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Commit eb361653 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
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sysfs: implement bin_buffer 



Implement bin_buffer which contains a mutex and pointer to PAGE_SIZE
buffer to properly synchronize accesses to per-openfile buffer and
prepare for immediate-kobj-disconnect.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 2b29ac25

fs/sysfs/bin.c

+49 −15
Original line number Diff line number Diff line
@@ -20,6 +20,11 @@ 


#include "sysfs.h"



struct bin_buffer {

	struct mutex	mutex;

	void		*buffer;

};



static int

fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)

{
@@ -36,7 +41,7 @@ fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count) 
static ssize_t

read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off)

{

	char *buffer = file->private_data;

	struct bin_buffer *bb = file->private_data;

	struct dentry *dentry = file->f_path.dentry;

	int size = dentry->d_inode->i_size;

	loff_t offs = *off;
@@ -49,17 +54,23 @@ read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off) 
			count = size - offs;

	}



	count = fill_read(dentry, buffer, offs, count);

	mutex_lock(&bb->mutex);



	count = fill_read(dentry, bb->buffer, offs, count);

	if (count < 0)

		return count;

		goto out_unlock;



	if (copy_to_user(userbuf, buffer, count))

		return -EFAULT;

	if (copy_to_user(userbuf, bb->buffer, count)) {

		count = -EFAULT;

		goto out_unlock;

	}



	pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);



	*off = offs + count;



 out_unlock:

	mutex_unlock(&bb->mutex);

	return count;

}
@@ -79,7 +90,7 @@ flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count) 
static ssize_t write(struct file *file, const char __user *userbuf,

		     size_t bytes, loff_t *off)

{

	char *buffer = file->private_data;

	struct bin_buffer *bb = file->private_data;

	struct dentry *dentry = file->f_path.dentry;

	int size = dentry->d_inode->i_size;

	loff_t offs = *off;
@@ -92,25 +103,38 @@ static ssize_t write(struct file *file, const char __user *userbuf, 
			count = size - offs;

	}



	if (copy_from_user(buffer, userbuf, count))

		return -EFAULT;

	mutex_lock(&bb->mutex);



	if (copy_from_user(bb->buffer, userbuf, count)) {

		count = -EFAULT;

		goto out_unlock;

	}



	count = flush_write(dentry, buffer, offs, count);

	count = flush_write(dentry, bb->buffer, offs, count);

	if (count > 0)

		*off = offs + count;



 out_unlock:

	mutex_unlock(&bb->mutex);

	return count;

}



static int mmap(struct file *file, struct vm_area_struct *vma)

{

	struct bin_buffer *bb = file->private_data;

	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;

	struct bin_attribute *attr = attr_sd->s_elem.bin_attr.bin_attr;

	struct kobject *kobj = to_kobj(file->f_path.dentry->d_parent);

	int rc;



	if (!attr->mmap)

		return -EINVAL;



	return attr->mmap(kobj, attr, vma);

	mutex_lock(&bb->mutex);

	rc = attr->mmap(kobj, attr, vma);

	mutex_unlock(&bb->mutex);



	return rc;

}



static int open(struct inode * inode, struct file * file)
@@ -118,6 +142,7 @@ static int open(struct inode * inode, struct file * file) 
	struct kobject *kobj = sysfs_get_kobject(file->f_path.dentry->d_parent);

	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;

	struct bin_attribute *attr = attr_sd->s_elem.bin_attr.bin_attr;

	struct bin_buffer *bb = NULL;

	int error = -EINVAL;



	if (!kobj || !attr)
@@ -135,14 +160,22 @@ static int open(struct inode * inode, struct file * file) 
		goto Error;



	error = -ENOMEM;

	file->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);

	if (!file->private_data)

	bb = kzalloc(sizeof(*bb), GFP_KERNEL);

	if (!bb)

		goto Error;



	bb->buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);

	if (!bb->buffer)

		goto Error;



	mutex_init(&bb->mutex);

	file->private_data = bb;



	error = 0;

	goto Done;



 Error:

	kfree(bb);

	module_put(attr->attr.owner);

 Done:

	if (error)
@@ -155,11 +188,12 @@ static int release(struct inode * inode, struct file * file) 
	struct kobject * kobj = to_kobj(file->f_path.dentry->d_parent);

	struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;

	struct bin_attribute *attr = attr_sd->s_elem.bin_attr.bin_attr;

	u8 * buffer = file->private_data;

	struct bin_buffer *bb = file->private_data;



	kobject_put(kobj);

	module_put(attr->attr.owner);

	kfree(buffer);

	kfree(bb->buffer);

	kfree(bb);

	return 0;

}