Messages in this thread Patch in this message | | | From | Borislav Petkov <> | Subject | [RFC PATCH -v2 1/4] trace events: Interface to add files to debugfs | Date | Thu, 16 Aug 2012 19:45:20 +0200 |
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From: Borislav Petkov <borislav.petkov@amd.com>
This generic interface is supposed to be used to add files to (debugfs)/tracing/events/<subsys>/<event_name>/ which are supposed to export additional events functionality to users.
For example, the file descriptor of a persistent event can be exported like this in the 'pers' node:
/mnt/dbg/tracing/events/mce/mce_record/ |-- enable |-- filter |-- format |-- id `-- persistent
So that userspace tools can read it out and map it directly.
Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> --- include/linux/ftrace_event.h | 3 +++ kernel/trace/trace.c | 4 ++++ kernel/trace/trace.h | 1 + kernel/trace/trace_events.c | 35 +++++++++++++++++++++++++++++++++++ 4 files changed, 43 insertions(+)
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 642928cf57b4..f4f283954cbf 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -265,6 +265,9 @@ extern int trace_define_field(struct ftrace_event_call *call, const char *type, int is_signed, int filter_type); extern int trace_add_event_call(struct ftrace_event_call *call); extern void trace_remove_event_call(struct ftrace_event_call *call); +extern struct dentry * +trace_add_file(const char *dir_name, const char *fname, umode_t mode, + void *data, const struct file_operations *fops); #define is_signed_type(type) (((type)(-1)) < 0) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 5c38c81496ce..e45479572328 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4641,6 +4641,10 @@ struct dentry *trace_create_file(const char *name, return ret; } +void trace_remove_file(struct dentry *d) +{ + return debugfs_remove(d); +} static struct dentry *trace_options_init_dentry(void) { diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 55e1f7f0db12..fd639f45c425 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -338,6 +338,7 @@ struct dentry *trace_create_file(const char *name, struct dentry *parent, void *data, const struct file_operations *fops); +void trace_remove_file(struct dentry *d); struct dentry *tracing_init_dentry(void); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 29111da1d100..5eda4f584380 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1199,6 +1199,41 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events, return 0; } +static struct dentry *__trace_add_file(struct ftrace_event_call *call, + const char *fname, umode_t mode, + void *data, + const struct file_operations *fops) +{ + struct dentry *ret; + + mutex_lock(&event_mutex); + ret = trace_create_file(fname, mode, call->dir, data, fops); + mutex_unlock(&event_mutex); + + return ret; +} + +/* + * Assumptions: + * - event debugfs dir is already initialized + * - trace event is not declared in a module + */ +struct dentry *trace_add_file(const char *dir_name, const char *fname, + umode_t mode, void *data, + const struct file_operations *fops) +{ + struct ftrace_event_call *call; + + if (!strlen(fname)) + return NULL; + + list_for_each_entry(call, &ftrace_events, list) { + if (!strncmp(call->name, dir_name, strlen(dir_name))) + return __trace_add_file(call, fname, mode, data, fops); + } + return NULL; +} + static int __trace_add_event_call(struct ftrace_event_call *call, struct module *mod, const struct file_operations *id, -- 1.7.11.rc1
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