diff options
24 files changed, 1278 insertions, 692 deletions
diff --git a/Documentation/trace/user_events.rst b/Documentation/trace/user_events.rst index f9530d0ac5d3..d8f12442aaa6 100644 --- a/Documentation/trace/user_events.rst +++ b/Documentation/trace/user_events.rst @@ -14,6 +14,11 @@ Programs can view status of the events via /sys/kernel/tracing/user_events_status and can both register and write data out via /sys/kernel/tracing/user_events_data. +Programs can also use /sys/kernel/tracing/dynamic_events to register and +delete user based events via the u: prefix. The format of the command to +dynamic_events is the same as the ioctl with the u: prefix applied. This +requires CAP_PERFMON due to the event persisting, otherwise -EPERM is returned. + Typically programs will register a set of events that they wish to expose to tools that can read trace_events (such as ftrace and perf). The registration process tells the kernel which address and bit to reflect if any tool has @@ -45,7 +50,7 @@ This command takes a packed struct user_reg as an argument:: /* Input: Enable size in bytes at address */ __u8 enable_size; - /* Input: Flags for future use, set to 0 */ + /* Input: Flags to use, if any */ __u16 flags; /* Input: Address to update when enabled */ @@ -69,7 +74,7 @@ The struct user_reg requires all the above inputs to be set appropriately. This must be 4 (32-bit) or 8 (64-bit). 64-bit values are only allowed to be used on 64-bit kernels, however, 32-bit can be used on all kernels. -+ flags: The flags to use, if any. For the initial version this must be 0. ++ flags: The flags to use, if any. Callers should first attempt to use flags and retry without flags to ensure support for lower versions of the kernel. If a flag is not supported -EINVAL is returned. @@ -80,6 +85,13 @@ The struct user_reg requires all the above inputs to be set appropriately. + name_args: The name and arguments to describe the event, see command format for details. +The following flags are currently supported. + ++ USER_EVENT_REG_PERSIST: The event will not delete upon the last reference + closing. Callers may use this if an event should exist even after the + process closes or unregisters the event. Requires CAP_PERFMON otherwise + -EPERM is returned. + Upon successful registration the following is set. + write_index: The index to use for this file descriptor that represents this @@ -141,7 +153,10 @@ event (in both user and kernel space). User programs should use a separate file to request deletes than the one used for registration due to this. **NOTE:** By default events will auto-delete when there are no references left -to the event. Flags in the future may change this logic. +to the event. If programs do not want auto-delete, they must use the +USER_EVENT_REG_PERSIST flag when registering the event. Once that flag is used +the event exists until DIAG_IOCSDEL is invoked. Both register and delete of an +event that persists requires CAP_PERFMON, otherwise -EPERM is returned. Unregistering ------------- diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 20f72cd1d813..ca92cf0ffde1 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -601,7 +601,6 @@ struct seq_buf ppc_hw_desc __initdata = { .buffer = ppc_hw_desc_buf, .size = sizeof(ppc_hw_desc_buf), .len = 0, - .readpos = 0, }; static __init void probe_machine(void) diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 8c8d64e76103..f8a594a50ae6 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -2,8 +2,9 @@ /* * event_inode.c - part of tracefs, a pseudo file system for activating tracing * - * Copyright (C) 2020-23 VMware Inc, author: Steven Rostedt (VMware) <rostedt@goodmis.org> + * Copyright (C) 2020-23 VMware Inc, author: Steven Rostedt <rostedt@goodmis.org> * Copyright (C) 2020-23 VMware Inc, author: Ajay Kaher <akaher@vmware.com> + * Copyright (C) 2023 Google, author: