* [PATCH v4 0/4] tracing: Add and use event_command parsing func helpers
@ 2021-12-10 21:16 Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 1/4] tracing: Change event_command func() to parse() Tom Zanussi
` (3 more replies)
0 siblings, 4 replies; 7+ messages in thread
From: Tom Zanussi @ 2021-12-10 21:16 UTC (permalink / raw)
To: rostedt; +Cc: mhiramat, linux-kernel
With more event commands being implemented, it's been pointed out that
it would make sense to clean up the existing ones and make it easier
to implement new ones without copying a lot of boilerplate. The main
culprit here is the event_command.func() callback - the rest of the
event_command infrastructure has default implementations that work for
most implementations. The func() callback is a little different in
that every new command needs to customize parsing to some extent.
This patchset attempts to help clean that up and make it easier for
new users to deal with.
v4: Added two patches changing the names of event_command.func() and
event_trigger_ops.func() to make them reflect their functions.
Added back missing kfree(trigger_data) in event_trigger_callback().
Changed char *param to const char *param in
event_trigger_check_remove() and event_trigger_empty_param().
Changed event_trigger_separate_filter() to use separate param and
filter outparams, and changed the name of the param inparam to
param_and_filter to better reflect its contents and avoid the
clash with new param outparam. Changed all parse()
implementations to use this new scheme.
Fixed some typos and added more extensive comments with examples
explaining various things that were mentioned as causing confusion
and just in general tried to clarify things with respect to the
callbacks and parameters.
v3: broke up event_trigger_check() into smaller functions instead of
parameterizing it, and added function documentation.
v2: removed unused event_trigger_remove(). No change in functionality.
The following changes since commit a6ed2aee54644cfa2d04ca86308767f5c3a087e8:
tracing: Switch to kvfree_rcu() API (2021-12-06 17:53:50 -0500)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/zanussi/linux-trace.git ftrace/cleanup-hist-func-v4
Tom Zanussi (4):
tracing: Change event_command func() to parse()
tracing: Change event_trigger_ops func() to trigger()
tracing: Add helper functions to simplify event_command.parse()
callback handling
tracing: Have existing event_command.parse() implementations use
helpers
kernel/trace/trace.h | 63 +++-
kernel/trace/trace_eprobe.c | 11 +-
kernel/trace/trace_events_hist.c | 109 +++---
kernel/trace/trace_events_trigger.c | 558 ++++++++++++++++++++--------
4 files changed, 515 insertions(+), 226 deletions(-)
--
2.17.1
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v4 1/4] tracing: Change event_command func() to parse()
2021-12-10 21:16 [PATCH v4 0/4] tracing: Add and use event_command parsing func helpers Tom Zanussi
@ 2021-12-10 21:16 ` Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 2/4] tracing: Change event_trigger_ops func() to trigger() Tom Zanussi
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Tom Zanussi @ 2021-12-10 21:16 UTC (permalink / raw)
To: rostedt; +Cc: mhiramat, linux-kernel
The name of the func() callback on event_command is too generic and is
easily confused with other callbacks with that name, so change it to
something that reflects its actual purpose.
In this case, the main purpose of the callback is to parse an event
command, so call it parse() instead.
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
---
kernel/trace/trace.h | 19 +++++++++++-------
kernel/trace/trace_eprobe.c | 8 ++++----
kernel/trace/trace_events_hist.c | 26 ++++++++++++-------------
kernel/trace/trace_events_trigger.c | 30 ++++++++++++++---------------
4 files changed, 44 insertions(+), 39 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8bd1a815ce90..25bd5706ef0b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1578,9 +1578,9 @@ extern int event_enable_trigger_print(struct seq_file *m,
struct event_trigger_data *data);
extern void event_enable_trigger_free(struct event_trigger_ops *ops,
struct event_trigger_data *data);
-extern int event_enable_trigger_func(struct event_command *cmd_ops,
- struct trace_event_file *file,
- char *glob, char *cmd, char *param);
+extern int event_enable_trigger_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param);
extern int event_enable_register_trigger(char *glob,
struct event_trigger_ops *ops,
struct event_trigger_data *data,
@@ -1702,7 +1702,7 @@ struct event_trigger_ops {
* All the methods below, except for @set_filter() and @unreg_all(),
* must be implemented.
*
- * @func: The callback function responsible for parsing and
+ * @parse: The callback function responsible for parsing and
* registering the trigger written to the 'trigger' file by the
* user. It allocates the trigger instance and registers it with
* the appropriate trace event. It makes use of the other
@@ -1737,15 +1737,20 @@ struct event_trigger_ops {
*
* @get_trigger_ops: The callback function invoked to retrieve the
* event_trigger_ops implementation associated with the command.
+ * This callback function allows a single event_command to
+ * support multiple trigger implementations via different sets of
+ * event_trigger_ops, depending on the value of the @param
+ * string.
*/
struct event_command {
struct list_head list;
char *name;
enum event_trigger_type trigger_type;
int flags;
- int (*func)(struct event_command *cmd_ops,
- struct trace_event_file *file,
- char *glob, char *cmd, char *params);
+ int (*parse)(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd,
+ char *param_and_filter);
int (*reg)(char *glob,
struct event_trigger_ops *ops,
struct event_trigger_data *data,
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 88487752d307..84d5bfa34a99 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -549,9 +549,9 @@ static struct event_trigger_ops eprobe_trigger_ops = {
.free = eprobe_trigger_free,
};
-static int eprobe_trigger_cmd_func(struct event_command *cmd_ops,
- struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param)
{
return -1;
}
@@ -580,7 +580,7 @@ static struct event_command event_trigger_cmd = {
.name = "eprobe",
.trigger_type = ETT_EVENT_EPROBE,
.flags = EVENT_CMD_FL_NEEDS_REC,
- .func = eprobe_trigger_cmd_func,
+ .parse = eprobe_trigger_cmd_parse,
.reg = eprobe_trigger_reg_func,
.unreg = eprobe_trigger_unreg_func,
.unreg_all = NULL,
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 9b8da439149c..89bbbbd3a3f5 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2761,9 +2761,9 @@ static char *find_trigger_filter(struct hist_trigger_data *hist_data,
}
static struct event_command trigger_hist_cmd;
-static int event_hist_trigger_func(struct event_command *cmd_ops,
- struct trace_event_file *file,
- char *glob, char *cmd, char *param);
+static int event_hist_trigger_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param);
static bool compatible_keys(struct hist_trigger_data *target_hist_data,
struct hist_trigger_data *hist_data,
@@ -2966,8 +2966,8 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data,
var_hist->hist_data = hist_data;
/* Create the new histogram with our variable */
- ret = event_hist_trigger_func(&trigger_hist_cmd, file,
- "", "hist", cmd);
+ ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
+ "", "hist", cmd);
if (ret) {
kfree(cmd);
kfree(var_hist->cmd);
@@ -5729,8 +5729,8 @@ static void unregister_field_var_hists(struct hist_trigger_data *hist_data)
for (i = 0; i < hist_data->n_field_var_hists; i++) {
file = hist_data->field_var_hists[i]->hist_data->event_file;
cmd = hist_data->field_var_hists[i]->cmd;
- ret = event_hist_trigger_func(&trigger_hist_cmd, file,
- "!hist", "hist", cmd);
+ ret = event_hist_trigger_parse(&trigger_hist_cmd, file,
+ "!hist", "hist", cmd);
WARN_ON_ONCE(ret < 0);
}
}
@@ -6146,9 +6146,9 @@ static void hist_unreg_all(struct trace_event_file *file)
}
}
-static int event_hist_trigger_func(struct event_command *cmd_ops,
- struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+static int event_hist_trigger_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param)
{
unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
struct event_trigger_data *trigger_data;
@@ -6331,7 +6331,7 @@ static struct event_command trigger_hist_cmd = {
.name = "hist",
.trigger_type = ETT_EVENT_HIST,
.flags = EVENT_CMD_FL_NEEDS_REC,
- .func = event_hist_trigger_func,
+ .parse = event_hist_trigger_parse,
.reg = hist_register_trigger,
.unreg = hist_unregister_trigger,
.unreg_all = hist_unreg_all,
@@ -6446,7 +6446,7 @@ static void hist_enable_unreg_all(struct trace_event_file *file)
static struct event_command trigger_hist_enable_cmd = {
.name = ENABLE_HIST_STR,
.trigger_type = ETT_HIST_ENABLE,
- .func = event_enable_trigger_func,
+ .parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.unreg_all = hist_enable_unreg_all,
@@ -6457,7 +6457,7 @@ static struct event_command trigger_hist_enable_cmd = {
static struct event_command trigger_hist_disable_cmd = {
.name = DISABLE_HIST_STR,
.trigger_type = ETT_HIST_ENABLE,
- .func = event_enable_trigger_func,
+ .parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.unreg_all = hist_enable_unreg_all,
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 3d5c07239a2a..15aae07cbe61 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -245,7 +245,7 @@ int trigger_process_regex(struct trace_event_file *file, char *buff)
mutex_lock(&trigger_cmd_mutex);
list_for_each_entry(p, &trigger_commands, list) {
if (strcmp(p->name, command) == 0) {
- ret = p->func(p, file, buff, command, next);
+ ret = p->parse(p, file, buff, command, next);
goto out_unlock;
}
}
@@ -622,7 +622,7 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
}
/**
- * event_trigger_callback - Generic event_command @func implementation
+ * event_trigger_parse - Generic event_command @parse implementation
* @cmd_ops: The command ops, used for trigger registration
* @file: The trace_event_file associated with the event
* @glob: The raw string used to register the trigger
@@ -632,15 +632,15 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
* Common implementation for event command parsing and trigger
* instantiation.
