Re: [PATCH 2/4] tracing: Remove check_arg() callbacks from dynevent args

[Masami Hiramatsu]

On Fri, 31 Jan 2020 15:55:32 -0600
Tom Zanussi <zanussi@xxxxxxxxxx> wrote:

> It's kind of strange to have check_arg() callbacks as part of the arg
> objects themselves; it makes more sense to just pass these in when the
> args are added instead.
> 
> Remove the check_arg() callbacks from those objects which also means
> removing the check_arg() args from the init functions, adding them to
> the add functions and fixing up existing callers.

Looks good to me.

Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Thank you,

> 
> Signed-off-by: Tom Zanussi <zanussi@xxxxxxxxxx>
> ---
>  kernel/trace/trace_dynevent.c    | 62 ++++++++++++++++++----------------------
>  kernel/trace/trace_dynevent.h    | 11 ++++---
>  kernel/trace/trace_events_hist.c | 16 +++++------
>  kernel/trace/trace_kprobe.c      | 10 +++----
>  4 files changed, 46 insertions(+), 53 deletions(-)
> 
> diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
> index 6ffdbc4fda53..f9cfcdc9d1f3 100644
> --- a/kernel/trace/trace_dynevent.c
> +++ b/kernel/trace/trace_dynevent.c
> @@ -228,27 +228,30 @@ fs_initcall(init_dynamic_event);
>   * dynevent_arg_add - Add an arg to a dynevent_cmd
>   * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd
>   * @arg: The argument to append to the current cmd
> + * @check_arg: An (optional) pointer to a function checking arg sanity
>   *
>   * Append an argument to a dynevent_cmd.  The argument string will be
>   * appended to the current cmd string, followed by a separator, if
> - * applicable.  Before the argument is added, the check_arg()
> - * function, if defined, is called.
> + * applicable.  Before the argument is added, the @check_arg function,
> + * if present, will be used to check the sanity of the current arg
> + * string.
>   *
> - * The cmd string, separator, and check_arg() function should be set
> - * using the dynevent_arg_init() before any arguments are added using
> - * this function.
> + * The cmd string and separator should be set using the
> + * dynevent_arg_init() before any arguments are added using this
> + * function.
>   *
>   * Return: 0 if successful, error otherwise.
>   */
>  int dynevent_arg_add(struct dynevent_cmd *cmd,
> -		     struct dynevent_arg *arg)
> +		     struct dynevent_arg *arg,
> +		     dynevent_check_arg_fn_t check_arg)
>  {
>  	int ret = 0;
>  	int delta;
>  	char *q;
>  
> -	if (arg->check_arg) {
> -		ret = arg->check_arg(arg);
> +	if (check_arg) {
> +		ret = check_arg(arg);
>  		if (ret)
>  			return ret;
>  	}
> @@ -269,6 +272,7 @@ int dynevent_arg_add(struct dynevent_cmd *cmd,
>   * dynevent_arg_pair_add - Add an arg pair to a dynevent_cmd
>   * @cmd: A pointer to the dynevent_cmd struct representing the new event cmd
>   * @arg_pair: The argument pair to append to the current cmd
> + * @check_arg: An (optional) pointer to a function checking arg sanity
>   *
>   * Append an argument pair to a dynevent_cmd.  An argument pair
>   * consists of a left-hand-side argument and a right-hand-side
> @@ -278,24 +282,26 @@ int dynevent_arg_add(struct dynevent_cmd *cmd,
>   *
>   * The lhs argument string will be appended to the current cmd string,
>   * followed by an operator, if applicable, followd by the rhs string,
> - * followed finally by a separator, if applicable.  Before anything is
> - * added, the check_arg() function, if defined, is called.
> + * followed finally by a separator, if applicable.  Before the
> + * argument is added, the @check_arg function, if present, will be
> + * used to check the sanity of the current arg strings.
>   *
> - * The cmd strings, operator, separator, and check_arg() function
> - * should be set using the dynevent_arg_pair_init() before any arguments
> - * are added using this function.
> + * The cmd strings, operator, and separator should be set using the
> + * dynevent_arg_pair_init() before any arguments are added using this
> + * function.
>   *
