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From:   Petr Pavlu <petr.pavlu@suse.com>
To:     tariqt@nvidia.com, yishaih@nvidia.com, leon@kernel.org
Cc:     davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, jgg@ziepe.ca, netdev@vger.kernel.org,
        linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
        Petr Pavlu <petr.pavlu@suse.com>,
        Leon Romanovsky <leonro@nvidia.com>
Subject: [PATCH net-next v2 07/10] mlx4: Register mlx4 devices to an auxiliary virtual bus
Date:   Sun, 13 Aug 2023 16:51:24 +0200
Message-Id: <20230813145127.10653-8-petr.pavlu@suse.com>
In-Reply-To: <20230813145127.10653-1-petr.pavlu@suse.com>
References: <20230813145127.10653-1-petr.pavlu@suse.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Add an auxiliary virtual bus to model the mlx4 driver structure. The
code is added along the current custom device management logic.
Subsequent patches switch mlx4_en and mlx4_ib to the auxiliary bus and
the old interface is then removed.

Structure mlx4_priv gains a new adev dynamic array to keep track of its
auxiliary devices. Access to the array is protected by the global
mlx4_intf mutex.

Functions mlx4_register_device() and mlx4_unregister_device() are
updated to expose auxiliary devices on the bus in order to load mlx4_en
and/or mlx4_ib. Functions mlx4_register_auxiliary_driver() and
mlx4_unregister_auxiliary_driver() are added to substitute
mlx4_register_interface() and mlx4_unregister_interface(), respectively.
Function mlx4_do_bond() is adjusted to walk over the adev array and
re-adds a specific auxiliary device if its driver sets the
MLX4_INTFF_BONDING flag.

Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Tested-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx4/Kconfig |   1 +
 drivers/net/ethernet/mellanox/mlx4/intf.c  | 230 ++++++++++++++++++++-
 drivers/net/ethernet/mellanox/mlx4/main.c  |  17 +-
 drivers/net/ethernet/mellanox/mlx4/mlx4.h  |   6 +
 include/linux/mlx4/device.h                |   7 +
 include/linux/mlx4/driver.h                |  11 +
 6 files changed, 268 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/Kconfig b/drivers/net/ethernet/mellanox/mlx4/Kconfig
index 1b4b1f642317..825e05fb8607 100644
--- a/drivers/net/ethernet/mellanox/mlx4/Kconfig
+++ b/drivers/net/ethernet/mellanox/mlx4/Kconfig
@@ -27,6 +27,7 @@ config MLX4_EN_DCB
 config MLX4_CORE
 	tristate
 	depends on PCI
+	select AUXILIARY_BUS
 	select NET_DEVLINK
 	default n
 
diff --git a/drivers/net/ethernet/mellanox/mlx4/intf.c b/drivers/net/ethernet/mellanox/mlx4/intf.c
index 30aead34ce08..4b1e18e4a682 100644
--- a/drivers/net/ethernet/mellanox/mlx4/intf.c
+++ b/drivers/net/ethernet/mellanox/mlx4/intf.c
@@ -48,6 +48,89 @@ struct mlx4_device_context {
 static LIST_HEAD(intf_list);
 static LIST_HEAD(dev_list);
 static DEFINE_MUTEX(intf_mutex);
+static DEFINE_IDA(mlx4_adev_ida);
+
+static const struct mlx4_adev_device {
+	const char *suffix;
+	bool (*is_supported)(struct mlx4_dev *dev);
+} mlx4_adev_devices[1] = {};
+
+int mlx4_adev_init(struct mlx4_dev *dev)
+{
+	struct mlx4_priv *priv = mlx4_priv(dev);
+
+	priv->adev_idx = ida_alloc(&mlx4_adev_ida, GFP_KERNEL);
+	if (priv->adev_idx < 0)
+		return priv->adev_idx;
+
+	priv->adev = kcalloc(ARRAY_SIZE(mlx4_adev_devices),
+			     sizeof(struct mlx4_adev *), GFP_KERNEL);
+	if (!priv->adev) {
+		ida_free(&mlx4_adev_ida, priv->adev_idx);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+void mlx4_adev_cleanup(struct mlx4_dev *dev)
+{
+	struct mlx4_priv *priv = mlx4_priv(dev);
+
+	kfree(priv->adev);
+	ida_free(&mlx4_adev_ida, priv->adev_idx);
+}
+
+static void adev_release(struct device *dev)
+{
+	struct mlx4_adev *mlx4_adev =
+		container_of(dev, struct mlx4_adev, adev.dev);
+	struct mlx4_priv *priv = mlx4_priv(mlx4_adev->mdev);
+	int idx = mlx4_adev->idx;
+
+	kfree(mlx4_adev);
+	priv->adev[idx] = NULL;
+}
+
+static struct mlx4_adev *add_adev(struct mlx4_dev *dev, int idx)
+{
+	struct mlx4_priv *priv = mlx4_priv(dev);
+	const char *suffix = mlx4_adev_devices[idx].suffix;
+	struct auxiliary_device *adev;
+	struct mlx4_adev *madev;
+	int ret;
+
+	madev = kzalloc(sizeof(*madev), GFP_KERNEL);
+	if (!madev)
+		return ERR_PTR(-ENOMEM);
+
+	adev = &madev->adev;
+	adev->id = priv->adev_idx;
+	adev->name = suffix;
+	adev->dev.parent = &dev->persist->pdev->dev;
+	adev->dev.release = adev_release;
+	madev->mdev = dev;
+	madev->idx = idx;
+
+	ret = auxiliary_device_init(adev);
+	if (ret) {
+		kfree(madev);
+		return ERR_PTR(ret);
+	}
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		return ERR_PTR(ret);
+	}
+	return madev;
+}
+
+static void del_adev(struct auxiliary_device *adev)
+{
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
 
