unreg;
 
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 	pf->ddir = nfp_net_debugfs_device_add(pf->pdev);
 
 	/* Allocate the vnics and do basic init */
@@ -729,7 +734,7 @@ int nfp_net_pci_probe(struct nfp_pf *pf)
 	if (err)
 		goto err_stop_app;
 
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 	devlink_register(devlink);
 
 	return 0;
@@ -742,7 +747,7 @@ int nfp_net_pci_probe(struct nfp_pf *pf)
 	nfp_net_pf_free_vnics(pf);
 err_clean_ddir:
 	nfp_net_debugfs_dir_clean(&pf->ddir);
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 	nfp_devlink_params_unregister(pf);
 err_shared_buf_unreg:
 	nfp_shared_buf_unregister(pf);
@@ -756,10 +761,11 @@ int nfp_net_pci_probe(struct nfp_pf *pf)
 
 void nfp_net_pci_remove(struct nfp_pf *pf)
 {
+	struct devlink *devlink = priv_to_devlink(pf);
 	struct nfp_net *nn, *next;
 
 	devlink_unregister(priv_to_devlink(pf));
-	mutex_lock(&pf->lock);
+	devl_lock(devlink);
 	list_for_each_entry_safe(nn, next, &pf->vnics, vnic_list) {
 		if (!nfp_net_is_data_vnic(nn))
 			continue;
@@ -771,7 +777,7 @@ void nfp_net_pci_remove(struct nfp_pf *pf)
 	/* stop app first, to avoid double free of ctrl vNIC's ddir */
 	nfp_net_debugfs_dir_clean(&pf->ddir);
 
-	mutex_unlock(&pf->lock);
+	devl_unlock(devlink);
 
 	nfp_devlink_params_unregister(pf);
 	nfp_shared_buf_unregister(pf);
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_port.c b/drivers/net/ethernet/netronome/nfp/nfp_port.c
index 93c5bfc0510b..6f3ea1700a15 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_port.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_port.c
@@ -78,9 +78,10 @@ int nfp_port_set_features(struct net_device *netdev, netdev_features_t features)
 struct nfp_port *
 nfp_port_from_id(struct nfp_pf *pf, enum nfp_port_type type, unsigned int id)
 {
+	struct devlink *devlink = priv_to_devlink(pf);
 	struct nfp_port *port;
 
-	lockdep_assert_held(&pf->lock);
+	assert_devl_locked(devlink);
 
 	if (type != NFP_PORT_PHYS_PORT)
 		return NULL;
-- 
2.34.1

[RFT net-next 4/6] eth: mlxsw: switch to explicit locking for port registration

[Jakub Kicinski]

Explicitly lock the devlink instance and use devl_ API.

This will be used by the subsequent patch to invoke
.port_split / .port_unsplit callbacks with devlink
instance lock held.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/mellanox/mlxsw/core.c     |  4 ++--
 drivers/net/ethernet/mellanox/mlxsw/minimal.c  |  6 ++++++
 drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 14 ++++++++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c
index 0bf1d64644ba..e2a6a759eb6c 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -2983,7 +2983,7 @@ static int __mlxsw_core_port_init(struct mlxsw_core *mlxsw_core, u16 local_port,
 	attrs.switch_id.id_len = switch_id_len;
 	mlxsw_core_port->local_port = local_port;
 	devlink_port_attrs_set(devlink_port, &attrs);
-	err = devlink_port_register(devlink, devlink_port, local_port);
+	err = devl_port_register(devlink, devlink_port, local_port);
 	if (err)
 		memset(mlxsw_core_port, 0, sizeof(*mlxsw_core_port));
 	return err;
@@ -2995,7 +2995,7 @@ static void __mlxsw_core_port_fini(struct mlxsw_core *mlxsw_core, u16 local_port
 					&mlxsw_core->ports[local_port];
 	struct devlink_port *devlink_port = &mlxsw_core_port->devlink_port;
 
-	devlink_port_unregister(devlink_port);
+	devl_port_unregister(devlink_port);
 	memset(mlxsw_core_port, 0, sizeof(*mlxsw_core_port));
 }
 
diff --git a/drivers/net/ethernet/mellanox/mlxsw/minimal.c b/drivers/net/ethernet/mellanox/mlxsw/minimal.c
index 060209983438..3bc012dafd08 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/minimal.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/minimal.c
@@ -422,6 +422,7 @@ static int mlxsw_m_init(struct mlxsw_core *mlxsw_core,
 			struct netlink_ext_ack *extack)
 {
 	struct mlxsw_m *mlxsw_m = mlxsw_core_driver_priv(mlxsw_core);
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 	int err;
 
 	mlxsw_m->core = mlxsw_core;
@@ -437,7 +438,9 @@ static int mlxsw_m_init(struct mlxsw_core *mlxsw_core,
 		return err;
 	}
 
+	devl_lock(devlink);
 	err = mlxsw_m_ports_create(mlxsw_m);
+	devl_unlock(devlink);
 	if (err) {
 		dev_err(mlxsw_m->bus_info->dev, "Failed to create ports\n");
 		return err;
@@ -449,8 +452,11 @@ static int mlxsw_m_init(struct mlxsw_core *mlxsw_core,
 static void mlxsw_m_fini(struct mlxsw_core *mlxsw_core)
 {
 	struct mlxsw_m *mlxsw_m = mlxsw_core_driver_priv(mlxsw_core);
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 
+	devl_lock(devlink);
 	mlxsw_m_ports_remove(mlxsw_m);
+	devl_unlock(devlink);
 }
 
 static const struct mlxsw_config_profile mlxsw_m_config_profile;
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 7b7b17183d10..1e823b669d1c 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -2025,6 +2025,7 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 			       struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 	struct mlxsw_sp_port_mapping port_mapping;
 	struct mlxsw_sp_port *mlxsw_sp_port;
 	enum mlxsw_reg_pmtdb_status status;
@@ -2062,6 +2063,7 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 
 	port_mapping = mlxsw_sp_port->mapping;
 
+	devl_lock(devlink);
 	for (i = 0; i < count; i++) {
 		u16 s_local_port = mlxsw_reg_pmtdb_port_num_get(pmtdb_pl, i);
 
@@ -2075,11 +2077,13 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 		dev_err(mlxsw_sp->bus_info->dev, "Failed to create split ports\n");
 		goto err_port_split_create;
 	}
+	devl_unlock(devlink);
 
 	return 0;
 
 err_port_split_create:
 	mlxsw_sp_port_unsplit_create(mlxsw_sp, count, pmtdb_pl);
+	devl_unlock(devlink);
 	return err;
 }
 
@@ -2087,6 +2091,7 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 				 struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 	struct mlxsw_sp_port *mlxsw_sp_port;
 	char pmtdb_pl[MLXSW_REG_PMTDB_LEN];
 	unsigned int count;
@@ -2118,6 +2123,7 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 		return err;
 	}
 
+	devl_lock(devlink);
 	for (i = 0; i < count; i++) {
 		u16 s_local_port = mlxsw_reg_pmtdb_port_num_get(pmtdb_pl, i);
 
@@ -2126,6 +2132,7 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 	}
 
 	mlxsw_sp_port_unsplit_create(mlxsw_sp, count, pmtdb_pl);
+	devl_unlock(devlink);
 
 	return 0;
 }
@@ -2818,6 +2825,7 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 			 struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 	int err;
 
 	mlxsw_sp->core = mlxsw_core;
@@ -2978,7 +2986,9 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 		goto err_sample_trigger_init;
 	}
 
