]> rtime.felk.cvut.cz Git - linux-imx.git/blobdiff - kernel/trace/trace_events.c
Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty...
[linux-imx.git] / kernel / trace / trace_events.c
index 7d854290bf817ef8c6b116b031830dc060ae5dc7..29a7ebcfb42621d05cb9a74a7bcf291515b38461 100644 (file)
@@ -409,33 +409,42 @@ static void put_system(struct ftrace_subsystem_dir *dir)
        mutex_unlock(&event_mutex);
 }
 
-/*
- * Open and update trace_array ref count.
- * Must have the current trace_array passed to it.
- */
-static int tracing_open_generic_file(struct inode *inode, struct file *filp)
+static void remove_subsystem(struct ftrace_subsystem_dir *dir)
 {
-       struct ftrace_event_file *file = inode->i_private;
-       struct trace_array *tr = file->tr;
-       int ret;
+       if (!dir)
+               return;
 
-       if (trace_array_get(tr) < 0)
-               return -ENODEV;
+       if (!--dir->nr_events) {
+               debugfs_remove_recursive(dir->entry);
+               list_del(&dir->list);
+               __put_system_dir(dir);
+       }
+}
 
-       ret = tracing_open_generic(inode, filp);
-       if (ret < 0)
-               trace_array_put(tr);
-       return ret;
+static void *event_file_data(struct file *filp)
+{
+       return ACCESS_ONCE(file_inode(filp)->i_private);
 }
 
-static int tracing_release_generic_file(struct inode *inode, struct file *filp)
+static void remove_event_file_dir(struct ftrace_event_file *file)
 {
-       struct ftrace_event_file *file = inode->i_private;
-       struct trace_array *tr = file->tr;
+       struct dentry *dir = file->dir;
+       struct dentry *child;
 
-       trace_array_put(tr);
+       if (dir) {
+               spin_lock(&dir->d_lock);        /* probably unneeded */
+               list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) {
+                       if (child->d_inode)     /* probably unneeded */
+                               child->d_inode->i_private = NULL;
+               }
+               spin_unlock(&dir->d_lock);
 
-       return 0;
+               debugfs_remove_recursive(dir);
+       }
+
+       list_del(&file->list);
+       remove_subsystem(file->system);
+       kmem_cache_free(file_cachep, file);
 }
 
 /*
@@ -679,15 +688,25 @@ static ssize_t
 event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
                  loff_t *ppos)
 {
-       struct ftrace_event_file *file = filp->private_data;
+       struct ftrace_event_file *file;
+       unsigned long flags;
        char buf[4] = "0";
 
-       if (file->flags & FTRACE_EVENT_FL_ENABLED &&
-           !(file->flags & FTRACE_EVENT_FL_SOFT_DISABLED))
+       mutex_lock(&event_mutex);
+       file = event_file_data(filp);
+       if (likely(file))
+               flags = file->flags;
+       mutex_unlock(&event_mutex);
+
+       if (!file)
+               return -ENODEV;
+
+       if (flags & FTRACE_EVENT_FL_ENABLED &&
+           !(flags & FTRACE_EVENT_FL_SOFT_DISABLED))
                strcpy(buf, "1");
 
-       if (file->flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
-           file->flags & FTRACE_EVENT_FL_SOFT_MODE)
+       if (flags & FTRACE_EVENT_FL_SOFT_DISABLED ||
+           flags & FTRACE_EVENT_FL_SOFT_MODE)
                strcat(buf, "*");
 
        strcat(buf, "\n");
@@ -699,13 +718,10 @@ static ssize_t
 event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
                   loff_t *ppos)
 {
-       struct ftrace_event_file *file = filp->private_data;
+       struct ftrace_event_file *file;
        unsigned long val;
        int ret;
 
-       if (!file)
-               return -EINVAL;
-
        ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
        if (ret)
                return ret;
@@ -717,8 +733,11 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
        switch (val) {
        case 0:
        case 1:
+               ret = -ENODEV;
                mutex_lock(&event_mutex);
-               ret = ftrace_event_enable_disable(file, val);
+               file = event_file_data(filp);
+               if (likely(file))
+                       ret = ftrace_event_enable_disable(file, val);
                mutex_unlock(&event_mutex);
                break;
 
