[PATCH v2 4/6] tracing: Use __free() in trace_probe for cleanup

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhira...@kernel.org>

Use __free() in trace_probe to cleanup some gotos.

Signed-off-by: Masami Hiramatsu (Google) <mhira...@kernel.org>
---
 kernel/trace/trace_probe.c |   52 +++++++++++++++-----------------------------
 1 file changed, 18 insertions(+), 34 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 16a5e368e7b7..bf6a7b81ae95 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1409,7 +1409,7 @@ static int traceprobe_parse_probe_arg_body(const char 
*argv, ssize_t *size,
                                           struct traceprobe_parse_context *ctx)
 {
        struct fetch_insn *code, *tmp = NULL;
-       char *type, *arg;
+       char *type, *arg __free(kfree) = NULL;
        int ret, len;
 
        len = strlen(argv);
@@ -1426,22 +1426,16 @@ static int traceprobe_parse_probe_arg_body(const char 
*argv, ssize_t *size,
                return -ENOMEM;
 
        parg->comm = kstrdup(arg, GFP_KERNEL);
-       if (!parg->comm) {
-               ret = -ENOMEM;
-               goto out;
-       }
+       if (!parg->comm)
+               return -ENOMEM;
 
        type = parse_probe_arg_type(arg, parg, ctx);
-       if (IS_ERR(type)) {
-               ret = PTR_ERR(type);
-               goto out;
-       }
+       if (IS_ERR(type))
+               return PTR_ERR(type);
 
        code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
-       if (!code) {
-               ret = -ENOMEM;
-               goto out;
-       }
+       if (!code)
+               return -ENOMEM;
        code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
 
        ctx->last_type = NULL;
@@ -1497,8 +1491,6 @@ static int traceprobe_parse_probe_arg_body(const char 
*argv, ssize_t *size,
                                kfree(code->data);
        }
        kfree(tmp);
-out:
-       kfree(arg);
 
        return ret;
 }
@@ -1668,7 +1660,7 @@ const char **traceprobe_expand_meta_args(int argc, const 
char *argv[],
 {
        const struct btf_param *params = NULL;
        int i, j, n, used, ret, args_idx = -1;
-       const char **new_argv = NULL;
+       const char **new_argv __free(kfree) = NULL;
 
        ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
        if (ret < 0)
@@ -1707,7 +1699,7 @@ const char **traceprobe_expand_meta_args(int argc, const 
char *argv[],
                                ret = sprint_nth_btf_arg(n, "", buf + used,
                                                         bufsize - used, ctx);
                                if (ret < 0)
-                                       goto error;
+                                       return ERR_PTR(ret);
 
                                new_argv[j++] = buf + used;
                                used += ret + 1;
@@ -1721,25 +1713,20 @@ const char **traceprobe_expand_meta_args(int argc, 
const char *argv[],
                        n = simple_strtoul(argv[i] + 4, &type, 10);
                        if (type && !(*type == ':' || *type == '\0')) {
                                trace_probe_log_err(0, BAD_VAR);
-                               ret = -ENOENT;
-                               goto error;
+                               return ERR_PTR(-ENOENT);
                        }
                        /* Note: $argN starts from $arg1 */
                        ret = sprint_nth_btf_arg(n - 1, type, buf + used,
                                                 bufsize - used, ctx);
                        if (ret < 0)
-                               goto error;
+                               return ERR_PTR(ret);
                        new_argv[j++] = buf + used;
                        used += ret + 1;
                } else
                        new_argv[j++] = argv[i];
        }
 
-       return new_argv;
-
-error:
-       kfree(new_argv);
-       return ERR_PTR(ret);
+       return_ptr(new_argv);
 }
 
 /* @buf: *buf must be equal to NULL. Caller must to free *buf */
@@ -1747,14 +1734,14 @@ int traceprobe_expand_dentry_args(int argc, const char 
*argv[], char **buf)
 {
        int i, used, ret;
        const int bufsize = MAX_DENTRY_ARGS_LEN;
-       char *tmpbuf = NULL;
+       char *tmpbuf __free(kfree) = NULL;
 
        if (*buf)
                return -EINVAL;
 
        used = 0;
        for (i = 0; i < argc; i++) {
-               char *tmp;
+               char *tmp __free(kfree) = NULL;
                char *equal;
                size_t arg_len;
 
@@ -1769,7 +1756,7 @@ int traceprobe_expand_dentry_args(int argc, const char 
*argv[], char **buf)
 
                tmp = kstrdup(argv[i], GFP_KERNEL);
                if (!tmp)
-                       goto nomem;
+                       return -ENOMEM;
 
                equal = strchr(tmp, '=');
                if (equal)
@@ -1790,18 +1777,15 @@ int traceprobe_expand_dentry_args(int argc, const char 
*argv[], char **buf)
                                       offsetof(struct file, f_path.dentry),
                                       equal ? equal + 1 : tmp);
 
-               kfree(tmp);
+               kfree(no_free_ptr(tmp));
                if (ret >= bufsize - used)
-                       goto nomem;
+                       return -ENOMEM;
                argv[i] = tmpbuf + used;
                used += ret + 1;
        }
 
-       *buf = tmpbuf;
+       *buf = no_free_ptr(tmpbuf);
        return 0;
-nomem:
-       kfree(tmpbuf);
-       return -ENOMEM;
 }
 
 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)