+	devl_lock(devlink);
 	err = mlxsw_sp_ports_create(mlxsw_sp);
+	devl_unlock(devlink);
 	if (err) {
 		dev_err(mlxsw_sp->bus_info->dev, "Failed to create ports\n");
 		goto err_ports_create;
@@ -3159,8 +3169,12 @@ static int mlxsw_sp4_init(struct mlxsw_core *mlxsw_core,
 static void mlxsw_sp_fini(struct mlxsw_core *mlxsw_core)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 
+	devl_lock(devlink);
 	mlxsw_sp_ports_remove(mlxsw_sp);
+	devl_unlock(devlink);
+
 	rhashtable_destroy(&mlxsw_sp->sample_trigger_ht);
 	mlxsw_sp_port_module_info_fini(mlxsw_sp);
 	mlxsw_sp_dpipe_fini(mlxsw_sp);
-- 
2.34.1

[RFT net-next 5/6] devlink: hold the instance lock in port_split / port_unsplit callbacks

[Jakub Kicinski]

Let the core take the devlink instance lock around port splitting
and remove the now redundant locking in the drivers.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 .../net/ethernet/mellanox/mlxsw/spectrum.c    |  7 ----
 .../net/ethernet/netronome/nfp/nfp_devlink.c  | 32 +++++--------------
 net/core/devlink.c                            |  2 --
 3 files changed, 8 insertions(+), 33 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 1e823b669d1c..8eb05090ffec 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -2025,7 +2025,6 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 			       struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
-	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 	struct mlxsw_sp_port_mapping port_mapping;
 	struct mlxsw_sp_port *mlxsw_sp_port;
 	enum mlxsw_reg_pmtdb_status status;
@@ -2063,7 +2062,6 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 
 	port_mapping = mlxsw_sp_port->mapping;
 
-	devl_lock(devlink);
 	for (i = 0; i < count; i++) {
 		u16 s_local_port = mlxsw_reg_pmtdb_port_num_get(pmtdb_pl, i);
 
@@ -2077,13 +2075,11 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u16 local_port,
 		dev_err(mlxsw_sp->bus_info->dev, "Failed to create split ports\n");
 		goto err_port_split_create;
 	}
-	devl_unlock(devlink);
 
 	return 0;
 
 err_port_split_create:
 	mlxsw_sp_port_unsplit_create(mlxsw_sp, count, pmtdb_pl);
-	devl_unlock(devlink);
 	return err;
 }
 
@@ -2091,7 +2087,6 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 				 struct netlink_ext_ack *extack)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
-	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 	struct mlxsw_sp_port *mlxsw_sp_port;
 	char pmtdb_pl[MLXSW_REG_PMTDB_LEN];
 	unsigned int count;
@@ -2123,7 +2118,6 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 		return err;
 	}
 
-	devl_lock(devlink);
 	for (i = 0; i < count; i++) {
 		u16 s_local_port = mlxsw_reg_pmtdb_port_num_get(pmtdb_pl, i);
 
@@ -2132,7 +2126,6 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u16 local_port,
 	}
 
 	mlxsw_sp_port_unsplit_create(mlxsw_sp, count, pmtdb_pl);
-	devl_unlock(devlink);
 
 	return 0;
 }
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
index 865f62958a72..6bd6f4a67c30 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
@@ -70,29 +70,21 @@ nfp_devlink_port_split(struct devlink *devlink, unsigned int port_index,
 	unsigned int lanes;
 	int ret;
 
-	devl_lock(devlink);
-
 	rtnl_lock();
 	ret = nfp_devlink_fill_eth_port_from_id(pf, port_index, &eth_port);
 	rtnl_unlock();
 	if (ret)
-		goto out;
+		return ret;
 
-	if (eth_port.port_lanes % count) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (eth_port.port_lanes % count)
+		return -EINVAL;
 
 	/* Special case the 100G CXP -> 2x40G split */
 	lanes = eth_port.port_lanes / count;
 	if (eth_port.lanes == 10 && count == 2)
 		lanes = 8 / count;
 
-	ret = nfp_devlink_set_lanes(pf, eth_port.index, lanes);
-out:
-	devl_unlock(devlink);
-
-	return ret;
+	return nfp_devlink_set_lanes(pf, eth_port.index, lanes);
 }
 
 static int
@@ -104,29 +96,21 @@ nfp_devlink_port_unsplit(struct devlink *devlink, unsigned int port_index,
 	unsigned int lanes;
 	int ret;
 
-	devl_lock(devlink);
-
 	rtnl_lock();
 	ret = nfp_devlink_fill_eth_port_from_id(pf, port_index, &eth_port);
 	rtnl_unlock();
 	if (ret)
-		goto out;
+		return ret;
 
-	if (!eth_port.is_split) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (!eth_port.is_split)
+		return -EINVAL;
 
 	/* Special case the 100G CXP -> 2x40G unsplit */
 	lanes = eth_port.port_lanes;
 	if (eth_port.port_lanes == 8)
 		lanes = 10;
 
-	ret = nfp_devlink_set_lanes(pf, eth_port.index, lanes);
-out:
-	devl_unlock(devlink);
-
-	return ret;
+	return nfp_devlink_set_lanes(pf, eth_port.index, lanes);
 }
 
 static int
diff --git a/net/core/devlink.c b/net/core/devlink.c
index c30da1fc023d..3069a3833576 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -8676,14 +8676,12 @@ static const struct genl_small_ops devlink_nl_ops[] = {
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 		.doit = devlink_nl_cmd_port_split_doit,
 		.flags = GENL_ADMIN_PERM,
-		.internal_flags = DEVLINK_NL_FLAG_NO_LOCK,
 	},
 	{
 		.cmd = DEVLINK_CMD_PORT_UNSPLIT,
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 		.doit = devlink_nl_cmd_port_unsplit_doit,
 		.flags = GENL_ADMIN_PERM,
-		.internal_flags = DEVLINK_NL_FLAG_NO_LOCK,
 	},
 	{
 		.cmd = DEVLINK_CMD_PORT_NEW,
-- 
2.34.1

[RFT net-next 6/6] devlink: pass devlink_port to port_split / port_unsplit callbacks

[Jakub Kicinski]

Now that devlink ports are protected by the instance lock
it seems natural to pass devlink_port as an argument to
the port_split / port_unsplit callbacks.

This should save the drivers from doing a lookup.

In theory drivers may have supported unsplitting ports
which were not registered prior to this change.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/mellanox/mlxsw/core.c    | 32 ++++++-------
 .../net/ethernet/netronome/nfp/nfp_devlink.c  | 15 +++---
 drivers/net/ethernet/netronome/nfp/nfp_port.c | 18 -------
 drivers/net/ethernet/netronome/nfp/nfp_port.h |  2 -
 include/net/devlink.h                         |  4 +-
 net/core/devlink.c                            | 47 +++++--------------
 6 files changed, 35 insertions(+), 83 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c
index e2a6a759eb6c..b13e0f8d232a 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -1217,36 +1217,37 @@ static void mlxsw_core_fw_params_unregister(struct mlxsw_core *mlxsw_core)
 				  ARRAY_SIZE(mlxsw_core_fw_devlink_params));
 }
 
+static void *__dl_port(struct devlink_port *devlink_port)
+{
+	return container_of(devlink_port, struct mlxsw_core_port, devlink_port);
+}
+
 static int mlxsw_devlink_port_split(struct devlink *devlink,
-				    unsigned int port_index,
+				    struct devlink_port *port,
 				    unsigned int count,
 				    struct netlink_ext_ack *extack)
 {
+	struct mlxsw_core_port *mlxsw_core_port = __dl_port(port);
 	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
 
-	if (port_index >= mlxsw_core->max_ports) {
-		NL_SET_ERR_MSG_MOD(extack, "Port index exceeds maximum number of ports");
-		return -EINVAL;
-	}
 	if (!mlxsw_core->driver->port_split)
 		return -EOPNOTSUPP;
-	return mlxsw_core->driver->port_split(mlxsw_core, port_index, count,
-					      extack);
+	return mlxsw_core->driver->port_split(mlxsw_core,
+					      mlxsw_core_port->local_port,
+					      count, extack);
 }
 
 static int mlxsw_devlink_port_unsplit(struct devlink *devlink,
-				      unsigned int port_index,
+				      struct devlink_port *port,
 				      struct netlink_ext_ack *extack)
 {
+	struct mlxsw_core_port *mlxsw_core_port = __dl_port(port);
 	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
 
