From 14e426bf1a4d77ac87d0fa2a964092a23f863e44 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 18 Mar 2022 12:23:44 -0700 Subject: [PATCH] devlink: hold the instance lock during eswitch_mode callbacks Make the devlink core hold the instance lock during eswitch_mode callbacks. Cheat in case of mlx5 (see the cover letter). Reviewed-by: Leon Romanovsky Reviewed-by: Jiri Pirko Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c | 22 +++------ .../ethernet/mellanox/mlx5/core/eswitch_offloads.c | 54 +++++++++++++++++----- drivers/net/ethernet/netronome/nfp/nfp_devlink.c | 7 +-- drivers/net/netdevsim/dev.c | 16 ++----- net/core/devlink.c | 6 --- 5 files changed, 54 insertions(+), 51 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c index b2a9528..eb4803b 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c @@ -559,44 +559,34 @@ int bnxt_dl_eswitch_mode_set(struct devlink *devlink, u16 mode, struct netlink_ext_ack *extack) { struct bnxt *bp = bnxt_get_bp_from_dl(devlink); - int rc = 0; - devl_lock(devlink); if (bp->eswitch_mode == mode) { netdev_info(bp->dev, "already in %s eswitch mode\n", mode == DEVLINK_ESWITCH_MODE_LEGACY ? "legacy" : "switchdev"); - rc = -EINVAL; - goto done; + return -EINVAL; } switch (mode) { case DEVLINK_ESWITCH_MODE_LEGACY: bnxt_vf_reps_destroy(bp); - break; + return 0; case DEVLINK_ESWITCH_MODE_SWITCHDEV: if (bp->hwrm_spec_code < 0x10803) { netdev_warn(bp->dev, "FW does not support SRIOV E-Switch SWITCHDEV mode\n"); - rc = -ENOTSUPP; - goto done; + return -ENOTSUPP; } if (pci_num_vf(bp->pdev) == 0) { netdev_info(bp->dev, "Enable VFs before setting switchdev mode\n"); - rc = -EPERM; - goto done; + return -EPERM; } - rc = bnxt_vf_reps_create(bp); - break; + return bnxt_vf_reps_create(bp); default: - rc = -EINVAL; - goto done; + return -EINVAL; } -done: - devl_unlock(devlink); - return rc; } #endif diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c index 35cf4cb..3f63df1 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c @@ -3337,6 +3337,27 @@ static int eswitch_devlink_esw_mode_check(const struct mlx5_eswitch *esw) !mlx5_core_is_ecpf_esw_manager(esw->dev)) ? -EOPNOTSUPP : 0; } +/* FIXME: devl_unlock() followed by devl_lock() inside driver callback + * is never correct and prone to races. It's a transitional workaround, + * never repeat this pattern. + * + * This code MUST be fixed before removing devlink_mutex as it is safe + * to do only because of that mutex. + */ +static void mlx5_eswtich_mode_callback_enter(struct devlink *devlink, + struct mlx5_eswitch *esw) +{ + devl_unlock(devlink); + down_write(&esw->mode_lock); +} + +static void mlx5_eswtich_mode_callback_exit(struct devlink *devlink, + struct mlx5_eswitch *esw) +{ + up_write(&esw->mode_lock); + devl_lock(devlink); +} + int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode, struct netlink_ext_ack *extack) { @@ -3351,6 +3372,15 @@ int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode, if (esw_mode_from_devlink(mode, &mlx5_mode)) return -EINVAL; + /* FIXME: devl_unlock() followed by devl_lock() inside driver callback + * is never correct and prone to races. It's a transitional workaround, + * never repeat this pattern. + * + * This code MUST be fixed before removing devlink_mutex as it is safe + * to do only because of that mutex. + */ + devl_unlock(devlink); + mlx5_lag_disable_change(esw->dev); err = mlx5_esw_try_lock(esw); if (err < 0) { @@ -3381,6 +3411,7 @@ unlock: mlx5_esw_unlock(esw); enable_lag: mlx5_lag_enable_change(esw->dev); + devl_lock(devlink); return err; } @@ -3393,14 +3424,14 @@ int mlx5_devlink_eswitch_mode_get(struct devlink *devlink, u16 *mode) if (IS_ERR(esw)) return PTR_ERR(esw); - down_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_enter(devlink, esw); err = eswitch_devlink_esw_mode_check(esw); if (err) goto unlock; err = esw_mode_to_devlink(esw->mode, mode); unlock: - up_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_exit(devlink, esw); return err; } @@ -3447,7 +3478,7 @@ int mlx5_devlink_eswitch_inline_mode_set(struct devlink *devlink, u8 mode, if (IS_ERR(esw)) return PTR_ERR(esw); - down_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_enter(devlink, esw); err = eswitch_devlink_esw_mode_check(esw); if (err) goto out; @@ -3484,11 +3515,11 @@ int mlx5_devlink_eswitch_inline_mode_set(struct devlink *devlink, u8 mode, goto out; esw->offloads.inline_mode = mlx5_mode; - up_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_exit(devlink, esw); return 0; out: - up_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_exit(devlink, esw); return err; } @@ -3501,14 +3532,14 @@ int mlx5_devlink_eswitch_inline_mode_get(struct devlink *devlink, u8 *mode) if (IS_ERR(esw)) return PTR_ERR(esw); - down_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_enter(devlink, esw); err = eswitch_devlink_esw_mode_check(esw); if (err) goto unlock; err = esw_inline_mode_to_devlink(esw->offloads.inline_mode, mode); unlock: - up_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_exit(devlink, esw); return err; } @@ -3524,7 +3555,7 @@ int mlx5_devlink_eswitch_encap_mode_set(struct devlink *devlink, if (IS_ERR(esw)) return PTR_ERR(esw); - down_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_enter(devlink, esw); err = eswitch_devlink_esw_mode_check(esw); if (err) goto unlock; @@ -3570,7 +3601,7 @@ int mlx5_devlink_eswitch_encap_mode_set(struct devlink *devlink, } unlock: - up_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_exit(devlink, esw); return err; } @@ -3584,15 +3615,14 @@ int mlx5_devlink_eswitch_encap_mode_get(struct devlink *devlink, if (IS_ERR(esw)) return PTR_ERR(esw); - - down_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_enter(devlink, esw); err = eswitch_devlink_esw_mode_check(esw); if (err) goto unlock; *encap = esw->offloads.encap; unlock: - up_write(&esw->mode_lock); + mlx5_eswtich_mode_callback_exit(devlink, esw); return err; } diff --git a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c index 48b9556..405786c 100644 --- a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c +++ b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c @@ -144,13 +144,8 @@ static int nfp_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode, struct netlink_ext_ack *extack) { struct nfp_pf *pf = devlink_priv(devlink); - int ret; - - devl_lock(devlink); - ret = nfp_app_eswitch_mode_set(pf->app, mode); - devl_unlock(devlink); - return ret; + return nfp_app_eswitch_mode_set(pf->app, mode); } static const struct nfp_devlink_versions_simple { diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c index 68cd1de..57a3ac8 100644 --- a/drivers/net/netdevsim/dev.c +++ b/drivers/net/netdevsim/dev.c @@ -615,22 +615,16 @@ static int nsim_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode, struct netlink_ext_ack *extack) { struct nsim_dev *nsim_dev = devlink_priv(devlink); - int err = 0; - devl_lock(devlink); if (mode == nsim_dev->esw_mode) - goto unlock; + return 0; if (mode == DEVLINK_ESWITCH_MODE_LEGACY) - err = nsim_esw_legacy_enable(nsim_dev, extack); - else if (mode == DEVLINK_ESWITCH_MODE_SWITCHDEV) - err = nsim_esw_switchdev_enable(nsim_dev, extack); - else - err = -EINVAL; + return nsim_esw_legacy_enable(nsim_dev, extack); + if (mode == DEVLINK_ESWITCH_MODE_SWITCHDEV) + return nsim_esw_switchdev_enable(nsim_dev, extack); -unlock: - devl_unlock(devlink); - return err; + return -EINVAL; } static int nsim_devlink_eswitch_mode_get(struct devlink *devlink, u16 *mode) diff --git a/net/core/devlink.c b/net/core/devlink.c index 5aac537..aeca13b 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -2868,15 +2868,11 @@ static int devlink_rate_nodes_check(struct devlink *devlink, u16 mode, { struct devlink_rate *devlink_rate; - /* Take the lock to sync with destroy */ - mutex_lock(&devlink->lock); list_for_each_entry(devlink_rate, &devlink->rate_list, list) if (devlink_rate_is_node(devlink_rate)) { - mutex_unlock(&devlink->lock); NL_SET_ERR_MSG_MOD(extack, "Rate node(s) exists."); return -EBUSY; } - mutex_unlock(&devlink->lock); return 0; } @@ -8735,14 +8731,12 @@ static const struct genl_small_ops devlink_nl_ops[] = { .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, .doit = devlink_nl_cmd_eswitch_get_doit, .flags = GENL_ADMIN_PERM, - .internal_flags = DEVLINK_NL_FLAG_NO_LOCK, }, { .cmd = DEVLINK_CMD_ESWITCH_SET, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, .doit = devlink_nl_cmd_eswitch_set_doit, .flags = GENL_ADMIN_PERM, - .internal_flags = DEVLINK_NL_FLAG_NO_LOCK, }, { .cmd = DEVLINK_CMD_DPIPE_TABLE_GET, -- 2.7.4