Steven Rostedt <rostedt@goodmis.org> * * eventfs is used to dynamically create inodes and dentries based on the * meta data provided by the tracing system. @@ -23,48 +24,30 @@ #include <linux/delay.h> #include "internal.h" -struct eventfs_inode { - struct list_head e_top_files; -}; +/* + * eventfs_mutex protects the eventfs_inode (ei) dentry. Any access + * to the ei->dentry must be done under this mutex and after checking + * if ei->is_freed is not set. The ei->dentry is released under the + * mutex at the same time ei->is_freed is set. If ei->is_freed is set + * then the ei->dentry is invalid. + */ +static DEFINE_MUTEX(eventfs_mutex); /* - * struct eventfs_file - hold the properties of the eventfs files and - * directories. - * @name: the name of the file or directory to create - * @d_parent: holds parent's dentry - * @dentry: once accessed holds dentry - * @list: file or directory to be added to parent directory - * @ei: list of files and directories within directory - * @fop: file_operations for file or directory - * @iop: inode_operations for file or directory - * @data: something that the caller will want to get to later on - * @mode: the permission that the file or directory should have + * The eventfs_inode (ei) itself is protected by SRCU. It is released from + * its parent's list and will have is_freed set (under eventfs_mutex). + * After the SRCU grace period is over, the ei may be freed. */ -struct eventfs_file { - const char *name; - struct dentry *d_parent; - struct dentry *dentry; - struct list_head list; - struct eventfs_inode *ei; - const struct file_operations *fop; - const struct inode_operations *iop; - /* - * Union - used for deletion - * @del_list: list of eventfs_file to delete - * @rcu: eventfs_file to delete in RCU - * @is_freed: node is freed if one of the above is set - */ - union { - struct list_head del_list; - struct rcu_head rcu; - unsigned long is_freed; - }; - void *data; - umode_t mode; +DEFINE_STATIC_SRCU(eventfs_srcu); + +/* Mode is unsigned short, use the upper bits for flags */ +enum { + EVENTFS_SAVE_MODE = BIT(16), + EVENTFS_SAVE_UID = BIT(17), + EVENTFS_SAVE_GID = BIT(18), }; -static DEFINE_MUTEX(eventfs_mutex); -DEFINE_STATIC_SRCU(eventfs_srcu); +#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1) static struct dentry *eventfs_root_lookup(struct inode *dir, struct dentry *dentry, @@ -73,8 +56,88 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file); static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx); static int eventfs_release(struct inode *inode, struct file *file); +static void update_attr(struct eventfs_attr *attr, struct iattr *iattr) +{ + unsigned int ia_valid = iattr->ia_valid; + + if (ia_valid & ATTR_MODE) { + attr->mode = (attr->mode & ~EVENTFS_MODE_MASK) | + (iattr->ia_mode & EVENTFS_MODE_MASK) | + EVENTFS_SAVE_MODE; + } + if (ia_valid & ATTR_UID) { + attr->mode |= EVENTFS_SAVE_UID; + attr->uid = iattr->ia_uid; + } + if (ia_valid & ATTR_GID) { + attr->mode |= EVENTFS_SAVE_GID; + attr->gid = iattr->ia_gid; + } +} + +static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *iattr) +{ + const struct eventfs_entry *entry; + struct eventfs_inode *ei; + const char *name; + int ret; + + mutex_lock(&eventfs_mutex); + ei = dentry->d_fsdata; + if (ei->is_freed) { + /* Do not allow changes if the event is about to be removed. */ + mutex_unlock(&eventfs_mutex); + return -ENODEV; + } + + /* Preallocate the children mode array if necessary */ + if (!