From 13f16d209161c95e92aef40e350cc6cf56ac440b Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 8 Dec 2009 11:16:11 +0800 Subject: [PATCH] tracing: Use seq file for trace_clock The buffer for the output is as small as 64 bytes, so it'll overflow if we add more clock type. Use seq file instead. Signed-off-by: Li Zefan Acked-by: Steven Rostedt LKML-Reference: <4B1DC4FB.5030407@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a6c41cc..886268e 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3366,21 +3366,18 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, return cnt; } -static ssize_t tracing_clock_read(struct file *filp, char __user *ubuf, - size_t cnt, loff_t *ppos) +static int tracing_clock_show(struct seq_file *m, void *v) { - char buf[64]; - int bufiter = 0; int i; for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) - bufiter += snprintf(buf + bufiter, sizeof(buf) - bufiter, + seq_printf(m, "%s%s%s%s", i ? " " : "", i == trace_clock_id ? "[" : "", trace_clocks[i].name, i == trace_clock_id ? "]" : ""); - bufiter += snprintf(buf + bufiter, sizeof(buf) - bufiter, "\n"); + seq_putc(m, '\n'); - return simple_read_from_buffer(ubuf, cnt, ppos, buf, bufiter); + return 0; } static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, @@ -3422,6 +3419,13 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf, return cnt; } +static int tracing_clock_open(struct inode *inode, struct file *file) +{ + if (tracing_disabled) + return -ENODEV; + return single_open(file, tracing_clock_show, NULL); +} + static const struct file_operations tracing_max_lat_fops = { .open = tracing_open_generic, .read = tracing_max_lat_read, @@ -3460,8 +3464,10 @@ static const struct file_operations tracing_mark_fops = { }; static const struct file_operations trace_clock_fops = { - .open = tracing_open_generic, - .read = tracing_clock_read, + .open = tracing_clock_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, .write = tracing_clock_write, }; -- 2.7.4