-	if (port_index >= mlxsw_core->max_ports) {
-		NL_SET_ERR_MSG_MOD(extack, "Port index exceeds maximum number of ports");
-		return -EINVAL;
-	}
 	if (!mlxsw_core->driver->port_unsplit)
 		return -EOPNOTSUPP;
-	return mlxsw_core->driver->port_unsplit(mlxsw_core, port_index,
+	return mlxsw_core->driver->port_unsplit(mlxsw_core,
+						mlxsw_core_port->local_port,
 						extack);
 }
 
@@ -1280,11 +1281,6 @@ mlxsw_devlink_sb_pool_set(struct devlink *devlink,
 					 extack);
 }
 
-static void *__dl_port(struct devlink_port *devlink_port)
-{
-	return container_of(devlink_port, struct mlxsw_core_port, devlink_port);
-}
-
 static int mlxsw_devlink_port_type_set(struct devlink_port *devlink_port,
 				       enum devlink_port_type port_type)
 {
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
index 6bd6f4a67c30..48b95566b52b 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
@@ -26,12 +26,11 @@ nfp_devlink_fill_eth_port(struct nfp_port *port,
 }
 
 static int
-nfp_devlink_fill_eth_port_from_id(struct nfp_pf *pf, unsigned int port_index,
+nfp_devlink_fill_eth_port_from_id(struct nfp_pf *pf,
+				  struct devlink_port *dl_port,
 				  struct nfp_eth_table_port *copy)
 {
-	struct nfp_port *port;
-
-	port = nfp_port_from_id(pf, NFP_PORT_PHYS_PORT, port_index);
+	struct nfp_port *port = container_of(dl_port, struct nfp_port, dl_port);
 
 	return nfp_devlink_fill_eth_port(port, copy);
 }
@@ -62,7 +61,7 @@ nfp_devlink_set_lanes(struct nfp_pf *pf, unsigned int idx, unsigned int lanes)
 }
 
 static int
-nfp_devlink_port_split(struct devlink *devlink, unsigned int port_index,
+nfp_devlink_port_split(struct devlink *devlink, struct devlink_port *port,
 		       unsigned int count, struct netlink_ext_ack *extack)
 {
 	struct nfp_pf *pf = devlink_priv(devlink);
@@ -71,7 +70,7 @@ nfp_devlink_port_split(struct devlink *devlink, unsigned int port_index,
 	int ret;
 
 	rtnl_lock();
-	ret = nfp_devlink_fill_eth_port_from_id(pf, port_index, &eth_port);
+	ret = nfp_devlink_fill_eth_port_from_id(pf, port, &eth_port);
 	rtnl_unlock();
 	if (ret)
 		return ret;
@@ -88,7 +87,7 @@ nfp_devlink_port_split(struct devlink *devlink, unsigned int port_index,
 }
 
 static int
-nfp_devlink_port_unsplit(struct devlink *devlink, unsigned int port_index,
+nfp_devlink_port_unsplit(struct devlink *devlink, struct devlink_port *port,
 			 struct netlink_ext_ack *extack)
 {
 	struct nfp_pf *pf = devlink_priv(devlink);
@@ -97,7 +96,7 @@ nfp_devlink_port_unsplit(struct devlink *devlink, unsigned int port_index,
 	int ret;
 
 	rtnl_lock();
-	ret = nfp_devlink_fill_eth_port_from_id(pf, port_index, &eth_port);
+	ret = nfp_devlink_fill_eth_port_from_id(pf, port, &eth_port);
 	rtnl_unlock();
 	if (ret)
 		return ret;
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_port.c b/drivers/net/ethernet/netronome/nfp/nfp_port.c
index 6f3ea1700a15..4f2308570dcf 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_port.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_port.c
@@ -75,24 +75,6 @@ int nfp_port_set_features(struct net_device *netdev, netdev_features_t features)
 	return 0;
 }
 
-struct nfp_port *
-nfp_port_from_id(struct nfp_pf *pf, enum nfp_port_type type, unsigned int id)
-{
-	struct devlink *devlink = priv_to_devlink(pf);
-	struct nfp_port *port;
-
-	assert_devl_locked(devlink);
-
-	if (type != NFP_PORT_PHYS_PORT)
-		return NULL;
-
-	list_for_each_entry(port, &pf->ports, port_list)
-		if (port->eth_id == id)
-			return port;
-
-	return NULL;
-}
-
 struct nfp_eth_table_port *__nfp_port_get_eth_port(struct nfp_port *port)
 {
 	if (!port)
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_port.h b/drivers/net/ethernet/netronome/nfp/nfp_port.h
index df316b9e891d..d1ebe6c72f7f 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_port.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_port.h
@@ -106,8 +106,6 @@ nfp_port_set_features(struct net_device *netdev, netdev_features_t features);
 struct nfp_port *nfp_port_from_netdev(struct net_device *netdev);
 int nfp_port_get_port_parent_id(struct net_device *netdev,
 				struct netdev_phys_item_id *ppid);
-struct nfp_port *
-nfp_port_from_id(struct nfp_pf *pf, enum nfp_port_type type, unsigned int id);
 struct nfp_eth_table_port *__nfp_port_get_eth_port(struct nfp_port *port);
 struct nfp_eth_table_port *nfp_port_get_eth_port(struct nfp_port *port);
 
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 9de0d091aee9..fd89a17adea1 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -1197,9 +1197,9 @@ struct devlink_ops {
 			 struct netlink_ext_ack *extack);
 	int (*port_type_set)(struct devlink_port *devlink_port,
 			     enum devlink_port_type port_type);
-	int (*port_split)(struct devlink *devlink, unsigned int port_index,
+	int (*port_split)(struct devlink *devlink, struct devlink_port *port,
 			  unsigned int count, struct netlink_ext_ack *extack);
-	int (*port_unsplit)(struct devlink *devlink, unsigned int port_index,
+	int (*port_unsplit)(struct devlink *devlink, struct devlink_port *port,
 			    struct netlink_ext_ack *extack);
 	int (*sb_pool_get)(struct devlink *devlink, unsigned int sb_index,
 			   u16 pool_index,
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 3069a3833576..2549ae1aaa6f 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -1572,35 +1572,20 @@ static int devlink_nl_cmd_port_set_doit(struct sk_buff *skb,
 	return 0;
 }
 
-static int devlink_port_split(struct devlink *devlink, u32 port_index,
-			      u32 count, struct netlink_ext_ack *extack)
-
-{
-	if (devlink->ops->port_split)
-		return devlink->ops->port_split(devlink, port_index, count,
-						extack);
-	return -EOPNOTSUPP;
-}
-
 static int devlink_nl_cmd_port_split_doit(struct sk_buff *skb,
 					  struct genl_info *info)
 {
+	struct devlink_port *devlink_port = info->user_ptr[1];
 	struct devlink *devlink = info->user_ptr[0];
-	struct devlink_port *devlink_port;
-	u32 port_index;
 	u32 count;
 
-	if (!info->attrs[DEVLINK_ATTR_PORT_INDEX] ||
-	    !info->attrs[DEVLINK_ATTR_PORT_SPLIT_COUNT])
+	if (!info->attrs[DEVLINK_ATTR_PORT_SPLIT_COUNT])
 		return -EINVAL;
+	if (!devlink->ops->port_split)
+		return -EOPNOTSUPP;
 
-	devlink_port = devlink_port_get_from_info(devlink, info);
-	port_index = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_INDEX]);
 	count = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_SPLIT_COUNT]);
 
