From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- fs/sysfs/mount.c | 103 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 fs/sysfs/mount.c (limited to 'fs/sysfs/mount.c') diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c new file mode 100644 index 000000000..88c10823f --- /dev/null +++ b/fs/sysfs/mount.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * fs/sysfs/symlink.c - operations for initializing and mounting sysfs + * + * Copyright (c) 2001-3 Patrick Mochel + * Copyright (c) 2007 SUSE Linux Products GmbH + * Copyright (c) 2007 Tejun Heo + * + * Please see Documentation/filesystems/sysfs.rst for more information. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "sysfs.h" + +static struct kernfs_root *sysfs_root; +struct kernfs_node *sysfs_root_kn; + +static void sysfs_fs_context_free(struct fs_context *fc) +{ + struct kernfs_fs_context *kfc = fc->fs_private; + + if (kfc->ns_tag) + kobj_ns_drop(KOBJ_NS_TYPE_NET, kfc->ns_tag); + kernfs_free_fs_context(fc); + kfree(kfc); +} + +static const struct fs_context_operations sysfs_fs_context_ops = { + .free = sysfs_fs_context_free, + .get_tree = kernfs_get_tree, +}; + +static int sysfs_init_fs_context(struct fs_context *fc) +{ + struct kernfs_fs_context *kfc; + struct ns_common *ns; + + if (!(fc->sb_flags & SB_KERNMOUNT)) { + if (!kobj_ns_current_may_mount(KOBJ_NS_TYPE_NET)) + return -EPERM; + } + + kfc = kzalloc_obj(struct kernfs_fs_context); + if (!kfc) + return -ENOMEM; + + kfc->ns_tag = ns = kobj_ns_grab_current(KOBJ_NS_TYPE_NET); + kfc->root = sysfs_root; + kfc->magic = SYSFS_MAGIC; + fc->fs_private = kfc; + fc->ops = &sysfs_fs_context_ops; + if (ns) { + struct net *netns = to_net_ns(ns); + + put_user_ns(fc->user_ns); + fc->user_ns = get_user_ns(netns->user_ns); + } + fc->global = true; + return 0; +} + +static void sysfs_kill_sb(struct super_block *sb) +{ + struct ns_common *ns = (struct ns_common *)kernfs_super_ns(sb); + + kernfs_kill_sb(sb); + kobj_ns_drop(KOBJ_NS_TYPE_NET, ns); +} + +static struct file_system_type sysfs_fs_type = { + .name = "sysfs", + .init_fs_context = sysfs_init_fs_context, + .kill_sb = sysfs_kill_sb, + .fs_flags = FS_USERNS_MOUNT | FS_USERNS_MOUNT_RESTRICTED, +}; + +int __init sysfs_init(void) +{ + int err; + + sysfs_root = kernfs_create_root(NULL, KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK, + NULL); + if (IS_ERR(sysfs_root)) + return PTR_ERR(sysfs_root); + + sysfs_root_kn = kernfs_root_to_node(sysfs_root); + + err = register_filesystem(&sysfs_fs_type); + if (err) { + kernfs_destroy_root(sysfs_root); + return err; + } + + return 0; +} -- cgit v1.3.1