From: Jiri Pirko <[email protected]> Prepare namespace moves for per-netns names. Check user-initiated moves for destination-name conflicts before disabling the device, keep same-netns moves as no-ops, and make teardown moves detach from the exiting namespace even if fallback naming fails.
Signed-off-by: Jiri Pirko <[email protected]> --- drivers/infiniband/core/device.c | 155 ++++++++++++++++++++++++++----- drivers/infiniband/core/nldev.c | 3 + 2 files changed, 137 insertions(+), 21 deletions(-) diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index de610f52c9b2..8d169658e312 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -268,7 +268,7 @@ static struct notifier_block ibdev_lsm_nb = { }; static int rdma_dev_change_netns(struct ib_device *device, struct net *cur_net, - struct net *net); + struct net *net, const char *fallback_pattern); /* Pointer to the RCU head at the start of the ib_port_data array */ struct ib_port_data_rcu { @@ -437,7 +437,8 @@ int ib_device_set_dim(struct ib_device *ibdev, u8 use_dim) } /* Pick a free index for the '%d' style @name pattern. */ -static int alloc_name_id(struct net *net, const char *name) +static int __alloc_name_id(struct net *net, const char *name, + const struct ib_device *skip) { struct ib_device *device; unsigned long index; @@ -450,6 +451,8 @@ static int alloc_name_id(struct net *net, const char *name) xa_for_each (&devices, index, device) { char buf[IB_DEVICE_NAME_MAX]; + if (device == skip) + continue; if (sscanf(dev_name(&device->dev), name, &i) != 1) continue; if (i < 0 || i >= INT_MAX) @@ -469,6 +472,11 @@ static int alloc_name_id(struct net *net, const char *name) return rc; } +static int alloc_name_id(struct net *net, const char *name) +{ + return __alloc_name_id(net, name, NULL); +} + static int alloc_name(struct ib_device *ibdev, const char *name) { int id; @@ -1160,8 +1168,17 @@ static void rdma_dev_exit_net(struct net *net) /* * If the real device is in the NS then move it back to init. + * Provide a fallback pattern so a name conflict in init_net + * cannot make the teardown move fail. */ - rdma_dev_change_netns(dev, net, &init_net); + if (net_eq(net, read_pnet(&dev->coredev.rdma_net))) { + ret = rdma_dev_change_netns(dev, net, &init_net, + "ibdev%d"); + if (ret) + WARN(1, + "Failed to move RDMA device %s to init_net on netns exit: %d\n", + dev_name(&dev->dev), ret); + } put_device(&dev->dev); down_read(&devices_rwsem); @@ -1680,14 +1697,71 @@ void ib_unregister_device_queued(struct ib_device *ib_dev) } EXPORT_SYMBOL(ib_unregister_device_queued); +static bool rdma_dev_name_in_netns(struct ib_device *skip, struct net *net, + const char *name) +{ + struct ib_device *device; + unsigned long index; + + lockdep_assert_held_write(&devices_rwsem); + + xa_for_each(&devices, index, device) + if (device != skip && + !strcmp(name, dev_name(&device->dev))) + return true; + + return false; +} + +/* + * Choose the name @device should use in net namespace @net: keep the current + * name when it is free, otherwise use a trusted '%d' @fallback_pattern + * (namespace teardown) to pick a free index. The caller must hold the write + * side of devices_rwsem. + */ +static int rdma_dev_pick_netns_name(struct ib_device *device, struct net *net, + const char *fallback_pattern, + char *buf, size_t buf_len, + const char **new_name) +{ + int id; + + lockdep_assert_held_write(&devices_rwsem); + + if (!rdma_dev_name_in_netns(device, net, dev_name(&device->dev))) { + *new_name = dev_name(&device->dev); + return 0; + } + + if (!fallback_pattern) + return -EEXIST; + + snprintf(buf, buf_len, "ibdev%u", device->index); + if (!rdma_dev_name_in_netns(device, net, buf)) { + *new_name = buf; + return 0; + } + + id = __alloc_name_id(net, fallback_pattern, device); + if (id < 0) + return id; + snprintf(buf, buf_len, fallback_pattern, id); + *new_name = buf; + return 0; +} + /* * The caller must pass in a device that has the kref held and the refcount * released. If the device is in cur_net and still registered then it is moved * into net. + * + * Naming rules are handled by rdma_dev_pick_netns_name(). */ static int rdma_dev_change_netns(struct ib_device *device, struct net *cur_net, - struct net *net) + struct net *net, const char *fallback_pattern) { + char buf[IB_DEVICE_NAME_MAX]; + const char *new_name; int ret2 = -EINVAL; int ret; @@ -1704,30 +1778,63 @@ static int rdma_dev_change_netns(struct ib_device *device, struct net *cur_net, goto out; } + if (!fallback_pattern) { + /* + * Reject a predictable name conflict before tearing anything + * down, so a doomed user move does not disable a live device. + */ + down_write(&devices_rwsem); + ret = rdma_dev_pick_netns_name(device, net, fallback_pattern, + buf, sizeof(buf), &new_name); + up_write(&devices_rwsem); + if (ret) + goto out; + } + kobject_uevent(&device->dev.kobj, KOBJ_REMOVE); disable_device(device); /* - * At this point no one can be using the device, so it is safe to - * change the namespace. + * Recompute the destination name under the write side of devices_rwsem + * now that the device is disabled, closing races with a concurrent + * registration or rename, then publish the new namespace at the sysfs + * level. */ - write_pnet(&device->coredev.rdma_net, net); + down_write(&devices_rwsem); + ret = rdma_dev_pick_netns_name(device, net, fallback_pattern, buf, + sizeof(buf), &new_name); + if (ret) { + if (fallback_pattern) { + WARN(1, + "%s: failed to pick device name during namespace teardown: %d\n", + __func__, ret); + write_pnet(&device->coredev.rdma_net, net); + ret = 0; + } + goto rename_done; + } - down_read(&devices_rwsem); - /* - * Currently rdma devices are system wide unique. So the device name - * is guaranteed free in the new namespace. Publish the new namespace - * at the sysfs level. - */ - ret = device_rename(&device->dev, dev_name(&device->dev)); - up_read(&devices_rwsem); + write_pnet(&device->coredev.rdma_net, net); + ret = device_rename(&device->dev, new_name); if (ret) { - dev_warn(&device->dev, - "%s: Couldn't rename device after namespace change\n", - __func__); - /* Try and put things back and re-enable the device */ - write_pnet(&device->coredev.rdma_net, cur_net); + if (fallback_pattern) { + WARN(1, + "%s: failed to rename device during namespace teardown: %d\n", + __func__, ret); + ret = 0; + } else { + dev_warn(&device->dev, + "%s: Couldn't rename device after namespace change\n", + __func__); + /* Try and put things back and re-enable the device */ + write_pnet(&device->coredev.rdma_net, cur_net); + } + } else { + strscpy(device->name, dev_name(&device->dev), + IB_DEVICE_NAME_MAX); } +rename_done: + up_write(&devices_rwsem); ret2 = enable_device_and_get(device); if (ret2) { @@ -1766,6 +1873,12 @@ int ib_device_set_netns_put(struct sk_buff *skb, goto ns_err; } + /* Moving a device to the namespace it already lives in is a no-op. */ + if (net_eq(net, read_pnet(&dev->coredev.rdma_net))) { + ret = 0; + goto ns_err; + } + /* * All the ib_clients, including uverbs, are reset when the namespace is * changed and this cannot be blocked waiting for userspace to do @@ -1778,7 +1891,7 @@ int ib_device_set_netns_put(struct sk_buff *skb, get_device(&dev->dev); ib_device_put(dev); - ret = rdma_dev_change_netns(dev, current->nsproxy->net_ns, net); + ret = rdma_dev_change_netns(dev, current->nsproxy->net_ns, net, NULL); put_device(&dev->dev); put_net(net); diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c index f599c24b34e8..3a9ec43a16f1 100644 --- a/drivers/infiniband/core/nldev.c +++ b/drivers/infiniband/core/nldev.c @@ -1195,6 +1195,9 @@ static int nldev_set_doit(struct sk_buff *skb, struct nlmsghdr *nlh, ns_fd = nla_get_u32(tb[RDMA_NLDEV_NET_NS_FD]); err = ib_device_set_netns_put(skb, device, ns_fd); + if (err == -EEXIST) + NL_SET_ERR_MSG(extack, + "Device name already exists in the target net namespace"); goto put_done; } -- 2.54.0