 static void mlx4_add_device(struct mlx4_interface *intf, struct mlx4_priv *priv)
 {
@@ -120,12 +203,24 @@ void mlx4_unregister_interface(struct mlx4_interface *intf)
 }
 EXPORT_SYMBOL_GPL(mlx4_unregister_interface);
 
+int mlx4_register_auxiliary_driver(struct mlx4_adrv *madrv)
+{
+	return auxiliary_driver_register(&madrv->adrv);
+}
+EXPORT_SYMBOL_GPL(mlx4_register_auxiliary_driver);
+
+void mlx4_unregister_auxiliary_driver(struct mlx4_adrv *madrv)
+{
+	auxiliary_driver_unregister(&madrv->adrv);
+}
+EXPORT_SYMBOL_GPL(mlx4_unregister_auxiliary_driver);
+
 int mlx4_do_bond(struct mlx4_dev *dev, bool enable)
 {
 	struct mlx4_priv *priv = mlx4_priv(dev);
 	struct mlx4_device_context *dev_ctx = NULL, *temp_dev_ctx;
 	unsigned long flags;
-	int ret;
+	int i, ret;
 	LIST_HEAD(bond_list);
 
 	if (!(dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_PORT_REMAP))
@@ -177,6 +272,57 @@ int mlx4_do_bond(struct mlx4_dev *dev, bool enable)
 			 dev_ctx->intf->protocol, enable ?
 			 "enabled" : "disabled");
 	}
+
+	mutex_lock(&intf_mutex);
+
+	for (i = 0; i < ARRAY_SIZE(mlx4_adev_devices); i++) {
+		struct mlx4_adev *madev = priv->adev[i];
+		struct mlx4_adrv *madrv;
+		enum mlx4_protocol protocol;
+
+		if (!madev)
+			continue;
+
+		device_lock(&madev->adev.dev);
+		if (!madev->adev.dev.driver) {
+			device_unlock(&madev->adev.dev);
+			continue;
+		}
+
+		madrv = container_of(madev->adev.dev.driver, struct mlx4_adrv,
+				     adrv.driver);
+		if (!(madrv->flags & MLX4_INTFF_BONDING)) {
+			device_unlock(&madev->adev.dev);
+			continue;
+		}
+
+		if (mlx4_is_mfunc(dev)) {
+			mlx4_dbg(dev,
+				 "SRIOV, disabled HA mode for intf proto %d\n",
+				 madrv->protocol);
+			device_unlock(&madev->adev.dev);
+			continue;
+		}
+
+		protocol = madrv->protocol;
+		device_unlock(&madev->adev.dev);
+
+		del_adev(&madev->adev);
+		priv->adev[i] = add_adev(dev, i);
+		if (IS_ERR(priv->adev[i])) {
+			mlx4_warn(dev, "Device[%d] (%s) failed to load\n", i,
+				  mlx4_adev_devices[i].suffix);
+			priv->adev[i] = NULL;
+			continue;
+		}
+
+		mlx4_dbg(dev,
+			 "Interface for protocol %d restarted with bonded mode %s\n",
+			 protocol, enable ? "enabled" : "disabled");
+	}
+
+	mutex_unlock(&intf_mutex);
+
 	return 0;
 }
 
