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trace/hwlat: Use trace_min_max_param for width and window params

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Use the trace_min_max_param to reduce code duplication.

No functional change.

Link: https://lkml.kernel.org/r/b91accd5a7c6c14ea02d3379aae974ba22b47dd6.1624372313.git.bristot@redhat.com

Cc: Phil Auld <pauld@redhat.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Kate Carcia <kcarcia@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexandre Chartre <alexandre.chartre@oracle.com>
Cc: Clark Willaims <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Daniel Bristot de Oliveira 2021-06-22 16:42:24 +02:00 committed by Steven Rostedt (VMware)
parent bc87cf0a08
commit f27a1c9e1b
1 changed files with 24 additions and 121 deletions
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145
kernel/trace/trace_hwlat.c
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@ -527,115 +527,6 @@ out_error:
return retval;
}
/*
* hwlat_read - Wrapper read function for reading both window and width
* @filp: The active open file structure
* @ubuf: The userspace provided buffer to read value into
* @cnt: The maximum number of bytes to read
* @ppos: The current "file" position
*
* This function provides a generic read implementation for the global state
* "hwlat_data" structure filesystem entries.
*/
static ssize_t hwlat_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[U64STR_SIZE];
u64 *entry = filp->private_data;
u64 val;
int len;
if (!entry)
return -EFAULT;
if (cnt > sizeof(buf))
cnt = sizeof(buf);
val = *entry;
len = snprintf(buf, sizeof(buf), "%llu\n", val);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
}
/**
* hwlat_width_write - Write function for "width" entry
* @filp: The active open file structure
* @ubuf: The user buffer that contains the value to write
* @cnt: The maximum number of bytes to write to "file"
* @ppos: The current position in @file
*
* This function provides a write implementation for the "width" interface
* to the hardware latency detector. It can be used to configure
* for how many us of the total window us we will actively sample for any
* hardware-induced latency periods. Obviously, it is not possible to
* sample constantly and have the system respond to a sample reader, or,
* worse, without having the system appear to have gone out to lunch. It
* is enforced that width is less that the total window size.
*/
static ssize_t
hwlat_width_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
u64 val;
int err;
err = kstrtoull_from_user(ubuf, cnt, 10, &val);
if (err)
return err;
mutex_lock(&hwlat_data.lock);
if (val < hwlat_data.sample_window)
hwlat_data.sample_width = val;
else
err = -EINVAL;
mutex_unlock(&hwlat_data.lock);
if (err)
return err;
return cnt;
}
/**
* hwlat_window_write - Write function for "window" entry
* @filp: The active open file structure
* @ubuf: The user buffer that contains the value to write
* @cnt: The maximum number of bytes to write to "file"
* @ppos: The current position in @file
*
* This function provides a write implementation for the "window" interface
* to the hardware latency detector. The window is the total time
* in us that will be considered one sample period. Conceptually, windows
* occur back-to-back and contain a sample width period during which
* actual sampling occurs. Can be used to write a new total window size. It
* is enforced that any value written must be greater than the sample width
* size, or an error results.
*/
static ssize_t
hwlat_window_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
u64 val;
int err;
err = kstrtoull_from_user(ubuf, cnt, 10, &val);
if (err)
return err;
mutex_lock(&hwlat_data.lock);
if (hwlat_data.sample_width < val)
hwlat_data.sample_window = val;
else
err = -EINVAL;
mutex_unlock(&hwlat_data.lock);
if (err)
return err;
return cnt;
}
static void *s_mode_start(struct seq_file *s, loff_t *pos)
{
int mode = *pos;
@ -760,16 +651,28 @@ static ssize_t hwlat_mode_write(struct file *filp, const char __user *ubuf,
return ret;
}
static const struct file_operations width_fops = {
.open = tracing_open_generic,
.read = hwlat_read,
.write = hwlat_width_write,
/*
* The width parameter is read/write using the generic trace_min_max_param
* method. The *val is protected by the hwlat_data lock and is upper
* bounded by the window parameter.
*/
static struct trace_min_max_param hwlat_width = {
.lock = &hwlat_data.lock,
.val = &hwlat_data.sample_width,
.max = &hwlat_data.sample_window,
.min = NULL,
};
static const struct file_operations window_fops = {
.open = tracing_open_generic,
.read = hwlat_read,
.write = hwlat_window_write,
/*
* The window parameter is read/write using the generic trace_min_max_param
* method. The *val is protected by the hwlat_data lock and is lower
* bounded by the width parameter.
*/
static struct trace_min_max_param hwlat_window = {
.lock = &hwlat_data.lock,
.val = &hwlat_data.sample_window,
.max = NULL,
.min = &hwlat_data.sample_width,
};
static const struct file_operations thread_mode_fops = {
@ -802,15 +705,15 @@ static int init_tracefs(void)
hwlat_sample_window = tracefs_create_file("window", 0640,
top_dir,
&hwlat_data.sample_window,
&window_fops);
&hwlat_window,
&trace_min_max_fops);
if (!hwlat_sample_window)
goto err;
hwlat_sample_width = tracefs_create_file("width", 0644,
top_dir,
&hwlat_data.sample_width,
&width_fops);
&hwlat_width,
&trace_min_max_fops);
if (!hwlat_sample_width)
goto err;