linux-imx

/*

 * Copyright (C) 2016 Facebook

 * Copyright (C) 2013-2014 Jens Axboe

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public

 * License v2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */

​

#include <linux/sched.h>

#include <linux/random.h>

#include <linux/sbitmap.h>

#include <linux/seq_file.h>

​

/*

 * See if we have deferred clears that we can batch move

 */

static inline bool sbitmap_deferred_clear(struct sbitmap *sb, int index)

{

    unsigned long mask, val;

    bool ret = false;

    unsigned long flags;

​

    spin_lock_irqsave(&sb->map[index].swap_lock, flags);

​

    if (!sb->map[index].cleared)

        goto out_unlock;

​

    /*

     * First get a stable cleared mask, setting the old mask to 0.

     */

    do {

        mask = sb->map[index].cleared;

    } while (cmpxchg(&sb->map[index].cleared, mask, 0) != mask);

​

    /*

     * Now clear the masked bits in our free word

     */

    do {

        val = sb->map[index].word;

    } while (cmpxchg(&sb->map[index].word, val, val & ~mask) != val);

​

    ret = true;

out_unlock:

    spin_unlock_irqrestore(&sb->map[index].swap_lock, flags);

    return ret;

}

​

int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,

              gfp_t flags, int node)

{

    unsigned int bits_per_word;

    unsigned int i;

​

    if (shift < 0) {