From e704eff3ff5138a462443dcd64d071165df18782 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 2 Feb 2017 20:34:37 -0500 Subject: [PATCH] ftrace: Have set_graph_function handle multiple functions in one write Currently, only one function can be written to set_graph_function and set_graph_notrace. The last function in the list will have saved, even though other functions will be added then removed. Change the behavior to be the same as set_ftrace_function as to allow multiple functions to be written. If any one fails, none of them will be added. The addition of the functions are done at the end when the file is closed. Acked-by: Namhyung Kim Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 105 +++++++++++++++++++++++++----------------- 1 file changed, 64 insertions(+), 41 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b3a4896ef78a..0c0609326391 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4564,12 +4564,13 @@ enum graph_filter_type { #define FTRACE_GRAPH_EMPTY ((void *)1) struct ftrace_graph_data { - struct ftrace_hash *hash; - struct ftrace_func_entry *entry; - int idx; /* for hash table iteration */ - enum graph_filter_type type; - struct ftrace_hash *new_hash; - const struct seq_operations *seq_ops; + struct ftrace_hash *hash; + struct ftrace_func_entry *entry; + int idx; /* for hash table iteration */ + enum graph_filter_type type; + struct ftrace_hash *new_hash; + const struct seq_operations *seq_ops; + struct trace_parser parser; }; static void * @@ -4676,6 +4677,9 @@ __ftrace_graph_open(struct inode *inode, struct file *file, if (file->f_mode & FMODE_WRITE) { const int size_bits = FTRACE_HASH_DEFAULT_BITS; + if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX)) + return -ENOMEM; + if (file->f_flags & O_TRUNC) new_hash = alloc_ftrace_hash(size_bits); else @@ -4701,6 +4705,9 @@ __ftrace_graph_open(struct inode *inode, struct file *file, file->private_data = fgd; out: + if (ret < 0 && file->f_mode & FMODE_WRITE) + trace_parser_put(&fgd->parser); + fgd->new_hash = new_hash; /* @@ -4773,6 +4780,9 @@ static int ftrace_graph_release(struct inode *inode, struct file *file) { struct ftrace_graph_data *fgd; + struct ftrace_hash *old_hash, *new_hash; + struct trace_parser *parser; + int ret = 0; if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; @@ -4783,10 +4793,50 @@ ftrace_graph_release(struct inode *inode, struct file *file) fgd = file->private_data; } + + if (file->f_mode & FMODE_WRITE) { + + parser = &fgd->parser; + + if (trace_parser_loaded((parser))) { + parser->buffer[parser->idx] = 0; + ret = ftrace_graph_set_hash(fgd->new_hash, + parser->buffer); + } + + trace_parser_put(parser); + + new_hash = __ftrace_hash_move(fgd->new_hash); + if (!new_hash) { + ret = -ENOMEM; + goto out; + } + + mutex_lock(&graph_lock); + + if (fgd->type == GRAPH_FILTER_FUNCTION) { + old_hash = rcu_dereference_protected(ftrace_graph_hash, + lockdep_is_held(&graph_lock)); + rcu_assign_pointer(ftrace_graph_hash, new_hash); + } else { + old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash, + lockdep_is_held(&graph_lock)); + rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash); + } + + mutex_unlock(&graph_lock); + + /* Wait till all users are no longer using the old hash */ + synchronize_sched(); + + free_ftrace_hash(old_hash); + } + + out: kfree(fgd->new_hash); kfree(fgd); - return 0; + return ret; } static int @@ -4848,61 +4898,34 @@ static ssize_t ftrace_graph_write(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos) { - struct trace_parser parser; ssize_t read, ret = 0; struct ftrace_graph_data *fgd = file->private_data; - struct ftrace_hash *old_hash, *new_hash; + struct trace_parser *parser; if (!cnt) return 0; - if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) - return -ENOMEM; - /* Read mode uses seq functions */ if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data; fgd = m->private; } - read = trace_get_user(&parser, ubuf, cnt, ppos); + parser = &fgd->parser; - if (read >= 0 && trace_parser_loaded((&parser))) { - parser.buffer[parser.idx] = 0; + read = trace_get_user(parser, ubuf, cnt, ppos); - mutex_lock(&graph_lock); + if (read >= 0 && trace_parser_loaded(parser) && + !trace_parser_cont(parser)) { - /* we allow only one expression at a time */ ret = ftrace_graph_set_hash(fgd->new_hash, - parser.buffer); - - new_hash = __ftrace_hash_move(fgd->new_hash); - if (!new_hash) - ret = -ENOMEM; - - if (fgd->type == GRAPH_FILTER_FUNCTION) { - old_hash = rcu_dereference_protected(ftrace_graph_hash, - lockdep_is_held(&graph_lock)); - rcu_assign_pointer(ftrace_graph_hash, new_hash); - } else { - old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash, - lockdep_is_held(&graph_lock)); - rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash); - } - - mutex_unlock(&graph_lock); - - /* Wait till all users are no longer using the old hash */ - synchronize_sched(); - - free_ftrace_hash(old_hash); + parser->buffer); + trace_parser_clear(parser); } if (!ret) ret = read; - trace_parser_put(&parser); - return ret; } -- 2.20.1