On Thu 30-07-15 13:48:00, Dongsheng Yang wrote:
> There is a lot of duplicated code in get_super and user_get_super.
> This commit introduc a __get_super as a common function to reduce
> the duplication of it.
>
> Signed-off-by: Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx>
The patch looks good to me. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxxx>
Honza
> ---
> fs/super.c | 64 ++++++++++++++++++++++++++++++--------------------------------
> 1 file changed, 31 insertions(+), 33 deletions(-)
>
> diff --git a/fs/super.c b/fs/super.c
> index fadb677..46fd1f1 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -559,19 +559,20 @@ void iterate_supers_type(struct file_system_type *type,
> }
> EXPORT_SYMBOL(iterate_supers_type);
>
> -/**
> - * get_super - get the superblock of a device
> - * @bdev: device to get the superblock for
> - *
> - * Scans the superblock list and finds the superblock of the file system
> - * mounted on the device given. %NULL is returned if no match is found.
> +/*
> + * __get_super - helper function for the other functions in get_super class
> + * @compare: function pointer to compare sb in list and key
> + * @key: key of the sb you want
> + *
> + * Scans the superblock list and finds the superblock you want. %NULL is
> + * returned if no match is found.
> */
> -
> -struct super_block *get_super(struct block_device *bdev)
> +static struct super_block *__get_super(
> + int (*compare)(struct super_block *, void *), void *key)
> {
> struct super_block *sb;
>
> - if (!bdev)
> + if (!key)
> return NULL;
>
> spin_lock(&sb_lock);
> @@ -579,7 +580,7 @@ rescan:
> list_for_each_entry(sb, &super_blocks, s_list) {
> if (hlist_unhashed(&sb->s_instances))
> continue;
> - if (sb->s_bdev == bdev) {
> + if (compare(sb, key)) {
> sb->s_count++;
> spin_unlock(&sb_lock);
> down_read(&sb->s_umount);
> @@ -596,6 +597,20 @@ rescan:
> spin_unlock(&sb_lock);
> return NULL;
> }
> +
> +static int bdev_compare(struct super_block *sb, void *key)
> +{
> + return (sb->s_bdev == (struct block_device *)key);
> +}
> +
> +/**
> + * get_super - get the superblock of a device
> + * @bdev: device to get the superblock for
> + */
> +struct super_block *get_super(struct block_device *bdev)
> +{
> + return __get_super(bdev_compare, bdev);
> +}
> EXPORT_SYMBOL(get_super);
>
> /**
> @@ -651,32 +666,15 @@ restart:
> spin_unlock(&sb_lock);
> return NULL;
> }
> +
> +static int user_compare(struct super_block *sb, void *key)
> +{
> + return (sb->s_dev == *(dev_t *)key);
> +}
>
> struct super_block *user_get_super(dev_t dev)
> {
> - struct super_block *sb;
> -
> - spin_lock(&sb_lock);
> -rescan:
> - list_for_each_entry(sb, &super_blocks, s_list) {
> - if (hlist_unhashed(&sb->s_instances))
> - continue;
> - if (sb->s_dev == dev) {
> - sb->s_count++;
> - spin_unlock(&sb_lock);
> - down_read(&sb->s_umount);
> - /* still alive? */
> - if (sb->s_root && (sb->s_flags & MS_BORN))
> - return sb;
> - up_read(&sb->s_umount);
> - /* nope, got unmounted */
> - spin_lock(&sb_lock);
> - __put_super(sb);
> - goto rescan;
> - }
> - }
> - spin_unlock(&sb_lock);
> - return NULL;
> + return __get_super(user_compare, &dev);
> }
>
> /**
> --
> 1.8.4.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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