From 1695b97b291e79295bf5c26cba5ecc4b443d8ac7 Mon Sep 17 00:00:00 2001 From: Yishai Hadas Date: Thu, 24 Feb 2022 16:20:14 +0200 Subject: [PATCH] net/mlx5: Expose APIs to get/put the mlx5 core device Expose an API to get the mlx5 core device from a given VF PCI device if mlx5_core is its driver. Upon the get API we stay with the intf_state_mutex locked to make sure that the device can't be gone/unloaded till the caller will complete its job over the device, this expects to be for a short period of time for any flow that the lock is taken. Upon the put API we unlock the intf_state_mutex. The use case for those APIs is the migration flow of a VF over VFIO PCI. In that case the VF doesn't ride on mlx5_core, because the device is driving *two* different PCI devices, the PF owned by mlx5_core and the VF owned by the vfio driver. The mlx5_core of the PF is accessed only during the narrow window of the VF's ioctl that requires its services. This allows the PF driver to be more independent of the VF driver, so long as it doesn't reset the FW. Link: https://lore.kernel.org/all/20220224142024.147653-6-yishaih@nvidia.com Signed-off-by: Yishai Hadas Signed-off-by: Leon Romanovsky --- drivers/net/ethernet/mellanox/mlx5/core/main.c | 44 ++++++++++++++++++++++++++ include/linux/mlx5/driver.h | 3 ++ 2 files changed, 47 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c index 5b89581..e9aeba4 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c @@ -1881,6 +1881,50 @@ static struct pci_driver mlx5_core_driver = { .sriov_set_msix_vec_count = mlx5_core_sriov_set_msix_vec_count, }; +/** + * mlx5_vf_get_core_dev - Get the mlx5 core device from a given VF PCI device if + * mlx5_core is its driver. + * @pdev: The associated PCI device. + * + * Upon return the interface state lock stay held to let caller uses it safely. + * Caller must ensure to use the returned mlx5 device for a narrow window + * and put it back with mlx5_vf_put_core_dev() immediately once usage was over. + * + * Return: Pointer to the associated mlx5_core_dev or NULL. + */ +struct mlx5_core_dev *mlx5_vf_get_core_dev(struct pci_dev *pdev) + __acquires(&mdev->intf_state_mutex) +{ + struct mlx5_core_dev *mdev; + + mdev = pci_iov_get_pf_drvdata(pdev, &mlx5_core_driver); + if (IS_ERR(mdev)) + return NULL; + + mutex_lock(&mdev->intf_state_mutex); + if (!test_bit(MLX5_INTERFACE_STATE_UP, &mdev->intf_state)) { + mutex_unlock(&mdev->intf_state_mutex); + return NULL; + } + + return mdev; +} +EXPORT_SYMBOL(mlx5_vf_get_core_dev); + +/** + * mlx5_vf_put_core_dev - Put the mlx5 core device back. + * @mdev: The mlx5 core device. + * + * Upon return the interface state lock is unlocked and caller should not + * access the mdev any more. + */ +void mlx5_vf_put_core_dev(struct mlx5_core_dev *mdev) + __releases(&mdev->intf_state_mutex) +{ + mutex_unlock(&mdev->intf_state_mutex); +} +EXPORT_SYMBOL(mlx5_vf_put_core_dev); + static void mlx5_core_verify_params(void) { if (prof_sel >= ARRAY_SIZE(profile)) { diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h index 78655d8..319322a 100644 --- a/include/linux/mlx5/driver.h +++ b/include/linux/mlx5/driver.h @@ -1143,6 +1143,9 @@ int mlx5_dm_sw_icm_alloc(struct mlx5_core_dev *dev, enum mlx5_sw_icm_type type, int mlx5_dm_sw_icm_dealloc(struct mlx5_core_dev *dev, enum mlx5_sw_icm_type type, u64 length, u16 uid, phys_addr_t addr, u32 obj_id); +struct mlx5_core_dev *mlx5_vf_get_core_dev(struct pci_dev *pdev); +void mlx5_vf_put_core_dev(struct mlx5_core_dev *mdev); + #ifdef CONFIG_MLX5_CORE_IPOIB struct net_device *mlx5_rdma_netdev_alloc(struct mlx5_core_dev *mdev, struct ib_device *ibdev, -- 2.7.4