Unmatched semaphore usage in fs/super.c

["Peter Teoh" <htmldeveloper@xxxxxxxxx>]

In fs/super.c, I saw a down_read() without a matching up_read() as shown below:

/**
 *      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.
 */

struct super_block * get_super(struct block_device *bdev)
{
        struct super_block *sb;

        if (!bdev)
                return NULL;

        spin_lock(&sb_lock);
rescan:
        list_for_each_entry(sb, &super_blocks, s_list) {
                if (sb->s_bdev == bdev) {
                        sb->s_count++;
                        spin_unlock(&sb_lock);
                        down_read(&sb->s_umount);
                        if (sb->s_root)
                                return sb;
                        up_read(&sb->s_umount);
                        /* restart only when sb is no longer on the list */
                        spin_lock(&sb_lock);
                        if (__put_super_and_need_restart(sb))
                                goto rescan;
                }
        }
        spin_unlock(&sb_lock);
        return NULL;
}

EXPORT_SYMBOL(get_super);

Neither did the get_super() caller remember and correct the semaphore
either.   Is this a problem?

Thanks.

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