tracing: Use seq_buf for building dynevent_cmd string

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>

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 7c307a7..67f528e 100644 (file)
--- 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 204275e..9f2e852 100644 (file)
--- 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 d2817fe..b3bcfd8 100644 (file)
--- 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 fe183d4..51efc79 100644 (file)
--- 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);
 }
 
 /**