lkml.org 
[lkml]   [2014]   [Oct]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] sysfs - allow attributes to request write buffer be pre-allocated.
Hello,

Generally looks good to me. Some nitpicks follow.

On Tue, Sep 30, 2014 at 12:33:34PM +1000, NeilBrown wrote:
...
> diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
> index 4429d6d9217f..73bd5ed143cd 100644
> --- a/fs/kernfs/file.c
> +++ b/fs/kernfs/file.c
> @@ -278,16 +278,12 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
> len = min_t(size_t, count, PAGE_SIZE);
> }
>
> - buf = kmalloc(len + 1, GFP_KERNEL);
> + buf = of->buf;
> + if (!buf)
> + buf = kmalloc(len + 1, GFP_KERNEL);
> if (!buf)
> return -ENOMEM;
>
> - if (copy_from_user(buf, user_buf, len)) {
> - len = -EFAULT;
> - goto out_free;
> - }
> - buf[len] = '\0'; /* guarantee string termination */
> -
> /*
> * @of->mutex nests outside active ref and is just to ensure that
> * the ops aren't called concurrently for the same open file.

We probably should update the above comment.

> diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
> index 30faf797c2c3..07c326761671 100644
> --- a/include/linux/kernfs.h
> +++ b/include/linux/kernfs.h
> @@ -179,6 +179,7 @@ struct kernfs_open_file {
> struct mutex mutex;
> int event;
> struct list_head list;
> + char *buf;

Maybe something like ->prealloc_buf is better?

Thanks.

--
tejun


\
 
 \ /
  Last update: 2014-10-05 22:21    [W:0.040 / U:0.128 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site