-	if (IS_ERR(devlink_port))
-		return -EINVAL;
-
 	if (!devlink_port->attrs.splittable) {
 		/* Split ports cannot be split. */
 		if (devlink_port->attrs.split)
@@ -1615,29 +1600,19 @@ static int devlink_nl_cmd_port_split_doit(struct sk_buff *skb,
 		return -EINVAL;
 	}
 
-	return devlink_port_split(devlink, port_index, count, info->extack);
-}
-
-static int devlink_port_unsplit(struct devlink *devlink, u32 port_index,
-				struct netlink_ext_ack *extack)
-
-{
-	if (devlink->ops->port_unsplit)
-		return devlink->ops->port_unsplit(devlink, port_index, extack);
-	return -EOPNOTSUPP;
+	return devlink->ops->port_split(devlink, devlink_port, count,
+					info->extack);
 }
 
 static int devlink_nl_cmd_port_unsplit_doit(struct sk_buff *skb,
 					    struct genl_info *info)
 {
+	struct devlink_port *devlink_port = info->user_ptr[1];
 	struct devlink *devlink = info->user_ptr[0];
-	u32 port_index;
 
-	if (!info->attrs[DEVLINK_ATTR_PORT_INDEX])
-		return -EINVAL;
-
-	port_index = nla_get_u32(info->attrs[DEVLINK_ATTR_PORT_INDEX]);
-	return devlink_port_unsplit(devlink, port_index, info->extack);
+	if (!devlink->ops->port_unsplit)
+		return -EOPNOTSUPP;
+	return devlink->ops->port_unsplit(devlink, devlink_port, info->extack);
 }
 
 static int devlink_port_new_notifiy(struct devlink *devlink,
@@ -8676,12 +8651,14 @@ static const struct genl_small_ops devlink_nl_ops[] = {
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 		.doit = devlink_nl_cmd_port_split_doit,
 		.flags = GENL_ADMIN_PERM,
+		.internal_flags = DEVLINK_NL_FLAG_NEED_PORT,
 	},
 	{
 		.cmd = DEVLINK_CMD_PORT_UNSPLIT,
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 		.doit = devlink_nl_cmd_port_unsplit_doit,
 		.flags = GENL_ADMIN_PERM,
+		.internal_flags = DEVLINK_NL_FLAG_NEED_PORT,
 	},
 	{
 		.cmd = DEVLINK_CMD_PORT_NEW,
-- 
2.34.1

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Ido Schimmel]

On Wed, Mar 09, 2022 at 04:16:26PM -0800, Jakub Kicinski wrote:
> This series puts the devlink ports fully under the devlink instance
> lock's protection. As discussed in the past it implements my preferred
> solution of exposing the instance lock to the drivers. This way drivers
> which want to support port splitting can lock the devlink instance
> themselves on the probe path, and we can take that lock in the core
> on the split/unsplit paths.
> 
> nfp and mlxsw are converted, with slightly deeper changes done in
> nfp since I'm more familiar with that driver.
> 
> Now that the devlink port is protected we can pass a pointer to
> the drivers, instead of passing a port index and forcing the drivers
> to do their own lookups. Both nfp and mlxsw can container_of() to
> their own structures.
> 
> I'd appreciate some testing, I don't have access to this HW.

Thanks for working on this. I ran a few tests that exercise these code
paths with a debug config and did not see any immediate problems. I will
go over the patches later today

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Jiri Pirko]

Thu, Mar 10, 2022 at 01:16:26AM CET, kuba@kernel.org wrote:
>This series puts the devlink ports fully under the devlink instance
>lock's protection. As discussed in the past it implements my preferred
>solution of exposing the instance lock to the drivers. This way drivers
>which want to support port splitting can lock the devlink instance
>themselves on the probe path, and we can take that lock in the core
>on the split/unsplit paths.
>
>nfp and mlxsw are converted, with slightly deeper changes done in
>nfp since I'm more familiar with that driver.
>
>Now that the devlink port is protected we can pass a pointer to
>the drivers, instead of passing a port index and forcing the drivers
>to do their own lookups. Both nfp and mlxsw can container_of() to
>their own structures.
>
>I'd appreciate some testing, I don't have access to this HW.

I like this patchset. To be honest, I made a mistake to not do have it
like this from the beginning. I tried to hide the devlink lock from the
user/driver, but as it turned out, that was probably not a good idea :)


>
>Jakub Kicinski (6):
>  devlink: expose instance locking and add locked port registering
>  eth: nfp: wrap locking assertions in helpers
>  eth: nfp: replace driver's "pf" lock with devlink instance lock
>  eth: mlxsw: switch to explicit locking for port registration
>  devlink: hold the instance lock in port_split / port_unsplit callbacks
>  devlink: pass devlink_port to port_split / port_unsplit callbacks
>
> drivers/net/ethernet/mellanox/mlxsw/core.c    |  36 ++---
> drivers/net/ethernet/mellanox/mlxsw/minimal.c |   6 +
> .../net/ethernet/mellanox/mlxsw/spectrum.c    |   7 +
> .../net/ethernet/netronome/nfp/flower/main.c  |   4 +-
> drivers/net/ethernet/netronome/nfp/nfp_app.c  |   2 +-
> drivers/net/ethernet/netronome/nfp/nfp_app.h  |  12 +-
> .../net/ethernet/netronome/nfp/nfp_devlink.c  |  55 +++----
> drivers/net/ethernet/netronome/nfp/nfp_main.c |  19 +--
> drivers/net/ethernet/netronome/nfp/nfp_main.h |   6 +-
> .../net/ethernet/netronome/nfp/nfp_net_main.c |  34 ++--
> .../net/ethernet/netronome/nfp/nfp_net_repr.c |   4 +-
> drivers/net/ethernet/netronome/nfp/nfp_port.c |  17 --
> drivers/net/ethernet/netronome/nfp/nfp_port.h |   2 -
> include/net/devlink.h                         |  15 +-
> net/core/devlink.c                            | 148 ++++++++++--------
> 15 files changed, 196 insertions(+), 171 deletions(-)
>
>-- 
>2.34.1
>

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Leon Romanovsky]

On Wed, Mar 09, 2022 at 04:16:26PM -0800, Jakub Kicinski wrote:
> This series puts the devlink ports fully under the devlink instance
> lock's protection. As discussed in the past it implements my preferred
> solution of exposing the instance lock to the drivers. This way drivers
> which want to support port splitting can lock the devlink instance
> themselves on the probe path, and we can take that lock in the core
> on the split/unsplit paths.
> 
> nfp and mlxsw are converted, with slightly deeper changes done in
> nfp since I'm more familiar with that driver.
> 
> Now that the devlink port is protected we can pass a pointer to
> the drivers, instead of passing a port index and forcing the drivers
> to do their own lookups. Both nfp and mlxsw can container_of() to
> their own structures.
> 
> I'd appreciate some testing, I don't have access to this HW.
> 
> Jakub Kicinski (6):
>   devlink: expose instance locking and add locked port registering
>   eth: nfp: wrap locking assertions in helpers
>   eth: nfp: replace driver's "pf" lock with devlink instance lock
>   eth: mlxsw: switch to explicit locking for port registration
>   devlink: hold the instance lock in port_split / port_unsplit callbacks
>   devlink: pass devlink_port to port_split / port_unsplit callbacks

Jakub,

Thanks for pursuing in cleanup this devlink mess.

Do you plan to send a series that removes devlink_mutex?

