From mboxrd@z Thu Jan  1 00:00:00 1970
From: compudj@krystal.dyndns.org (Mathieu Desnoyers)
Date: Wed, 4 Mar 2009 12:10:22 -0500
Subject: [ltt-dev] [PATCH] LTTNG: Make marker enabled in advance
In-Reply-To: <49AC9C77.5050206@cn.fujitsu.com>
References: <49AC9C77.5050206@cn.fujitsu.com>
Message-ID: <20090304171022.GA2554@Krystal>

* Gui Jianfeng (guijianfeng at cn.fujitsu.com) wrote:
> Hi Mathieu,
> 
> This patch makes marker enabled in advance.
> IOW, even if the marker isn't present for the moment,
> you can still enable it for future use.
> As soon as the marker is inserted into kernel, tracing 
> work can be started immediately.
> 
> Here is an example for using the user interface:
> This patch assumes the marker control patch is applied.
> 
> [root at localhost markers]# cd /mnt/debugfs/ltt/markers
> [root at localhost markers]# mkdir fs
> [root at localhost markers]# cd fs
> [root at localhost fs]# mkdir close
> [root at localhost fs]# cd close/
> [root at localhost close]# ls
> enable  info
> [root at localhost close]# echo 1 > enable
> [root at localhost close]# cat enable
> 2
> [root at localhost close]# cat info
> marker is not present now!
> [root at localhost close]# modprobe fs_trace
> [root at localhost close]# cat enable
> 1
> [root at localhost close]# cat info
> format: "fd %u"
> state: 1
> event_id: 1
> call: 0xc0468167
> probe single : 0xc0520cdc
> 
> Signed-off-by: Gui Jianfeng <guijianfeng at cn.fujitsu.com>
> ---
>  ltt/ltt-trace-control.c |  357 ++++++++++++++++++++++++++++++++---------------
>  1 files changed, 247 insertions(+), 110 deletions(-)
> 
> diff --git a/ltt/ltt-trace-control.c b/ltt/ltt-trace-control.c
> index 128db4e..7e1c32e 100644
> --- a/ltt/ltt-trace-control.c
> +++ b/ltt/ltt-trace-control.c
> @@ -19,6 +19,7 @@
>  #include <linux/debugfs.h>
>  #include <linux/ltt-tracer.h>
>  #include <linux/notifier.h>
> +#include <linux/mutex.h>
>  
>  #define LTT_CONTROL_DIR "control"
>  #define MARKERS_CONTROL_DIR "markers"
> @@ -27,9 +28,240 @@
>  
>  #define LTT_WRITE_MAXLEN	(128)
>  
> +#define MARKER_ENABLE_MASK 0x7UL

What is this doing ?

> +
> +static DEFINE_MUTEX(unload_mutex);

Can you tell me exactly what this protects, where it is nested ?

Mathieu

> +
>  struct dentry *ltt_control_dir, *ltt_setup_trace_file, *ltt_destroy_trace_file,
>  	*markers_control_dir;
>  
> +#define get_marker_addr(p) \
> +	((struct marker *)((unsigned long)p & ~MARKER_ENABLE_MASK))
> +#define is_pre_enabled(p) ((unsigned long)p & MARKER_ENABLE_MASK)
> +
> +static int marker_enable_open(struct inode *inode, struct file *filp)
> +{
> +	filp->private_data = inode->i_private;
> +	return 0;
> +}
> +
> +static ssize_t marker_enable_read(struct file *filp, char __user *ubuf,
> +			    size_t cnt, loff_t *ppos)
> +{
> +	struct marker *marker;
> +	char *buf;
> +	int len;
> +
> +	marker = get_marker_addr(filp->private_data);
> +	buf = kmalloc(1024, GFP_KERNEL);
> +
> +	if (marker)
> +		len = sprintf(buf, "%d\n", _imv_read(marker->state));
> +	else {
> +		if (is_pre_enabled(filp->private_data))
> +			len = sprintf(buf, "%d\n", 2);
> +		else
> +			len = sprintf(buf, "%d\n", 0);
> +	}
> +	len = simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
> +	kfree(buf);
> +
> +	return len;
> +}
> +
> +static ssize_t marker_enable_write(struct file *filp, const char __user *ubuf,
> +				size_t cnt, loff_t *ppos)
> +{
> +	char buf[NAME_MAX];
> +	int buf_size;
> +	int err = 0;
> +	struct marker *marker;
> +	const char *channel_name, *marker_name;
> +