*
- * Usually used directly as the @func method in event command
+ * Usually used directly as the @parse method in event command
* implementations.
*
* Return: 0 on success, errno otherwise
*/
static int
-event_trigger_callback(struct event_command *cmd_ops,
- struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+event_trigger_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param)
{
struct event_trigger_data *trigger_data;
struct event_trigger_ops *trigger_ops;
@@ -1069,7 +1069,7 @@ onoff_get_trigger_ops(char *cmd, char *param)
static struct event_command trigger_traceon_cmd = {
.name = "traceon",
.trigger_type = ETT_TRACE_ONOFF,
- .func = event_trigger_callback,
+ .parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
.get_trigger_ops = onoff_get_trigger_ops,
@@ -1080,7 +1080,7 @@ static struct event_command trigger_traceoff_cmd = {
.name = "traceoff",
.trigger_type = ETT_TRACE_ONOFF,
.flags = EVENT_CMD_FL_POST_TRIGGER,
- .func = event_trigger_callback,
+ .parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
.get_trigger_ops = onoff_get_trigger_ops,
@@ -1157,7 +1157,7 @@ snapshot_get_trigger_ops(char *cmd, char *param)
static struct event_command trigger_snapshot_cmd = {
.name = "snapshot",
.trigger_type = ETT_SNAPSHOT,
- .func = event_trigger_callback,
+ .parse = event_trigger_parse,
.reg = register_snapshot_trigger,
.unreg = unregister_trigger,
.get_trigger_ops = snapshot_get_trigger_ops,
@@ -1249,7 +1249,7 @@ static struct event_command trigger_stacktrace_cmd = {
.name = "stacktrace",
.trigger_type = ETT_STACKTRACE,
.flags = EVENT_CMD_FL_POST_TRIGGER,
- .func = event_trigger_callback,
+ .parse = event_trigger_parse,
.reg = register_trigger,
.unreg = unregister_trigger,
.get_trigger_ops = stacktrace_get_trigger_ops,
@@ -1380,9 +1380,9 @@ static struct event_trigger_ops event_disable_count_trigger_ops = {
.free = event_enable_trigger_free,
};
-int event_enable_trigger_func(struct event_command *cmd_ops,
- struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+int event_enable_trigger_parse(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param)
{
struct trace_event_file *event_enable_file;
struct enable_trigger_data *enable_data;
@@ -1628,7 +1628,7 @@ event_enable_get_trigger_ops(char *cmd, char *param)
static struct event_command trigger_enable_cmd = {
.name = ENABLE_EVENT_STR,
.trigger_type = ETT_EVENT_ENABLE,
- .func = event_enable_trigger_func,
+ .parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.get_trigger_ops = event_enable_get_trigger_ops,
@@ -1638,7 +1638,7 @@ static struct event_command trigger_enable_cmd = {
static struct event_command trigger_disable_cmd = {
.name = DISABLE_EVENT_STR,
.trigger_type = ETT_EVENT_ENABLE,
- .func = event_enable_trigger_func,
+ .parse = event_enable_trigger_parse,
.reg = event_enable_register_trigger,
.unreg = event_enable_unregister_trigger,
.get_trigger_ops = event_enable_get_trigger_ops,
--
2.17.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v4 2/4] tracing: Change event_trigger_ops func() to trigger()
2021-12-10 21:16 [PATCH v4 0/4] tracing: Add and use event_command parsing func helpers Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 1/4] tracing: Change event_command func() to parse() Tom Zanussi
@ 2021-12-10 21:16 ` Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 3/4] tracing: Add helper functions to simplify event_command.parse() callback handling Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 4/4] tracing: Have existing event_command.parse() implementations use helpers Tom Zanussi
3 siblings, 0 replies; 7+ messages in thread
From: Tom Zanussi @ 2021-12-10 21:16 UTC (permalink / raw)
To: rostedt; +Cc: mhiramat, linux-kernel
The name of the func() callback on event_trigger_ops is too generic
and is easily confused with other callbacks with that name, so change
it to something that reflects its actual purpose.
In this case, the main purpose of the callback is to implement an
event trigger, so call it trigger() instead.
Also add some more documentation to event_trigger_ops describing the
callbacks a bit better.
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
---
kernel/trace/trace.h | 19 ++++++++++++++----
kernel/trace/trace_eprobe.c | 2 +-
kernel/trace/trace_events_hist.c | 12 ++++++------
kernel/trace/trace_events_trigger.c | 30 ++++++++++++++---------------
4 files changed, 37 insertions(+), 26 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 25bd5706ef0b..1a73659222d4 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1619,10 +1619,20 @@ extern int register_trigger_hist_enable_disable_cmds(void);
* The methods in this structure provide per-event trigger hooks for
* various trigger operations.
*
+ * The @init and @free methods are used during trigger setup and
+ * teardown, typically called from an event_command's @parse()
+ * function implementation.
+ *
+ * The @print method is used to print the trigger spec.
+ *
+ * The @trigger method is the function that actually implements the
+ * trigger and is called in the context of the triggering event
+ * whenever that event occurs.
+ *
* All the methods below, except for @init() and @free(), must be
* implemented.
*
- * @func: The trigger 'probe' function called when the triggering
+ * @trigger: The trigger 'probe' function called when the triggering
* event occurs. The data passed into this callback is the data
* that was supplied to the event_command @reg() function that
* registered the trigger (see struct event_command) along with
@@ -1651,9 +1661,10 @@ extern int register_trigger_hist_enable_disable_cmds(void);
* (see trace_event_triggers.c).
