// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2019 Christoph Hellwig.
 */
#include "xfs_platform.h"

static inline unsigned int bio_max_vecs(unsigned int count)
{
        return bio_max_segs(howmany(count, PAGE_SIZE));
}

int
xfs_rw_bdev(
        struct block_device     *bdev,
        sector_t                sector,
        unsigned int            count,
        char                    *data,
        enum req_op             op)

{
        unsigned int            done = 0, added;
        int                     error;
        struct bio              *bio;

        op |= REQ_META | REQ_SYNC;
        if (!is_vmalloc_addr(data))
                return bdev_rw_virt(bdev, sector, data, count, op);

        bio = bio_alloc(bdev, bio_max_vecs(count), op, GFP_KERNEL);
        bio->bi_iter.bi_sector = sector;

        do {
                added = bio_add_vmalloc_chunk(bio, data + done, count - done);
                if (!added) {
                        struct bio      *prev = bio;

                        bio = bio_alloc(prev->bi_bdev,
                                        bio_max_vecs(count - done),
                                        prev->bi_opf, GFP_KERNEL);
                        bio->bi_iter.bi_sector = bio_end_sector(prev);
                        bio_chain(prev, bio);
                        submit_bio(prev);
                }
                done += added;
        } while (done < count);

        error = submit_bio_wait(bio);
        bio_put(bio);

        if (op == REQ_OP_READ)
                invalidate_kernel_vmap_range(data, count);
        return error;
}