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tracing: Remove open-coding of hist trigger var_ref management 

Have create_var_ref() manage the hist trigger's var_ref list, rather
than having similar code doing it in multiple places.  This cleans up
the code and makes sure var_refs are always accounted properly.

Also, document the var_ref-related functions to make what their
purpose clearer.

Link: http://lkml.kernel.org/r/05ddae93ff514e66fc03897d6665231892939913.1545161087.git.tom.zanussi@linux.intel.com

Acked-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Tom Zanussi 2018-12-18 14:33:23 -06:00 committed by Steven Rostedt (VMware)
parent e4f6d24503
commit de40f033d4
1 changed files with 75 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

93
kernel/trace/trace_events_hist.c
View File

@ -1292,6 +1292,17 @@ static u64 hist_field_cpu(struct hist_field *hist_field,
return cpu;
}
/**
* check_field_for_var_ref - Check if a VAR_REF field references a variable
* @hist_field: The VAR_REF field to check
* @var_data: The hist trigger that owns the variable
* @var_idx: The trigger variable identifier
*
* Check the given VAR_REF field to see whether or not it references
* the given variable associated with the given trigger.
*
* Return: The VAR_REF field if it does reference the variable, NULL if not
*/
static struct hist_field *
check_field_for_var_ref(struct hist_field *hist_field,
struct hist_trigger_data *var_data,
@ -1306,6 +1317,18 @@ check_field_for_var_ref(struct hist_field *hist_field,
return NULL;
}
/**
* find_var_ref - Check if a trigger has a reference to a trigger variable
* @hist_data: The hist trigger that might have a reference to the variable
* @var_data: The hist trigger that owns the variable
* @var_idx: The trigger variable identifier
*
* Check the list of var_refs[] on the first hist trigger to see
* whether any of them are references to the variable on the second
* trigger.
*
* Return: The VAR_REF field referencing the variable if so, NULL if not
*/
static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
struct hist_trigger_data *var_data,
unsigned int var_idx)
@ -1322,6 +1345,20 @@ static struct hist_field *find_var_ref(struct hist_trigger_data *hist_data,
return NULL;
}
/**
* find_any_var_ref - Check if there is a reference to a given trigger variable
* @hist_data: The hist trigger
* @var_idx: The trigger variable identifier
*
* Check to see whether the given variable is currently referenced by
* any other trigger.
*
* The trigger the variable is defined on is explicitly excluded - the
* assumption being that a self-reference doesn't prevent a trigger
* from being removed.
*
* Return: The VAR_REF field referencing the variable if so, NULL if not
*/
static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
unsigned int var_idx)
{
@ -1340,6 +1377,19 @@ static struct hist_field *find_any_var_ref(struct hist_trigger_data *hist_data,
return found;
}
/**
* check_var_refs - Check if there is a reference to any of trigger's variables
* @hist_data: The hist trigger
*
* A trigger can define one or more variables. If any one of them is
* currently referenced by any other trigger, this function will
* determine that.
* Typically used to determine whether or not a trigger can be removed
* - if there are any references to a trigger's variables, it cannot.
*
* Return: True if there is a reference to any of trigger's variables
*/
static bool check_var_refs(struct hist_trigger_data *hist_data)
{
struct hist_field *field;
@ -2343,7 +2393,23 @@ static int init_var_ref(struct hist_field *ref_field,
goto out;
}
static struct hist_field *create_var_ref(struct hist_field *var_field,
/**
* create_var_ref - Create a variable reference and attach it to trigger
* @hist_data: The trigger that will be referencing the variable
* @var_field: The VAR field to create a reference to
* @system: The optional system string
* @event_name: The optional event_name string
*
* Given a variable hist_field, create a VAR_REF hist_field that
* represents a reference to it.
*
* This function also adds the reference to the trigger that
* now references the variable.
*
* Return: The VAR_REF field if successful, NULL if not
*/
static struct hist_field *create_var_ref(struct hist_trigger_data *hist_data,
struct hist_field *var_field,
char *system, char *event_name)
{
unsigned long flags = HIST_FIELD_FL_VAR_REF;
@ -2355,6 +2421,9 @@ static struct hist_field *create_var_ref(struct hist_field *var_field,
destroy_hist_field(ref_field, 0);
return NULL;
}
hist_data->var_refs[hist_data->n_var_refs] = ref_field;
ref_field->var_ref_idx = hist_data->n_var_refs++;
}
return ref_field;
@ -2428,7 +2497,8 @@ static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
var_field = find_event_var(hist_data, system, event_name, var_name);
if (var_field)
ref_field = create_var_ref(var_field, system, event_name);
ref_field = create_var_ref(hist_data, var_field,
system, event_name);
if (!ref_field)
hist_err_event("Couldn't find variable: $",
@ -2546,8 +2616,6 @@ static struct hist_field *parse_atom(struct hist_trigger_data *hist_data,
if (!s) {
hist_field = parse_var_ref(hist_data, ref_system, ref_event, ref_var);
if (hist_field) {
hist_data->var_refs[hist_data->n_var_refs] = hist_field;
hist_field->var_ref_idx = hist_data->n_var_refs++;
if (var_name) {
hist_field = create_alias(hist_data, hist_field, var_name);
if (!hist_field) {
@ -3321,7 +3389,6 @@ static int onmax_create(struct hist_trigger_data *hist_data,
unsigned int var_ref_idx = hist_data->n_var_refs;
struct field_var *field_var;
char *onmax_var_str, *param;
unsigned long flags;
unsigned int i;
int ret = 0;
@ -3338,18 +3405,10 @@ static int onmax_create(struct hist_trigger_data *hist_data,
return -EINVAL;
}
flags = HIST_FIELD_FL_VAR_REF;
ref_field = create_hist_field(hist_data, NULL, flags, NULL);
ref_field = create_var_ref(hist_data, var_field, NULL, NULL);
if (!ref_field)
return -ENOMEM;
if (init_var_ref(ref_field, var_field, NULL, NULL)) {
destroy_hist_field(ref_field, 0);
ret = -ENOMEM;
goto out;
}
hist_data->var_refs[hist_data->n_var_refs] = ref_field;
ref_field->var_ref_idx = hist_data->n_var_refs++;
data->onmax.var = ref_field;
data->fn = onmax_save;
@ -3538,9 +3597,6 @@ static void save_synth_var_ref(struct hist_trigger_data *hist_data,
struct hist_field *var_ref)
{
hist_data->synth_var_refs[hist_data->n_synth_var_refs++] = var_ref;
hist_data->var_refs[hist_data->n_var_refs] = var_ref;
var_ref->var_ref_idx = hist_data->n_var_refs++;
}
static int check_synth_field(struct synth_event *event,
@ -3694,7 +3750,8 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
}
if (check_synth_field(event, hist_field, field_pos) == 0) {
var_ref = create_var_ref(hist_field, system, event_name);
var_ref = create_var_ref(hist_data, hist_field,
system, event_name);
if (!var_ref) {
kfree(p);
ret = -ENOMEM;