@@ -206,10 +352,80 @@ int mlx4_unregister_event_notifier(struct mlx4_dev *dev,
 }
 EXPORT_SYMBOL(mlx4_unregister_event_notifier);
 
+static int add_drivers(struct mlx4_dev *dev)
+{
+	struct mlx4_priv *priv = mlx4_priv(dev);
+	int i, ret = 0;
+
+	for (i = 0; i < ARRAY_SIZE(mlx4_adev_devices); i++) {
+		bool is_supported = false;
+
+		if (priv->adev[i])
+			continue;
+
+		if (mlx4_adev_devices[i].is_supported)
+			is_supported = mlx4_adev_devices[i].is_supported(dev);
+
+		if (!is_supported)
+			continue;
+
+		priv->adev[i] = add_adev(dev, i);
+		if (IS_ERR(priv->adev[i])) {
+			mlx4_warn(dev, "Device[%d] (%s) failed to load\n", i,
+				  mlx4_adev_devices[i].suffix);
+			/* We continue to rescan drivers and leave to the caller
+			 * to make decision if to release everything or
+			 * continue. */
+			ret = PTR_ERR(priv->adev[i]);
+			priv->adev[i] = NULL;
+		}
+	}
+	return ret;
+}
+
+static void delete_drivers(struct mlx4_dev *dev)
+{
+	struct mlx4_priv *priv = mlx4_priv(dev);
+	bool delete_all;
+	int i;
+
+	delete_all = !(dev->persist->interface_state & MLX4_INTERFACE_STATE_UP);
+
+	for (i = ARRAY_SIZE(mlx4_adev_devices) - 1; i >= 0; i--) {
+		bool is_supported = false;
+
+		if (!priv->adev[i])
+			continue;
+
+		if (mlx4_adev_devices[i].is_supported && !delete_all)
+			is_supported = mlx4_adev_devices[i].is_supported(dev);
+
+		if (is_supported)
+			continue;
+
+		del_adev(&priv->adev[i]->adev);
+		priv->adev[i] = NULL;
+	}
+}
+
+/* This function is used after mlx4_dev is reconfigured.
+ */
+static int rescan_drivers_locked(struct mlx4_dev *dev)
+{
+	lockdep_assert_held(&intf_mutex);
+
+	delete_drivers(dev);
+	if (!(dev->persist->interface_state & MLX4_INTERFACE_STATE_UP))
+		return 0;
+
+	return add_drivers(dev);
+}
+
 int mlx4_register_device(struct mlx4_dev *dev)
 {
 	struct mlx4_priv *priv = mlx4_priv(dev);
 	struct mlx4_interface *intf;
+	int ret;
 
 	mutex_lock(&intf_mutex);
 
@@ -218,10 +434,18 @@ int mlx4_register_device(struct mlx4_dev *dev)
 	list_for_each_entry(intf, &intf_list, list)
 		mlx4_add_device(intf, priv);
 
+	ret = rescan_drivers_locked(dev);
+
 	mutex_unlock(&intf_mutex);
+
+	if (ret) {
+		mlx4_unregister_device(dev);
+		return ret;
+	}
+
 	mlx4_start_catas_poll(dev);
 
-	return 0;
+	return ret;
 }
 
 void mlx4_unregister_device(struct mlx4_dev *dev)
@@ -253,6 +477,8 @@ void mlx4_unregister_device(struct mlx4_dev *dev)
 	list_del(&priv->dev_list);
 	dev->persist->interface_state &= ~MLX4_INTERFACE_STATE_UP;
 
+	rescan_drivers_locked(dev);
+
 	mutex_unlock(&intf_mutex);
 }
 
diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 0ed490b99163..c4ec7377aa71 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -3429,6 +3429,10 @@ static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 	INIT_LIST_HEAD(&priv->ctx_list);
 	spin_lock_init(&priv->ctx_lock);
 
+	err = mlx4_adev_init(dev);
+	if (err)
+		return err;
+
 	ATOMIC_INIT_NOTIFIER_HEAD(&priv->event_nh);
 
 	mutex_init(&priv->port_mutex);
@@ -3455,10 +3459,11 @@ static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 		err = mlx4_get_ownership(dev);
 		if (err) {
 			if (err < 0)
-				return err;
+				goto err_adev;
 			else {
 				mlx4_warn(dev, "Multiple PFs not yet supported - Skipping PF\n");
-				return -EINVAL;
+				err = -EINVAL;
+				goto err_adev;
 			}
 		}
 