*/
struct event_trigger_ops {
- void (*func)(struct event_trigger_data *data,
- struct trace_buffer *buffer, void *rec,
- struct ring_buffer_event *rbe);
+ void (*trigger)(struct event_trigger_data *data,
+ struct trace_buffer *buffer,
+ void *rec,
+ struct ring_buffer_event *rbe);
int (*init)(struct event_trigger_ops *ops,
struct event_trigger_data *data);
void (*free)(struct event_trigger_ops *ops,
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 84d5bfa34a99..6d363fd8a1e4 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -543,7 +543,7 @@ static void eprobe_trigger_func(struct event_trigger_data *data,
}
static struct event_trigger_ops eprobe_trigger_ops = {
- .func = eprobe_trigger_func,
+ .trigger = eprobe_trigger_func,
.print = eprobe_trigger_print,
.init = eprobe_trigger_init,
.free = eprobe_trigger_free,
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 89bbbbd3a3f5..229ce5c2dfd3 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -5759,7 +5759,7 @@ static void event_hist_trigger_free(struct event_trigger_ops *ops,
}
static struct event_trigger_ops event_hist_trigger_ops = {
- .func = event_hist_trigger,
+ .trigger = event_hist_trigger,
.print = event_hist_trigger_print,
.init = event_hist_trigger_init,
.free = event_hist_trigger_free,
@@ -5793,7 +5793,7 @@ static void event_hist_trigger_named_free(struct event_trigger_ops *ops,
}
static struct event_trigger_ops event_hist_trigger_named_ops = {
- .func = event_hist_trigger,
+ .trigger = event_hist_trigger,
.print = event_hist_trigger_print,
.init = event_hist_trigger_named_init,
.free = event_hist_trigger_named_free,
@@ -6383,28 +6383,28 @@ hist_enable_count_trigger(struct event_trigger_data *data,
}
static struct event_trigger_ops hist_enable_trigger_ops = {
- .func = hist_enable_trigger,
+ .trigger = hist_enable_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops hist_enable_count_trigger_ops = {
- .func = hist_enable_count_trigger,
+ .trigger = hist_enable_count_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops hist_disable_trigger_ops = {
- .func = hist_enable_trigger,
+ .trigger = hist_enable_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops hist_disable_count_trigger_ops = {
- .func = hist_enable_count_trigger,
+ .trigger = hist_enable_count_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 15aae07cbe61..24aceeb50dc0 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -68,7 +68,7 @@ event_triggers_call(struct trace_event_file *file,
if (data->paused)
continue;
if (!rec) {
- data->ops->func(data, buffer, rec, event);
+ data->ops->trigger(data, buffer, rec, event);
continue;
}
filter = rcu_dereference_sched(data->filter);
@@ -78,7 +78,7 @@ event_triggers_call(struct trace_event_file *file,
tt |= data->cmd_ops->trigger_type;
continue;
}
- data->ops->func(data, buffer, rec, event);
+ data->ops->trigger(data, buffer, rec, event);
}
return tt;
}
@@ -106,7 +106,7 @@ event_triggers_post_call(struct trace_event_file *file,
if (data->paused)
continue;
if (data->cmd_ops->trigger_type & tt)
- data->ops->func(data, NULL, NULL, NULL);
+ data->ops->trigger(data, NULL, NULL, NULL);
}
}
EXPORT_SYMBOL_GPL(event_triggers_post_call);
@@ -1023,28 +1023,28 @@ traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
}
static struct event_trigger_ops traceon_trigger_ops = {
- .func = traceon_trigger,
+ .trigger = traceon_trigger,
.print = traceon_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops traceon_count_trigger_ops = {
- .func = traceon_count_trigger,
+ .trigger = traceon_count_trigger,
.print = traceon_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops traceoff_trigger_ops = {
- .func = traceoff_trigger,
+ .trigger = traceoff_trigger,
.print = traceoff_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops traceoff_count_trigger_ops = {
- .func = traceoff_count_trigger,
+ .trigger = traceoff_count_trigger,
.print = traceoff_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
@@ -1135,14 +1135,14 @@ snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
}
static struct event_trigger_ops snapshot_trigger_ops = {
- .func = snapshot_trigger,
+ .trigger = snapshot_trigger,
.print = snapshot_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops snapshot_count_trigger_ops = {
- .func = snapshot_count_trigger,
+ .trigger = snapshot_count_trigger,
.print = snapshot_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
@@ -1226,14 +1226,14 @@ stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
}
static struct event_trigger_ops stacktrace_trigger_ops = {
- .func = stacktrace_trigger,
+ .trigger = stacktrace_trigger,
.print = stacktrace_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
};
static struct event_trigger_ops stacktrace_count_trigger_ops = {
- .func = stacktrace_count_trigger,
+ .trigger = stacktrace_count_trigger,
.print = stacktrace_trigger_print,
.init = event_trigger_init,
.free = event_trigger_free,
@@ -1353,28 +1353,28 @@ void event_enable_trigger_free(struct event_trigger_ops *ops,
}
static struct event_trigger_ops event_enable_trigger_ops = {
- .func = event_enable_trigger,
+ .trigger = event_enable_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops event_enable_count_trigger_ops = {
- .func = event_enable_count_trigger,
+ .trigger = event_enable_count_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops event_disable_trigger_ops = {
- .func = event_enable_trigger,
+ .trigger = event_enable_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
};
static struct event_trigger_ops event_disable_count_trigger_ops = {
- .func = event_enable_count_trigger,
+ .trigger = event_enable_count_trigger,
.print = event_enable_trigger_print,
.init = event_trigger_init,
.free = event_enable_trigger_free,
--
2.17.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v4 3/4] tracing: Add helper functions to simplify event_command.parse() callback handling
2021-12-10 21:16 [PATCH v4 0/4] tracing: Add and use event_command parsing func helpers Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 1/4] tracing: Change event_command func() to parse() Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 2/4] tracing: Change event_trigger_ops func() to trigger() Tom Zanussi
@ 2021-12-10 21:16 ` Tom Zanussi
2021-12-13 13:46 ` Masami Hiramatsu
2021-12-10 21:16 ` [PATCH v4 4/4] tracing: Have existing event_command.parse() implementations use helpers Tom Zanussi
3 siblings, 1 reply; 7+ messages in thread
From: Tom Zanussi @ 2021-12-10 21:16 UTC (permalink / raw)
To: rostedt; +Cc: mhiramat, linux-kernel
The event_command.parse() callback is responsible for parsing and
registering triggers. The existing command implementions for this
callback duplicate a lot of the same code, so to clean up and
consolidate those implementations, introduce a handful of helper
functions for implementors to use.
This also makes it easier for new commands to be implemented and
allows them to focus more on the customizations they provide rather
than obscuring and complicating it with boilerplate code.
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
---
kernel/trace/trace.h | 24 ++
kernel/trace/trace_events_trigger.c | 344 ++++++++++++++++++++++++++++
2 files changed, 368 insertions(+)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 1a73659222d4..440afe2ab763 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1612,6 +1612,30 @@ get_named_trigger_data(struct event_trigger_data *data);
extern int register_event_command(struct event_command *cmd);
extern int unregister_event_command(struct event_command *cmd);
extern int register_trigger_hist_enable_disable_cmds(void);
+extern bool event_trigger_check_remove(const char *glob);
+extern bool event_trigger_empty_param(const char *param);
+extern int event_trigger_separate_filter(char *param_and_filter, char **param,
+ char **filter, bool param_required);
+extern struct event_trigger_data *
+event_trigger_alloc(struct event_command *cmd_ops,
+ char *cmd,
+ char *param,
+ void *private_data);
+extern int event_trigger_parse_num(char *trigger,
+ struct event_trigger_data *trigger_data);
+extern int event_trigger_set_filter(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *param,
+ struct event_trigger_data *trigger_data);
+extern void event_trigger_reset_filter(struct event_command *cmd_ops,
+ struct event_trigger_data *trigger_data);
+extern int event_trigger_register(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob,
+ char *cmd,
+ char *trigger,
+ struct event_trigger_data *trigger_data,
+ int *n_registered);
/**
* struct event_trigger_ops - callbacks for trace event triggers
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 24aceeb50dc0..69afae171b21 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -621,6 +621,350 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
data->ops->free(data->ops, data);
}
+/*
+ * Event trigger parsing helper functions.
+ *
+ * These functions help make it easier to write an event trigger
+ * parsing function i.e. the struct event_command.parse() callback
+ * function responsible for parsing and registering a trigger command
+ * written to the 'trigger' file.
+ *
+ * A trigger command (or just 'trigger' for short) takes the form:
+ * [trigger] [if filter]
+ *
+ * The struct event_command.parse() callback (and other struct
+ * event_command functions) refer to several components of a trigger
+ * command. Those same components are referenced by the event trigger
+ * parsing helper functions defined below. These components are:
+ *
+ * cmd - the trigger command name
+ * glob - the trigger command name optionally prefaced with '!'
+ * param - text remaining after the command is stripped of cmd and ':'
+ * filter - the optional filter text following (and including) 'if'
+ *
+ * To illustrate the use of these componenents, here are some concrete
+ * examples. For the following triggers:
+ *
+ * echo 'traceon:5 if pid == 0' > trigger
+ * - 'traceon' is both cmd and glob
+ * - '5 if pid == 0' is the param
+ * - 'if pid == 0' is the filter
+ *
+ * echo 'enable_event:sys:event:n' > trigger
+ * - 'enable_event' is both cmd and glob
+ * - 'sys:event:n' is the param
+ * - there is no filter
+ *
+ * echo 'hist:keys=pid if prio > 50' > trigger
+ * - 'hist' is both cmd and glob
+ * - 'keys=pid if prio > 50' is the param
+ * - 'if prio > 50' is the filter
+ *
+ * echo '!enable_event:sys:event:n' > trigger
+ * - 'enable_event' the cmd
+ * - '!enable_event' is the glob
+ * - 'sys:event:n' is the param
+ * - there is no filter
+ *
+ * echo 'traceoff' > trigger
+ * - 'traceoff' is both cmd and glob
+ * - there is no param
+ * - there is no filter
+ *
+ * There are a few different categories of event trigger covered by
+ * these helpers:
+ *
+ * - triggers that don't require a parameter e.g. traceon
+ * - triggers that do require a parameter e.g. enable_event and hist
+ * - triggers that though they may not require a param may support an
+ * optional 'n' param (n = number of times the trigger should fire)
+ * e.g.: traceon:5 or enable_event:sys:event:n
+ * - triggers that do not support an 'n' param e.g. hist
+ *
+ * These functions can be used or ignored as necessary - it all
+ * depends on the complexity of the trigger, and the granularity of
+ * the functions supported reflects the fact that some implementations
+ * may need to customize certain aspects of their implementations and
+ * won't need certain functions. For instance, the hist trigger
+ * implementation doesn't use event_trigger_separate_filter() because
+ * it has special requirements for handling the filter.
+ */
+
+/**
+ * event_trigger_check_remove - check whether an event trigger specifies remove
+ * @glob: The trigger command string, with optional remove(!) operator
+ *
+ * The event trigger callback implementations pass in 'glob' as a
+ * parameter. This is the command name either with or without a
+ * remove(!) operator. This function simply parses the glob and
+ * determines whether the command corresponds to a trigger removal or
+ * a trigger addition.
