From 5cc8976bd52153678ca37cc1e3000833b20276f3 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 20 Apr 2016 15:19:54 -0400 Subject: [PATCH] tracing: Move the pid_list seq_file functions to be global To allow other aspects of ftrace to use the pid_list logic, we need to reuse the seq_file functions. Making the generic part into functions that can be called by other files will help in this regard. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 71 +++++++++++++++++++++++++++++++++++++ kernel/trace/trace.h | 3 ++ kernel/trace/trace_events.c | 34 ++---------------- 3 files changed, 77 insertions(+), 31 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0b87fe8e6d0b..7943e306cc7f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -397,6 +397,77 @@ void trace_filter_add_remove_task(struct trace_pid_list *pid_list, clear_bit(task->pid, pid_list->pids); } +/** + * trace_pid_next - Used for seq_file to get to the next pid of a pid_list + * @pid_list: The pid list to show + * @v: The last pid that was shown (+1 the actual pid to let zero be displayed) + * @pos: The position of the file + * + * This is used by the seq_file "next" operation to iterate the pids + * listed in a trace_pid_list structure. + * + * Returns the pid+1 as we want to display pid of zero, but NULL would + * stop the iteration. + */ +void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos) +{ + unsigned long pid = (unsigned long)v; + + (*pos)++; + + /* pid already is +1 of the actual prevous bit */ + pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid); + + /* Return pid + 1 to allow zero to be represented */ + if (pid < pid_list->pid_max) + return (void *)(pid + 1); + + return NULL; +} + +/** + * trace_pid_start - Used for seq_file to start reading pid lists + * @pid_list: The pid list to show + * @pos: The position of the file + * + * This is used by seq_file "start" operation to start the iteration + * of listing pids. + * + * Returns the pid+1 as we want to display pid of zero, but NULL would + * stop the iteration. + */ +void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos) +{ + unsigned long pid; + loff_t l = 0; + + pid = find_first_bit(pid_list->pids, pid_list->pid_max); + if (pid >= pid_list->pid_max) + return NULL; + + /* Return pid + 1 so that zero can be the exit value */ + for (pid++; pid && l < *pos; + pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l)) + ; + return (void *)pid; +} + +/** + * trace_pid_show - show the current pid in seq_file processing + * @m: The seq_file structure to write into + * @v: A void pointer of the pid (+1) value to display + * + * Can be directly used by seq_file operations to display the current + * pid value. + */ +int trace_pid_show(struct seq_file *m, void *v) +{ + unsigned long pid = (unsigned long)v - 1; + + seq_printf(m, "%lu\n", pid); + return 0; +} + static cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu) { u64 ts; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 172330891c6d..45442d5842f2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -636,6 +636,9 @@ bool trace_ignore_this_task(struct trace_pid_list *filtered_pids, void trace_filter_add_remove_task(struct trace_pid_list *pid_list, struct task_struct *self, struct task_struct *task); +void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos); +void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos); +int trace_pid_show(struct seq_file *m, void *v); #ifdef CONFIG_TRACER_MAX_TRACE void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index a11e6d9a3841..fd831a972bae 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -983,18 +983,8 @@ p_next(struct seq_file *m, void *v, loff_t *pos) { struct trace_array *tr = m->private; struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids); - unsigned long pid = (unsigned long)v; - (*pos)++; - - /* pid already is +1 of the actual prevous bit */ - pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid); - - /* Return pid + 1 to allow zero to be represented */ - if (pid < pid_list->pid_max) - return (void *)(pid + 1); - - return NULL; + return trace_pid_next(pid_list, v, pos); } static void *p_start(struct seq_file *m, loff_t *pos) @@ -1002,8 +992,6 @@ static void *p_start(struct seq_file *m, loff_t *pos) { struct trace_pid_list *pid_list; struct trace_array *tr = m->private; - unsigned long pid; - loff_t l = 0; /* * Grab the mutex, to keep calls to p_next() having the same @@ -1019,15 +1007,7 @@ static void *p_start(struct seq_file *m, loff_t *pos) if (!pid_list) return NULL; - pid = find_first_bit(pid_list->pids, pid_list->pid_max); - if (pid >= pid_list->pid_max) - return NULL; - - /* Return pid + 1 so that zero can be the exit value */ - for (pid++; pid && l < *pos; - pid = (unsigned long)p_next(m, (void *)pid, &l)) - ; - return (void *)pid; + return trace_pid_start(pid_list, pos); } static void p_stop(struct seq_file *m, void *p) @@ -1037,14 +1017,6 @@ static void p_stop(struct seq_file *m, void *p) mutex_unlock(&event_mutex); } -static int p_show(struct seq_file *m, void *v) -{ - unsigned long pid = (unsigned long)v - 1; - - seq_printf(m, "%lu\n", pid); - return 0; -} - static ssize_t event_enable_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) @@ -1795,7 +1767,7 @@ static const struct seq_operations show_set_event_seq_ops = { static const struct seq_operations show_set_pid_seq_ops = { .start = p_start, .next = p_next, - .show = p_show, + .show = trace_pid_show, .stop = p_stop, }; -- 2.20.1