Commit 92705460 authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google)
Browse files

tracing/kprobes: Simplify __trace_kprobe_create() by removing gotos 

Simplify __trace_kprobe_create() by removing gotos.

Link: https://lore.kernel.org/all/173643301102.1514810.6149004416601259466.stgit@devnote2/



Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 7dcc3520

kernel/trace/trace_kprobe.c

+49 −48
Original line number Diff line number Diff line
@@ -836,7 +836,8 @@ static int validate_probe_symbol(char *symbol) 
static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,

				      struct pt_regs *regs);



static int __trace_kprobe_create(int argc, const char *argv[])

static int trace_kprobe_create_internal(int argc, const char *argv[],

					struct traceprobe_parse_context *ctx)

{

	/*

	 * Argument syntax:
@@ -877,7 +878,6 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
	char gbuf[MAX_EVENT_NAME_LEN];

	char abuf[MAX_BTF_ARGS_LEN];

	char *dbuf __free(kfree) = NULL;

	struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };



	switch (argv[0][0]) {

	case 'r':
@@ -891,8 +891,6 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
	if (argc < 2)

		return -ECANCELED;



	trace_probe_log_init("trace_kprobe", argc, argv);



	event = strchr(&argv[0][1], ':');

	if (event)

		event++;
@@ -900,7 +898,7 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
	if (isdigit(argv[0][1])) {

		if (!is_return) {

			trace_probe_log_err(1, BAD_MAXACT_TYPE);

			goto parse_error;

			return -EINVAL;

		}

		if (event)

			len = event - &argv[0][1] - 1;
@@ -908,21 +906,21 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
			len = strlen(&argv[0][1]);

		if (len > MAX_EVENT_NAME_LEN - 1) {

			trace_probe_log_err(1, BAD_MAXACT);

			goto parse_error;

			return -EINVAL;

		}

		memcpy(buf, &argv[0][1], len);

		buf[len] = '\0';

		ret = kstrtouint(buf, 0, &maxactive);

		if (ret || !maxactive) {

			trace_probe_log_err(1, BAD_MAXACT);

			goto parse_error;

			return -EINVAL;

		}

		/* kretprobes instances are iterated over via a list. The

		 * maximum should stay reasonable.

		 */

		if (maxactive > KRETPROBE_MAXACTIVE_MAX) {

			trace_probe_log_err(1, MAXACT_TOO_BIG);

			goto parse_error;

			return -EINVAL;

		}

	}
@@ -931,16 +929,13 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
	if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {

		trace_probe_log_set_index(1);

		/* Check whether uprobe event specified */

		if (strchr(argv[1], '/') && strchr(argv[1], ':')) {

			ret = -ECANCELED;

			goto out;

		}

		if (strchr(argv[1], '/') && strchr(argv[1], ':'))

			return -ECANCELED;



		/* a symbol specified */

		symbol = kstrdup(argv[1], GFP_KERNEL);

		if (!symbol) {

			ret = -ENOMEM;

			goto out;

		}

		if (!symbol)

			return -ENOMEM;



		tmp = strchr(symbol, '%');

		if (tmp) {
@@ -949,7 +944,7 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
				is_return = true;

			} else {

				trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);

				goto parse_error;

				return -EINVAL;

			}

		}
@@ -957,7 +952,7 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
		ret = traceprobe_split_symbol_offset(symbol, &offset);

		if (ret || offset < 0 || offset > UINT_MAX) {

			trace_probe_log_err(0, BAD_PROBE_ADDR);

			goto parse_error;

			return -EINVAL;

		}

		ret = validate_probe_symbol(symbol);

		if (ret) {
@@ -965,17 +960,17 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
				trace_probe_log_err(0, NON_UNIQ_SYMBOL);

			else

				trace_probe_log_err(0, BAD_PROBE_ADDR);

			goto parse_error;

			return -EINVAL;

		}

		if (is_return)

			ctx.flags |= TPARG_FL_RETURN;

			ctx->flags |= TPARG_FL_RETURN;

		ret = kprobe_on_func_entry(NULL, symbol, offset);

		if (ret == 0 && !is_return)

			ctx.flags |= TPARG_FL_FENTRY;

			ctx->flags |= TPARG_FL_FENTRY;

		/* Defer the ENOENT case until register kprobe */

		if (ret == -EINVAL && is_return) {

			trace_probe_log_err(0, BAD_RETPROBE);

			goto parse_error;

			return -EINVAL;

		}

	}
@@ -984,7 +979,7 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
		ret = traceprobe_parse_event_name(&event, &group, gbuf,

						  event - argv[0]);

		if (ret)

			goto parse_error;

			return ret;

	}



	if (!event) {
@@ -1000,26 +995,24 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
	}



	argc -= 2; argv += 2;

	ctx.funcname = symbol;

	ctx->funcname = symbol;

	new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,

					       abuf, MAX_BTF_ARGS_LEN, &ctx);

					       abuf, MAX_BTF_ARGS_LEN, ctx);

	if (IS_ERR(new_argv)) {

		ret = PTR_ERR(new_argv);

		new_argv = NULL;

		goto out;

		return ret;

	}

	if (new_argv) {

		argc = new_argc;

		argv = new_argv;

	}

	if (argc > MAX_TRACE_ARGS) {

		ret = -E2BIG;

		goto out;

	}

	if (argc > MAX_TRACE_ARGS)

		return -E2BIG;



	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);

	if (ret)

		goto out;

		return ret;



	/* setup a probe */

	tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
@@ -1028,16 +1021,16 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
		ret = PTR_ERR(tk);

		/* This must return -ENOMEM, else there is a bug */

		WARN_ON_ONCE(ret != -ENOMEM);

		goto out;	/* We know tk is not allocated */

		return ret;	/* We know tk is not allocated */

	}



	/* parse arguments */

	for (i = 0; i < argc; i++) {

		trace_probe_log_set_index(i + 2);

		ctx.offset = 0;

		ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);

		ctx->offset = 0;

		ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], ctx);

		if (ret)

			goto out;	/* This can be -ENOMEM */

			return ret;	/* This can be -ENOMEM */

	}

	/* entry handler for kretprobe */

	if (is_return && tk->tp.entry_arg) {
@@ -1048,7 +1041,7 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
	ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;

	ret = traceprobe_set_print_fmt(&tk->tp, ptype);

	if (ret < 0)

		goto out;

		return ret;



	ret = register_trace_kprobe(tk);

	if (ret) {
@@ -1059,26 +1052,34 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
			trace_probe_log_err(0, BAD_PROBE_ADDR);

		else if (ret != -ENOMEM && ret != -EEXIST)

			trace_probe_log_err(0, FAIL_REG_PROBE);

	} else

		return ret;

	}

	/*

	 * Here, 'tk' has been registered to the list successfully,

	 * so we don't need to free it.

	 */

	tk = NULL;



out:

	return 0;

}



static int trace_kprobe_create_cb(int argc, const char *argv[])

{

	struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };

	int ret;



	trace_probe_log_init("trace_kprobe", argc, argv);



	ret = trace_kprobe_create_internal(argc, argv, &ctx);



	traceprobe_finish_parse(&ctx);

	trace_probe_log_clear();

	return ret;



parse_error:

	ret = -EINVAL;

	goto out;

}



static int trace_kprobe_create(const char *raw_command)

{

	return trace_probe_create(raw_command, __trace_kprobe_create);

	return trace_probe_create(raw_command, trace_kprobe_create_cb);

}



static int create_or_delete_trace_kprobe(const char *raw_command)