Messages in this thread Patch in this message |  | | | From | Arnd Bergmann <> | | Subject | [PATCH 03/10] cgroups: __rcu annotations | | Date | Wed, 24 Feb 2010 21:03:59 +0100 |
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Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- include/linux/cgroup.h | 6 ++-- include/linux/sched.h | 2 +- kernel/cgroup.c | 63 +++++++++++++++++++++++++---------------------- kernel/cpuset.c | 2 +- 4 files changed, 38 insertions(+), 35 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 0008dee..832092d 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -66,7 +66,7 @@ struct cgroup_subsys_state { unsigned long flags; /* ID for this css, if possible */ - struct css_id *id; + struct css_id __rcu *id; }; /* bits in struct cgroup_subsys_state flags field */ @@ -190,7 +190,7 @@ struct cgroup { struct list_head children; /* my children */ struct cgroup *parent; /* my parent */ - struct dentry *dentry; /* cgroup fs entry, RCU protected */ + struct dentry __rcu *dentry; /* cgroup fs entry, RCU protected */ /* Private pointers for each registered subsystem */ struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; @@ -486,7 +486,7 @@ static inline struct cgroup_subsys_state *cgroup_subsys_state( static inline struct cgroup_subsys_state *task_subsys_state( struct task_struct *task, int subsys_id) { - return rcu_dereference(task->cgroups->subsys[subsys_id]); + return rcu_dereference(task->cgroups)->subsys[subsys_id]; } static inline struct cgroup* task_cgroup(struct task_struct *task, diff --git a/include/linux/sched.h b/include/linux/sched.h index 78efe7c..038e16f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1489,7 +1489,7 @@ struct task_struct { #endif #ifdef CONFIG_CGROUPS /* Control Group info protected by css_set_lock */ - struct css_set *cgroups; + struct css_set __rcu *cgroups; /* cg_list protected by css_set_lock and tsk->alloc_lock */ struct list_head cg_list; #endif diff --git a/kernel/cgroup.c b/kernel/cgroup.c index aa3bee5..e0f379e 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -127,7 +127,7 @@ struct css_id { * is called after synchronize_rcu(). But for safe use, css_is_removed() * css_tryget() should be used for avoiding race. */ - struct cgroup_subsys_state *css; + struct cgroup_subsys_state __rcu *css; /* * ID of this css. */ @@ -605,7 +605,7 @@ static struct cgroup *task_cgroup_from_root(struct task_struct *task, * task can't change groups, so the only thing that can happen * is that it exits and its css is set back to init_css_set. */ - css = task->cgroups; + css = __rcu_dereference(task->cgroups); if (css == &init_css_set) { res = &root->top_cgroup; } else { @@ -850,7 +850,7 @@ static void cgroup_d_remove_dir(struct dentry *dentry) * * CGRP_WAIT_ON_RMDIR flag is set under cgroup's inode->i_mutex; */ -DECLARE_WAIT_QUEUE_HEAD(cgroup_rmdir_waitq); +static DECLARE_WAIT_QUEUE_HEAD(cgroup_rmdir_waitq); static void cgroup_wakeup_rmdir_waiter(struct cgroup *cgrp) { @@ -1081,9 +1081,11 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data) struct cgroupfs_root *root = sb->s_fs_info; struct cgroup *cgrp = &root->top_cgroup; struct cgroup_sb_opts opts; + struct dentry *dentry; lock_kernel(); - mutex_lock(&cgrp->dentry->d_inode->i_mutex); + dentry = __rcu_dereference(cgrp->dentry); + mutex_lock(&dentry->d_inode->i_mutex); mutex_lock(&cgroup_mutex); /* See what subsystems are wanted */ @@ -1116,7 +1118,7 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data) kfree(opts.release_agent); kfree(opts.name); mutex_unlock(&cgroup_mutex); - mutex_unlock(&cgrp->dentry->d_inode->i_mutex); + mutex_unlock(&dentry->d_inode->i_mutex); unlock_kernel(); return