Thanks

> 
>  drivers/net/ethernet/mellanox/mlxsw/core.c    |  36 ++---
>  drivers/net/ethernet/mellanox/mlxsw/minimal.c |   6 +
>  .../net/ethernet/mellanox/mlxsw/spectrum.c    |   7 +
>  .../net/ethernet/netronome/nfp/flower/main.c  |   4 +-
>  drivers/net/ethernet/netronome/nfp/nfp_app.c  |   2 +-
>  drivers/net/ethernet/netronome/nfp/nfp_app.h  |  12 +-
>  .../net/ethernet/netronome/nfp/nfp_devlink.c  |  55 +++----
>  drivers/net/ethernet/netronome/nfp/nfp_main.c |  19 +--
>  drivers/net/ethernet/netronome/nfp/nfp_main.h |   6 +-
>  .../net/ethernet/netronome/nfp/nfp_net_main.c |  34 ++--
>  .../net/ethernet/netronome/nfp/nfp_net_repr.c |   4 +-
>  drivers/net/ethernet/netronome/nfp/nfp_port.c |  17 --
>  drivers/net/ethernet/netronome/nfp/nfp_port.h |   2 -
>  include/net/devlink.h                         |  15 +-
>  net/core/devlink.c                            | 148 ++++++++++--------
>  15 files changed, 196 insertions(+), 171 deletions(-)
> 
> -- 
> 2.34.1
> 

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jiri Pirko]

Thu, Mar 10, 2022 at 01:16:27AM CET, kuba@kernel.org wrote:
>It should be familiar and beneficial to expose devlink instance
>lock to the drivers. This way drivers can block devlink from
>calling them during critical sections without breakneck locking.
>
>Add port helpers, port splitting callbacks will be the first
>target.
>
>Use 'devl_' prefix for "explicitly locked" API. Initial RFC used
>'__devlink' but that's too much typing.
>
>Signed-off-by: Jakub Kicinski <kuba@kernel.org>
>---
> include/net/devlink.h | 11 +++++
> net/core/devlink.c    | 99 ++++++++++++++++++++++++++++++++-----------
> 2 files changed, 86 insertions(+), 24 deletions(-)
>
>diff --git a/include/net/devlink.h b/include/net/devlink.h
>index 8d5349d2fb68..9de0d091aee9 100644
>--- a/include/net/devlink.h
>+++ b/include/net/devlink.h
>@@ -1479,6 +1479,17 @@ void *devlink_priv(struct devlink *devlink);
> struct devlink *priv_to_devlink(void *priv);
> struct device *devlink_to_dev(const struct devlink *devlink);
> 
>+/* Devlink instance explicit locking */
>+void devl_lock(struct devlink *devlink);
>+void devl_unlock(struct devlink *devlink);
>+void devl_assert_locked(struct devlink *devlink);
>+bool devl_lock_is_held(struct devlink *devlink);
>+
>+int devl_port_register(struct devlink *devlink,

It is kind of confusing to have:
devlink_* - locked api
devl_* - unlocked api

And not really, because by this division, devl_lock() should be called
devlink_lock(). So it is oddly mixed..

I believe that "_" or "__" prefix is prefered here and everyone knows
with away what it it is good for.

If you find "__devlink_port_register" as "too much typing" (I don't),
why don't we have all devlink api shortened to:
devl_*
and then the unlocked api could be called:
__devl_*
?


[...]


>+bool devl_lock_is_held(struct devlink *devlink)
>+{
>+	/* We have to check this at runtime because struct devlink
>+	 * is now private. Normally lock_is_held() should be eliminated

"is now private" belong more to the patch description, not to the actual
code I believe.

[...]

Re: [RFT net-next 4/6] eth: mlxsw: switch to explicit locking for port registration

[Jiri Pirko]

Thu, Mar 10, 2022 at 01:16:30AM CET, kuba@kernel.org wrote:
>Explicitly lock the devlink instance and use devl_ API.
>
>This will be used by the subsequent patch to invoke
>.port_split / .port_unsplit callbacks with devlink
>instance lock held.
>
>Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Looks fine. I was about to propose a helpers for the lock/unlock that
would take mlxsw_core, but I see you are removing most of them in the
next patch :)

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jakub Kicinski]

On Thu, 10 Mar 2022 10:14:26 +0100 Jiri Pirko wrote:
> It is kind of confusing to have:
> devlink_* - locked api
> devl_* - unlocked api
> 
> And not really, because by this division, devl_lock() should be called
> devlink_lock(). So it is oddly mixed..
> 
> I believe that "_" or "__" prefix is prefered here and everyone knows
> with away what it it is good for.
> 
> If you find "__devlink_port_register" as "too much typing" (I don't),
> why don't we have all devlink api shortened to:
> devl_*
> and then the unlocked api could be called:
> __devl_*
> ?

The goal is for that API to be the main one, we can rename the devlink_
to something else at the end. The parts of it which are not completely
removed.

> >+bool devl_lock_is_held(struct devlink *devlink)
> >+{
> >+	/* We have to check this at runtime because struct devlink
> >+	 * is now private. Normally lock_is_held() should be eliminated  
> 
> "is now private" belong more to the patch description, not to the actual
> code I believe.

Alright. The comment started as a warning not to use this for anything
but lockdep but I couldn't resist taking a dig at hiding the structure.

Re: [RFT net-next 4/6] eth: mlxsw: switch to explicit locking for port registration

[Jakub Kicinski]

On Thu, 10 Mar 2022 10:17:42 +0100 Jiri Pirko wrote:
> Thu, Mar 10, 2022 at 01:16:30AM CET, kuba@kernel.org wrote:
> >Explicitly lock the devlink instance and use devl_ API.
> >
> >This will be used by the subsequent patch to invoke
> >.port_split / .port_unsplit callbacks with devlink
> >instance lock held.
> >
> >Signed-off-by: Jakub Kicinski <kuba@kernel.org>  
> 
> Looks fine. I was about to propose a helpers for the lock/unlock that
> would take mlxsw_core, but I see you are removing most of them in the
> next patch :)

Yup :) the end result should be one lock / unlock in probe and remove
paths.

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Jakub Kicinski]

On Thu, 10 Mar 2022 11:07:14 +0200 Leon Romanovsky wrote:
> On Wed, Mar 09, 2022 at 04:16:26PM -0800, Jakub Kicinski wrote:
> > This series puts the devlink ports fully under the devlink instance
> > lock's protection. As discussed in the past it implements my preferred
> > solution of exposing the instance lock to the drivers. This way drivers
> > which want to support port splitting can lock the devlink instance
> > themselves on the probe path, and we can take that lock in the core
> > on the split/unsplit paths.
> > 
> > nfp and mlxsw are converted, with slightly deeper changes done in
> > nfp since I'm more familiar with that driver.
> > 
> > Now that the devlink port is protected we can pass a pointer to
> > the drivers, instead of passing a port index and forcing the drivers
> > to do their own lookups. Both nfp and mlxsw can container_of() to
> > their own structures.
> > 
> > I'd appreciate some testing, I don't have access to this HW.
>
> Thanks for pursuing in cleanup this devlink mess.
> 
> Do you plan to send a series that removes devlink_mutex?

I would like to convert enough to explicit locking to allow simpler
reload handling. I'm happy to leave devlink_mutex removal to someone
else, but if there are no takers will do it as well. Let's see how 
it goes.

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Ido Schimmel]

On Thu, Mar 10, 2022 at 10:57:17AM +0200, Ido Schimmel wrote:
> On Wed, Mar 09, 2022 at 04:16:26PM -0800, Jakub Kicinski wrote:
> > This series puts the devlink ports fully under the devlink instance
> > lock's protection. As discussed in the past it implements my preferred
> > solution of exposing the instance lock to the drivers. This way drivers
> > which want to support port splitting can lock the devlink instance
> > themselves on the probe path, and we can take that lock in the core
> > on the split/unsplit paths.
> > 
> > nfp and mlxsw are converted, with slightly deeper changes done in
> > nfp since I'm more familiar with that driver.
> > 
> > Now that the devlink port is protected we can pass a pointer to
> > the drivers, instead of passing a port index and forcing the drivers
> > to do their own lookups. Both nfp and mlxsw can container_of() to
> > their own structures.
> > 
> > I'd appreciate some testing, I don't have access to this HW.
> 
> Thanks for working on this. I ran a few tests that exercise these code
> paths with a debug config and did not see any immediate problems. I will
> go over the patches later today

Went over the patches and they look good to me. Thanks again. Will run a
full regression with them on Sunday.

