Messages in this thread Patch in this message | | | From | "Yordan Karadzhov (VMware)" <> | Subject | [PATCH v2 4/5] tracing: Unify the logic for function tracing options | Date | Mon, 29 Mar 2021 16:05:32 +0300 |
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Currently the logic for dealing with the options for function tracing has two different implementations. One is used when we set the flags (in "static int func_set_flag()") and another used when we initialize the tracer (in "static int function_trace_init()"). Those two implementations are meant to do essentially the same thing and they are both not very convenient for adding new options. In this patch we add a helper function that provides a single implementation of the logic for dealing with the options and we make it such that new options can be easily added.
Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com> --- kernel/trace/trace_functions.c | 66 ++++++++++++++++++++-------------- 1 file changed, 40 insertions(+), 26 deletions(-)
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index f93723ca66bc..6c912eb0508a 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -27,13 +27,17 @@ function_trace_call(unsigned long ip, unsigned long parent_ip, static void function_stack_trace_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct ftrace_regs *fregs); +static ftrace_func_t select_trace_function(u32 flags_val); static struct tracer_flags func_flags; /* Our option */ enum { + TRACE_FUNC_NO_OPTS = 0x0, /* No flags set. */ TRACE_FUNC_OPT_STACK = 0x1, }; +#define TRACE_FUNC_OPT_MASK (TRACE_FUNC_OPT_STACK) + int ftrace_allocate_ftrace_ops(struct trace_array *tr) { struct ftrace_ops *ops; @@ -97,12 +101,9 @@ static int function_trace_init(struct trace_array *tr) if (!tr->ops) return -ENOMEM; - /* Currently only the global instance can do stack tracing */ - if (tr->flags & TRACE_ARRAY_FL_GLOBAL && - func_flags.val & TRACE_FUNC_OPT_STACK) - func = function_stack_trace_call; - else - func = function_trace_call; + func = select_trace_function(func_flags.val); + if (!func) + return -EINVAL; ftrace_init_array_ops(tr, func); @@ -205,6 +206,18 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip, local_irq_restore(flags); } +static ftrace_func_t select_trace_function(u32 flags_val) +{ + switch (flags_val & TRACE_FUNC_OPT_MASK) { + case TRACE_FUNC_NO_OPTS: + return function_trace_call; + case TRACE_FUNC_OPT_STACK: + return function_stack_trace_call; + default: + return NULL; + } +} + static struct tracer_opt func_opts[] = { #ifdef CONFIG_STACKTRACE { TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) }, @@ -213,7 +226,7 @@ static struct tracer_opt func_opts[] = { }; static struct tracer_flags func_flags = { - .val = 0, /* By default: all flags disabled */ + .val = TRACE_FUNC_NO_OPTS, /* By default: all flags disabled */ .opts = func_opts }; @@ -235,30 +248,31 @@ static struct tracer function_trace; static int func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) { - switch (bit) { - case TRACE_FUNC_OPT_STACK: - /* do nothing if already set */ - if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK)) - break; + ftrace_func_t func; + u32 new_flags_val; - /* We can change this flag when not running. */ - if (tr->current_trace != &function_trace) - break; + /* Do nothing if already set. */ + if (!!set == !!(func_flags.val & bit)) + return 0; - unregister_ftrace_function(tr->ops); + /* We can change this flag only when not running. */ + if (tr->current_trace != &function_trace) + return 0; - if (set) { - tr->ops->func = function_stack_trace_call; - register_ftrace_function(tr->ops); - } else { - tr->ops->func = function_trace_call; - register_ftrace_function(tr->ops); - } + new_flags_val = (func_flags.val & ~(1UL << (bit - 1))); + new_flags_val |= (set << (bit - 1)); - break; - default: + func = select_trace_function(new_flags_val); + if (!func) return -EINVAL; - } + + /* Check if there's anything to change. */ + if (tr->ops->func == func) + return 0; + + unregister_ftrace_function(tr->ops); + tr->ops->func = func; + register_ftrace_function(tr->ops); return 0; } -- 2.25.1
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