+++ /dev/null
-/*
- * ltt/ltt-channels.c
- *
- * (C) Copyright 2008 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
- *
- * LTTng channel management.
- *
- * Author:
- * Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
- */
-
-//ust// #include <linux/module.h>
-//ust// #include <linux/ltt-channels.h>
-//ust// #include <linux/mutex.h>
-//ust// #include <linux/vmalloc.h>
-
-#include "kernelcompat.h"
-#include "channels.h"
-#include "usterr.h"
-
-/*
- * ltt_channel_mutex may be nested inside the LTT trace mutex.
- * ltt_channel_mutex mutex may be nested inside markers mutex.
- */
-static DEFINE_MUTEX(ltt_channel_mutex);
-static LIST_HEAD(ltt_channels);
-/*
- * Index of next channel in array. Makes sure that as long as a trace channel is
- * allocated, no array index will be re-used when a channel is freed and then
- * another channel is allocated. This index is cleared and the array indexeds
- * get reassigned when the index_kref goes back to 0, which indicates that no
- * more trace channels are allocated.
- */
-static unsigned int free_index;
-static struct kref index_kref; /* Keeps track of allocated trace channels */
-
-static struct ltt_channel_setting *lookup_channel(const char *name)
-{
- struct ltt_channel_setting *iter;
-
- list_for_each_entry(iter, <t_channels, list)
- if (strcmp(name, iter->name) == 0)
- return iter;
- return NULL;
-}
-
-/*
- * Must be called when channel refcount falls to 0 _and_ also when the last
- * trace is freed. This function is responsible for compacting the channel and
- * event IDs when no users are active.
- *
- * Called with lock_markers() and channels mutex held.
- */
-static void release_channel_setting(struct kref *kref)
-{
- struct ltt_channel_setting *setting = container_of(kref,
- struct ltt_channel_setting, kref);
- struct ltt_channel_setting *iter;
-
- if (atomic_read(&index_kref.refcount) == 0
- && atomic_read(&setting->kref.refcount) == 0) {
- list_del(&setting->list);
- kfree(setting);
-
- free_index = 0;
- list_for_each_entry(iter, <t_channels, list) {
- iter->index = free_index++;
- iter->free_event_id = 0;
- }
-//ust// markers_compact_event_ids();
- }
-}
-
-/*
- * Perform channel index compaction when the last trace channel is freed.
- *
- * Called with lock_markers() and channels mutex held.
- */
-static void release_trace_channel(struct kref *kref)
-{
- struct ltt_channel_setting *iter, *n;
-
- list_for_each_entry_safe(iter, n, <t_channels, list)
- release_channel_setting(&iter->kref);
-}
-
-/**
- * ltt_channels_register - Register a trace channel.
- * @name: channel name
- *
- * Uses refcounting.
- */
-int ltt_channels_register(const char *name)
-{
- struct ltt_channel_setting *setting;
- int ret = 0;
-
- mutex_lock(<t_channel_mutex);
- setting = lookup_channel(name);
- if (setting) {
- if (atomic_read(&setting->kref.refcount) == 0)
- goto init_kref;
- else {
- kref_get(&setting->kref);
- goto end;
- }
- }
- setting = kzalloc(sizeof(*setting), GFP_KERNEL);
- if (!setting) {
- ret = -ENOMEM;
- goto end;
- }
- list_add(&setting->list, <t_channels);
- strncpy(setting->name, name, PATH_MAX-1);
- setting->index = free_index++;
-init_kref:
- kref_init(&setting->kref);
-end:
- mutex_unlock(<t_channel_mutex);
- return ret;
-}
-//ust// EXPORT_SYMBOL_GPL(ltt_channels_register);
-
-/**
- * ltt_channels_unregister - Unregister a trace channel.
- * @name: channel name
- *
- * Must be called with markers mutex held.
- */
-int ltt_channels_unregister(const char *name)
-{
- struct ltt_channel_setting *setting;
- int ret = 0;
-
- mutex_lock(<t_channel_mutex);
- setting = lookup_channel(name);
- if (!setting || atomic_read(&setting->kref.refcount) == 0) {
- ret = -ENOENT;
- goto end;
- }
- kref_put(&setting->kref, release_channel_setting);
-end:
- mutex_unlock(<t_channel_mutex);
- return ret;
-}
-//ust// EXPORT_SYMBOL_GPL(ltt_channels_unregister);
-
-/**
- * ltt_channels_set_default - Set channel default behavior.
- * @name: default channel name
- * @subbuf_size: size of the subbuffers
- * @subbuf_cnt: number of subbuffers
- */
-int ltt_channels_set_default(const char *name,
- unsigned int subbuf_size,
- unsigned int subbuf_cnt)
-{
- struct ltt_channel_setting *setting;
- int ret = 0;
-
- mutex_lock(<t_channel_mutex);
- setting = lookup_channel(name);
- if (!setting || atomic_read(&setting->kref.refcount) == 0) {
- ret = -ENOENT;
- goto end;
- }
- setting->subbuf_size = subbuf_size;
- setting->subbuf_cnt = subbuf_cnt;
-end:
- mutex_unlock(<t_channel_mutex);
- return ret;
-}
-//ust// EXPORT_SYMBOL_GPL(ltt_channels_set_default);
-
-/**
- * ltt_channels_get_name_from_index - get channel name from channel index
- * @index: channel index
- *
- * Allows to lookup the channel name given its index. Done to keep the name
- * information outside of each trace channel instance.