(dentry->d_inode->i_mode & S_IFDIR)) { + if (!ei->entry_attrs) { + ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries, + GFP_KERNEL); + if (!ei->entry_attrs) { + ret = -ENOMEM; + goto out; + } + } + } + + ret = simple_setattr(idmap, dentry, iattr); + if (ret < 0) + goto out; + + /* + * If this is a dir, then update the ei cache, only the file + * mode is saved in the ei->m_children, and the ownership is + * determined by the parent directory. + */ + if (dentry->d_inode->i_mode & S_IFDIR) { + update_attr(&ei->attr, iattr); + + } else { + name = dentry->d_name.name; + + for (int i = 0; i < ei->nr_entries; i++) { + entry = &ei->entries[i]; + if (strcmp(name, entry->name) == 0) { + update_attr(&ei->entry_attrs[i], iattr); + break; + } + } + } + out: + mutex_unlock(&eventfs_mutex); + return ret; +} + static const struct inode_operations eventfs_root_dir_inode_operations = { .lookup = eventfs_root_lookup, + .setattr = eventfs_set_attr, +}; + +static const struct inode_operations eventfs_file_inode_operations = { + .setattr = eventfs_set_attr, }; static const struct file_operations eventfs_file_operations = { @@ -85,26 +148,40 @@ static const struct file_operations eventfs_file_operations = { .release = eventfs_release, }; +static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, umode_t mode) +{ + if (!attr) { + inode->i_mode = mode; + return; + } + + if (attr->mode & EVENTFS_SAVE_MODE) + inode->i_mode = attr->mode & EVENTFS_MODE_MASK; + else + inode->i_mode = mode; + + if (attr->mode & EVENTFS_SAVE_UID) + inode->i_uid = attr->uid; + + if (attr->mode & EVENTFS_SAVE_GID) + inode->i_gid = attr->gid; +} + /** * create_file - create a file in the tracefs filesystem * @name: the name of the file to create. * @mode: the permission that the file should have. + * @attr: saved attributes changed by user * @parent: parent dentry for this file. * @data: something that the caller will want to get to later on. * @fop: struct file_operations that should be used for this file. * - * This is the basic "create a file" function for tracefs. It allows for a - * wide range of flexibility in creating a file. - * - * This function will return a pointer to a dentry if it succeeds. This - * pointer must be passed to the tracefs_remove() function when the file is - * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %NULL will be returned. - * - * If tracefs is not enabled in the kernel, the value -%ENODEV will be - * returned. + * This function creates a dentry that represents a file in the eventsfs_inode + * directory. The inode.i_private pointer will point to @data in the open() + * call. */ static struct dentry *create_file(const char *name, umode_t mode, + struct eventfs_attr *attr, struct dentry *parent, void *data, const struct file_operations *fop) { @@ -118,6 +195,7 @@ static struct dentry *create_file(const char *name, umode_t mode, if (WARN_ON_ONCE(!S_ISREG(mode))) return NULL; + WARN_ON_ONCE(!parent); dentry = eventfs_start_creating(name, parent); if (IS_ERR(dentry)) @@ -127,7 +205,10 @@ static struct dentry *create_file(const char *name, umode_t mode, if (unlikely(!inode)) return eventfs_failed_creating(dentry); - inode->i_mode = mode; + /* If the user updated the directory's attributes, use them */ + update_inode_attr(inode, attr, mode); + + inode->i_op = &eventfs_file_inode_operations; inode->i_fop = fop; inode->i_private = data; @@ -140,28 +221,19 @@ static struct dentry *create_file(const char *name, umode_t mode, /** * create_dir - create a dir in the tracefs filesystem - * @name: the name of the file to create. + * @ei: the eventfs_inode that represents the directory to create * @parent: parent dentry for this file. - * @data: something that the caller will want to get to later on. * - * This is the basic "create a dir" function for eventfs. It allows for a - * wide range of flexibility in creating a dir. - * - * This function will return a pointer to a dentry if it succeeds. This - * pointer must be passed to the tracefs_remove() function when the file is - * to be removed (no automatic cleanup happens if your module is unloaded, - * you are responsible here.) If an error occurs, %NULL will be returned. - * - * If tracefs is not enabled in the kernel, the value -%ENODEV will be - * returned. + * This