... Explain why we want this! ...
... Explain why we make these changes ...
---
include/linux/trace.h | 4 ++
kernel/trace/trace.c | 142 ++++++++++++++++++++++++++++++------------
2 files changed, 105 insertions(+), 41 deletions(-)
diff --git a/include/linux/trace.h b/include/linux/trace.h
index 7fd86d3c691f..337454e859f4 100644
--- a/include/linux/trace.h
+++ b/include/linux/trace.h
@@ -30,8 +30,12 @@ void trace_printk_init_buffers(void);
int trace_array_printk(struct trace_array *tr, unsigned long ip,
const char *fmt, ...);
void trace_array_put(struct trace_array *tr);
+struct trace_array *trace_array_create(void);
struct trace_array *trace_array_get_by_name(const char *name);
int trace_array_destroy(struct trace_array *tr);
+
+int anon_trace_getfd(const char *name, struct trace_array *tr);
+
#endif /* CONFIG_TRACING */
#endif /* _LINUX_TRACE_H */
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8f7fdc25f230..6c2286b81b4a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -48,6 +48,7 @@
#include <linux/fsnotify.h>
#include <linux/irq_work.h>
#include <linux/workqueue.h>
+#include <linux/anon_inodes.h>
#include "trace.h"
#include "trace_output.h"
@@ -4140,7 +4141,7 @@ static int s_show(struct seq_file *m, void *v)
*/
static inline int tracing_get_cpu(struct inode *inode)
{
- if (inode->i_cdev) /* See trace_create_cpu_file() */
+ if (inode && inode->i_cdev) /* See trace_create_cpu_file() */
return (long)inode->i_cdev - 1;
return RING_BUFFER_ALL_CPUS;
}
@@ -5938,32 +5939,22 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf,
#endif
-static int tracing_open_pipe(struct inode *inode, struct file *filp)
+static struct trace_iterator *
+tracing_create_pipe_iter(struct trace_array *tr, struct inode *inode)
{
- struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
- int ret;
-
- ret = tracing_check_open_get_tr(tr);
- if (ret)
- return ret;
-
- mutex_lock(&trace_types_lock);
/* create a buffer to store the information to pass to userspace */
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
- if (!iter) {
- ret = -ENOMEM;
- __trace_array_put(tr);
- goto out;
- }
+ if (!iter)
+ return ERR_PTR(-ENOMEM);
trace_seq_init(&iter->seq);
iter->trace = tr->current_trace;
if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
- ret = -ENOMEM;
- goto fail;
+ kfree(iter);
+ return ERR_PTR(-ENOMEM);
}
/* trace pipe does not show start of buffer */
@@ -5980,6 +5971,29 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
iter->trace_buffer = &tr->trace_buffer;
iter->cpu_file = tracing_get_cpu(inode);
mutex_init(&iter->mutex);
+
+ return iter;
+}
+
+static int tracing_open_pipe(struct inode *inode, struct file *filp)
+{
+ struct trace_array *tr = inode->i_private;
+ struct trace_iterator *iter;
+ int ret;
+
+ ret = tracing_check_open_get_tr(tr);
+ if (ret)
+ return ret;
+
+ mutex_lock(&trace_types_lock);
+
+ iter = tracing_create_pipe_iter(tr, inode);
+ if (IS_ERR(iter)) {
+ ret = PTR_ERR(iter);
+ __trace_array_put(tr);
+ goto out;
+ }
+
filp->private_data = iter;
if (iter->trace->pipe_open)
@@ -5991,18 +6005,12 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
out:
mutex_unlock(&trace_types_lock);
return ret;
-
-fail:
- kfree(iter);
- __trace_array_put(tr);
- mutex_unlock(&trace_types_lock);
- return ret;
}
static int tracing_release_pipe(struct inode *inode, struct file *file)
{
struct trace_iterator *iter = file->private_data;
- struct trace_array *tr = inode->i_private;
+ struct trace_array *tr = iter->tr;
mutex_lock(&trace_types_lock);
@@ -7868,7 +7876,7 @@ static inline __init int register_snapshot_cmd(void) { return 0; }
static struct dentry *tracing_get_dentry(struct trace_array *tr)
{
- if (WARN_ON(!tr->dir))
