From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [for-next][PATCH 04/12] tracing: Move pid_list write processing into its own function
Date: Sun, 03 Jul 2016 16:33:06 -0400 [thread overview]
Message-ID: <20160703203334.612340117@goodmis.org> (raw)
In-Reply-To: 20160703203302.877954992@goodmis.org
[-- Attachment #1: 0004-tracing-Move-pid_list-write-processing-into-its-own-.patch --]
[-- Type: text/plain, Size: 9143 bytes --]
From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
The addition of PIDs into a pid_list via the write operation of
set_event_pid is a bit complex. The same operation will be needed for
function tracing pids. Move the code into its own generic function in
trace.c, so that we can avoid duplication of this code.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace.c | 109 ++++++++++++++++++++++++++++++++++++++++++-
kernel/trace/trace.h | 7 +++
kernel/trace/trace_events.c | 110 ++++----------------------------------------
3 files changed, 124 insertions(+), 102 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7943e306cc7f..a8bb7485fd1d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -25,7 +25,7 @@
#include <linux/hardirq.h>
#include <linux/linkage.h>
#include <linux/uaccess.h>
-#include <linux/kprobes.h>
+#include <linux/vmalloc.h>
#include <linux/ftrace.h>
#include <linux/module.h>
#include <linux/percpu.h>
@@ -319,6 +319,12 @@ int call_filter_check_discard(struct trace_event_call *call, void *rec,
return 0;
}
+void trace_free_pid_list(struct trace_pid_list *pid_list)
+{
+ vfree(pid_list->pids);
+ kfree(pid_list);
+}
+
/**
* trace_find_filtered_pid - check if a pid exists in a filtered_pid list
* @filtered_pids: The list of pids to check
@@ -468,6 +474,107 @@ int trace_pid_show(struct seq_file *m, void *v)
return 0;
}
+/* 128 should be much more than enough */
+#define PID_BUF_SIZE 127
+
+int trace_pid_write(struct trace_pid_list *filtered_pids,
+ struct trace_pid_list **new_pid_list,
+ const char __user *ubuf, size_t cnt)
+{
+ struct trace_pid_list *pid_list;
+ struct trace_parser parser;
+ unsigned long val;
+ int nr_pids = 0;
+ ssize_t read = 0;
+ ssize_t ret = 0;
+ loff_t pos;
+ pid_t pid;
+
+ if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
+ return -ENOMEM;
+
+ /*
+ * Always recreate a new array. The write is an all or nothing
+ * operation. Always create a new array when adding new pids by
+ * the user. If the operation fails, then the current list is
+ * not modified.
+ */
+ pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
+ if (!pid_list)
+ return -ENOMEM;
+
+ pid_list->pid_max = READ_ONCE(pid_max);
+
+ /* Only truncating will shrink pid_max */
+ if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
+ pid_list->pid_max = filtered_pids->pid_max;
+
+ pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
+ if (!pid_list->pids) {
+ kfree(pid_list);
+ return -ENOMEM;
+ }
+
+ if (filtered_pids) {
+ /* copy the current bits to the new max */
+ pid = find_first_bit(filtered_pids->pids,
+ filtered_pids->pid_max);
+ while (pid < filtered_pids->pid_max) {
+ set_bit(pid, pid_list->pids);
+ pid = find_next_bit(filtered_pids->pids,
+ filtered_pids->pid_max,
+ pid + 1);
+ nr_pids++;
+ }
+ }
+
+ while (cnt > 0) {
+
+ pos = 0;
+
+ ret = trace_get_user(&parser, ubuf, cnt, &pos);
+ if (ret < 0 || !trace_parser_loaded(&parser))
+ break;
+
+ read += ret;
+ ubuf += ret;
+ cnt -= ret;
+
+ parser.buffer[parser.idx] = 0;
+
+ ret = -EINVAL;
+ if (kstrtoul(parser.buffer, 0, &val))
+ break;
+ if (val >= pid_list->pid_max)
+ break;
+
+ pid = (pid_t)val;
+
+ set_bit(pid, pid_list->pids);
+ nr_pids++;
+
+ trace_parser_clear(&parser);
+ ret = 0;
+ }
+ trace_parser_put(&parser);
+
+ if (ret < 0) {
+ trace_free_pid_list(pid_list);
+ return ret;
+ }
+
+ if (!nr_pids) {
+ /* Cleared the list of pids */
+ trace_free_pid_list(pid_list);
+ read = ret;
+ pid_list = NULL;
+ }
+
+ *new_pid_list = pid_list;
+
+ return read;
+}
+
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 45442d5842f2..a4dce1ef9e03 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -629,6 +629,9 @@ extern unsigned long nsecs_to_usecs(unsigned long nsecs);
extern unsigned long tracing_thresh;
/* PID filtering */
+
+extern int pid_max;
+
bool trace_find_filtered_pid(struct trace_pid_list *filtered_pids,
pid_t search_pid);
bool trace_ignore_this_task(struct trace_pid_list *filtered_pids,
@@ -639,6 +642,10 @@ void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
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);
+void trace_free_pid_list(struct trace_pid_list *pid_list);
+int trace_pid_write(struct trace_pid_list *filtered_pids,
+ struct trace_pid_list **new_pid_list,
+ const char __user *ubuf, size_t cnt);
#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 fd831a972bae..fd449eb138cf 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -15,7 +15,6 @@
#include <linux/kthread.h>
#include <linux/tracefs.h>
#include <linux/uaccess.h>
-#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/sort.h>
@@ -499,9 +498,6 @@ static void ftrace_clear_events(struct trace_array *tr)
mutex_unlock(&event_mutex);
}
-/* Shouldn't this be in a header? */
-extern int pid_max;
-
static void
event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
{
@@ -634,8 +630,7 @@ static void __ftrace_clear_event_pids(struct trace_array *tr)
/* Wait till all users are no longer using pid filtering */
synchronize_sched();
- vfree(pid_list->pids);
- kfree(pid_list);
+ trace_free_pid_list(pid_list);
}
static void ftrace_clear_event_pids(struct trace_array *tr)
@@ -1587,13 +1582,7 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
struct trace_pid_list *filtered_pids = NULL;
struct trace_pid_list *pid_list;
struct trace_event_file *file;
- struct trace_parser parser;
- unsigned long val;
- loff_t this_pos;
- ssize_t read = 0;
- ssize_t ret = 0;
- pid_t pid;
- int nr_pids = 0;
+ ssize_t ret;
if (!cnt)
return 0;
@@ -1602,93 +1591,15 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
if (ret < 0)
return ret;
- if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
- return -ENOMEM;
-
mutex_lock(&event_mutex);
+
filtered_pids = rcu_dereference_protected(tr->filtered_pids,
lockdep_is_held(&event_mutex));
- /*
- * Always recreate a new array. The write is an all or nothing
- * operation. Always create a new array when adding new pids by
- * the user. If the operation fails, then the current list is
- * not modified.