I read [1] and [2] again to refresh my memory about this conversion. Can
you provide a rough outline of how you plan to go about it? Asking so
that I will know what to expect and how it all fits together. I expect
that eventually 'DEVLINK_NL_FLAG_NO_LOCK' will be removed from
'DEVLINK_CMD_RELOAD' and then the devl_lock()/devl_unlock() that you
left in drivers will be moved to earlier in the probe path so that we
don't deadlock on reload.

[1] https://lore.kernel.org/lkml/YYgJ1bnECwUWvNqD@shredder/
[2] https://lore.kernel.org/netdev/20211030231254.2477599-1-kuba@kernel.org/

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Jakub Kicinski]

On Thu, 10 Mar 2022 23:13:02 +0200 Ido Schimmel wrote:
> On Thu, Mar 10, 2022 at 10:57:17AM +0200, Ido Schimmel wrote:
> > Thanks for working on this. I ran a few tests that exercise these code
> > paths with a debug config and did not see any immediate problems. I will
> > go over the patches later today  
> 
> Went over the patches and they look good to me. Thanks again. Will run a
> full regression with them on Sunday.

Thanks!

> I read [1] and [2] again to refresh my memory about this conversion. Can
> you provide a rough outline of how you plan to go about it?

TBH I haven't started on breaking out more patches, yet. My rough 
idea was to try to tackle the eswitch callback next and then the
reset callback.

> Asking so that I will know what to expect and how it all fits
> together. I expect that eventually 'DEVLINK_NL_FLAG_NO_LOCK' will be
> removed from 'DEVLINK_CMD_RELOAD' and then the
> devl_lock()/devl_unlock() that you left in drivers will be moved to
> earlier in the probe path so that we don't deadlock on reload.

Yup, that's the end goal 🤞

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Leon Romanovsky]

On Thu, Mar 10, 2022 at 12:13:48PM -0800, Jakub Kicinski wrote:
> On Thu, 10 Mar 2022 11:07:14 +0200 Leon Romanovsky wrote:
> > On Wed, Mar 09, 2022 at 04:16:26PM -0800, Jakub Kicinski wrote:
> > > This series puts the devlink ports fully under the devlink instance
> > > lock's protection. As discussed in the past it implements my preferred
> > > solution of exposing the instance lock to the drivers. This way drivers
> > > which want to support port splitting can lock the devlink instance
> > > themselves on the probe path, and we can take that lock in the core
> > > on the split/unsplit paths.
> > > 
> > > nfp and mlxsw are converted, with slightly deeper changes done in
> > > nfp since I'm more familiar with that driver.
> > > 
> > > Now that the devlink port is protected we can pass a pointer to
> > > the drivers, instead of passing a port index and forcing the drivers
> > > to do their own lookups. Both nfp and mlxsw can container_of() to
> > > their own structures.
> > > 
> > > I'd appreciate some testing, I don't have access to this HW.
> >
> > Thanks for pursuing in cleanup this devlink mess.
> > 
> > Do you plan to send a series that removes devlink_mutex?
> 
> I would like to convert enough to explicit locking to allow simpler
> reload handling. I'm happy to leave devlink_mutex removal to someone
> else, but if there are no takers will do it as well. Let's see how 
> it goes.

Alright, let's see.

The main obstacle to remove devlink_mutex was netdevsim port creation sysfs,
so after your locking series, that change will be more or less trivial.

Thanks

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jiri Pirko]

Thu, Mar 10, 2022 at 09:06:24PM CET, kuba@kernel.org wrote:
>On Thu, 10 Mar 2022 10:14:26 +0100 Jiri Pirko wrote:
>> It is kind of confusing to have:
>> devlink_* - locked api
>> devl_* - unlocked api
>> 
>> And not really, because by this division, devl_lock() should be called
>> devlink_lock(). So it is oddly mixed..
>> 
>> I believe that "_" or "__" prefix is prefered here and everyone knows
>> with away what it it is good for.
>> 
>> If you find "__devlink_port_register" as "too much typing" (I don't),
>> why don't we have all devlink api shortened to:
>> devl_*
>> and then the unlocked api could be called:
>> __devl_*
>> ?
>
>The goal is for that API to be the main one, we can rename the devlink_
>to something else at the end. The parts of it which are not completely
>removed.

Okay. So please have it as:
devl_* - normal
__devl_* - unlocked

Thanks!


>
>> >+bool devl_lock_is_held(struct devlink *devlink)
>> >+{
>> >+	/* We have to check this at runtime because struct devlink
>> >+	 * is now private. Normally lock_is_held() should be eliminated  
>> 
>> "is now private" belong more to the patch description, not to the actual
>> code I believe.
>
>Alright. The comment started as a warning not to use this for anything
>but lockdep but I couldn't resist taking a dig at hiding the structure.

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Simon Horman]

On Wed, Mar 09, 2022 at 04:16:26PM -0800, Jakub Kicinski wrote:
> This series puts the devlink ports fully under the devlink instance
> lock's protection. As discussed in the past it implements my preferred
> solution of exposing the instance lock to the drivers. This way drivers
> which want to support port splitting can lock the devlink instance
> themselves on the probe path, and we can take that lock in the core
> on the split/unsplit paths.
> 
> nfp and mlxsw are converted, with slightly deeper changes done in
> nfp since I'm more familiar with that driver.
> 
> Now that the devlink port is protected we can pass a pointer to
> the drivers, instead of passing a port index and forcing the drivers
> to do their own lookups. Both nfp and mlxsw can container_of() to
> their own structures.
> 
> I'd appreciate some testing, I don't have access to this HW.

Thanks Jakub,

this looks like a nice improvement :)

We have exercised this patch-set on NFP-based NICs and have not observed
any regressions.

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Leon Romanovsky]

On Wed, Mar 09, 2022 at 04:16:27PM -0800, Jakub Kicinski wrote:
> It should be familiar and beneficial to expose devlink instance
> lock to the drivers. This way drivers can block devlink from
> calling them during critical sections without breakneck locking.
> 
> Add port helpers, port splitting callbacks will be the first
> target.
> 
> Use 'devl_' prefix for "explicitly locked" API. Initial RFC used
> '__devlink' but that's too much typing.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>  include/net/devlink.h | 11 +++++
>  net/core/devlink.c    | 99 ++++++++++++++++++++++++++++++++-----------
>  2 files changed, 86 insertions(+), 24 deletions(-)
> 
> diff --git a/include/net/devlink.h b/include/net/devlink.h
> index 8d5349d2fb68..9de0d091aee9 100644
> --- a/include/net/devlink.h
> +++ b/include/net/devlink.h
> @@ -1479,6 +1479,17 @@ void *devlink_priv(struct devlink *devlink);
>  struct devlink *priv_to_devlink(void *priv);
>  struct device *devlink_to_dev(const struct devlink *devlink);
>  
> +/* Devlink instance explicit locking */
> +void devl_lock(struct devlink *devlink);
> +void devl_unlock(struct devlink *devlink);
> +void devl_assert_locked(struct devlink *devlink);
> +bool devl_lock_is_held(struct devlink *devlink);
> +
> +int devl_port_register(struct devlink *devlink,
> +		       struct devlink_port *devlink_port,
> +		       unsigned int port_index);
> +void devl_port_unregister(struct devlink_port *devlink_port);
> +
>  struct ib_device;
>  
>  struct net *devlink_net(const struct devlink *devlink);
> diff --git a/net/core/devlink.c b/net/core/devlink.c
> index fcd9f6d85cf1..c30da1fc023d 100644
> --- a/net/core/devlink.c
> +++ b/net/core/devlink.c
> @@ -225,6 +225,37 @@ struct devlink *__must_check devlink_try_get(struct devlink *devlink)
>  	return NULL;
>  }
>  
> +void devl_assert_locked(struct devlink *devlink)
> +{
> +	lockdep_assert_held(&devlink->lock);
> +}
> +EXPORT_SYMBOL_GPL(devl_assert_locked);
> +
> +bool devl_lock_is_held(struct devlink *devlink)
> +{
> +	/* We have to check this at runtime because struct devlink
> +	 * is now private. Normally lock_is_held() should be eliminated
> +	 * as dead code in the caller and we can depend on the linker error.
> +	 */
> +	if (!IS_ENABLED(CONFIG_LOCKDEP))
> +		return WARN_ON_ONCE(true);
> +
> +	return lockdep_is_held(&devlink->lock);
> +}
> +EXPORT_SYMBOL_GPL(devl_lock_is_held);