+ *
+ * Return: true if this is a remove command, false otherwise
+ */
+bool event_trigger_check_remove(const char *glob)
+{
+ return (glob && glob[0] == '!') ? true : false;
+}
+
+/**
+ * event_trigger_empty_param - check whether the param is empty
+ * @param: The trigger param string
+ *
+ * The event trigger callback implementations pass in 'param' as a
+ * parameter. This corresponds to the string following the command
+ * name minus the command name. This function can be called by a
+ * callback implementation for any command that requires a param; a
+ * callback that doesn't require a param can ignore it.
+ *
+ * Return: true if this is an empty param, false otherwise
+ */
+bool event_trigger_empty_param(const char *param)
+{
+ return !param;
+}
+
+/**
+ * event_trigger_separate_filter - separate an event trigger from a filter
+ * @param: The param string containing trigger and possibly filter
+ * @trigger: outparam, will be filled with a pointer to the trigger
+ * @filter: outparam, will be filled with a pointer to the filter
+ * @param_required: Specifies whether or not the param string is required
+ *
+ * Given a param string of the form '[trigger] [if filter]', this
+ * function separates the filter from the trigger and returns the
+ * trigger in *trigger and the filter in *filter. Either the *trigger
+ * or the *filter may be set to NULL by this function - if not set to
+ * NULL, they will contain strings corresponding to the trigger and
+ * filter.
+ *
+ * There are two cases that need to be handled with respect to the
+ * passed-in param: either the param is required, or it is not
+ * required. If @param_required is set, and there's no param, it will
+ * return -EINVAL. If @param_required is not set and there's a param
+ * that starts with a number, that corresponds to the case of a
+ * trigger with :n (n = number of times the trigger should fire) and
+ * the parsing continues normally; otherwise the function just returns
+ * and assumes param just contains a filter and there's nothing else
+ * to do.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_separate_filter(char *param_and_filter, char **param,
+ char **filter, bool param_required)
+{
+ int ret = 0;
+
+ *param = *filter = NULL;
+
+ if (!param_and_filter) {
+ if (param_required)
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Here we check for an optional param. The only legal
+ * optional param is :n, and if that's the case, continue
+ * below. Otherwise we assume what's left is a filter and
+ * return it as the filter string for the caller to deal with.
+ */
+ if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
+ *filter = param_and_filter;
+ goto out;
+ }
+
+ /*
+ * Separate the param from the filter (param [if filter]).
+ * Here we have either an optional :n param or a required
+ * param and an optional filter.
+ */
+ *param = strsep(¶m_and_filter, " \t");
+ if (!*param) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Here we have a filter, though it may be empty.
+ */
+ if (param_and_filter) {
+ *filter = skip_spaces(param_and_filter);
+ if (!**filter)
+ *filter = NULL;
+ }
+out:
+ return ret;
+}
+
+/**
+ * event_trigger_alloc - allocate and init event_trigger_data for a trigger
+ * @cmd_ops: The event_command operations for the trigger
+ * @cmd: The cmd string
+ * @param: The param string
+ * @private_data: User data to associate with the event trigger
+ *
+ * Allocate an event_trigger_data instance and initialize it. The
+ * @cmd_ops are used along with the @cmd and @param to get the
+ * trigger_ops to assign to the event_trigger_data. @private_data can
+ * also be passed in and associated with the event_trigger_data.
+ *
+ * Use event_trigger_free() to free an event_trigger_data object.
+ *
+ * Return: The trigger_data object success, NULL otherwise
+ */
+struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
+ char *cmd,
+ char *param,
+ void *private_data)
+{
+ struct event_trigger_data *trigger_data;
+ struct event_trigger_ops *trigger_ops;
+
+ trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
+
+ trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
+ if (!trigger_data)
+ return NULL;
+
+ trigger_data->count = -1;
+ trigger_data->ops = trigger_ops;
+ trigger_data->cmd_ops = cmd_ops;
+ trigger_data->private_data = private_data;
+
+ INIT_LIST_HEAD(&trigger_data->list);
+ INIT_LIST_HEAD(&trigger_data->named_list);
+ RCU_INIT_POINTER(trigger_data->filter, NULL);
+
+ return trigger_data;
+}
+
+/**
+ * event_trigger_parse_num - parse and return the number param for a trigger
+ * @trigger: The trigger string
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Parse the :n (n = number of times the trigger should fire) param
+ * and set the count variable in the trigger_data to the parsed count.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_parse_num(char *trigger,
+ struct event_trigger_data *trigger_data)
+{
+ char *number;
+ int ret = 0;
+
+ if (trigger) {
+ number = strsep(&trigger, ":");
+
+ if (!strlen(number))
+ return -EINVAL;
+
+ /*
+ * We use the callback data field (which is a pointer)
+ * as our counter.
+ */
+ ret = kstrtoul(number, 0, &trigger_data->count);
+ }
+
+ return ret;
+}
+
+/**
+ * event_trigger_set_filter - set an event trigger's filter
+ * @cmd_ops: The event_command operations for the trigger
+ * @file: The event file for the trigger's event
+ * @param: The string containing the filter
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Set the filter for the trigger. If the filter is NULL, just return
+ * without error.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_set_filter(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *param,
+ struct event_trigger_data *trigger_data)
+{
+ if (param && cmd_ops->set_filter)
+ return cmd_ops->set_filter(param, trigger_data, file);
+
+ return 0;
+}
+
+/**
+ * event_trigger_reset_filter - reset an event trigger's filter
+ * @cmd_ops: The event_command operations for the trigger
+ * @trigger_data: The trigger_data for the trigger
+ *
+ * Reset the filter for the trigger to no filter.
+ */
+void event_trigger_reset_filter(struct event_command *cmd_ops,
+ struct event_trigger_data *trigger_data)
+{
+ if (cmd_ops->set_filter)
+ cmd_ops->set_filter(NULL, trigger_data, NULL);
+}
+
+/**
+ * event_trigger_register - register an event trigger
+ * @cmd_ops: The event_command operations for the trigger
+ * @file: The event file for the trigger's event
+ * @glob: The trigger command string, with optional remove(!) operator
+ * @cmd: The cmd string
+ * @param: The param string
+ * @trigger_data: The trigger_data for the trigger
+ * @n_registered: optional outparam, the number of triggers registered
+ *
+ * Register an event trigger. The @cmd_ops are used along with the
+ * @cmd and @param to get the trigger_ops to pass to the
+ * cmd_ops->reg() function which actually does the registration. The
+ * cmd_ops->reg() function returns the number of triggers registered,
+ * which is assigned to n_registered, if n_registered is non-NULL.
+ *
+ * Return: 0 on success, errno otherwise
+ */
+int event_trigger_register(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob,
+ char *cmd,
+ char *param,
+ struct event_trigger_data *trigger_data,
+ int *n_registered)
+{
+ struct event_trigger_ops *trigger_ops;
+ int ret;
+
+ if (n_registered)
+ *n_registered = 0;
+
+ trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
+
+ ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
+ /*
+ * The above returns on success the # of functions enabled,
+ * but if it didn't find any functions it returns zero.
+ * Consider no functions a failure too.
+ */
+ if (!ret) {
+ cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
+ ret = -ENOENT;
+ } else if (ret > 0) {
+ if (n_registered)
+ *n_registered = ret;
+ /* Just return zero, not the number of enabled functions */
+ ret = 0;
+ }
+
+ return ret;
+}
+
+/*
+ * End event trigger parsing helper functions.
+ */
+
/**
* event_trigger_parse - Generic event_command @parse implementation
* @cmd_ops: The command ops, used for trigger registration
--
2.17.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v4 4/4] tracing: Have existing event_command.parse() implementations use helpers
2021-12-10 21:16 [PATCH v4 0/4] tracing: Add and use event_command parsing func helpers Tom Zanussi
` (2 preceding siblings ...)
2021-12-10 21:16 ` [PATCH v4 3/4] tracing: Add helper functions to simplify event_command.parse() callback handling Tom Zanussi
@ 2021-12-10 21:16 ` Tom Zanussi
3 siblings, 0 replies; 7+ messages in thread
From: Tom Zanussi @ 2021-12-10 21:16 UTC (permalink / raw)
To: rostedt; +Cc: mhiramat, linux-kernel
Simplify the existing event_command.parse() implementations by having
them make use of the helper functions previously introduced.