@@ -825,65 +844,39 @@ enum {
 
 static void *f_next(struct seq_file *m, void *v, loff_t *pos)
 {
-       struct ftrace_event_call *call = m->private;
-       struct ftrace_event_field *field;
+       struct ftrace_event_call *call = event_file_data(m->private);
        struct list_head *common_head = &ftrace_common_fields;
        struct list_head *head = trace_get_fields(call);
+       struct list_head *node = v;
 
        (*pos)++;
 
        switch ((unsigned long)v) {
        case FORMAT_HEADER:
-               if (unlikely(list_empty(common_head)))
-                       return NULL;
-
-               field = list_entry(common_head->prev,
-                                  struct ftrace_event_field, link);
-               return field;
+               node = common_head;
+               break;
 
        case FORMAT_FIELD_SEPERATOR:
-               if (unlikely(list_empty(head)))
-                       return NULL;
-
-               field = list_entry(head->prev, struct ftrace_event_field, link);
-               return field;
+               node = head;
+               break;
 
        case FORMAT_PRINTFMT:
                /* all done */
                return NULL;
        }
 
-       field = v;
-       if (field->link.prev == common_head)
+       node = node->prev;
+       if (node == common_head)
                return (void *)FORMAT_FIELD_SEPERATOR;
-       else if (field->link.prev == head)
+       else if (node == head)
                return (void *)FORMAT_PRINTFMT;
-
-       field = list_entry(field->link.prev, struct ftrace_event_field, link);
-
-       return field;
-}
-
-static void *f_start(struct seq_file *m, loff_t *pos)
-{
-       loff_t l = 0;
-       void *p;
-
-       /* Start by showing the header */
-       if (!*pos)
-               return (void *)FORMAT_HEADER;
-
-       p = (void *)FORMAT_HEADER;
-       do {
-               p = f_next(m, p, &l);
-       } while (p && l < *pos);
-
-       return p;
+       else
+               return node;
 }
 
 static int f_show(struct seq_file *m, void *v)
 {
-       struct ftrace_event_call *call = m->private;
+       struct ftrace_event_call *call = event_file_data(m->private);
        struct ftrace_event_field *field;
        const char *array_descriptor;
 
@@ -904,8 +897,7 @@ static int f_show(struct seq_file *m, void *v)
                return 0;
        }
 
-       field = v;
-
+       field = list_entry(v, struct ftrace_event_field, link);
        /*
         * Smartly shows the array type(except dynamic array).
         * Normal:
@@ -932,8 +924,25 @@ static int f_show(struct seq_file *m, void *v)
        return 0;
 }
 
+static void *f_start(struct seq_file *m, loff_t *pos)
+{
+       void *p = (void *)FORMAT_HEADER;
+       loff_t l = 0;
+
+       /* ->stop() is called even if ->start() fails */
+       mutex_lock(&event_mutex);
+       if (!event_file_data(m->private))
+               return ERR_PTR(-ENODEV);
+
+       while (l < *pos && p)
+               p = f_next(m, p, &l);
+
+       return p;
+}
+
 static void f_stop(struct seq_file *m, void *p)
 {
+       mutex_unlock(&event_mutex);
 }
 
 static const struct seq_operations trace_format_seq_ops = {
@@ -945,7 +954,6 @@ static const struct seq_operations trace_format_seq_ops = {
 
 static int trace_format_open(struct inode *inode, struct file *file)
 {
-       struct ftrace_event_call *call = inode->i_private;
        struct seq_file *m;
        int ret;
 
@@ -954,7 +962,7 @@ static int trace_format_open(struct inode *inode, struct file *file)
                return ret;
 
        m = file->private_data;
-       m->private = call;
+       m->private = file;
 
        return 0;
 }
@@ -962,45 +970,47 @@ static int trace_format_open(struct inode *inode, struct file *file)
 static ssize_t
 event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 {
-       struct ftrace_event_call *call = filp->private_data;
-       struct trace_seq *s;
-       int r;
+       int id = (long)event_file_data(filp);
+       char buf[32];
+       int len;
 
        if (*ppos)
                return 0;
 