What about this?

diff --git a/include/net/devlink.h b/include/net/devlink.h
index 8d5349d2fb68..33b47d1a6800 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -1762,5 +1762,12 @@ devlink_compat_switch_id_get(struct net_device *dev,
 }
 
 #endif
-
+#if IS_ENABLED(CONFIG_LOCKDEP)
+bool devl_lock_is_held(struct devlink *devlink);
+#else
+static inline bool devl_lock_is_held(struct devlink *devlink)
+{
+       return true;
+}
+#endif
 #endif /* _NET_DEVLINK_H_ */

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jakub Kicinski]

On Fri, 11 Mar 2022 18:09:36 +0200 Leon Romanovsky wrote:
> What about this?

Is it better? Can do it you prefer, but I'd lean towards a version
without an ifdef myself.

> diff --git a/include/net/devlink.h b/include/net/devlink.h
> index 8d5349d2fb68..33b47d1a6800 100644
> --- a/include/net/devlink.h
> +++ b/include/net/devlink.h
> @@ -1762,5 +1762,12 @@ devlink_compat_switch_id_get(struct net_device *dev,
>  }
>  
>  #endif
> -
> +#if IS_ENABLED(CONFIG_LOCKDEP)
> +bool devl_lock_is_held(struct devlink *devlink);
> +#else
> +static inline bool devl_lock_is_held(struct devlink *devlink)
> +{
> +       return true;
> +}
> +#endif
>  #endif /* _NET_DEVLINK_H_ */

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jakub Kicinski]

On Fri, 11 Mar 2022 10:15:30 +0100 Jiri Pirko wrote:
>> The goal is for that API to be the main one, we can rename the devlink_
>> to something else at the end. The parts of it which are not completely
>> removed.  
> 
> Okay. So please have it as:
> devl_* - normal
> __devl_* - unlocked

Isn't it fairly awkward for the main intended API to have __ in the
name? __ means unsafe / make sure you know what you're doing.

There's little room for confusion here, we have locking asserts
everywhere.

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Jakub Kicinski]

On Fri, 11 Mar 2022 11:48:53 +0100 Simon Horman wrote:
> Thanks Jakub,
> 
> this looks like a nice improvement :)
> 
> We have exercised this patch-set on NFP-based NICs and have not observed
> any regressions.

Awesome, thanks a lot for testing! :)

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Leon Romanovsky]

On Fri, Mar 11, 2022 at 08:26:11AM -0800, Jakub Kicinski wrote:
> On Fri, 11 Mar 2022 18:09:36 +0200 Leon Romanovsky wrote:
> > What about this?
> 
> Is it better? 

I think so. It doesn't create shadow dependency on LOCKDEP.
In your variant, all users of this call will generate WARN
in production systems that run without lockdep.

So if you want the "eliminate" thing like you wrote in the comment,
the ifdef is a common solution.

> Can do it you prefer, but I'd lean towards a version
> without an ifdef myself.

So you need to add CONFIG_LOCKDEP dependency in devlink Kconfig.

Thanks

> 
> > diff --git a/include/net/devlink.h b/include/net/devlink.h
> > index 8d5349d2fb68..33b47d1a6800 100644
> > --- a/include/net/devlink.h
> > +++ b/include/net/devlink.h
> > @@ -1762,5 +1762,12 @@ devlink_compat_switch_id_get(struct net_device *dev,
> >  }
> >  
> >  #endif
> > -
> > +#if IS_ENABLED(CONFIG_LOCKDEP)
> > +bool devl_lock_is_held(struct devlink *devlink);
> > +#else
> > +static inline bool devl_lock_is_held(struct devlink *devlink)
> > +{
> > +       return true;
> > +}
> > +#endif
> >  #endif /* _NET_DEVLINK_H_ */

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jakub Kicinski]

On Fri, 11 Mar 2022 18:57:35 +0200 Leon Romanovsky wrote:
> On Fri, Mar 11, 2022 at 08:26:11AM -0800, Jakub Kicinski wrote:
> > On Fri, 11 Mar 2022 18:09:36 +0200 Leon Romanovsky wrote:  
> > > What about this?  
> > 
> > Is it better?   
> 
> I think so. It doesn't create shadow dependency on LOCKDEP.
> In your variant, all users of this call will generate WARN
> in production systems that run without lockdep.

No, no, that function is mostly for rcu dereference checking.
The calls should be eliminated as dead code on production systems.

> So if you want the "eliminate" thing like you wrote in the comment,
> the ifdef is a common solution.

I think these days people try to use IS_ENABLED() whenever possible.

> > Can do it you prefer, but I'd lean towards a version
> > without an ifdef myself.  
> 
> So you need to add CONFIG_LOCKDEP dependency in devlink Kconfig.

I don't see why.

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jakub Kicinski]

On Fri, 11 Mar 2022 09:39:13 -0800 Jakub Kicinski wrote:
> > I think so. It doesn't create shadow dependency on LOCKDEP.
> > In your variant, all users of this call will generate WARN
> > in production systems that run without lockdep.  
> 
> No, no, that function is mostly for rcu dereference checking.
> The calls should be eliminated as dead code on production systems.
> 
> > So if you want the "eliminate" thing like you wrote in the comment,
> > the ifdef is a common solution.  
> 
> I think these days people try to use IS_ENABLED() whenever possible.

Let me wrap the implementation in an ifdef, I guess that may be least
confusing and the linker error vs runtime warning is worth the cost.

> > > Can do it you prefer, but I'd lean towards a version
> > > without an ifdef myself.    
> > 
> > So you need to add CONFIG_LOCKDEP dependency in devlink Kconfig.  
> 
> I don't see why.

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Leon Romanovsky]

On Fri, Mar 11, 2022 at 09:39:13AM -0800, Jakub Kicinski wrote:
> On Fri, 11 Mar 2022 18:57:35 +0200 Leon Romanovsky wrote:
> > On Fri, Mar 11, 2022 at 08:26:11AM -0800, Jakub Kicinski wrote:
> > > On Fri, 11 Mar 2022 18:09:36 +0200 Leon Romanovsky wrote:  
> > > > What about this?  
> > > 
> > > Is it better?   
> > 
> > I think so. It doesn't create shadow dependency on LOCKDEP.
> > In your variant, all users of this call will generate WARN
> > in production systems that run without lockdep.
> 
> No, no, that function is mostly for rcu dereference checking.
> The calls should be eliminated as dead code on production systems.

On systems without LOCKDEP, the devl_lock_is_held function will be
generated to be like this:
bool devl_lock_is_held(struct devlink *devlink)
{
	return WARN_ON_ONCE(true);
}
EXPORT_SYMBOL_GPL(devl_lock_is_held);

> 
> > So if you want the "eliminate" thing like you wrote in the comment,
> > the ifdef is a common solution.
> 
> I think these days people try to use IS_ENABLED() whenever possible.

I'm one of such people, but here you put always WARN if LOCKDEP is not
enabled.