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
---
kernel/trace/trace.h | 3 +-
kernel/trace/trace_eprobe.c | 3 +-
kernel/trace/trace_events_hist.c | 75 +++++-------
kernel/trace/trace_events_trigger.c | 176 ++++++++--------------------
4 files changed, 81 insertions(+), 176 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 440afe2ab763..9387ea2759a5 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1580,7 +1580,8 @@ extern void event_enable_trigger_free(struct event_trigger_ops *ops,
struct event_trigger_data *data);
extern int event_enable_trigger_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
- char *glob, char *cmd, char *param);
+ char *glob, char *cmd,
+ char *param_and_filter);
extern int event_enable_register_trigger(char *glob,
struct event_trigger_ops *ops,
struct event_trigger_data *data,
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 6d363fd8a1e4..78f14ff6b99c 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -551,7 +551,8 @@ static struct event_trigger_ops eprobe_trigger_ops = {
static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+ char *glob, char *cmd,
+ char *param_and_filter)
{
return -1;
}
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 229ce5c2dfd3..e810a10ef8b7 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2763,7 +2763,8 @@ static char *find_trigger_filter(struct hist_trigger_data *hist_data,
static struct event_command trigger_hist_cmd;
static int event_hist_trigger_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
- char *glob, char *cmd, char *param);
+ char *glob, char *cmd,
+ char *param_and_filter);
static bool compatible_keys(struct hist_trigger_data *target_hist_data,
struct hist_trigger_data *hist_data,
@@ -6148,48 +6149,49 @@ static void hist_unreg_all(struct trace_event_file *file)
static int event_hist_trigger_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+ char *glob, char *cmd,
+ char *param_and_filter)
{
unsigned int hist_trigger_bits = TRACING_MAP_BITS_DEFAULT;
struct event_trigger_data *trigger_data;
struct hist_trigger_attrs *attrs;
struct event_trigger_ops *trigger_ops;
struct hist_trigger_data *hist_data;
+ char *param, *filter, *p, *start;
struct synth_event *se;
const char *se_name;
- bool remove = false;
- char *trigger, *p, *start;
+ int n_registered;
+ bool remove;
int ret = 0;
lockdep_assert_held(&event_mutex);
if (glob && strlen(glob)) {
hist_err_clear();
- last_cmd_set(file, param);
+ last_cmd_set(file, param_and_filter);
}
- if (!param)
- return -EINVAL;
+ remove = event_trigger_check_remove(glob);
- if (glob[0] == '!')
- remove = true;
+ if (event_trigger_empty_param(param_and_filter))
+ return -EINVAL;
/*
* separate the trigger from the filter (k:v [if filter])
* allowing for whitespace in the trigger
*/
- p = trigger = param;
+ p = param = param_and_filter;
do {
p = strstr(p, "if");
if (!p)
break;
- if (p == param)
+ if (p == param_and_filter)
return -EINVAL;
if (*(p - 1) != ' ' && *(p - 1) != '\t') {
p++;
continue;
}
- if (p >= param + strlen(param) - (sizeof("if") - 1) - 1)
+ if (p >= param_and_filter + strlen(param_and_filter) - (sizeof("if") - 1) - 1)
return -EINVAL;
if (*(p + sizeof("if") - 1) != ' ' && *(p + sizeof("if") - 1) != '\t') {
p++;
@@ -6199,24 +6201,24 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
} while (p);
if (!p)
- param = NULL;
+ filter = NULL;
else {
*(p - 1) = '\0';
- param = strstrip(p);
- trigger = strstrip(trigger);
+ filter = strstrip(p);
+ param = strstrip(param);
}
/*
* To simplify arithmetic expression parsing, replace occurrences of
* '.sym-offset' modifier with '.symXoffset'
*/
- start = strstr(trigger, ".sym-offset");
+ start = strstr(param, ".sym-offset");
while (start) {
*(start + 4) = 'X';
start = strstr(start + 11, ".sym-offset");
}
- attrs = parse_hist_trigger_attrs(file->tr, trigger);
+ attrs = parse_hist_trigger_attrs(file->tr, param);
if (IS_ERR(attrs))
return PTR_ERR(attrs);
@@ -6229,29 +6231,15 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
return PTR_ERR(hist_data);
}
- trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
-
- trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
+ trigger_data = event_trigger_alloc(cmd_ops, cmd, param, hist_data);
if (!trigger_data) {
ret = -ENOMEM;
goto out_free;
}
- trigger_data->count = -1;
- trigger_data->ops = trigger_ops;
- trigger_data->cmd_ops = cmd_ops;
-
- INIT_LIST_HEAD(&trigger_data->list);
- RCU_INIT_POINTER(trigger_data->filter, NULL);
-
- trigger_data->private_data = hist_data;
-
- /* if param is non-empty, it's supposed to be a filter */
- if (param && cmd_ops->set_filter) {
- ret = cmd_ops->set_filter(param, trigger_data, file);
- if (ret < 0)
- goto out_free;
- }
+ ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
+ if (ret < 0)
+ goto out_free;
if (remove) {
if (!have_hist_trigger_match(trigger_data, file))
@@ -6271,18 +6259,14 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
goto out_free;
}
- ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
- /*
- * The above returns on success the # of triggers registered,
- * but if it didn't register any it returns zero. Consider no
- * triggers registered a failure too.
- */
- if (!ret) {
+ ret = event_trigger_register(cmd_ops, file, glob, cmd, param, trigger_data, &n_registered);
+ if (ret)
+ goto out_free;
+ if ((ret == 0) && (n_registered == 0)) {
if (!(attrs->pause || attrs->cont || attrs->clear))
ret = -ENOENT;
goto out_free;
- } else if (ret < 0)
- goto out_free;
+ }
if (get_named_trigger_data(trigger_data))
goto enable;
@@ -6316,8 +6300,7 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
out_unreg:
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
out_free:
- if (cmd_ops->set_filter)
- cmd_ops->set_filter(NULL, trigger_data, NULL);
+ event_trigger_reset_filter(cmd_ops, trigger_data);
remove_hist_vars(hist_data);
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 69afae171b21..adcef09557af 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -971,7 +971,7 @@ int event_trigger_register(struct event_command *cmd_ops,
* @file: The trace_event_file associated with the event
* @glob: The raw string used to register the trigger
* @cmd: The cmd portion of the string used to register the trigger
- * @param: The params portion of the string used to register the trigger
+ * @param_and_filter: The param and filter portion of the string used to register the trigger
*
* Common implementation for event command parsing and trigger
* instantiation.
@@ -984,94 +984,53 @@ int event_trigger_register(struct event_command *cmd_ops,
static int
event_trigger_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+ char *glob, char *cmd, char *param_and_filter)
{
struct event_trigger_data *trigger_data;
struct event_trigger_ops *trigger_ops;
- char *trigger = NULL;
- char *number;
+ char *param, *filter;
+ bool remove;
int ret;
- /* separate the trigger from the filter (t:n [if filter]) */
- if (param && isdigit(param[0])) {
- trigger = strsep(¶m, " \t");
- if (param) {
- param = skip_spaces(param);
- if (!*param)
- param = NULL;
- }
- }
+ remove = event_trigger_check_remove(glob);
- trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
+ ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, false);
+ if (ret)
+ return ret;
ret = -ENOMEM;
- trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
+ trigger_data = event_trigger_alloc(cmd_ops, cmd, param, file);
if (!trigger_data)
goto out;
- trigger_data->count = -1;
- trigger_data->ops = trigger_ops;
- trigger_data->cmd_ops = cmd_ops;
- trigger_data->private_data = file;
- INIT_LIST_HEAD(&trigger_data->list);
- INIT_LIST_HEAD(&trigger_data->named_list);
-
- if (glob[0] == '!') {
+ if (remove) {
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
kfree(trigger_data);
ret = 0;
goto out;
}
- if (trigger) {
- number = strsep(&trigger, ":");
-
- ret = -EINVAL;
- if (!strlen(number))
- goto out_free;
-
- /*
- * We use the callback data field (which is a pointer)
- * as our counter.
- */
- ret = kstrtoul(number, 0, &trigger_data->count);
- if (ret)
- goto out_free;
- }
-
- if (!param) /* if param is non-empty, it's supposed to be a filter */
- goto out_reg;
-
- if (!cmd_ops->set_filter)
- goto out_reg;
+ ret = event_trigger_parse_num(param, trigger_data);
+ if (ret)
+ goto out_free;
- ret = cmd_ops->set_filter(param, trigger_data, file);
+ ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
if (ret < 0)
goto out_free;
- out_reg:
/* Up the trigger_data count to make sure reg doesn't free it on failure */
event_trigger_init(trigger_ops, trigger_data);
- ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
- /*
- * The above returns on success the # of functions enabled,
- * but if it didn't find any functions it returns zero.
- * Consider no functions a failure too.
