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tracing: Add tracer_uses_snapshot() helper to remove #ifdefs

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Instead of having #ifdef CONFIG_TRACER_MAX_TRACE around every access to
the struct tracer's use_max_tr field, add a helper function for that
access and if CONFIG_TRACER_MAX_TRACE is not configured it just returns
false.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://patch.msgid.link/20260208183856.599390238@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt
2026-02-08 13:38:34 -05:00
committed by Steven Rostedt (Google)
parent 694b3f6fe0
commit e4c1a09afb
2 changed files with 28 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files

51
kernel/trace/trace.c
View File

@@ -810,7 +810,6 @@ EXPORT_SYMBOL_GPL(tracing_on);
static void tracing_snapshot_instance_cond(struct trace_array *tr,
void *cond_data)
{
struct tracer *tracer = tr->current_trace;
unsigned long flags;
if (in_nmi()) {
@@ -827,7 +826,7 @@ static void tracing_snapshot_instance_cond(struct trace_array *tr,
}
/* Note, snapshot can not be used when the tracer uses it */
if (tracer->use_max_tr) {
if (tracer_uses_snapshot(tr->current_trace)) {
trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
return;
@@ -1076,7 +1075,7 @@ int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
guard(mutex)(&trace_types_lock);
if (tr->current_trace->use_max_tr)
if (tracer_uses_snapshot(tr->current_trace))
return -EBUSY;
/*
@@ -1787,7 +1786,7 @@ static int run_tracer_selftest(struct tracer *type)
tr->current_trace_flags = type->flags ? : type->default_flags;
#ifdef CONFIG_TRACER_MAX_TRACE
if (type->use_max_tr) {
if (tracer_uses_snapshot(type)) {
/* If we expanded the buffers, make sure the max is expanded too */
if (tr->ring_buffer_expanded)
ring_buffer_resize(tr->snapshot_buffer.buffer, trace_buf_size,
@@ -1812,7 +1811,7 @@ static int run_tracer_selftest(struct tracer *type)
tracing_reset_online_cpus(&tr->array_buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
if (type->use_max_tr) {
if (tracer_uses_snapshot(type)) {
tr->allocated_snapshot = false;
/* Shrink the max buffer again */
@@ -3240,10 +3239,8 @@ static void *s_start(struct seq_file *m, loff_t *pos)
}
mutex_unlock(&trace_types_lock);
#ifdef CONFIG_TRACER_MAX_TRACE
if (iter->snapshot && iter->trace->use_max_tr)
if (iter->snapshot && tracer_uses_snapshot(iter->trace))
return ERR_PTR(-EBUSY);
#endif
if (*pos != iter->pos) {
iter->ent = NULL;
@@ -3282,10 +3279,8 @@ static void s_stop(struct seq_file *m, void *p)
{
struct trace_iterator *iter = m->private;
#ifdef CONFIG_TRACER_MAX_TRACE
if (iter->snapshot && iter->trace->use_max_tr)
if (iter->snapshot && tracer_uses_snapshot(iter->trace))
return;
#endif
trace_access_unlock(iter->cpu_file);
trace_event_read_unlock();
@@ -4177,11 +4172,9 @@ static int tracing_open(struct inode *inode, struct file *file)
static bool
trace_ok_for_array(struct tracer *t, struct trace_array *tr)
{
#ifdef CONFIG_TRACER_SNAPSHOT
/* arrays with mapped buffer range do not have snapshots */
if (tr->range_addr_start && t->use_max_tr)
if (tr->range_addr_start && tracer_uses_snapshot(t))
return false;
#endif
return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
}
@@ -5550,9 +5543,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
{
struct tracer *trace = NULL;
struct tracers *t;
#ifdef CONFIG_TRACER_MAX_TRACE
bool had_max_tr;
#endif
int ret;
guard(mutex)(&trace_types_lock);
@@ -5580,7 +5571,7 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
return 0;
#ifdef CONFIG_TRACER_SNAPSHOT
if (trace->use_max_tr) {
if (tracer_uses_snapshot(trace)) {
local_irq_disable();
arch_spin_lock(&tr->max_lock);
ret = tr->cond_snapshot ? -EBUSY : 0;
@@ -5612,14 +5603,13 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
if (tr->current_trace->reset)
tr->current_trace->reset(tr);
#ifdef CONFIG_TRACER_MAX_TRACE
had_max_tr = tr->current_trace->use_max_tr;
had_max_tr = tracer_uses_snapshot(tr->current_trace);
/* Current trace needs to be nop_trace before synchronize_rcu */
tr->current_trace = &nop_trace;
tr->current_trace_flags = nop_trace.flags;
if (had_max_tr && !trace->use_max_tr) {
if (had_max_tr && !tracer_uses_snapshot(trace)) {
/*
* We need to make sure that the update_max_tr sees that
* current_trace changed to nop_trace to keep it from
@@ -5632,24 +5622,19 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf)
tracing_disarm_snapshot(tr);
}
if (!had_max_tr && trace->use_max_tr) {
if (!had_max_tr && tracer_uses_snapshot(trace)) {
ret = tracing_arm_snapshot_locked(tr);
if (ret)
return ret;
}
#else
tr->current_trace = &nop_trace;
#endif
tr->current_trace_flags = t->flags ? : t->tracer->flags;
if (trace->init) {
ret = tracer_init(trace, tr);
if (ret) {
#ifdef CONFIG_TRACER_MAX_TRACE
if (trace->use_max_tr)
if (tracer_uses_snapshot(trace))
tracing_disarm_snapshot(tr);
#endif
tr->current_trace_flags = nop_trace.flags;
return ret;
}
@@ -7207,7 +7192,7 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
guard(mutex)(&trace_types_lock);
if (tr->current_trace->use_max_tr)
if (tracer_uses_snapshot(tr->current_trace))
return -EBUSY;
local_irq_disable();
@@ -7306,7 +7291,7 @@ static int snapshot_raw_open(struct inode *inode, struct file *filp)
info = filp->private_data;
if (info->iter.trace->use_max_tr) {
if (tracer_uses_snapshot(info->iter.trace)) {
tracing_buffers_release(inode, filp);
return -EBUSY;
}
@@ -7862,10 +7847,8 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
if (!count)
return 0;
#ifdef CONFIG_TRACER_MAX_TRACE
if (iter->snapshot && iter->tr->current_trace->use_max_tr)
if (iter->snapshot && tracer_uses_snapshot(iter->tr->current_trace))
return -EBUSY;
#endif
page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
@@ -8049,10 +8032,8 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
int entries, i;
ssize_t ret = 0;
#ifdef CONFIG_TRACER_MAX_TRACE
if (iter->snapshot && iter->tr->current_trace->use_max_tr)
if (iter->snapshot && tracer_uses_snapshot(iter->tr->current_trace))
return -EBUSY;
#endif
page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
if (*ppos & (page_size - 1))

12
kernel/trace/trace.h
View File

@@ -817,6 +817,18 @@ static inline void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
}
#endif /* CONFIG_STACKTRACE */
#ifdef CONFIG_TRACER_MAX_TRACE
static inline bool tracer_uses_snapshot(struct tracer *tracer)
{
return tracer->use_max_tr;
}
#else
static inline bool tracer_uses_snapshot(struct tracer *tracer)
{
return false;
}
#endif
void trace_last_func_repeats(struct trace_array *tr,
struct trace_func_repeats *last_info,
unsigned int trace_ctx);