- */
-const char *ltt_channels_get_name_from_index(unsigned int index)
-{
- struct ltt_channel_setting *iter;
-
- list_for_each_entry(iter, <t_channels, list)
- if (iter->index == index && atomic_read(&iter->kref.refcount))
- return iter->name;
- return NULL;
-}
-//ust// EXPORT_SYMBOL_GPL(ltt_channels_get_name_from_index);
-
-static struct ltt_channel_setting *
-ltt_channels_get_setting_from_name(const char *name)
-{
- struct ltt_channel_setting *iter;
-
- list_for_each_entry(iter, <t_channels, list)
- if (!strcmp(iter->name, name)
- && atomic_read(&iter->kref.refcount))
- return iter;
- return NULL;
-}
-
-/**
- * ltt_channels_get_index_from_name - get channel index from channel name
- * @name: channel name
- *
- * Allows to lookup the channel index given its name. Done to keep the name
- * information outside of each trace channel instance.
- * Returns -1 if not found.
- */
-int ltt_channels_get_index_from_name(const char *name)
-{
- struct ltt_channel_setting *setting;
-
- setting = ltt_channels_get_setting_from_name(name);
- if (setting)
- return setting->index;
- else
- return -1;
-}
-//ust// EXPORT_SYMBOL_GPL(ltt_channels_get_index_from_name);
-
-/**
- * ltt_channels_trace_alloc - Allocate channel structures for a trace
- * @subbuf_size: subbuffer size. 0 uses default.
- * @subbuf_cnt: number of subbuffers per per-cpu buffers. 0 uses default.
- * @flags: Default channel flags
- *
- * Use the current channel list to allocate the channels for a trace.
- * Called with trace lock held. Does not perform the trace buffer allocation,
- * because we must let the user overwrite specific channel sizes.
- */
-struct ltt_channel_struct *ltt_channels_trace_alloc(unsigned int *nr_channels,
- int overwrite,
- int active)
-{
- struct ltt_channel_struct *channel = NULL;
- struct ltt_channel_setting *iter;
-
- mutex_lock(<t_channel_mutex);
- if (!free_index) {
- WARN("ltt_channels_trace_alloc: no free_index; are there any probes connected?");
- goto end;
- }
- if (!atomic_read(&index_kref.refcount))
- kref_init(&index_kref);
- else
- kref_get(&index_kref);
- *nr_channels = free_index;
- channel = kzalloc(sizeof(struct ltt_channel_struct) * free_index,
- GFP_KERNEL);
- if (!channel) {
- WARN("ltt_channel_struct: channel null after alloc");
- goto end;
- }
- list_for_each_entry(iter, <t_channels, list) {
- if (!atomic_read(&iter->kref.refcount))
- continue;
- channel[iter->index].subbuf_size = iter->subbuf_size;
- channel[iter->index].subbuf_cnt = iter->subbuf_cnt;
- channel[iter->index].overwrite = overwrite;
- channel[iter->index].active = active;
- channel[iter->index].channel_name = iter->name;
- }
-end:
- mutex_unlock(<t_channel_mutex);
- return channel;
-}
-//ust// EXPORT_SYMBOL_GPL(ltt_channels_trace_alloc);
-
-/**
- * ltt_channels_trace_free - Free one trace's channels
- * @channels: channels to free
- *
- * Called with trace lock held. The actual channel buffers must be freed before
- * this function is called.
- */
-void ltt_channels_trace_free(struct ltt_channel_struct *channels)
-{
- lock_markers();
- mutex_lock(<t_channel_mutex);
- kfree(channels);
- kref_put(&index_kref, release_trace_channel);
- mutex_unlock(<t_channel_mutex);
- unlock_markers();
-}
-//ust// EXPORT_SYMBOL_GPL(ltt_channels_trace_free);
-
-/**
- * _ltt_channels_get_event_id - get next event ID for a marker
- * @channel: channel name
- * @name: event name
- *
- * Returns a unique event ID (for this channel) or < 0 on error.
- * Must be called with channels mutex held.
- */
-int _ltt_channels_get_event_id(const char *channel, const char *name)
-{
- struct ltt_channel_setting *setting;
- int ret;
-
- setting = ltt_channels_get_setting_from_name(channel);
- if (!setting) {
- ret = -ENOENT;
- goto end;
- }
- if (strcmp(channel, "metadata") == 0) {
- if (strcmp(name, "core_marker_id") == 0)
- ret = 0;
- else if (strcmp(name, "core_marker_format") == 0)
- ret = 1;
- else if (strcmp(name, "testev") == 0)
- ret = 2;
- else
- ret = -ENOENT;
- goto end;
- }
- if (setting->free_event_id == EVENTS_PER_CHANNEL - 1) {
- ret = -ENOSPC;
- goto end;
- }
- ret = setting->free_event_id++;
-end:
- return ret;
-}
-
-/**
- * ltt_channels_get_event_id - get next event ID for a marker
- * @channel: channel name
- * @name: event name
- *
- * Returns a unique event ID (for this channel) or < 0 on error.
- */
-int ltt_channels_get_event_id(const char *channel, const char *name)
-{
- int ret;
-
- mutex_lock(<t_channel_mutex);
- ret = _ltt_channels_get_event_id(channel, name);
- mutex_unlock(<t_channel_mutex);
- return ret;
-}
-
-//ust// MODULE_LICENSE("GPL");
-//ust// MODULE_AUTHOR("Mathieu Desnoyers");
-//ust// MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Channel Management");
projects / ust.git / blobdiff