> 
> > > Can do it you prefer, but I'd lean towards a version
> > > without an ifdef myself.  
> > 
> > So you need to add CONFIG_LOCKDEP dependency in devlink Kconfig.
> 
> I don't see why.

Because of WARN_ON_ONCE.

Thanks

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jakub Kicinski]

On Fri, 11 Mar 2022 19:49:36 +0200 Leon Romanovsky wrote:
> > No, no, that function is mostly for rcu dereference checking.
> > The calls should be eliminated as dead code on production systems.  
> 
> On systems without LOCKDEP, the devl_lock_is_held function will be
> generated to be like this:
> bool devl_lock_is_held(struct devlink *devlink)
> {
> 	return WARN_ON_ONCE(true);
> }
> EXPORT_SYMBOL_GPL(devl_lock_is_held);

I think you missed my first sentence. Anyway, this is what I'll do in
v1:

#ifdef CONFIG_LOCKDEP
/* For use in conjunction with LOCKDEP only e.g. rcu_dereference_protected() */
bool devl_lock_is_held(struct devlink *devlink)
{
	return lockdep_is_held(&devlink->lock);
}
EXPORT_SYMBOL_GPL(devl_lock_is_held);
#endif

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Leon Romanovsky]

On Fri, Mar 11, 2022 at 10:06:11AM -0800, Jakub Kicinski wrote:
> On Fri, 11 Mar 2022 19:49:36 +0200 Leon Romanovsky wrote:
> > > No, no, that function is mostly for rcu dereference checking.
> > > The calls should be eliminated as dead code on production systems.  
> > 
> > On systems without LOCKDEP, the devl_lock_is_held function will be
> > generated to be like this:
> > bool devl_lock_is_held(struct devlink *devlink)
> > {
> > 	return WARN_ON_ONCE(true);
> > }
> > EXPORT_SYMBOL_GPL(devl_lock_is_held);
> 
> I think you missed my first sentence. Anyway, this is what I'll do in
> v1:
> 
> #ifdef CONFIG_LOCKDEP
> /* For use in conjunction with LOCKDEP only e.g. rcu_dereference_protected() */
> bool devl_lock_is_held(struct devlink *devlink)
> {
> 	return lockdep_is_held(&devlink->lock);
> }
> EXPORT_SYMBOL_GPL(devl_lock_is_held);
> #endif

Because you put EXPORT_SYMBOL_GPL, this function will be used by drivers
too, which will need to write something like this:

if (IS_ENABLED(CONFIG_LOCKDEP))
     devl_lock_is_held(devlink)

Otherwise, they will get linkage error in systems without LOCKDEP.

Thanks

Re: [RFT net-next 1/6] devlink: expose instance locking and add locked port registering

[Jiri Pirko]

Fri, Mar 11, 2022 at 05:33:32PM CET, kuba@kernel.org wrote:
>On Fri, 11 Mar 2022 10:15:30 +0100 Jiri Pirko wrote:
>>> The goal is for that API to be the main one, we can rename the devlink_
>>> to something else at the end. The parts of it which are not completely
>>> removed.  
>> 
>> Okay. So please have it as:
>> devl_* - normal
>> __devl_* - unlocked
>
>Isn't it fairly awkward for the main intended API to have __ in the
>name? __ means unsafe / make sure you know what you're doing.
>
>There's little room for confusion here, we have locking asserts
>everywhere.

Well, I think it is common to have "__" prefixed for unlocked variant.
Idk.

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Jakub Kicinski]

On Thu, 10 Mar 2022 23:13:02 +0200 Ido Schimmel wrote:
> Went over the patches and they look good to me. Thanks again. Will run a
> full regression with them on Sunday.

Hi Ido, no news?

Do you have a preference for these patches getting merged for 5.18 
or waiting after the merge window? IOW I'm wondering if it's more
beneficial for potential backports / out-of-tree builds to have the
ability to lock the devlink instance in 5.18 already or to do as much
of the conversions as possible in a single release (that'd mean waiting
for 5.19)?

If there's no clear preference I'll go for 5.18.

I have the eswitch mode conversion patches almost ready with the
"almost" being mlx5. I may just give up on that one and unlock/lock
in the handler :S

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Ido Schimmel]

On Mon, Mar 14, 2022 at 11:46:45AM -0700, Jakub Kicinski wrote:
> On Thu, 10 Mar 2022 23:13:02 +0200 Ido Schimmel wrote:
> > Went over the patches and they look good to me. Thanks again. Will run a
> > full regression with them on Sunday.
> 
> Hi Ido, no news?

Sorry, forgot to update you. All the tests passed :)

> 
> Do you have a preference for these patches getting merged for 5.18 
> or waiting after the merge window? IOW I'm wondering if it's more
> beneficial for potential backports / out-of-tree builds to have the
> ability to lock the devlink instance in 5.18 already or to do as much
> of the conversions as possible in a single release (that'd mean waiting
> for 5.19)?
> 
> If there's no clear preference I'll go for 5.18.

5.18 is fine by me.

Thanks!

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Jakub Kicinski]

On Mon, 14 Mar 2022 21:10:31 +0200 Ido Schimmel wrote:
> > Hi Ido, no news?  
> 
> Sorry, forgot to update you. All the tests passed :)

Perfect, thank you!

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Leon Romanovsky]

On Mon, Mar 14, 2022 at 11:46:45AM -0700, Jakub Kicinski wrote:
> On Thu, 10 Mar 2022 23:13:02 +0200 Ido Schimmel wrote:

<...>

> I have the eswitch mode conversion patches almost ready with the
> "almost" being mlx5. 

I wonder why do you need to change eswitch locking in mlx5?

Thanks

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Jakub Kicinski]

On Tue, 15 Mar 2022 09:39:31 +0200 Leon Romanovsky wrote:
> > I have the eswitch mode conversion patches almost ready with the
> > "almost" being mlx5.   
> 
> I wonder why do you need to change eswitch locking in mlx5?

I want DEVLINK_CMD_ESWITCH_SET to drop the DEVLINK_NL_FLAG_NO_LOCK
marking.

Other drivers are rather simple in terms of locking (bnxt, nfp,
netdevsim) and I can replace driver locking completely with a few 
minor changes. Other drivers have no locking (insert cry/laugh emoji).

mlx5 has layers and multiple locks, if you're okay with devl_unlock() /
devl_lock() inside the callback that's perfect for me.

Re: [RFT net-next 0/6] devlink: expose instance locking and simplify port splitting

[Leon Romanovsky]

On Tue, Mar 15, 2022 at 08:58:29AM -0700, Jakub Kicinski wrote:
> On Tue, 15 Mar 2022 09:39:31 +0200 Leon Romanovsky wrote:
> > > I have the eswitch mode conversion patches almost ready with the
> > > "almost" being mlx5.   
> > 
> > I wonder why do you need to change eswitch locking in mlx5?
> 
> I want DEVLINK_CMD_ESWITCH_SET to drop the DEVLINK_NL_FLAG_NO_LOCK
> marking.

+1

> 
> Other drivers are rather simple in terms of locking (bnxt, nfp,
> netdevsim) and I can replace driver locking completely with a few 
> minor changes. Other drivers have no locking (insert cry/laugh emoji).

I saw it too :)

> 
> mlx5 has layers and multiple locks, 

I would say that mlx5 has too many locks.

> if you're okay with devl_unlock() / devl_lock() inside the callback that's perfect for me.

The need of DEVLINK_NL_FLAG_NO_LOCK for eswitch is because of
questionable locking in devlink_rate_*() calls. 

If you success to remove mutex_lock from devlink_rate_nodes_check()
and devlink_rate_nodes_destroy(), you won't need devl_unlock/devl_lock
for eswitch.

Right now, the eswitch set flow doesn't suffer from races and/or other
bugs, just because of global devlink_mutex that protects unlocked parts
of devlink_nl_cmd_eswitch_set_doit().

Thanks