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Message-Id: <20220318192344.1587891-6-kuba@kernel.org>
Date: Fri, 18 Mar 2022 12:23:44 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, jiri@...nulli.us, leonro@...dia.com,
saeedm@...dia.com, idosch@...sch.org, michael.chan@...adcom.com,
simon.horman@...igine.com, Jakub Kicinski <kuba@...nel.org>,
Jiri Pirko <jiri@...dia.com>
Subject: [PATCH net-next v2 5/5] 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 <leonro@...dia.com>
Reviewed-by: Jiri Pirko <jiri@...dia.com>
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
drivers/net/ethernet/broadcom/bnxt/bnxt_vfr.c | 22 +++-----
.../mellanox/mlx5/core/eswitch_offloads.c | 54 ++++++++++++++-----
.../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 b2a9528b456b..eb4803b11c0e 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 35cf4cb3098e..3f63df127091 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 @@ int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
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 48b95566b52b..405786c00334 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 68cd1defe990..57a3ac893792 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 5aac5370c136..aeca13b6e57b 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,
--
2.34.1
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