ret; } @@ -1375,7 +1377,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type, root_count++; sb->s_root->d_fsdata = root_cgrp; - root->top_cgroup.dentry = sb->s_root; + __rcu_assign_pointer(root->top_cgroup.dentry, sb->s_root); /* Link the top cgroup in this hierarchy into all * the css_set objects */ @@ -1513,7 +1515,7 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) int len = dentry->d_name.len; if ((start -= len) < buf) return -ENAMETOOLONG; - memcpy(start, cgrp->dentry->d_name.name, len); + memcpy(start, dentry->d_name.name, len); cgrp = cgrp->parent; if (!cgrp) break; @@ -1559,7 +1561,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) } task_lock(tsk); - cg = tsk->cgroups; + cg = __rcu_dereference(tsk->cgroups); get_css_set(cg); task_unlock(tsk); /* @@ -1986,7 +1988,7 @@ static int cgroup_create_dir(struct cgroup *cgrp, struct dentry *dentry, struct dentry *parent; int error = 0; - parent = cgrp->parent->dentry; + parent = __rcu_dereference(cgrp->parent->dentry); error = cgroup_create_file(dentry, S_IFDIR | mode, cgrp->root->sb); if (!error) { dentry->d_fsdata = cgrp; @@ -2030,7 +2032,7 @@ int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys, const struct cftype *cft) { - struct dentry *dir = cgrp->dentry; + struct dentry *dir = __rcu_dereference(cgrp->dentry); struct dentry *dentry; int error; mode_t mode; @@ -2135,7 +2137,7 @@ static void cgroup_enable_task_cg_lists(void) * entry won't be deleted though the process has exited. */ if (!(p->flags & PF_EXITING) && list_empty(&p->cg_list)) - list_add(&p->cg_list, &p->cgroups->tasks); + list_add(&p->cg_list, &__rcu_dereference(p->cgroups)->tasks); task_unlock(p); } while_each_thread(g, p); write_unlock(&css_set_lock); @@ -2828,7 +2830,7 @@ static int cgroup_populate_dir(struct cgroup *cgrp) struct cgroup_subsys *ss; /* First clear out any existing files */ - cgroup_clear_directory(cgrp->dentry); + cgroup_clear_directory(__rcu_dereference(cgrp->dentry)); err = cgroup_add_files(cgrp, NULL, files, ARRAY_SIZE(files)); if (err < 0) @@ -2852,7 +2854,7 @@ static int cgroup_populate_dir(struct cgroup *cgrp) * from RCU-read-side without locks. */ if (css->id) - rcu_assign_pointer(css->id->css, css); + rcu_assign_pointer(__rcu_dereference(css->id)->css, css); } return 0; @@ -2960,13 +2962,13 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, goto err_remove; /* The cgroup directory was pre-locked for us */ - BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex)); + BUG_ON(!mutex_is_locked(&__rcu_dereference(cgrp->dentry)->d_inode->i_mutex)); err = cgroup_populate_dir(cgrp); /* If err < 0, we have a half-filled directory - oh well ;) */ mutex_unlock(&cgroup_mutex); - mutex_unlock(&cgrp->dentry->d_inode->i_mutex); + mutex_unlock(&__rcu_dereference(cgrp->dentry)->d_inode->i_mutex); return 0; @@ -3164,8 +3166,8 @@ again: list_del(&cgrp->sibling); cgroup_unlock_hierarchy(cgrp->root); - spin_lock(&cgrp->dentry->d_lock); - d = dget(cgrp->dentry); + spin_lock(&__rcu_dereference(cgrp->dentry)->d_lock); + d = dget(__rcu_dereference(cgrp->dentry)); spin_unlock(&d->d_lock); cgroup_d_remove_dir(d); @@ -3203,7 +3205,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) /* At system boot, before all subsystems have been * registered, no tasks have been forked, so we don't * need to invoke fork callbacks here. */ - BUG_ON(!list_empty(&init_task.tasks)); + BUG_ON(!list_empty_rcu(&init_task.tasks)); mutex_init(&ss->hierarchy_mutex); lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key); @@ -3226,7 +3228,7 @@ int __init cgroup_init_early(void) css_set_count = 1; init_cgroup_root(&rootnode); root_count = 1; - init_task.cgroups = &init_css_set; + __rcu_assign_pointer(init_task.cgroups, &init_css_set); init_css_set_link.cg = &init_css_set; init_css_set_link.cgrp = dummytop; @@ -3425,7 +3427,7 @@ void cgroup_fork(struct task_struct *child) { task_lock(current); child->cgroups = current->cgroups; - get_css_set(child->cgroups); + get_css_set(__rcu_dereference(child->cgroups)); task_unlock(current); INIT_LIST_HEAD(&child->cg_list); } @@ -3465,7 +3467,8 @@ void cgroup_post_fork(struct task_struct *child) write_lock(&css_set_lock); task_lock(child); if (list_empty(&child->cg_list)) - list_add(&child->cg_list, &child->cgroups->tasks); + list_add(&child->cg_list, + &__rcu_dereference(child->cgroups)->tasks); task_unlock(child); write_unlock(&css_set_lock); } @@ -3532,8 +3535,8 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks) /* Reassign the task to the init_css_set. */ task_lock(tsk); - cg = tsk->cgroups; - tsk->cgroups = &init_css_set; + cg = __rcu_dereference(tsk->cgroups); + __rcu_assign_pointer(tsk->cgroups, &init_css_set); task_unlock(tsk); if (cg) put_css_set_taskexit(cg); @@ -3583,19 +3586,19 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys, /* Keep the cgroup alive */ task_lock(tsk); parent = task_cgroup(tsk, subsys->subsys_id); - cg = tsk->cgroups; + cg = __rcu_dereference(tsk->cgroups); get_css_set(cg); task_unlock(tsk); mutex_unlock(&cgroup_mutex); /* Now do the VFS work to create a cgroup */ - inode = parent->dentry->d_inode; + inode = __rcu_dereference(parent->dentry)->d_inode; /* Hold the parent directory mutex across this operation to * stop anyone else deleting the new cgroup */ mutex_lock(&inode->i_mutex); - dentry = lookup_one_len(nodename, parent->dentry, strlen(nodename)); + dentry = lookup_one_len(nodename, __rcu_dereference(parent->dentry), strlen(nodename)); if (IS_ERR(dentry)) { printk(KERN_INFO "cgroup: Couldn't allocate dentry for %s: %ld\n", nodename, @@ -3864,7 +3867,7 @@ static void __free_css_id_cb(struct rcu_head *head) void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css) { - struct css_id *id = css->id; + struct css_id *id = __rcu_dereference(css->id); /* When this is called before css_id initialization, id can be NULL */ if (!id) return; @@ -3941,8 +3944,8 @@ static int __init cgroup_subsys_init_idr(struct cgroup_subsys *ss) return PTR_ERR(newid); newid->stack[0] = newid->id; - newid->css = rootcss; - rootcss->id = newid; + __rcu_assign_pointer(newid->css, rootcss); + __rcu_assign_pointer(rootcss->id, newid); return 0; } @@ -3957,7 +3960,7 @@ static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, parent_css = parent->subsys[subsys_id]; child_css = child->subsys[subsys_id]; depth = css_depth(parent_css) + 1; - parent_id = parent_css->id; + parent_id = __rcu_dereference(parent_css->id); child_id = get_new_cssid(ss, depth); if (IS_ERR(child_id)) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index ba401fa..42d4851 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -2434,7 +2434,7 @@ void cpuset_print_task_mems_allowed(struct task_struct *tsk) { struct dentry *dentry; - dentry = task_cs(tsk)->css.cgroup->dentry; + dentry = __rcu_dereference(task_cs(tsk)->css.cgroup->dentry); spin_lock(&cpuset_buffer_lock); snprintf(cpuset_name, CPUSET_NAME_LEN, dentry ? (const char *)dentry->d_name.name : "/"); -- 1.6.3.3
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