function will create a dentry for a directory represented by + * a eventfs_inode. */ -static struct dentry *create_dir(const char *name, struct dentry *parent, void *data) +static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent) { struct tracefs_inode *ti; struct dentry *dentry; struct inode *inode; - dentry = eventfs_start_creating(name, parent); + dentry = eventfs_start_creating(ei->name, parent); if (IS_ERR(dentry)) return dentry; @@ -169,10 +241,11 @@ static struct dentry *create_dir(const char *name, struct dentry *parent, void * if (unlikely(!inode)) return eventfs_failed_creating(dentry); - inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + /* If the user updated the directory's attributes, use them */ + update_inode_attr(inode, &ei->attr, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); + inode->i_op = &eventfs_root_dir_inode_operations; inode->i_fop = &eventfs_file_operations; - inode->i_private = data; ti = get_tracefs(inode); ti->flags |= TRACEFS_EVENT_INODE; @@ -184,117 +257,198 @@ static struct dentry *create_dir(const char *name, struct dentry *parent, void * return eventfs_end_creating(dentry); } +static void free_ei(struct eventfs_inode *ei) +{ + kfree_const(ei->name); + kfree(ei->d_children); + kfree(ei->entry_attrs); + kfree(ei); +} + /** - * eventfs_set_ef_status_free - set the ef->status to free + * eventfs_set_ei_status_free - remove the dentry reference from an eventfs_inode * @ti: the tracefs_inode of the dentry - * @dentry: dentry who's status to be freed + * @dentry: dentry which has the reference to remove. * - * eventfs_set_ef_status_free will be called if no more - * references remain + * Remove the association between a dentry from an eventfs_inode. */ -void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry) +void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry) { - struct tracefs_inode *ti_parent; struct eventfs_inode *ei; - struct eventfs_file *ef, *tmp; - - /* The top level events directory may be freed by this */ - if (unlikely(ti->flags & TRACEFS_EVENT_TOP_INODE)) { - LIST_HEAD(ef_del_list); + int i; - mutex_lock(&eventfs_mutex); + mutex_lock(&eventfs_mutex); - ei = ti->private; + ei = dentry->d_fsdata; + if (!ei) + goto out; - /* Record all the top level files */ - list_for_each_entry_srcu(ef, &ei->e_top_files, list, - lockdep_is_held(&eventfs_mutex)) { - list_add_tail(&ef->del_list, &ef_del_list); + /* This could belong to one of the files of the ei */ + if (ei->dentry != dentry) { + for (i = 0; i < ei->nr_entries; i++) { + if (ei->d_children[i] == dentry) + break; } + if (WARN_ON_ONCE(i == ei->nr_entries)) + goto out; + ei->d_children[i] = NULL; + } else if (ei->is_freed) { + free_ei(ei); + } else { + ei->dentry = NULL; + } + + dentry->d_fsdata = NULL; + out: + mutex_unlock(&eventfs_mutex); +} - /* Nothing should access this, but just in case! */ - ti->private = NULL; +/** + * create_file_dentry - create a dentry for a file of an eventfs_inode + * @ei: the eventfs_inode that the file will be created under + * @idx: the index into the d_children[] of the @ei + * @parent: The parent dentry of the created file. + * @name: The name of the file to create + * @mode: The mode of the file. + * @data: The data to use to set the inode of the file with on open() + * @fops: The fops of the file to be created. + * @lookup: If called by the lookup routine, in which case, dput() the created dentry. + * + * Create a dentry for a file of an eventfs_inode @ei and place it into the + * address located at @e_dentry. If the @e_dentry already has a dentry, then + * just do a dget() on it and return. Otherwise create the dentry and attach it. + */ +static struct dentry * +create_file_dentry(struct eventfs_inode *ei, int idx, + struct dentry *parent, const char *name, umode_t mode, void *data, + const struct file_operations *fops, bool lookup) +{ + struct