- */
- if (!ret) {
- cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
- ret = -ENOENT;
- } else if (ret > 0)
- ret = 0;
+
+ ret = event_trigger_register(cmd_ops, file, glob, cmd, param, trigger_data, NULL);
+ if (ret)
+ goto out_free;
/* Down the counter of trigger_data or free it if not used anymore */
event_trigger_free(trigger_ops, trigger_data);
out:
return ret;
-
out_free:
- if (cmd_ops->set_filter)
- cmd_ops->set_filter(NULL, trigger_data, NULL);
+ event_trigger_reset_filter(cmd_ops, trigger_data);
kfree(trigger_data);
goto out;
}
@@ -1726,39 +1685,34 @@ static struct event_trigger_ops event_disable_count_trigger_ops = {
int event_enable_trigger_parse(struct event_command *cmd_ops,
struct trace_event_file *file,
- char *glob, char *cmd, char *param)
+ char *glob, char *cmd, char *param_and_filter)
{
struct trace_event_file *event_enable_file;
struct enable_trigger_data *enable_data;
struct event_trigger_data *trigger_data;
struct event_trigger_ops *trigger_ops;
struct trace_array *tr = file->tr;
+ char *param, *filter;
+ bool enable, remove;
const char *system;
const char *event;
bool hist = false;
- char *trigger;
- char *number;
- bool enable;
int ret;
- if (!param)
- return -EINVAL;
+ remove = event_trigger_check_remove(glob);
- /* separate the trigger from the filter (s:e:n [if filter]) */
- trigger = strsep(¶m, " \t");
- if (!trigger)
+ if (event_trigger_empty_param(param_and_filter))
return -EINVAL;
- if (param) {
- param = skip_spaces(param);
- if (!*param)
- param = NULL;
- }
- system = strsep(&trigger, ":");
- if (!trigger)
+ ret = event_trigger_separate_filter(param_and_filter, ¶m, &filter, true);
+ if (ret)
+ return ret;
+
+ system = strsep(¶m, ":");
+ if (!param)
return -EINVAL;
- event = strsep(&trigger, ":");
+ event = strsep(¶m, ":");
ret = -EINVAL;
event_enable_file = find_event_file(tr, system, event);
@@ -1774,31 +1728,26 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
#else
enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
#endif
- trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
+ trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
ret = -ENOMEM;
- trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
- if (!trigger_data)
- goto out;
-
enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
if (!enable_data) {
kfree(trigger_data);
goto out;
}
- trigger_data->count = -1;
- trigger_data->ops = trigger_ops;
- trigger_data->cmd_ops = cmd_ops;
- INIT_LIST_HEAD(&trigger_data->list);
- RCU_INIT_POINTER(trigger_data->filter, NULL);
-
enable_data->hist = hist;
enable_data->enable = enable;
enable_data->file = event_enable_file;
- trigger_data->private_data = enable_data;
- if (glob[0] == '!') {
+ trigger_data = event_trigger_alloc(cmd_ops, cmd, param, enable_data);
+ if (!trigger_data) {
+ kfree(enable_data);
+ goto out;
+ }
+
+ if (remove) {
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
kfree(trigger_data);
kfree(enable_data);
@@ -1809,33 +1758,14 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
/* Up the trigger_data count to make sure nothing frees it on failure */
event_trigger_init(trigger_ops, trigger_data);
- if (trigger) {
- number = strsep(&trigger, ":");
-
- ret = -EINVAL;
- if (!strlen(number))
- goto out_free;
-
- /*
- * We use the callback data field (which is a pointer)
- * as our counter.
- */
- ret = kstrtoul(number, 0, &trigger_data->count);
- if (ret)
- goto out_free;
- }
-
- if (!param) /* if param is non-empty, it's supposed to be a filter */
- goto out_reg;
-
- if (!cmd_ops->set_filter)
- goto out_reg;
+ ret = event_trigger_parse_num(param, trigger_data);
+ if (ret)
+ goto out_free;
- ret = cmd_ops->set_filter(param, trigger_data, file);
+ ret = event_trigger_set_filter(cmd_ops, file, filter, trigger_data);
if (ret < 0)
goto out_free;
- out_reg:
/* Don't let event modules unload while probe registered */
ret = trace_event_try_get_ref(event_enable_file->event_call);
if (!ret) {
@@ -1846,30 +1776,20 @@ int event_enable_trigger_parse(struct event_command *cmd_ops,
ret = trace_event_enable_disable(event_enable_file, 1, 1);
if (ret < 0)
goto out_put;
- ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
- /*
- * The above returns on success the # of functions enabled,
- * but if it didn't find any functions it returns zero.
- * Consider no functions a failure too.
- */
- if (!ret) {
- ret = -ENOENT;
- goto out_disable;
- } else if (ret < 0)
+
+ ret = event_trigger_register(cmd_ops, file, glob, cmd, param, trigger_data, NULL);
+ if (ret)
goto out_disable;
- /* Just return zero, not the number of enabled functions */
- ret = 0;
+
event_trigger_free(trigger_ops, trigger_data);
out:
return ret;
-
out_disable:
trace_event_enable_disable(event_enable_file, 0, 1);
out_put:
trace_event_put_ref(event_enable_file->event_call);
out_free:
- if (cmd_ops->set_filter)
- cmd_ops->set_filter(NULL, trigger_data, NULL);
+ event_trigger_reset_filter(cmd_ops, trigger_data);
event_trigger_free(trigger_ops, trigger_data);
kfree(enable_data);
goto out;
--
2.17.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v4 3/4] tracing: Add helper functions to simplify event_command.parse() callback handling
2021-12-10 21:16 ` [PATCH v4 3/4] tracing: Add helper functions to simplify event_command.parse() callback handling Tom Zanussi
@ 2021-12-13 13:46 ` Masami Hiramatsu
2021-12-13 20:21 ` Tom Zanussi
0 siblings, 1 reply; 7+ messages in thread
From: Masami Hiramatsu @ 2021-12-13 13:46 UTC (permalink / raw)
To: Tom Zanussi; +Cc: rostedt, mhiramat, linux-kernel
Hi Tom,
On Fri, 10 Dec 2021 15:16:24 -0600
Tom Zanussi <zanussi@kernel.org> wrote:
> +/*
> + * Event trigger parsing helper functions.
> + *
> + * These functions help make it easier to write an event trigger
> + * parsing function i.e. the struct event_command.parse() callback
> + * function responsible for parsing and registering a trigger command
> + * written to the 'trigger' file.
> + *
> + * A trigger command (or just 'trigger' for short) takes the form:
> + * [trigger] [if filter]
> + *
> + * The struct event_command.parse() callback (and other struct
> + * event_command functions) refer to several components of a trigger
> + * command. Those same components are referenced by the event trigger
> + * parsing helper functions defined below. These components are:
> + *
> + * cmd - the trigger command name
> + * glob - the trigger command name optionally prefaced with '!'
> + * param - text remaining after the command is stripped of cmd and ':'
> + * filter - the optional filter text following (and including) 'if'
> + *
> + * To illustrate the use of these componenents, here are some concrete
> + * examples. For the following triggers:
> + *
> + * echo 'traceon:5 if pid == 0' > trigger
> + * - 'traceon' is both cmd and glob
> + * - '5 if pid == 0' is the param
> + * - 'if pid == 0' is the filter
I would like to know why both 'param' and 'filter' has "if pid == 0".
I thought that part is (generic) filter and not a parameter.
If I missed any discussion on this point, sorry about that.
> + *
> + * echo 'enable_event:sys:event:n' > trigger
> + * - 'enable_event' is both cmd and glob
> + * - 'sys:event:n' is the param
> + * - there is no filter
> + *
> + * echo 'hist:keys=pid if prio > 50' > trigger
> + * - 'hist' is both cmd and glob
> + * - 'keys=pid if prio > 50' is the param
> + * - 'if prio > 50' is the filter
> + *
> + * echo '!enable_event:sys:event:n' > trigger
> + * - 'enable_event' the cmd
> + * - '!enable_event' is the glob
> + * - 'sys:event:n' is the param
> + * - there is no filter
> + *
> + * echo 'traceoff' > trigger
> + * - 'traceoff' is both cmd and glob
> + * - there is no param
> + * - there is no filter
> + *
> + * There are a few different categories of event trigger covered by
> + * these helpers:
> + *
> + * - triggers that don't require a parameter e.g. traceon
> + * - triggers that do require a parameter e.g. enable_event and hist
> + * - triggers that though they may not require a param may support an
> + * optional 'n' param (n = number of times the trigger should fire)
> + * e.g.: traceon:5 or enable_event:sys:event:n
> + * - triggers that do not support an 'n' param e.g. hist
> + *
> + * These functions can be used or ignored as necessary - it all
> + * depends on the complexity of the trigger, and the granularity of
> + * the functions supported reflects the fact that some implementations
> + * may need to customize certain aspects of their implementations and
> + * won't need certain functions. For instance, the hist trigger
> + * implementation doesn't use event_trigger_separate_filter() because
> + * it has special requirements for handling the filter.
> + */
> +
> +/**
> + * event_trigger_check_remove - check whether an event trigger specifies remove
> + * @glob: The trigger command string, with optional remove(!) operator
> + *
> + * The event trigger callback implementations pass in 'glob' as a
> + * parameter. This is the command name either with or without a
> + * remove(!) operator. This function simply parses the glob and
> + * determines whether the command corresponds to a trigger removal or
> + * a trigger addition.