>   * Return: 0 if successful, error otherwise.
>   */
>  int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
> -			  struct dynevent_arg_pair *arg_pair)
> +			  struct dynevent_arg_pair *arg_pair,
> +			  dynevent_check_arg_fn_t check_arg)
>  {
>  	int ret = 0;
>  	int delta;
>  	char *q;
>  
> -	if (arg_pair->check_arg) {
> -		ret = arg_pair->check_arg(arg_pair);
> +	if (check_arg) {
> +		ret = check_arg(arg_pair);
>  		if (ret)
>  			return ret;
>  	}
> @@ -385,20 +391,16 @@ void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen,
>  /**
>   * dynevent_arg_init - Initialize a dynevent_arg object
>   * @arg: A pointer to the dynevent_arg struct representing the arg
> - * @check_arg: An (optional) pointer to a function checking arg sanity
>   * @separator: An (optional) separator, appended after adding the arg
>   *
>   * Initialize a dynevent_arg object.  A dynevent_arg represents an
>   * object used to append single arguments to the current command
> - * string.  The @check_arg function, if present, will be used to check
> - * the sanity of the current arg string (which is directly set by the
> - * caller).  After the arg string is successfully appended to the
> + * string.  After the arg string is successfully appended to the
>   * command string, the optional @separator is appended.  If no
>   * separator was specified when initializing the arg, a space will be
>   * appended.
>   */
>  void dynevent_arg_init(struct dynevent_arg *arg,
> -		       dynevent_check_arg_fn_t check_arg,
>  		       char separator)
>  {
>  	memset(arg, '\0', sizeof(*arg));
> @@ -406,14 +408,11 @@ void dynevent_arg_init(struct dynevent_arg *arg,
>  	if (!separator)
>  		separator = ' ';
>  	arg->separator = separator;
> -
> -	arg->check_arg = check_arg;
>  }
>  
>  /**
>   * dynevent_arg_pair_init - Initialize a dynevent_arg_pair object
>   * @arg_pair: A pointer to the dynevent_arg_pair struct representing the arg
> - * @check_arg: An (optional) pointer to a function checking arg sanity
>   * @operator: An (optional) operator, appended after adding the first arg
>   * @separator: An (optional) separator, appended after adding the second arg
>   *
> @@ -422,16 +421,13 @@ void dynevent_arg_init(struct dynevent_arg *arg,
>   * variable_name;' or 'x+y' to the current command string.  An
>   * argument pair consists of a left-hand-side argument and a
>   * right-hand-side argument separated by an operator, which can be
> - * whitespace, all followed by a separator, if applicable. The
> - * @check_arg function, if present, will be used to check the sanity
> - * of the current arg strings (which is directly set by the caller).
> - * After the first arg string is successfully appended to the command
> - * string, the optional @operator is appended, followed by the second
> - * arg and and optional @separator.  If no separator was specified
> - * when initializing the arg, a space will be appended.
> + * whitespace, all followed by a separator, if applicable.  After the
> + * first arg string is successfully appended to the command string,
> + * the optional @operator is appended, followed by the second arg and
> + * and optional @separator.  If no separator was specified when
> + * initializing the arg, a space will be appended.
>   */
>  void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair,
> -			    dynevent_check_arg_fn_t check_arg,
>  			    char operator, char separator)
>  {
>  	memset(arg_pair, '\0', sizeof(*arg_pair));
> @@ -443,8 +439,6 @@ void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair,
>  	if (!separator)
>  		separator = ' ';
>  	arg_pair->separator = separator;
> -
> -	arg_pair->check_arg = check_arg;
>  }
>  
>  /**
> diff --git a/kernel/trace/trace_dynevent.h b/kernel/trace/trace_dynevent.h
> index b593fc34c5b1..d6857a254ede 100644
> --- a/kernel/trace/trace_dynevent.h
> +++ b/kernel/trace/trace_dynevent.h
> @@ -126,28 +126,27 @@ typedef int (*dynevent_check_arg_fn_t)(void *data);
>  struct dynevent_arg {
