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Date: Sat, 1 Feb 2020 16:48:47 +0900
From: Masami Hiramatsu <mhiramat@...nel.org>
To: Tom Zanussi <zanussi@...nel.org>
Cc: rostedt@...dmis.org, artem.bityutskiy@...ux.intel.com,
mhiramat@...nel.org, linux-kernel@...r.kernel.org,
linux-rt-users@...r.kernel.org
Subject: Re: [PATCH 4/4] tracing: Use seq_buf for building dynevent_cmd
string
On Fri, 31 Jan 2020 15:55:34 -0600
Tom Zanussi <zanussi@...nel.org> wrote:
> The dynevent_cmd commands that build up the command string don't need
> to do that themselves - there's a seq_buf facility that does pretty
> much the same thing those command are doing manually, so use it
> instead.
Looks so neat :)
Reviewed-by: Masami Hiramatsu <mhiramat@...nel.org>
Thank you,
>
> Signed-off-by: Tom Zanussi <zanussi@...nel.org>
> ---
> include/linux/trace_events.h | 4 +---
> kernel/trace/trace_dynevent.c | 48 +++++++++++-----------------------------
> kernel/trace/trace_events_hist.c | 2 +-
> kernel/trace/trace_kprobe.c | 2 +-
> 4 files changed, 16 insertions(+), 40 deletions(-)
>
> diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
> index 7c307a7c9c6a..67f528ecb9e5 100644
> --- a/include/linux/trace_events.h
> +++ b/include/linux/trace_events.h
> @@ -367,10 +367,8 @@ struct dynevent_cmd;
> typedef int (*dynevent_create_fn_t)(struct dynevent_cmd *cmd);
>
> struct dynevent_cmd {
> - char *buf;
> + struct seq_buf seq;
> const char *event_name;
> - int maxlen;
> - int remaining;
> unsigned int n_fields;
> enum dynevent_type type;
> dynevent_create_fn_t run_command;
> diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
> index 204275ec8d71..9f2e8520b748 100644
> --- a/kernel/trace/trace_dynevent.c
> +++ b/kernel/trace/trace_dynevent.c
> @@ -247,8 +247,6 @@ int dynevent_arg_add(struct dynevent_cmd *cmd,
> dynevent_check_arg_fn_t check_arg)
> {
> int ret = 0;
> - int delta;
> - char *q;
>
> if (check_arg) {
> ret = check_arg(arg);
> @@ -256,14 +254,11 @@ int dynevent_arg_add(struct dynevent_cmd *cmd,
> return ret;
> }
>
> - q = cmd->buf + (cmd->maxlen - cmd->remaining);
> -
> - delta = snprintf(q, cmd->remaining, " %s%c", arg->str, arg->separator);
> - if (delta >= cmd->remaining) {
> - pr_err("String is too long: %s\n", arg->str);
> + ret = seq_buf_printf(&cmd->seq, " %s%c", arg->str, arg->separator);
> + if (ret) {
> + pr_err("String is too long: %s%c\n", arg->str, arg->separator);
> return -E2BIG;
> }
> - cmd->remaining -= delta;
>
> return ret;
> }
> @@ -297,8 +292,6 @@ int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
> dynevent_check_arg_fn_t check_arg)
> {
> int ret = 0;
> - int delta;
> - char *q;
>
> if (check_arg) {
> ret = check_arg(arg_pair);
> @@ -306,23 +299,15 @@ int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
> return ret;
> }
>
> - q = cmd->buf + (cmd->maxlen - cmd->remaining);
> -
> - delta = snprintf(q, cmd->remaining, " %s%c", arg_pair->lhs,
> - arg_pair->operator);
> - if (delta >= cmd->remaining) {
> - pr_err("field string is too long: %s\n", arg_pair->lhs);
> - return -E2BIG;
> - }
> - cmd->remaining -= delta; q += delta;
> -
> - delta = snprintf(q, cmd->remaining, "%s%c", arg_pair->rhs,
> - arg_pair->separator);
> - if (delta >= cmd->remaining) {
> - pr_err("field string is too long: %s\n", arg_pair->rhs);
> + ret = seq_buf_printf(&cmd->seq, " %s%c%s%c", arg_pair->lhs,
> + arg_pair->operator, arg_pair->rhs,
> + arg_pair->separator);
> + if (ret) {
> + pr_err("field string is too long: %s%c%s%c\n", arg_pair->lhs,
> + arg_pair->operator, arg_pair->rhs,
> + arg_pair->separator);
> return -E2BIG;
> }
> - cmd->remaining -= delta;
>
> return ret;
> }
> @@ -340,17 +325,12 @@ int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
> int dynevent_str_add(struct dynevent_cmd *cmd, const char *str)
> {
> int ret = 0;
> - int delta;
> - char *q;
> -
> - q = cmd->buf + (cmd->maxlen - cmd->remaining);
>
> - delta = snprintf(q, cmd->remaining, "%s", str);
> - if (delta >= cmd->remaining) {
> + ret = seq_buf_puts(&cmd->seq, str);
> + if (ret) {
> pr_err("String is too long: %s\n", str);
> return -E2BIG;
> }
> - cmd->remaining -= delta;
>
> return ret;
> }
> @@ -381,9 +361,7 @@ void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen,
> {
> memset(cmd, '\0', sizeof(*cmd));
>
> - cmd->buf = buf;
> - cmd->maxlen = maxlen;
> - cmd->remaining = cmd->maxlen;
> + seq_buf_init(&cmd->seq, buf, maxlen);
> cmd->type = type;
> cmd->run_command = run_command;
> }
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index a566f5d290c1..6dc3078a6d02 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -1762,7 +1762,7 @@ static int synth_event_run_command(struct dynevent_cmd *cmd)
> struct synth_event *se;
> int ret;
>
> - ret = trace_run_command(cmd->buf, create_or_delete_synth_event);
> + ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event);
> if (ret)
> return ret;
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index fe183d4045d2..51efc790aea8 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -903,7 +903,7 @@ static int create_or_delete_trace_kprobe(int argc, char **argv)
>
> static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
> {
> - return trace_run_command(cmd->buf, create_or_delete_trace_kprobe);
> + return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
> }
>
> /**
> --
> 2.14.1
>
--
Masami Hiramatsu <mhiramat@...nel.org>
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