wireguard-linux/include/net/net_namespace.h, branch jd/bump-compilers

net: Don't register pernet_operations if only one of id or size is specified.

2024-08-03T21:38:44Z

We can allocate per-netns memory for struct pernet_operations by specifying id and size. register_pernet_operations() assigns an id to pernet_operations and later ops_init() allocates the specified size of memory as net->gen->ptr[id]. If id is missing, no memory is allocated. If size is not specified, pernet_operations just wastes an entry of net->gen->ptr[] for every netns. net_generic is available only when both id and size are specified, so let's ensure that. While we are at it, we add const to both fields. Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller

net: add exit_batch_rtnl() method

2024-02-08T02:55:10Z

Many (struct pernet_operations)->exit_batch() methods have to acquire rtnl. In presence of rtnl mutex pressure, this makes cleanup_net() very slow. This patch adds a new exit_batch_rtnl() method to reduce number of rtnl acquisitions from cleanup_net(). exit_batch_rtnl() handlers are called while rtnl is locked, and devices to be killed can be queued in a list provided as their second argument. A single unregister_netdevice_many() is called right before rtnl is released. exit_batch_rtnl() handlers are called before ->exit() and ->exit_batch() handlers. Signed-off-by: Eric Dumazet Reviewed-by: Antoine Tenart Link: https://lore.kernel.org/r/20240206144313.2050392-2-edumazet@google.com Signed-off-by: Jakub Kicinski

net: make dev_unreg_count global

2024-02-04T16:08:21Z

We can use a global dev_unreg_count counter instead of a per netns one. As a bonus we can factorize the changes done on it for bulk device removals. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: treat possible_net_t net pointer as an RCU one and add read_pnet_rcu()

2023-10-18T08:23:01Z

Make the net pointer stored in possible_net_t structure annotated as an RCU pointer. Change the access helpers to treat it as such. Introduce read_pnet_rcu() helper to allow caller to dereference the net pointer under RCU read lock. Signed-off-by: Jiri Pirko Reviewed-by: Simon Horman Signed-off-by: David S. Miller

Merge tag 'sysctl-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

2023-08-30T00:39:15Z

Pull sysctl updates from Luis Chamberlain: "Long ago we set out to remove the kitchen sink on kernel/sysctl.c arrays and placings sysctls to their own sybsystem or file to help avoid merge conflicts. Matthew Wilcox pointed out though that if we're going to do that we might as well also *save* space while at it and try to remove the extra last sysctl entry added at the end of each array, a sentintel, instead of bloating the kernel by adding a new sentinel with each array moved. Doing that was not so trivial, and has required slowing down the moves of kernel/sysctl.c arrays and measuring the impact on size by each new move. The complex part of the effort to help reduce the size of each sysctl is being done by the patient work of el señor Don Joel Granados. A lot of this is truly painful code refactoring and testing and then trying to measure the savings of each move and removing the sentinels. Although Joel already has code which does most of this work, experience with sysctl moves in the past shows is we need to be careful due to the slew of odd build failures that are possible due to the amount of random Kconfig options sysctls use. To that end Joel's work is split by first addressing the major housekeeping needed to remove the sentinels, which is part of this merge request. The rest of the work to actually remove the sentinels will be done later in future kernel releases. The preliminary math is showing this will all help reduce the overall build time size of the kernel and run time memory consumed by the kernel by about ~64 bytes per array where we are able to remove each sentinel in the future. That also means there is no more bloating the kernel with the extra ~64 bytes per array moved as no new sentinels are created" * tag 'sysctl-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: sysctl: Use ctl_table_size as stopping criteria for list macro sysctl: SIZE_MAX->ARRAY_SIZE in register_net_sysctl vrf: Update to register_net_sysctl_sz networking: Update to register_net_sysctl_sz netfilter: Update to register_net_sysctl_sz ax.25: Update to register_net_sysctl_sz sysctl: Add size to register_net_sysctl function sysctl: Add size arg to __register_sysctl_init sysctl: Add size to register_sysctl sysctl: Add a size arg to __register_sysctl_table sysctl: Add size argument to init_header sysctl: Add ctl_table_size to ctl_table_header sysctl: Use ctl_table_header in list_for_each_table_entry sysctl: Prefer ctl_table_header in proc_sysctl

sysctl: SIZE_MAX->ARRAY_SIZE in register_net_sysctl

2023-08-15T22:26:18Z

Replace SIZE_MAX with ARRAY_SIZE in the register_net_sysctl macro. Now that all the callers to register_net_sysctl are actual arrays, we can call ARRAY_SIZE() without any compilation warnings. By calculating the actual array size, this commit is making sure that register_net_sysctl and all its callers forward the table_size into sysctl backend for when the sentinel elements in the ctl_table arrays (last empty markers) are removed. Without it the removal would fail lacking a stopping criteria for traversing the ctl_table arrays. Stopping condition continues to be based on both table size and the procname null test. This is needed in order to allow for the systematic removal al the sentinel element in subsequent commits: Before removing sentinel the stopping criteria will be the last null element. When the sentinel is removed then the (correct) size will take over. Signed-off-by: Joel Granados Suggested-by: Jani Nikula Signed-off-by: Luis Chamberlain

