linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (C) 2016 CNEX Labs

 * Initial release: Javier Gonzalez <javier@cnexlabs.com>

 *

 * Based upon the circular ringbuffer.

 *

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

 * modify it under the terms of the GNU General Public License version

 * 2 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.

 *

 * pblk-rb.c - pblk's write buffer

 */

​

#include <linux/circ_buf.h>

​

#include "pblk.h"

​

static DECLARE_RWSEM(pblk_rb_lock);

​

static void pblk_rb_data_free(struct pblk_rb *rb)

{

    struct pblk_rb_pages *p, *t;

​

    down_write(&pblk_rb_lock);

    list_for_each_entry_safe(p, t, &rb->pages, list) {

        free_pages((unsigned long)page_address(p->pages), p->order);

        list_del(&p->list);

        kfree(p);

    }

    up_write(&pblk_rb_lock);

}

​

void pblk_rb_free(struct pblk_rb *rb)

{

    pblk_rb_data_free(rb);

    vfree(rb->entries);

}

​

/*

 * pblk_rb_calculate_size -- calculate the size of the write buffer

 */

static unsigned int pblk_rb_calculate_size(unsigned int nr_entries,

                       unsigned int threshold)

{

    unsigned int thr_sz = 1 << (get_count_order(threshold + NVM_MAX_VLBA));

    unsigned int max_sz = max(thr_sz, nr_entries);

    unsigned int max_io;

​

    /* Alloc a write buffer that can (i) fit at least two split bios

     * (considering max I/O size NVM_MAX_VLBA, and (ii) guarantee that the

     * threshold will be respected

     */

    max_io = (1 << max((int)(get_count_order(max_sz)),

                (int)(get_count_order(NVM_MAX_VLBA << 1))));

    if ((threshold + NVM_MAX_VLBA) >= max_io)

        max_io <<= 1;

​