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Subject[for-next][PATCH 6/6] tracing: Use seq_buf for building dynevent_cmd string
From: Tom Zanussi <zanussi@kernel.org>

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.

Link: http://lkml.kernel.org/r/eb8a6e835c964d0ab8a38cbf5ffa60746b54a465.1580506712.git.zanussi@kernel.org

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.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 d2817fe52f32..b3bcfd8c7332 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);
}

/**
--
2.24.1

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