>  	const char		*str;
>  	char			separator; /* e.g. ';', ',', or nothing */
> -	dynevent_check_arg_fn_t	check_arg;
>  };
>  
>  extern void dynevent_arg_init(struct dynevent_arg *arg,
> -			      dynevent_check_arg_fn_t check_arg,
>  			      char separator);
>  extern int dynevent_arg_add(struct dynevent_cmd *cmd,
> -			    struct dynevent_arg *arg);
> +			    struct dynevent_arg *arg,
> +			    dynevent_check_arg_fn_t check_arg);
>  
>  struct dynevent_arg_pair {
>  	const char		*lhs;
>  	const char		*rhs;
>  	char			operator; /* e.g. '=' or nothing */
>  	char			separator; /* e.g. ';', ',', or nothing */
> -	dynevent_check_arg_fn_t	check_arg;
>  };
>  
>  extern void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair,
> -				   dynevent_check_arg_fn_t check_arg,
>  				   char operator, char separator);
> +
>  extern int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
> -				 struct dynevent_arg_pair *arg_pair);
> +				 struct dynevent_arg_pair *arg_pair,
> +				 dynevent_check_arg_fn_t check_arg);
>  extern int dynevent_str_add(struct dynevent_cmd *cmd, const char *str);
>  
>  #endif
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 772bd3d7c29f..a566f5d290c1 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -1334,12 +1334,12 @@ int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
>  	if (!type || !name)
>  		return -EINVAL;
>  
> -	dynevent_arg_pair_init(&arg_pair, synth_event_check_arg_fn, 0, ';');
> +	dynevent_arg_pair_init(&arg_pair, 0, ';');
>  
>  	arg_pair.lhs = type;
>  	arg_pair.rhs = name;
>  
> -	ret = dynevent_arg_pair_add(cmd, &arg_pair);
> +	ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
>  	if (ret)
>  		return ret;
>  
> @@ -1377,11 +1377,11 @@ int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
>  	if (!type_name)
>  		return -EINVAL;
>  
> -	dynevent_arg_init(&arg, NULL, ';');
> +	dynevent_arg_init(&arg, ';');
>  
>  	arg.str = type_name;
>  
> -	ret = dynevent_arg_add(cmd, &arg);
> +	ret = dynevent_arg_add(cmd, &arg, NULL);
>  	if (ret)
>  		return ret;
>  
> @@ -1472,9 +1472,9 @@ int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
>  	if (cmd->type != DYNEVENT_TYPE_SYNTH)
>  		return -EINVAL;
>  
> -	dynevent_arg_init(&arg, NULL, 0);
> +	dynevent_arg_init(&arg, 0);
>  	arg.str = name;
> -	ret = dynevent_arg_add(cmd, &arg);
> +	ret = dynevent_arg_add(cmd, &arg, NULL);
>  	if (ret)
>  		return ret;
>  
> @@ -1546,9 +1546,9 @@ int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
>  	if (n_fields > SYNTH_FIELDS_MAX)
>  		return -EINVAL;
>  
> -	dynevent_arg_init(&arg, NULL, 0);
> +	dynevent_arg_init(&arg, 0);
>  	arg.str = name;
> -	ret = dynevent_arg_add(cmd, &arg);
> +	ret = dynevent_arg_add(cmd, &arg, NULL);
>  	if (ret)
>  		return ret;
>  
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 307abb724a71..fe183d4045d2 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -962,9 +962,9 @@ int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
>  	if (ret)
>  		return ret;
>  
> -	dynevent_arg_init(&arg, NULL, 0);
> +	dynevent_arg_init(&arg, 0);
>  	arg.str = loc;
> -	ret = dynevent_arg_add(cmd, &arg);
> +	ret = dynevent_arg_add(cmd, &arg, NULL);
>  	if (ret)
>  		return ret;
>  
> @@ -982,7 +982,7 @@ int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
>  		}
>  
>  		arg.str = field;
> -		ret = dynevent_arg_add(cmd, &arg);
> +		ret = dynevent_arg_add(cmd, &arg, NULL);
>  		if (ret)
>  			break;
>  	}
> @@ -1017,7 +1017,7 @@ int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
>  	if (cmd->type != DYNEVENT_TYPE_KPROBE)
>  		return -EINVAL;
>  
> -	dynevent_arg_init(&arg, NULL, 0);
> +	dynevent_arg_init(&arg, 0);
>  
>  	va_start(args, cmd);
>  	for (;;) {
> @@ -1033,7 +1033,7 @@ int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
>  		}
>  
>  		arg.str = field;
> -		ret = dynevent_arg_add(cmd, &arg);
> +		ret = dynevent_arg_add(cmd, &arg, NULL);
>  		if (ret)
>  			break;
>  	}
> -- 
> 2.14.1
> 


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>