@@ -3806,6 +3811,9 @@ static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 		mlx4_free_ownership(dev);
 
 	kfree(dev_cap);
+
+err_adev:
+	mlx4_adev_cleanup(dev);
 	return err;
 }
 
@@ -4186,6 +4194,8 @@ static void mlx4_unload_one(struct pci_dev *pdev)
 	mlx4_slave_destroy_special_qp_cap(dev);
 	kfree(dev->dev_vfs);
 
+	mlx4_adev_cleanup(dev);
+
 	mlx4_clean_dev(dev);
 	priv->pci_dev_data = pci_dev_data;
 	priv->removed = 1;
@@ -4573,6 +4583,9 @@ static int __init mlx4_init(void)
 {
 	int ret;
 
+	WARN_ONCE(strcmp(MLX4_ADEV_NAME, KBUILD_MODNAME),
+		  "mlx4_core name not in sync with kernel module name");
+
 	if (mlx4_verify_params())
 		return -EINVAL;
 
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4.h b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
index ece9acb6a869..d5050bfb342f 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
@@ -47,6 +47,7 @@
 #include <linux/spinlock.h>
 #include <net/devlink.h>
 #include <linux/rwsem.h>
+#include <linux/auxiliary_bus.h>
 #include <linux/notifier.h>
 
 #include <linux/mlx4/device.h>
@@ -884,6 +885,8 @@ struct mlx4_priv {
 	struct list_head	dev_list;
 	struct list_head	ctx_list;
 	spinlock_t		ctx_lock;
+	struct mlx4_adev	**adev;
+	int			adev_idx;
 	struct atomic_notifier_head event_nh;
 
 	int			pci_dev_data;
@@ -1052,6 +1055,9 @@ void mlx4_catas_end(struct mlx4_dev *dev);
 int mlx4_crdump_init(struct mlx4_dev *dev);
 void mlx4_crdump_end(struct mlx4_dev *dev);
 int mlx4_restart_one(struct pci_dev *pdev);
+
+int mlx4_adev_init(struct mlx4_dev *dev);
+void mlx4_adev_cleanup(struct mlx4_dev *dev);
 int mlx4_register_device(struct mlx4_dev *dev);
 void mlx4_unregister_device(struct mlx4_dev *dev);
 void mlx4_dispatch_event(struct mlx4_dev *dev, enum mlx4_dev_event type,
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 049d8a4b044d..27f42f713c89 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -33,6 +33,7 @@
 #ifndef MLX4_DEVICE_H
 #define MLX4_DEVICE_H
 
+#include <linux/auxiliary_bus.h>
 #include <linux/if_ether.h>
 #include <linux/pci.h>
 #include <linux/completion.h>
@@ -889,6 +890,12 @@ struct mlx4_dev {
 	u8  uar_page_shift;
 };
 
+struct mlx4_adev {
+	struct auxiliary_device adev;
+	struct mlx4_dev *mdev;
+	int idx;
+};
+
 struct mlx4_clock_params {
 	u64 offset;
 	u8 bar;
diff --git a/include/linux/mlx4/driver.h b/include/linux/mlx4/driver.h
index 781d5a0c2faa..9cf157d381c6 100644
--- a/include/linux/mlx4/driver.h
+++ b/include/linux/mlx4/driver.h
@@ -34,9 +34,12 @@
 #define MLX4_DRIVER_H
 
 #include <net/devlink.h>
+#include <linux/auxiliary_bus.h>
 #include <linux/notifier.h>
 #include <linux/mlx4/device.h>
 
+#define MLX4_ADEV_NAME "mlx4_core"
+
 struct mlx4_dev;
 
 #define MLX4_MAC_MASK	   0xffffffffffffULL
@@ -63,8 +66,16 @@ struct mlx4_interface {
 	int			flags;
 };
 
+struct mlx4_adrv {
+	struct auxiliary_driver	adrv;
+	enum mlx4_protocol	protocol;
+	int			flags;
+};
+
 int mlx4_register_interface(struct mlx4_interface *intf);
 void mlx4_unregister_interface(struct mlx4_interface *intf);
+int mlx4_register_auxiliary_driver(struct mlx4_adrv *madrv);
+void mlx4_unregister_auxiliary_driver(struct mlx4_adrv *madrv);
 
 int mlx4_register_event_notifier(struct mlx4_dev *dev,
 				 struct notifier_block *nb);
-- 
2.35.3