Commit 3a0d5bc7 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt (Google)
Browse files

tracing: Use switch statement instead of ifs in set_tracer_flag() 

The "mask" passed in to set_trace_flag() has a single bit set. The
function then checks if the mask is equal to one of the option masks and
performs the appropriate function associated to that option.

Instead of having a bunch of "if ()" statement, use a "switch ()"
statement instead to make it cleaner and a bit more optimal.

No function changes.

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/20251106003501.890298562@kernel.org


Reviewed-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 9c505308

kernel/trace/trace.c

+23 −15
Original line number Diff line number Diff line
@@ -5220,11 +5220,13 @@ int trace_keep_overwrite(struct tracer *tracer, u64 mask, int set) 


int set_tracer_flag(struct trace_array *tr, u64 mask, int enabled)

{

	if ((mask == TRACE_ITER(RECORD_TGID)) ||

	    (mask == TRACE_ITER(RECORD_CMD)) ||

	    (mask == TRACE_ITER(TRACE_PRINTK)) ||

	    (mask == TRACE_ITER(COPY_MARKER)))

	switch (mask) {

	case TRACE_ITER(RECORD_TGID):

	case TRACE_ITER(RECORD_CMD):

	case TRACE_ITER(TRACE_PRINTK):

	case TRACE_ITER(COPY_MARKER):

		lockdep_assert_held(&event_mutex);

	}



	/* do nothing if flag is already set */

	if (!!(tr->trace_flags & mask) == !!enabled)
@@ -5235,7 +5237,8 @@ int set_tracer_flag(struct trace_array *tr, u64 mask, int enabled) 
		if (tr->current_trace->flag_changed(tr, mask, !!enabled))

			return -EINVAL;



	if (mask == TRACE_ITER(TRACE_PRINTK)) {

	switch (mask) {

	case TRACE_ITER(TRACE_PRINTK):

		if (enabled) {

			update_printk_trace(tr);

		} else {
@@ -5252,9 +5255,9 @@ int set_tracer_flag(struct trace_array *tr, u64 mask, int enabled) 
			if (printk_trace == tr)

				update_printk_trace(&global_trace);

		}

	}

		break;



	if (mask == TRACE_ITER(COPY_MARKER)) {

	case TRACE_ITER(COPY_MARKER):

		update_marker_trace(tr, enabled);

		/* update_marker_trace updates the tr->trace_flags */

		return 0;
@@ -5265,10 +5268,12 @@ int set_tracer_flag(struct trace_array *tr, u64 mask, int enabled) 
	else

		tr->trace_flags &= ~mask;



	if (mask == TRACE_ITER(RECORD_CMD))

	switch (mask) {

	case TRACE_ITER(RECORD_CMD):

		trace_event_enable_cmd_record(enabled);

		break;



	if (mask == TRACE_ITER(RECORD_TGID)) {

	case TRACE_ITER(RECORD_TGID):



		if (trace_alloc_tgid_map() < 0) {

			tr->trace_flags &= ~TRACE_ITER(RECORD_TGID);
@@ -5276,24 +5281,27 @@ int set_tracer_flag(struct trace_array *tr, u64 mask, int enabled) 
		}



		trace_event_enable_tgid_record(enabled);

	}

		break;



	if (mask == TRACE_ITER(EVENT_FORK))

	case TRACE_ITER(EVENT_FORK):

		trace_event_follow_fork(tr, enabled);

		break;



	if (mask == TRACE_ITER(FUNC_FORK))

	case TRACE_ITER(FUNC_FORK):

		ftrace_pid_follow_fork(tr, enabled);

		break;



	if (mask == TRACE_ITER(OVERWRITE)) {

	case TRACE_ITER(OVERWRITE):

		ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);

#ifdef CONFIG_TRACER_MAX_TRACE

		ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);

#endif

	}

		break;



	if (mask == TRACE_ITER(PRINTK)) {

	case TRACE_ITER(PRINTK):

		trace_printk_start_stop_comm(enabled);

		trace_printk_control(enabled);

		break;

	}



	return 0;