- */
- pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
- if (!pid_list) {
- read = -ENOMEM;
- goto out;
- }
- pid_list->pid_max = READ_ONCE(pid_max);
- /* Only truncating will shrink pid_max */
- if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
- pid_list->pid_max = filtered_pids->pid_max;
- pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
- if (!pid_list->pids) {
- kfree(pid_list);
- read = -ENOMEM;
- goto out;
- }
- if (filtered_pids) {
- /* copy the current bits to the new max */
- pid = find_first_bit(filtered_pids->pids,
- filtered_pids->pid_max);
- while (pid < filtered_pids->pid_max) {
- set_bit(pid, pid_list->pids);
- pid = find_next_bit(filtered_pids->pids,
- filtered_pids->pid_max,
- pid + 1);
- nr_pids++;
- }
- }
-
- while (cnt > 0) {
-
- this_pos = 0;
-
- ret = trace_get_user(&parser, ubuf, cnt, &this_pos);
- if (ret < 0 || !trace_parser_loaded(&parser))
- break;
-
- read += ret;
- ubuf += ret;
- cnt -= ret;
-
- parser.buffer[parser.idx] = 0;
-
- ret = -EINVAL;
- if (kstrtoul(parser.buffer, 0, &val))
- break;
- if (val >= pid_list->pid_max)
- break;
-
- pid = (pid_t)val;
-
- set_bit(pid, pid_list->pids);
- nr_pids++;
-
- trace_parser_clear(&parser);
- ret = 0;
- }
- trace_parser_put(&parser);
-
- if (ret < 0) {
- vfree(pid_list->pids);
- kfree(pid_list);
- read = ret;
+ ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
+ if (ret < 0)
goto out;
- }
- if (!nr_pids) {
- /* Cleared the list of pids */
- vfree(pid_list->pids);
- kfree(pid_list);
- read = ret;
- if (!filtered_pids)
- goto out;
- pid_list = NULL;
- }
rcu_assign_pointer(tr->filtered_pids, pid_list);
list_for_each_entry(file, &tr->events, list) {
@@ -1697,10 +1608,8 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
if (filtered_pids) {
synchronize_sched();
-
- vfree(filtered_pids->pids);
- kfree(filtered_pids);
- } else {
+ trace_free_pid_list(filtered_pids);
+ } else if (pid_list) {
/*
* Register a probe that is called before all other probes
* to set ignore_pid if next or prev do not match.
@@ -1738,9 +1647,8 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
out:
mutex_unlock(&event_mutex);
- ret = read;
- if (read > 0)
- *ppos += read;
+ if (ret > 0)
+ *ppos += ret;
return ret;
}
--
2.8.1
next prev parent reply other threads:[~2016-07-03 20:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-03 20:33 [for-next][PATCH 00/12] tracing: Updates for 4.8 Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 01/12] tracing: Make the pid filtering helper functions global Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 02/12] tracing: Move filtered_pid helper functions into trace.c Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 03/12] tracing: Move the pid_list seq_file functions to be global Steven Rostedt
2016-07-03 20:33 ` Steven Rostedt [this message]
2016-07-03 20:33 ` [for-next][PATCH 05/12] ftrace: Have set_ftrace_pid use the bitmap like events do Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 06/12] tracing: expose current->comm to [ku]probe events Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 07/12] tracing: Choose static tp_printk buffer by explicit nesting count Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 08/12] tracing: Add trace_printk sample code Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 09/12] tracing: Show the preempt count of when the event was called Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 10/12] tracing: Expose CPU physical addresses (resource values) for PCI devices Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 11/12] tracing: Skip more functions when doing stack tracing of events Steven Rostedt
2016-07-03 20:33 ` [for-next][PATCH 12/12] tracing/function_graph: Fix filters for function_graph threshold Steven Rostedt
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