+ if (!tr->dir)
return ERR_PTR(-ENODEV);
/* Top directory uses NULL as the parent */
@@ -8461,7 +8469,7 @@ static void update_tracer_options(struct trace_array *tr)
mutex_unlock(&trace_types_lock);
}
-static struct trace_array *trace_array_create(const char *name)
+static struct trace_array *__trace_array_create(const char *name)
{
struct trace_array *tr;
int ret;
@@ -8471,9 +8479,11 @@ static struct trace_array *trace_array_create(const char *name)
if (!tr)
return ERR_PTR(ret);
- tr->name = kstrdup(name, GFP_KERNEL);
- if (!tr->name)
- goto out_free_tr;
+ if (name) {
+ tr->name = kstrdup(name, GFP_KERNEL);
+ if (!tr->name)
+ goto out_free_tr;
+ }
if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
goto out_free_tr;
@@ -8496,19 +8506,22 @@ static struct trace_array *trace_array_create(const char *name)
if (allocate_trace_buffers(tr, trace_buf_size) < 0)
goto out_free_tr;
- tr->dir = tracefs_create_dir(name, trace_instance_dir);
- if (!tr->dir)
- goto out_free_tr;
+ if (name) {
+ tr->dir = tracefs_create_dir(name, trace_instance_dir);
+ if (!tr->dir)
+ goto out_free_tr;
- ret = event_trace_add_tracer(tr->dir, tr);
- if (ret) {
- tracefs_remove_recursive(tr->dir);
- goto out_free_tr;
+ ret = event_trace_add_tracer(tr->dir, tr);
+ if (ret) {
+ tracefs_remove_recursive(tr->dir);
+ goto out_free_tr;
+ }
+
+ init_tracer_tracefs(tr, tr->dir);
}
ftrace_init_trace_array(tr);
- init_tracer_tracefs(tr, tr->dir);
init_trace_flags_index(tr);
__update_tracer_options(tr);
@@ -8516,7 +8529,6 @@ static struct trace_array *trace_array_create(const char *name)
tr->ref++;
-
return tr;
out_free_tr:
@@ -8528,6 +8540,12 @@ static struct trace_array *trace_array_create(const char *name)
return ERR_PTR(ret);
}
+struct trace_array *trace_array_create(void)
+{
+ return __trace_array_create(NULL);
+}
+EXPORT_SYMBOL_GPL(trace_array_create);
+
static int instance_mkdir(const char *name)
{
struct trace_array *tr;
@@ -8542,7 +8560,7 @@ static int instance_mkdir(const char *name)
goto out_unlock;
}
- tr = trace_array_create(name);
+ tr = __trace_array_create(name);
ret = PTR_ERR_OR_ZERO(tr);
@@ -8576,7 +8594,7 @@ struct trace_array *trace_array_get_by_name(const char *name)
goto out_unlock;
}
- tr = trace_array_create(name);
+ tr = __trace_array_create(name);
if (IS_ERR(tr))
tr = NULL;
@@ -8611,7 +8629,8 @@ static int __remove_instance(struct trace_array *tr)
event_trace_del_tracer(tr);
ftrace_clear_pids(tr);
ftrace_destroy_function_files(tr);
- tracefs_remove_recursive(tr->dir);
+ if (tr->dir)
+ tracefs_remove_recursive(tr->dir);
free_trace_buffers(tr);
for (i = 0; i < tr->nr_topts; i++) {
@@ -9157,6 +9176,47 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
}
EXPORT_SYMBOL_GPL(ftrace_dump);
+int anon_trace_getfd(const char *name, struct trace_array *tr)
+{
+ struct trace_iterator *iter;
+ int ret;
+
+ if (!tr || trace_array_get(tr) < 0)
+ return -ENODEV;
+
+ mutex_lock(&trace_types_lock);
+
+ iter = tracing_create_pipe_iter(tr, NULL);
+ if (IS_ERR(iter)) {
+ ret = PTR_ERR(iter);
+ __trace_array_put(tr);
+ goto out;
+ }
+
+ ret = anon_inode_getfd(name, &tracing_pipe_fops, iter, O_CLOEXEC);
+ if (ret < 0)
+ goto fail;
+
+ if (iter->trace->pipe_open)
+ iter->trace->pipe_open(iter);
+
+ tr->current_trace->ref++;
+out:
+ mutex_unlock(&trace_types_lock);
+ return ret;
+
+fail:
+ mutex_unlock(&trace_types_lock);
+
+ free_cpumask_var(iter->started);
+ mutex_destroy(&iter->mutex);
+ kfree(iter);
+
+ trace_array_put(tr);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(anon_trace_getfd);
+
int trace_run_command(const char *buf, int (*createfn)(int, char **))
{
char **argv;
--
2.25.0
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