Messages in this thread Patch in this message | | | Date | Mon, 07 Dec 2009 15:42:31 +0800 | From | Li Zefan <> | Subject | [PATCH 08/13] tracing: Use seq file for trace_clock |
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The buffer for the output is as small as 64 bytes, so it'll overflow if we add more clock types. Use seq file instead.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> --- kernel/trace/trace.c | 24 +++++++++++++++--------- 1 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e989fc9..75871e5 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3327,21 +3327,18 @@ 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, @@ -3383,6 +3380,13 @@ 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, @@ -3421,8 +3425,10 @@ 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, }; -- 1.6.3
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