> +	marker = get_marker_addr(filp->private_data);
> +	if (marker) {
> +		marker_name = marker->name;
> +		channel_name = marker->channel;
> +	} else {
> +		marker_name = filp->f_dentry->d_parent->d_name.name;
> +		channel_name = filp->f_dentry->d_parent->d_parent->d_name.name;
> +		filp->f_dentry->d_inode->i_private = (void *)1;
> +	}
> +
> +	buf_size = min(cnt, sizeof(buf) - 1);
> +	err = copy_from_user(buf, ubuf, buf_size);
> +	if (err)
> +		return err;
> +
> +	buf[buf_size] = 0;
> +
> +	switch (buf[0]) {
> +	case 'Y':
> +	case 'y':
> +	case '1':
> +		err = ltt_marker_connect(channel_name, marker_name,
> +					 "default");
> +		if (err)
> +			return err;
> +		break;
> +	case 'N':
> +	case 'n':
> +	case '0':
> +		err = ltt_marker_disconnect(channel_name,
> +					    marker_name, "default");
> +		if (err)
> +			return err;
> +		break;
> +	default:
> +		return -EPERM;
> +	}
> +
> +	return cnt;
> +}
> +
> +static const struct file_operations enable_fops = {
> +	.open = marker_enable_open,
> +	.read = marker_enable_read,
> +	.write = marker_enable_write,
> +};
> +
> +static int marker_info_open(struct inode *inode, struct file *filp)
> +{
> +	filp->private_data = inode->i_private;
> +	return 0;
> +}
> +
> +static ssize_t marker_info_read(struct file *filp, char __user *ubuf,
> +			    size_t cnt, loff_t *ppos)
> +{
> +	struct marker *marker;
> +	char *buf;
> +	int len;
> +
> +	marker = get_marker_addr(filp->private_data);
> +	buf = kmalloc(1024, GFP_KERNEL);
> +
> +	if (marker)
> +		len = sprintf(buf, "format: \"%s\"\nstate: %d\n"
> +			      "event_id: %hu\n"
> +			      "call: 0x%p\n"
> +			      "probe %s : 0x%p\n",
> +			      marker->format, _imv_read(marker->state),
> +			      marker->event_id, marker->call, marker->ptype ?
> +			      "multi" : "single", marker->ptype ?
> +			      (void *)marker->multi :
> +			      (void *)marker->single.func);
> +	else
> +		len = sprintf(buf, "marker is not present now!\n");
> +
> +	len = simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
> +	kfree(buf);
> +
> +	return len;
> +}
> +
> +static const struct file_operations info_fops = {
> +	.open = marker_info_open,
> +	.read = marker_info_read,
> +};
> +
> +void init_marker_dir(struct dentry *dentry, const struct inode_operations *opt)
> +{
> +	dentry->d_inode->i_op = opt;
> +}
> +
> +static int marker_mkdir(struct inode *dir, struct dentry *dentry, int mode)
> +{
> +	struct dentry *marker_d, *enable_d, *info_d, *channel_d;
> +	int ret;
> +
> +	ret = 0;
> +	channel_d = (struct dentry *)dir->i_private;
> +	mutex_unlock(&dir->i_mutex);
> +
> +	/*
> +	 * Prevent from removing files
> +	 */
> +	mutex_lock(&unload_mutex);
> +
> +	marker_d = debugfs_create_dir(dentry->d_name.name,
> +				       channel_d);
> +	if (IS_ERR(marker_d)) {
> +		ret = PTR_ERR(marker_d);
> +		goto out;
> +	}
> +
> +	enable_d = debugfs_create_file("enable", 0644, marker_d,
> +				       NULL, &enable_fops);
> +	if (IS_ERR(enable_d) || !enable_d) {
> +		printk(KERN_ERR
> +		       "%s: create file of %s failed\n",
> +		       __func__, "enable");
> +		ret = -ENOMEM;
> +		goto remove_marker_dir;
> +	}
> +
> +	info_d = debugfs_create_file("info", 0644, marker_d,
> +				       NULL, &info_fops);
> +	if (IS_ERR(info_d) || !info_d) {
> +		printk(KERN_ERR
> +		       "%s: create file of %s failed\n",
> +		       __func__, "info");
> +		ret = -ENOMEM;
> +		goto remove_enable_dir;
> +	}
> +
> +	goto out;
> +
> +remove_enable_dir:
> +	debugfs_remove(enable_d);
> +remove_marker_dir:
> +	debugfs_remove(marker_d);
> +out:
> +	mutex_unlock(&unload_mutex);
> +	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
> +	return ret;
> +}
> +
> +const struct inode_operations channel_dir_opt = {
> +	.lookup         = simple_lookup,
> +	.mkdir          = marker_mkdir,
> +};
> +
> +static int channel_mkdir(struct inode *dir, struct dentry *dentry, int mode)
> +{
> +	struct dentry *channel_d;
> +	int ret;
> +
> +	ret = 0;
> +	mutex_unlock(&dir->i_mutex);
> +
> +	/*
> +	 * Prevent from removing files
> +	 */
> +	mutex_lock(&unload_mutex);
> +
> +	channel_d = debugfs_create_dir(dentry->d_name.name,
> +				       markers_control_dir);
> +	if (IS_ERR(channel_d)) {
> +		ret = PTR_ERR(channel_d);
> +		goto out;
> +	}
> +
> +	channel_d->d_inode->i_private = (void *)channel_d;
> +	init_marker_dir(channel_d, &channel_dir_opt);
> +
> +out:
> +	mutex_unlock(&unload_mutex);
> +	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
> +	return ret;
> +}
> +
> +const struct inode_operations marker_control_root_dir_opt = {
> +	.lookup         = simple_lookup,
> +	.mkdir          = channel_mkdir,
> +};
> +
>  /*
>   * the traces_lock nests inside control_lock.
>   */
> @@ -697,112 +929,6 @@ static struct file_operations ltt_destroy_trace_operations = {
>  	.write = destroy_trace_write,
>  };
>  
> -static int marker_enable_open(struct inode *inode, struct file *filp)
> -{
> -	filp->private_data = inode->i_private;
> -	return 0;
> -}
> -
> -static ssize_t marker_enable_read(struct file *filp, char __user *ubuf,
> -			    size_t cnt, loff_t *ppos)
> -{
> -	struct marker *marker;
> -	char *buf;
> -	int len;
> -
> -	marker = (struct marker *)filp->private_data;
> -	buf = kmalloc(1024, GFP_KERNEL);
> -
> -	len = sprintf(buf, "%d\n", _imv_read(marker->state));
> -
> -	len = simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
> -	kfree(buf);
> -
> -	return len;
> -}
> -
> -static ssize_t marker_enable_write(struct file *filp, const char __user *ubuf,
> -				size_t cnt, loff_t *ppos)
> -{
> -	char buf[NAME_MAX];
> -	int buf_size;
> -	int err = 0;
> -	struct marker *marker;
> -
> -	marker = (struct marker *)filp->private_data;
> -	buf_size = min(cnt, sizeof(buf) - 1);
> -	err = copy_from_user(buf, ubuf, buf_size);
> -	if (err)
> -		return err;
> -
> -	buf[buf_size] = 0;
> -
> -	switch (buf[0]) {
> -	case 'Y':
> -	case 'y':
> -	case '1':
> -		err = ltt_marker_connect(marker->channel, marker->name,
> -					 "default");
> -		if (err)
> -			return err;
> -		break;
> -	case 'N':
> -	case 'n':
> -	case '0':
> -		err = ltt_marker_disconnect(marker->channel, marker->name,
> -					    "default");
> -		if (err)
> -			return err;
> -		break;
> -	default:
> -		return -EPERM;
> -	}
> -
> -	return cnt;
> -}
> -
> -static const struct file_operations enable_fops = {
> -	.open = marker_enable_open,
> -	.read = marker_enable_read,
> -	.write = marker_enable_write,
> -};
> -
> -static int marker_info_open(struct inode *inode, struct file *filp)
> -{
> -	filp->private_data = inode->i_private;
> -	return 0;
> -}
> -
> -static ssize_t marker_info_read(struct file *filp, char __user *ubuf,
> -			    size_t cnt, loff_t *ppos)
> -{
> -	struct marker *marker;
> -	char *buf;
> -	int len;
> -
> -	marker = (struct marker *)filp->private_data;
> -	buf = kmalloc(1024, GFP_KERNEL);
> -
> -	len = sprintf(buf, "format: \"%s\"\nstate: %d\n"
> -		      "event_id: %hu\n"
> -		      "call: 0x%p\n"
> -		      "probe %s : 0x%p\n",
> -		      marker->format, _imv_read(marker->state),
> -		      marker->event_id, marker->call, marker->ptype ?