eventfs_attr *attr = NULL; + struct dentry **e_dentry = &ei->d_children[idx]; + struct dentry *dentry; + bool invalidate = false; + mutex_lock(&eventfs_mutex); + if (ei->is_freed) { mutex_unlock(&eventfs_mutex); + return NULL; + } + /* If the e_dentry already has a dentry, use it */ + if (*e_dentry) { + /* lookup does not need to up the ref count */ + if (!lookup) + dget(*e_dentry); + mutex_unlock(&eventfs_mutex); + return *e_dentry; + } - /* Now safely free the top level files and their children */ - list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) { - list_del(&ef->del_list); - eventfs_remove(ef); - } + /* ei->entry_attrs are protected by SRCU */ + if (ei->entry_attrs) + attr = &ei->entry_attrs[idx]; - kfree(ei); - return; - } + mutex_unlock(&eventfs_mutex); - mutex_lock(&eventfs_mutex); + /* The lookup already has the parent->d_inode locked */ + if (!lookup) + inode_lock(parent->d_inode); - ti_parent = get_tracefs(dentry->d_parent->d_inode); - if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE)) - goto out; + dentry = create_file(name, mode, attr, parent, data, fops); - ef = dentry->d_fsdata; - if (!ef) - goto out; + if (!lookup) + inode_unlock(parent->d_inode); - /* - * If ef was freed, then the LSB bit is set for d_fsdata. - * But this should not happen, as it should still have a - * ref count that prevents it. Warn in case it does. - */ - if (WARN_ON_ONCE((unsigned long)ef & 1)) - goto out; + mutex_lock(&eventfs_mutex); - dentry->d_fsdata = NULL; - ef->dentry = NULL; -out: + if (IS_ERR_OR_NULL(dentry)) { + /* + * When the mutex was released, something else could have + * created the dentry for this e_dentry. In which case + * use that one. + * + * Note, with the mutex held, the e_dentry cannot have content + * and the ei->is_freed be true at the same time. + */ + dentry = *e_dentry; + if (WARN_ON_ONCE(dentry && ei->is_freed)) + dentry = NULL; + /* The lookup does not need to up the dentry refcount */ + if (dentry && !lookup) + dget(dentry); + mutex_unlock(&eventfs_mutex); + return dentry; + } + + if (!*e_dentry && !ei->is_freed) { + *e_dentry = dentry; + dentry->d_fsdata = ei; + } else { + /* + * Should never happen unless we get here due to being freed. + * Otherwise it means two dentries exist with the same name. + */ + WARN_ON_ONCE(!ei->is_freed); + invalidate = true; + } mutex_unlock(&eventfs_mutex); + + if (invalidate) + d_invalidate(dentry); + + if (lookup || invalidate) + dput(dentry); + + return invalidate ? NULL : dentry; } /** * eventfs_post_create_dir - post create dir routine - * @ef: eventfs_file of recently created dir + * @ei: eventfs_inode of recently created dir * * Map the meta-data of files within an eventfs dir to their parent dentry */ -static void eventfs_post_create_dir(struct eventfs_file *ef) +static void eventfs_post_create_dir(struct eventfs_inode *ei) { - struct eventfs_file *ef_child; + struct eventfs_inode *ei_child; struct tracefs_inode *ti; + lockdep_assert_held(&eventfs_mutex); + /* srcu lock already held */ /* fill parent-child relation */ - list_for_each_entry_srcu(ef_child, &ef->ei->e_top_files, list, + list_for_each_entry_srcu(ei_child, &ei->children, list, srcu_read_lock_held(&eventfs_srcu)) { - ef_child->d_parent = ef->dentry; + ei_child->d_parent = ei->dentry; } - ti = get_tracefs(ef->dentry->d_inode); - ti->private = ef->ei; + ti = get_tracefs(ei->dentry->d_inode); + ti->private = ei; } /** - * create_dentry - helper function to create dentry - * @ef: eventfs_file of file or directory to create - * @parent: parent dentry - * @lookup: true if called from lookup routine + * create_dir_dentry - Create a directory dentry for the eventfs_inode + * @pei: The eventfs_inode parent of ei. + * @ei: The eventfs_inode to create the directory for + * @parent: The dentry of the parent of this directory + * @lookup: True if this is called by the lookup