> + *
> + * Return: true if this is a remove command, false otherwise
> + */
> +bool event_trigger_check_remove(const char *glob)
> +{
> + return (glob && glob[0] == '!') ? true : false;
> +}
> +
> +/**
> + * event_trigger_empty_param - check whether the param is empty
> + * @param: The trigger param string
> + *
> + * The event trigger callback implementations pass in 'param' as a
> + * parameter. This corresponds to the string following the command
> + * name minus the command name. This function can be called by a
> + * callback implementation for any command that requires a param; a
> + * callback that doesn't require a param can ignore it.
> + *
> + * Return: true if this is an empty param, false otherwise
> + */
> +bool event_trigger_empty_param(const char *param)
> +{
> + return !param;
> +}
> +
> +/**
> + * event_trigger_separate_filter - separate an event trigger from a filter
> + * @param: The param string containing trigger and possibly filter
> + * @trigger: outparam, will be filled with a pointer to the trigger
> + * @filter: outparam, will be filled with a pointer to the filter
> + * @param_required: Specifies whether or not the param string is required
> + *
> + * Given a param string of the form '[trigger] [if filter]', this
> + * function separates the filter from the trigger and returns the
> + * trigger in *trigger and the filter in *filter. Either the *trigger
> + * or the *filter may be set to NULL by this function - if not set to
> + * NULL, they will contain strings corresponding to the trigger and
> + * filter.
> + *
> + * There are two cases that need to be handled with respect to the
> + * passed-in param: either the param is required, or it is not
> + * required. If @param_required is set, and there's no param, it will
> + * return -EINVAL. If @param_required is not set and there's a param
> + * that starts with a number, that corresponds to the case of a
> + * trigger with :n (n = number of times the trigger should fire) and
> + * the parsing continues normally; otherwise the function just returns
> + * and assumes param just contains a filter and there's nothing else
> + * to do.
> + *
> + * Return: 0 on success, errno otherwise
> + */
> +int event_trigger_separate_filter(char *param_and_filter, char **param,
> + char **filter, bool param_required)
> +{
> + int ret = 0;
> +
> + *param = *filter = NULL;
> +
> + if (!param_and_filter) {
> + if (param_required)
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + /*
> + * Here we check for an optional param. The only legal
> + * optional param is :n, and if that's the case, continue
> + * below. Otherwise we assume what's left is a filter and
> + * return it as the filter string for the caller to deal with.
> + */
> + if (!param_required && param_and_filter && !isdigit(param_and_filter[0])) {
> + *filter = param_and_filter;
> + goto out;
> + }
> +
> + /*
> + * Separate the param from the filter (param [if filter]).
> + * Here we have either an optional :n param or a required
> + * param and an optional filter.
> + */
> + *param = strsep(¶m_and_filter, " \t");
> + if (!*param) {
> + ret = -EINVAL;
This seems not happen because this means "!param_and_filter" and
that is already checked at the entry of this function.
> + goto out;
> + }
> +
> + /*
> + * Here we have a filter, though it may be empty.
> + */
> + if (param_and_filter) {
> + *filter = skip_spaces(param_and_filter);
> + if (!**filter)
> + *filter = NULL;
> + }
> +out:
> + return ret;
> +}
> +
> +/**
> + * event_trigger_alloc - allocate and init event_trigger_data for a trigger
> + * @cmd_ops: The event_command operations for the trigger
> + * @cmd: The cmd string
> + * @param: The param string
> + * @private_data: User data to associate with the event trigger
> + *
> + * Allocate an event_trigger_data instance and initialize it. The
> + * @cmd_ops are used along with the @cmd and @param to get the
> + * trigger_ops to assign to the event_trigger_data. @private_data can
> + * also be passed in and associated with the event_trigger_data.
> + *
> + * Use event_trigger_free() to free an event_trigger_data object.
> + *
> + * Return: The trigger_data object success, NULL otherwise
> + */
> +struct event_trigger_data *event_trigger_alloc(struct event_command *cmd_ops,
> + char *cmd,
> + char *param,
> + void *private_data)
> +{
> + struct event_trigger_data *trigger_data;
> + struct event_trigger_ops *trigger_ops;
> +
> + trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
> +
> + trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
> + if (!trigger_data)
> + return NULL;
> +
> + trigger_data->count = -1;
> + trigger_data->ops = trigger_ops;
> + trigger_data->cmd_ops = cmd_ops;
> + trigger_data->private_data = private_data;
> +
> + INIT_LIST_HEAD(&trigger_data->list);
> + INIT_LIST_HEAD(&trigger_data->named_list);
> + RCU_INIT_POINTER(trigger_data->filter, NULL);
> +
> + return trigger_data;
> +}
> +
> +/**
> + * event_trigger_parse_num - parse and return the number param for a trigger
> + * @trigger: The trigger string
Does this mean trigger parameter?
> + * @trigger_data: The trigger_data for the trigger
> + *
> + * Parse the :n (n = number of times the trigger should fire) param
> + * and set the count variable in the trigger_data to the parsed count.
> + *
> + * Return: 0 on success, errno otherwise
> + */
> +int event_trigger_parse_num(char *trigger,
> + struct event_trigger_data *trigger_data)
> +{
> + char *number;
> + int ret = 0;
> +
> + if (trigger) {
> + number = strsep(&trigger, ":");
> +
> + if (!strlen(number))
> + return -EINVAL;
> +
> + /*
> + * We use the callback data field (which is a pointer)
> + * as our counter.
> + */
> + ret = kstrtoul(number, 0, &trigger_data->count);
> + }
> +
> + return ret;
> +}
Does this work with '!enable_event:sys:event:n' case?
(we need to find the last parameter.)
Thank you,
--
Masami Hiramatsu <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v4 3/4] tracing: Add helper functions to simplify event_command.parse() callback handling
2021-12-13 13:46 ` Masami Hiramatsu
@ 2021-12-13 20:21 ` Tom Zanussi
0 siblings, 0 replies; 7+ messages in thread
From: Tom Zanussi @ 2021-12-13 20:21 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: rostedt, linux-kernel
Hi Masami,
On Mon, 2021-12-13 at 22:46 +0900, Masami Hiramatsu wrote:
> Hi Tom,
>
> On Fri, 10 Dec 2021 15:16:24 -0600
> Tom Zanussi <zanussi@kernel.org> wrote:
>
> > +/*
> > + * Event trigger parsing helper functions.
> > + *
> > + * These functions help make it easier to write an event trigger
> > + * parsing function i.e. the struct event_command.parse() callback
> > + * function responsible for parsing and registering a trigger
> > command
> > + * written to the 'trigger' file.
> > + *
> > + * A trigger command (or just 'trigger' for short) takes the form:
> > + * [trigger] [if filter]
> > + *
> > + * The struct event_command.parse() callback (and other struct
> > + * event_command functions) refer to several components of a
> > trigger
> > + * command. Those same components are referenced by the event
> > trigger
> > + * parsing helper functions defined below. These components are:
> > + *
> > + * cmd - the trigger command name
> > + * glob - the trigger command name optionally prefaced with
> > '!'
> > + * param - text remaining after the command is stripped of cmd
> > and ':'
> > + * filter - the optional filter text following (and including)
> > 'if'
> > + *
> > + * To illustrate the use of these componenents, here are some
> > concrete
> > + * examples. For the following triggers:
> > + *
> > + * echo 'traceon:5 if pid == 0' > trigger
> > + * - 'traceon' is both cmd and glob
> > + * - '5 if pid == 0' is the param
> > + * - 'if pid == 0' is the filter
>
> I would like to know why both 'param' and 'filter' has "if pid == 0".
> I thought that part is (generic) filter and not a parameter.
>
> If I missed any discussion on this point, sorry about that.
No discussion about this in particular, but from Steve's review I did
change 'param' to 'param_and_filter' in the code. So I guess I should
change these to strip the filter from the param when describing them,
and then it's obvious that param_and_filter refers to the combination.
I'll change that in the next version.
