Re: [PATCH 16/21] sysfs: implement bin_buffer

[Satyam Sharma]

On 4/28/07, Tejun Heo <htejun@xxxxxxxxx> wrote:
> 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: Tejun Heo <htejun@xxxxxxxxx>
> ---
> [...]
> @@ -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);

You could simply do a __get_free_page() here instead of a kmalloc(PAGE_SIZE).

> @@ -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);

And so this would become free_page().
-
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