-       s = kmalloc(sizeof(*s), GFP_KERNEL);
-       if (!s)
-               return -ENOMEM;
+       if (unlikely(!id))
+               return -ENODEV;
 
-       trace_seq_init(s);
-       trace_seq_printf(s, "%d\n", call->event.type);
+       len = sprintf(buf, "%d\n", id);
 
-       r = simple_read_from_buffer(ubuf, cnt, ppos,
-                                   s->buffer, s->len);
-       kfree(s);
-       return r;
+       return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
 }
 
 static ssize_t
 event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
                  loff_t *ppos)
 {
-       struct ftrace_event_call *call = filp->private_data;
+       struct ftrace_event_call *call;
        struct trace_seq *s;
-       int r;
+       int r = -ENODEV;
 
        if (*ppos)
                return 0;
 
        s = kmalloc(sizeof(*s), GFP_KERNEL);
+
        if (!s)
                return -ENOMEM;
 
        trace_seq_init(s);
 
-       print_event_filter(call, s);
-       r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+       mutex_lock(&event_mutex);
+       call = event_file_data(filp);
+       if (call)
+               print_event_filter(call, s);
+       mutex_unlock(&event_mutex);
+
+       if (call)
+               r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 
        kfree(s);
 
@@ -1011,9 +1021,9 @@ static ssize_t
 event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
                   loff_t *ppos)
 {
-       struct ftrace_event_call *call = filp->private_data;
+       struct ftrace_event_call *call;
        char *buf;
-       int err;
+       int err = -ENODEV;
 
        if (cnt >= PAGE_SIZE)
                return -EINVAL;
@@ -1028,7 +1038,12 @@ event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
        }
        buf[cnt] = '\0';
 
-       err = apply_event_filter(call, buf);
+       mutex_lock(&event_mutex);
+       call = event_file_data(filp);
+       if (call)
+               err = apply_event_filter(call, buf);
+       mutex_unlock(&event_mutex);
+
        free_page((unsigned long) buf);
        if (err < 0)
                return err;
@@ -1218,6 +1233,7 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 
 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
 static int ftrace_event_set_open(struct inode *inode, struct file *file);
+static int ftrace_event_release(struct inode *inode, struct file *file);
 
 static const struct seq_operations show_event_seq_ops = {
        .start = t_start,
@@ -1245,14 +1261,13 @@ static const struct file_operations ftrace_set_event_fops = {
        .read = seq_read,
        .write = ftrace_event_write,
        .llseek = seq_lseek,
-       .release = seq_release,
+       .release = ftrace_event_release,
 };
 
 static const struct file_operations ftrace_enable_fops = {
-       .open = tracing_open_generic_file,
+       .open = tracing_open_generic,
        .read = event_enable_read,
        .write = event_enable_write,
-       .release = tracing_release_generic_file,
        .llseek = default_llseek,
 };
 
@@ -1264,7 +1279,6 @@ static const struct file_operations ftrace_event_format_fops = {
 };
 
 static const struct file_operations ftrace_event_id_fops = {
-       .open = tracing_open_generic,
        .read = event_id_read,
        .llseek = default_llseek,
 };
@@ -1323,6 +1337,15 @@ ftrace_event_open(struct inode *inode, struct file *file,
        return ret;
 }
 
+static int ftrace_event_release(struct inode *inode, struct file *file)
+{
+       struct trace_array *tr = inode->i_private;
+
+       trace_array_put(tr);
+
+       return seq_release(inode, file);
+}
+
 static int
 ftrace_event_avail_open(struct inode *inode, struct file *file)
 {
@@ -1336,12 +1359,19 @@ ftrace_event_set_open(struct inode *inode, struct file *file)
 {
        const struct seq_operations *seq_ops = &show_set_event_seq_ops;
        struct trace_array *tr = inode->i_private;
+       int ret;
+
+       if (trace_array_get(tr) < 0)
+               return -ENODEV;
 
        if ((file->f_mode & FMODE_WRITE) &&
            (file->f_flags & O_TRUNC))
                ftrace_clear_events(tr);
 