code * - * Used to create a dentry for file/dir, executes post dentry creation routine + * This creates and attaches a directory dentry to the eventfs_inode @ei. */ static struct dentry * -create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup) +create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, + struct dentry *parent, bool lookup) { bool invalidate = false; - struct dentry *dentry; + struct dentry *dentry = NULL; mutex_lock(&eventfs_mutex); - if (ef->is_freed) { + if (pei->is_freed || ei->is_freed) { mutex_unlock(&eventfs_mutex); return NULL; } - if (ef->dentry) { - dentry = ef->dentry; - /* On dir open, up the ref count */ + if (ei->dentry) { + /* If the dentry already has a dentry, use it */ + dentry = ei->dentry; + /* lookup does not need to up the ref count */ if (!lookup) dget(dentry); mutex_unlock(&eventfs_mutex); @@ -302,42 +456,44 @@ create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup) } mutex_unlock(&eventfs_mutex); + /* The lookup already has the parent->d_inode locked */ if (!lookup) inode_lock(parent->d_inode); - if (ef->ei) - dentry = create_dir(ef->name, parent, ef->data); - else - dentry = create_file(ef->name, ef->mode, parent, - ef->data, ef->fop); + dentry = create_dir(ei, parent); if (!lookup) inode_unlock(parent->d_inode); mutex_lock(&eventfs_mutex); - if (IS_ERR_OR_NULL(dentry)) { - /* If the ef was already updated get it */ - dentry = ef->dentry; + + if (IS_ERR_OR_NULL(dentry) && !ei->is_freed) { + /* + * When the mutex was released, something else could have + * created the dentry for this e_dentry. In which case + * use that one. + * + * Note, with the mutex held, the e_dentry cannot have content + * and the ei->is_freed be true at the same time. + */ + dentry = ei->dentry; if (dentry && !lookup) dget(dentry); mutex_unlock(&eventfs_mutex); return dentry; } - if (!ef->dentry && !ef->is_freed) { - ef->dentry = dentry; - if (ef->ei) - eventfs_post_create_dir(ef); - dentry->d_fsdata = ef; + if (!ei->dentry && !ei->is_freed) { + ei->dentry = dentry; + eventfs_post_create_dir(ei); + dentry->d_fsdata = ei; } else { - /* A race here, should try again (unless freed) */ - invalidate = true; - /* * Should never happen unless we get here due to being freed. * Otherwise it means two dentries exist with the same name. */ - WARN_ON_ONCE(!ef->is_freed); + WARN_ON_ONCE(!ei->is_freed); + invalidate = true; } mutex_unlock(&eventfs_mutex); if (invalidate) @@ -349,50 +505,90 @@ create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup) return invalidate ? NULL : dentry; } -static bool match_event_file(struct eventfs_file *ef, const char *name) -{ - bool ret; - - mutex_lock(&eventfs_mutex); - ret = !ef->is_freed && strcmp(ef->name, name) == 0; - mutex_unlock(&eventfs_mutex); - - return ret; -} - /** * eventfs_root_lookup - lookup routine to create file/dir * @dir: in which a lookup is being done * @dentry: file/dir dentry - * @flags: to pass as flags parameter to simple lookup + * @flags: Just passed to simple_lookup() * - * Used to create a dynamic file/dir within @dir. Use the eventfs_inode - * list of meta data to find the information needed to create the file/dir. + * Used to create dynamic file/dir with-in @dir, search with-in @ei + * list, if @dentry found go ahead and create the file/dir */ + static struct dentry *eventfs_root_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { + const struct file_operations *fops; + const struct eventfs_entry *entry; + struct eventfs_inode *ei_child; struct tracefs_inode *ti; struct eventfs_inode *ei; - struct eventfs_file *ef; + struct dentry *ei_dentry = NULL; struct dentry *ret = NULL; + const char *name = dentry->d_name.name; + bool created = false; + umode_t mode; + void *data; int idx; + int i; + int r; ti = get_tracefs(dir); if (!