>
> > + *
> > + * echo 'enable_event:sys:event:n' > trigger
> > + * - 'enable_event' is both cmd and glob
> > + * - 'sys:event:n' is the param
> > + * - there is no filter
> > + *
> > + * echo 'hist:keys=pid if prio > 50' > trigger
> > + * - 'hist' is both cmd and glob
> > + * - 'keys=pid if prio > 50' is the param
> > + * - 'if prio > 50' is the filter
> > + *
> > + * echo '!enable_event:sys:event:n' > trigger
> > + * - 'enable_event' the cmd
> > + * - '!enable_event' is the glob
> > + * - 'sys:event:n' is the param
> > + * - there is no filter
> > + *
> > + * echo 'traceoff' > trigger
> > + * - 'traceoff' is both cmd and glob
> > + * - there is no param
> > + * - there is no filter
> > + *
> > + * There are a few different categories of event trigger covered
> > by
> > + * these helpers:
> > + *
> > + * - triggers that don't require a parameter e.g. traceon
> > + * - triggers that do require a parameter e.g. enable_event and
> > hist
> > + * - triggers that though they may not require a param may
> > support an
> > + * optional 'n' param (n = number of times the trigger should
> > fire)
> > + * e.g.: traceon:5 or enable_event:sys:event:n
> > + * - triggers that do not support an 'n' param e.g. hist
> > + *
> > + * These functions can be used or ignored as necessary - it all
> > + * depends on the complexity of the trigger, and the granularity
> > of
> > + * the functions supported reflects the fact that some
> > implementations
> > + * may need to customize certain aspects of their implementations
> > and
> > + * won't need certain functions. For instance, the hist trigger
> > + * implementation doesn't use event_trigger_separate_filter()
> > because
> > + * it has special requirements for handling the filter.
> > + */
> > +
> > +/**
> > + * event_trigger_check_remove - check whether an event trigger
> > specifies remove
> > + * @glob: The trigger command string, with optional remove(!)
> > operator
> > + *
> > + * The event trigger callback implementations pass in 'glob' as a
> > + * parameter. This is the command name either with or without a
> > + * remove(!) operator. This function simply parses the glob and
> > + * determines whether the command corresponds to a trigger removal
> > or
> > + * a trigger addition.
> > + *
> > + * Return: true if this is a remove command, false otherwise
> > + */
> > +bool event_trigger_check_remove(const char *glob)
> > +{
> > + return (glob && glob[0] == '!') ? true : false;
> > +}
> > +
> > +/**
> > + * event_trigger_empty_param - check whether the param is empty
> > + * @param: The trigger param string
> > + *
> > + * The event trigger callback implementations pass in 'param' as a
> > + * parameter. This corresponds to the string following the
> > command
> > + * name minus the command name. This function can be called by a
> > + * callback implementation for any command that requires a param;
> > a
> > + * callback that doesn't require a param can ignore it.
> > + *
> > + * Return: true if this is an empty param, false otherwise
> > + */
> > +bool event_trigger_empty_param(const char *param)
> > +{
> > + return !param;
> > +}
> > +
> > +/**
> > + * event_trigger_separate_filter - separate an event trigger from
> > a filter
> > + * @param: The param string containing trigger and possibly filter
> > + * @trigger: outparam, will be filled with a pointer to the
> > trigger
> > + * @filter: outparam, will be filled with a pointer to the filter
> > + * @param_required: Specifies whether or not the param string is
> > required
> > + *
> > + * Given a param string of the form '[trigger] [if filter]', this
> > + * function separates the filter from the trigger and returns the
> > + * trigger in *trigger and the filter in *filter. Either the
> > *trigger
> > + * or the *filter may be set to NULL by this function - if not set
> > to
> > + * NULL, they will contain strings corresponding to the trigger
> > and
> > + * filter.
> > + *
> > + * There are two cases that need to be handled with respect to the
> > + * passed-in param: either the param is required, or it is not
> > + * required. If @param_required is set, and there's no param, it
> > will
> > + * return -EINVAL. If @param_required is not set and there's a
> > param
> > + * that starts with a number, that corresponds to the case of a
> > + * trigger with :n (n = number of times the trigger should fire)
> > and
> > + * the parsing continues normally; otherwise the function just
> > returns
> > + * and assumes param just contains a filter and there's nothing
> > else
> > + * to do.
> > + *
> > + * Return: 0 on success, errno otherwise
> > + */
> > +int event_trigger_separate_filter(char *param_and_filter, char
> > **param,
> > + char **filter, bool param_required)
> > +{
> > + int ret = 0;
> > +
> > + *param = *filter = NULL;
> > +
> > + if (!param_and_filter) {
> > + if (param_required)
> > + ret = -EINVAL;
> > + goto out;
> > + }
> > +
> > + /*
> > + * Here we check for an optional param. The only legal
> > + * optional param is :n, and if that's the case, continue
> > + * below. Otherwise we assume what's left is a filter and
> > + * return it as the filter string for the caller to deal with.
> > + */
> > + if (!param_required && param_and_filter &&
> > !isdigit(param_and_filter[0])) {
> > + *filter = param_and_filter;
> > + goto out;
> > + }
> > +
> > + /*
> > + * Separate the param from the filter (param [if filter]).
> > + * Here we have either an optional :n param or a required
> > + * param and an optional filter.
> > + */
> > + *param = strsep(¶m_and_filter, " \t");
> > + if (!*param) {
> > + ret = -EINVAL;
>
> This seems not happen because this means "!param_and_filter" and
> that is already checked at the entry of this function.
Yes, I think you're correct. I can just remove that check.
>
> > + goto out;
> > + }
> > +
> > + /*
> > + * Here we have a filter, though it may be empty.
> > + */
> > + if (param_and_filter) {
> > + *filter = skip_spaces(param_and_filter);
> > + if (!**filter)
> > + *filter = NULL;
> > + }
> > +out:
> > + return ret;
> > +}
> > +
> > +/**
> > + * event_trigger_alloc - allocate and init event_trigger_data for
> > a trigger
> > + * @cmd_ops: The event_command operations for the trigger
> > + * @cmd: The cmd string
> > + * @param: The param string
> > + * @private_data: User data to associate with the event trigger
> > + *
> > + * Allocate an event_trigger_data instance and initialize it. The
> > + * @cmd_ops are used along with the @cmd and @param to get the
> > + * trigger_ops to assign to the event_trigger_data. @private_data
> > can
> > + * also be passed in and associated with the event_trigger_data.
> > + *
> > + * Use event_trigger_free() to free an event_trigger_data object.
> > + *
> > + * Return: The trigger_data object success, NULL otherwise
> > + */
> > +struct event_trigger_data *event_trigger_alloc(struct
> > event_command *cmd_ops,
> > + char *cmd,
> > + char *param,
> > + void *private_data)
> > +{
> > + struct event_trigger_data *trigger_data;
> > + struct event_trigger_ops *trigger_ops;
> > +
> > + trigger_ops = cmd_ops->get_trigger_ops(cmd, param);
> > +
> > + trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
> > + if (!trigger_data)
> > + return NULL;
> > +
> > + trigger_data->count = -1;
> > + trigger_data->ops = trigger_ops;
> > + trigger_data->cmd_ops = cmd_ops;
> > + trigger_data->private_data = private_data;
> > +
> > + INIT_LIST_HEAD(&trigger_data->list);
> > + INIT_LIST_HEAD(&trigger_data->named_list);
> > + RCU_INIT_POINTER(trigger_data->filter, NULL);
> > +
> > + return trigger_data;
> > +}
> > +
> > +/**
> > + * event_trigger_parse_num - parse and return the number param for
> > a trigger
> > + * @trigger: The trigger string
>
> Does this mean trigger parameter?
Yes, I'll change this to 'param'.
>
> > + * @trigger_data: The trigger_data for the trigger
> > + *
> > + * Parse the :n (n = number of times the trigger should fire)
> > param
> > + * and set the count variable in the trigger_data to the parsed
> > count.
> > + *
> > + * Return: 0 on success, errno otherwise
> > + */
> > +int event_trigger_parse_num(char *trigger,
> > + struct event_trigger_data *trigger_data)
> > +{
> > + char *number;
> > + int ret = 0;
> > +
> > + if (trigger) {
> > + number = strsep(&trigger, ":");
> > +
> > + if (!strlen(number))
> > + return -EINVAL;
> > +
> > + /*
> > + * We use the callback data field (which is a pointer)
> > + * as our counter.
> > + */
> > + ret = kstrtoul(number, 0, &trigger_data->count);
> > + }
> > +
> > + return ret;
> > +}
>
> Does this work with '!enable_event:sys:event:n' case?
> (we need to find the last parameter.)
Yes, because :n isn't used in that case. Since you can't have multiple
'enable_event:sys:event:n' where sys:event are the same, whether using
:n or not, it suffices for delete to use only sys:event and ignore :n.
Thanks,
Tom
>
> Thank you,
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2021-12-13 20:21 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-12-10 21:16 [PATCH v4 0/4] tracing: Add and use event_command parsing func helpers Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 1/4] tracing: Change event_command func() to parse() Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 2/4] tracing: Change event_trigger_ops func() to trigger() Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 3/4] tracing: Add helper functions to simplify event_command.parse() callback handling Tom Zanussi
2021-12-13 13:46 ` Masami Hiramatsu
2021-12-13 20:21 ` Tom Zanussi
2021-12-10 21:16 ` [PATCH v4 4/4] tracing: Have existing event_command.parse() implementations use helpers Tom Zanussi
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