sysctl: Add size to register_net_sysctl function

2023-08-15T22:26:17Z

This commit adds size to the register_net_sysctl indirection function to facilitate the removal of the sentinel elements (last empty markers) from the ctl_table arrays. Though we don't actually remove any sentinels in this commit, register_net_sysctl* now has the capability of forwarding table_size for when that happens. We create a new function register_net_sysctl_sz with an extra size argument. A macro replaces the existing register_net_sysctl. The size in the macro is SIZE_MAX instead of ARRAY_SIZE to avoid compilation errors while we systematically migrate to register_net_sysctl_sz. Will change to ARRAY_SIZE in subsequent commits. Care is taken to add table_size to the stopping criteria in such a way that when we remove the empty sentinel element, it will continue stopping in the last element of the ctl_table array. Signed-off-by: Joel Granados Suggested-by: Greg Kroah-Hartman Signed-off-by: Luis Chamberlain

net: store netdevs in an xarray

2023-07-28T18:35:58Z

Iterating over the netdev hash table for netlink dumps is hard. Dumps are done in "chunks" so we need to save the position after each chunk, so we know where to restart from. Because netdevs are stored in a hash table we remember which bucket we were in and how many devices we dumped. Since we don't hold any locks across the "chunks" - devices may come and go while we're dumping. If that happens we may miss a device (if device is deleted from the bucket we were in). We indicate to user space that this may have happened by setting NLM_F_DUMP_INTR. User space is supposed to dump again (I think) if it sees that. Somehow I doubt most user space gets this right.. To illustrate let's look at an example: System state: start: # [A, B, C] del: B # [A, C] with the hash table we may dump [A, B], missing C completely even tho it existed both before and after the "del B". Add an xarray and use it to allocate ifindexes. This way we can iterate ifindexes in order, without the worry that we'll skip one. We may still generate a dump of a state which "never existed", for example for a set of values and sequence of ops: System state: start: # [A, B] add: C # [A, C, B] del: B # [A, C] we may generate a dump of [A], if C got an index between A and B. System has never been in such state. But I'm 90% sure that's perfectly fine, important part is that we can't _miss_ devices which exist before and after. User space which wants to mirror kernel's state subscribes to notifications and does periodic dumps so it will know that C exists from the notification about its creation or from the next dump (next dump is _guaranteed_ to include C, if it doesn't get removed). To avoid any perf regressions keep the hash table for now. Most net namespaces have very few devices and microbenchmarking 1M lookups on Skylake I get the following results (not counting loopback to number of devs): #devs | hash | xa | delta 2 | 18.3 | 20.1 | + 9.8% 16 | 18.3 | 20.1 | + 9.5% 64 | 18.3 | 26.3 | +43.8% 128 | 20.4 | 26.3 | +28.6% 256 | 20.0 | 26.4 | +32.1% 1024 | 26.6 | 26.7 | + 0.2% 8192 |541.3 | 33.5 | -93.8% No surprises since the hash table has 256 entries. The microbenchmark scans indexes in order, if the pattern is more random xa starts to win at 512 devices already. But that's a lot of devices, in practice. Reviewed-by: Leon Romanovsky Link: https://lore.kernel.org/r/20230726185530.2247698-2-kuba@kernel.org Signed-off-by: Jakub Kicinski

net: add a refcount tracker for kernel sockets

2022-10-24T10:04:43Z

Commit ffa84b5ffb37 ("net: add netns refcount tracker to struct sock") added a tracker to sockets, but did not track kernel sockets. We still have syzbot reports hinting about netns being destroyed while some kernel TCP sockets had not been dismantled. This patch tracks kernel sockets, and adds a ref_tracker_dir_print() call to net_free() right before the netns is freed. Normally, each layer is responsible for properly releasing its kernel sockets before last call to net_free(). This debugging facility is enabled with CONFIG_NET_NS_REFCNT_TRACKER=y Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Tested-by: Kuniyuki Iwashima Signed-off-by: David S. Miller

netfilter: nf_flow_table: count pending offload workqueue tasks

2022-07-11T14:25:14Z

To improve hardware offload debuggability count pending 'add', 'del' and 'stats' flow_table offload workqueue tasks. Counters are incremented before scheduling new task and decremented when workqueue handler finishes executing. These counters allow user to diagnose congestion on hardware offload workqueues that can happen when either CPU is starved and workqueue jobs are executed at lower rate than new ones are added or when hardware/driver can't keep up with the rate. Implement the described counters as percpu counters inside new struct netns_ft which is stored inside struct net. Expose them via new procfs file '/proc/net/stats/nf_flowtable' that is similar to existing 'nf_conntrack' file. Signed-off-by: Vlad Buslov Signed-off-by: Oz Shlomo Signed-off-by: Pablo Neira Ayuso