From fdb372ed4cadbfe9dbba0e932a77d0523682e690 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 8 Dec 2009 11:15:59 +0800 Subject: [PATCH] tracing: Use seq file for trace_options Code simplification for reading trace_options. Signed-off-by: Li Zefan Acked-by: Steven Rostedt LKML-reference: <4B1DC4EF.3090106@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace.c | 60 +++++++++++++------------------------------- 1 file changed, 17 insertions(+), 43 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 88bd9ae2a9ed..a6c41cc63285 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2316,67 +2316,32 @@ static const struct file_operations tracing_cpumask_fops = { .write = tracing_cpumask_write, }; -static ssize_t -tracing_trace_options_read(struct file *filp, char __user *ubuf, - size_t cnt, loff_t *ppos) +static int tracing_trace_options_show(struct seq_file *m, void *v) { struct tracer_opt *trace_opts; u32 tracer_flags; - int len = 0; - char *buf; - int r = 0; int i; - - /* calculate max size */ - for (i = 0; trace_options[i]; i++) { - len += strlen(trace_options[i]); - len += 3; /* "no" and newline */ - } - mutex_lock(&trace_types_lock); tracer_flags = current_trace->flags->val; trace_opts = current_trace->flags->opts; - /* - * Increase the size with names of options specific - * of the current tracer. - */ - for (i = 0; trace_opts[i].name; i++) { - len += strlen(trace_opts[i].name); - len += 3; /* "no" and newline */ - } - - /* +1 for \0 */ - buf = kmalloc(len + 1, GFP_KERNEL); - if (!buf) { - mutex_unlock(&trace_types_lock); - return -ENOMEM; - } - for (i = 0; trace_options[i]; i++) { if (trace_flags & (1 << i)) - r += sprintf(buf + r, "%s\n", trace_options[i]); + seq_printf(m, "%s\n", trace_options[i]); else - r += sprintf(buf + r, "no%s\n", trace_options[i]); + seq_printf(m, "no%s\n", trace_options[i]); } for (i = 0; trace_opts[i].name; i++) { if (tracer_flags & trace_opts[i].bit) - r += sprintf(buf + r, "%s\n", - trace_opts[i].name); + seq_printf(m, "%s\n", trace_opts[i].name); else - r += sprintf(buf + r, "no%s\n", - trace_opts[i].name); + seq_printf(m, "no%s\n", trace_opts[i].name); } mutex_unlock(&trace_types_lock); - WARN_ON(r >= len + 1); - - r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); - - kfree(buf); - return r; + return 0; } /* Try to assign a tracer specific option */ @@ -2471,9 +2436,18 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, return cnt; } +static int tracing_trace_options_open(struct inode *inode, struct file *file) +{ + if (tracing_disabled) + return -ENODEV; + return single_open(file, tracing_trace_options_show, NULL); +} + static const struct file_operations tracing_iter_fops = { - .open = tracing_open_generic, - .read = tracing_trace_options_read, + .open = tracing_trace_options_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, .write = tracing_trace_options_write, }; -- 2.20.1