(ti->flags & TRACEFS_EVENT_INODE)) return NULL; - ei = ti->private; + /* Grab srcu to prevent the ei from going away */ idx = srcu_read_lock(&eventfs_srcu); - list_for_each_entry_srcu(ef, &ei->e_top_files, list, + + /* + * Grab the eventfs_mutex to consistent value from ti->private. + * This s + */ + mutex_lock(&eventfs_mutex); + ei = READ_ONCE(ti->private); + if (ei && !ei->is_freed) + ei_dentry = READ_ONCE(ei->dentry); + mutex_unlock(&eventfs_mutex); + + if (!ei || !ei_dentry) + goto out; + + data = ei->data; + + list_for_each_entry_srcu(ei_child, &ei->children, list, srcu_read_lock_held(&eventfs_srcu)) { - if (!match_event_file(ef, dentry->d_name.name)) + if (strcmp(ei_child->name, name) != 0) continue; ret = simple_lookup(dir, dentry, flags); - create_dentry(ef, ef->d_parent, true); + create_dir_dentry(ei, ei_child, ei_dentry, true); + created = true; break; } + + if (created) + goto out; + + for (i = 0; i < ei->nr_entries; i++) { + entry = &ei->entries[i]; + if (strcmp(name, entry->name) == 0) { + void *cdata = data; + mutex_lock(&eventfs_mutex); + /* If ei->is_freed, then the event itself may be too */ + if (!ei->is_freed) + r = entry->callback(name, &mode, &cdata, &fops); + else + r = -1; + mutex_unlock(&eventfs_mutex); + if (r <= 0) + continue; + ret = simple_lookup(dir, dentry, flags); + create_file_dentry(ei, i, ei_dentry, name, mode, cdata, + fops, true); + break; + } + } + out: srcu_read_unlock(&eventfs_srcu, idx); return ret; } @@ -432,29 +628,48 @@ static int eventfs_release(struct inode *inode, struct file *file) return dcache_dir_close(inode, file); } +static int add_dentries(struct dentry ***dentries, struct dentry *d, int cnt) +{ + struct dentry **tmp; + + tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_KERNEL); + if (!tmp) + return -1; + tmp[cnt] = d; + tmp[cnt + 1] = NULL; + *dentries = tmp; + return 0; +} + /** * dcache_dir_open_wrapper - eventfs open wrapper * @inode: not used - * @file: dir to be opened (to create its child) + * @file: dir to be opened (to create it's children) * - * Used to dynamically create the file/dir within @file. @file is really a - * directory and all the files/dirs of the children within @file will be - * created. If any of the files/dirs have already been created, their - * reference count will be incremented. + * Used to dynamic create file/dir with-in @file, all the + * file/dir will be created. If already created then references + * will be increased */ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file) { + const struct file_operations *fops; + const struct eventfs_entry *entry; + struct eventfs_inode *ei_child; struct tracefs_inode *ti; struct eventfs_inode *ei; - struct eventfs_file *ef; struct dentry_list *dlist; struct dentry **dentries = NULL; - struct dentry *dentry = file_dentry(file); + struct dentry *parent = file_dentry(file); struct dentry *d; struct inode *f_inode = file_inode(file); + const char *name = parent->d_name.name; + umode_t mode; + void *data; int cnt = 0; int idx; int ret; + int i; + int r; ti = get_tracefs(f_inode); if (!(ti->flags & TRACEFS_EVENT_INODE)) @@ -463,25 +678,56 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file) if (WARN_ON_ONCE(file->private_data)) return -EINVAL; + idx = srcu_read_lock(&eventfs_srcu); + + mutex_lock(&eventfs_mutex); + ei = READ_ONCE(ti->private); + mutex_unlock(&eventfs_mutex); + + if (!ei) { + srcu_read_unlock(&eventfs_srcu, idx); + return -EINVAL; + } + + + data = ei->data; + dlist = kmalloc(sizeof(*dlist), GFP_KERNEL); - if (!dlist) + if (!dlist) { + srcu_read_unlock(&eventfs_srcu, idx); return -ENOMEM; + } - ei = ti->private; - idx = srcu_read_lock(&eventfs_srcu); - list_for_each_entry_srcu(ef, &ei->e_top_files, list, + list_for_each_entry_srcu(ei_child, &ei->children, list, srcu_read_lock_held(&eventfs_srcu)) { - d = create_dentry(ef, dentry, false); + d = create_dir_dentry(ei, ei_child, parent, false); if (d) { - struct dentry **tmp; + ret = add_dentries(&a |