> -		      "multi" : "single", marker->ptype ?
> -		      (void *)marker->multi : (void *)marker->single.func);
> -
> -	len = simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
> -	kfree(buf);
> -
> -	return len;
> -}
> -
> -static const struct file_operations info_fops = {
> -	.open = marker_info_open,
> -	.read = marker_info_read,
> -};
> -
>  static int build_marker_file(struct marker *marker)
>  {
>  	struct dentry *channel_d, *marker_d, *enable_d, *info_d;
> @@ -820,8 +946,10 @@ static int build_marker_file(struct marker *marker)
>  			goto err_build_fail;
>  		}
>  	}
> +	channel_d->d_inode->i_private = (void *)channel_d;
> +	init_marker_dir(channel_d, &channel_dir_opt);
>  
> -	marker_d  = dir_lookup(channel_d, marker->name);
> +	marker_d = dir_lookup(channel_d, marker->name);
>  	if (!marker_d) {
>  		marker_d = debugfs_create_dir(marker->name, channel_d);
>  		if (IS_ERR(marker_d) || !marker_d) {
> @@ -832,6 +960,7 @@ static int build_marker_file(struct marker *marker)
>  			goto err_build_fail;
>  		}
>  	}
> +	marker_d->d_inode->i_private = (void *)marker_d;
>  
>  	enable_d = dir_lookup(marker_d, "enable");
>  	if (!enable_d) {
> @@ -844,7 +973,8 @@ static int build_marker_file(struct marker *marker)
>  			err = -ENOMEM;
>  			goto err_build_fail;
>  		}
> -	}
> +	} else
> +		enable_d->d_inode->i_private = (void *)marker;
>  
>  	info_d = dir_lookup(marker_d, "info");
>  	if (!info_d) {
> @@ -857,7 +987,8 @@ static int build_marker_file(struct marker *marker)
>  			err = -ENOMEM;
>  			goto err_build_fail;
>  		}
> -	}
> +	} else
> +		info_d->d_inode->i_private = (void *)marker;
>  
>  	return 0;
>  
> @@ -892,6 +1023,7 @@ static int remove_marker_control_dir(struct marker *marker)
>  {
>  	struct dentry *channel_d, *marker_d;
>  
> +	mutex_lock(&unload_mutex);
>  	channel_d = dir_lookup(markers_control_dir, marker->channel);
>  	if (!channel_d)
>  		return -ENOENT;
> @@ -904,6 +1036,7 @@ static int remove_marker_control_dir(struct marker *marker)
>  	if (list_empty(&channel_d->d_subdirs))
>  		debugfs_remove(channel_d);
>  
> +	mutex_unlock(&unload_mutex);
>  	return 0;
>  }
>  
> @@ -1012,6 +1145,8 @@ static int __init ltt_trace_control_init(void)
>  		goto err_create_marker_control_dir;
>  	}
>  
> +	init_marker_dir(markers_control_dir, &marker_control_root_dir_opt);
> +
>  	if (build_marker_control_files())
>  		goto err_build_fail;
>  
> @@ -1036,6 +1171,7 @@ static void __exit ltt_trace_control_exit(void)
>  {
>  	struct dentry *trace_dir;
>  
> +	mutex_lock(&unload_mutex);
>  	/* destory all traces */
>  	list_for_each_entry(trace_dir, &ltt_control_dir->d_subdirs,
>  		d_u.d_child) {
> @@ -1046,9 +1182,10 @@ static void __exit ltt_trace_control_exit(void)
>  	/* clean dirs in debugfs */
>  	debugfs_remove(ltt_setup_trace_file);
>  	debugfs_remove(ltt_destroy_trace_file);
> -	debugfs_remove_recursive(ltt_control_dir);
>  	debugfs_remove_recursive(markers_control_dir);
> +	debugfs_remove_recursive(ltt_control_dir);
>  	unregister_module_notifier(&module_nb);
> +	mutex_unlock(&unload_mutex);
>  }
>  
>  module_init(ltt_trace_control_init);
> -- 
> 1.5.4.rc3
> 
> 
> 
> 
> 
> 
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> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68