-       return ftrace_event_open(inode, file, seq_ops);
+       ret = ftrace_event_open(inode, file, seq_ops);
+       if (ret < 0)
+               trace_array_put(tr);
+       return ret;
 }
 
 static struct event_subsystem *
@@ -1496,8 +1526,8 @@ event_create_dir(struct dentry *parent,
 
 #ifdef CONFIG_PERF_EVENTS
        if (call->event.type && call->class->reg)
-               trace_create_file("id", 0444, file->dir, call,
-                                 id);
+               trace_create_file("id", 0444, file->dir,
+                                 (void *)(long)call->event.type, id);
 #endif
 
        /*
@@ -1522,33 +1552,16 @@ event_create_dir(struct dentry *parent,
        return 0;
 }
 
-static void remove_subsystem(struct ftrace_subsystem_dir *dir)
-{
-       if (!dir)
-               return;
-
-       if (!--dir->nr_events) {
-               debugfs_remove_recursive(dir->entry);
-               list_del(&dir->list);
-               __put_system_dir(dir);
-       }
-}
-
 static void remove_event_from_tracers(struct ftrace_event_call *call)
 {
        struct ftrace_event_file *file;
        struct trace_array *tr;
 
        do_for_each_event_file_safe(tr, file) {
-
                if (file->event_call != call)
                        continue;
 
-               list_del(&file->list);
-               debugfs_remove_recursive(file->dir);
-               remove_subsystem(file->system);
-               kmem_cache_free(file_cachep, file);
-
+               remove_event_file_dir(file);
                /*
                 * The do_for_each_event_file_safe() is
                 * a double loop. After finding the call for this
@@ -1700,16 +1713,53 @@ static void __trace_remove_event_call(struct ftrace_event_call *call)
        destroy_preds(call);
 }
 
+static int probe_remove_event_call(struct ftrace_event_call *call)
+{
+       struct trace_array *tr;
+       struct ftrace_event_file *file;
+
+#ifdef CONFIG_PERF_EVENTS
+       if (call->perf_refcount)
+               return -EBUSY;
+#endif
+       do_for_each_event_file(tr, file) {
+               if (file->event_call != call)
+                       continue;
+               /*
+                * We can't rely on ftrace_event_enable_disable(enable => 0)
+                * we are going to do, FTRACE_EVENT_FL_SOFT_MODE can suppress
+                * TRACE_REG_UNREGISTER.
+                */
+               if (file->flags & FTRACE_EVENT_FL_ENABLED)
+                       return -EBUSY;
+               /*
+                * The do_for_each_event_file_safe() is
+                * a double loop. After finding the call for this
+                * trace_array, we use break to jump to the next
+                * trace_array.
+                */
+               break;
+       } while_for_each_event_file();
+
+       __trace_remove_event_call(call);
+
+       return 0;
+}
+
 /* Remove an event_call */
-void trace_remove_event_call(struct ftrace_event_call *call)
+int trace_remove_event_call(struct ftrace_event_call *call)
 {
+       int ret;
+
        mutex_lock(&trace_types_lock);
        mutex_lock(&event_mutex);
        down_write(&trace_event_sem);
-       __trace_remove_event_call(call);
+       ret = probe_remove_event_call(call);
        up_write(&trace_event_sem);
        mutex_unlock(&event_mutex);
        mutex_unlock(&trace_types_lock);
+
+       return ret;
 }
 
 #define for_each_event(event, start, end)                      \
@@ -2278,12 +2328,8 @@ __trace_remove_event_dirs(struct trace_array *tr)
 {
        struct ftrace_event_file *file, *next;
 
-       list_for_each_entry_safe(file, next, &tr->events, list) {
-               list_del(&file->list);
-               debugfs_remove_recursive(file->dir);
-               remove_subsystem(file->system);
-               kmem_cache_free(file_cachep, file);
-       }
+       list_for_each_entry_safe(file, next, &tr->events, list)
+               remove_event_file_dir(file);
 }
 
 static void