/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef BLK_MQ_DMA_H
#define BLK_MQ_DMA_H

#include <linux/blk-mq.h>
#include <linux/pci-p2pdma.h>

struct blk_map_iter {
        struct bvec_iter                iter;
        struct bio                      *bio;
        struct bio_vec                  *bvecs;
        bool                            is_integrity;
};

struct blk_dma_iter {
        /* Output address range for this iteration */
        dma_addr_t                      addr;
        u32                             len;
        struct pci_p2pdma_map_state     p2pdma;

        /* Status code. Only valid when blk_rq_dma_map_iter_* returned false */
        blk_status_t                    status;

        /* Internal to blk_rq_dma_map_iter_* */
        struct blk_map_iter             iter;
};

bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev,
                struct dma_iova_state *state, struct blk_dma_iter *iter);
bool blk_rq_dma_map_iter_next(struct request *req, struct device *dma_dev,
                struct blk_dma_iter *iter);

/**
 * blk_rq_dma_map_coalesce - were all segments coalesced?
 * @state: DMA state to check
 *
 * Returns true if blk_rq_dma_map_iter_start coalesced all segments into a
 * single DMA range.
 */
static inline bool blk_rq_dma_map_coalesce(struct dma_iova_state *state)
{
        return dma_use_iova(state);
}

/**
 * blk_rq_dma_unmap - try to DMA unmap a request
 * @req:        request to unmap
 * @dma_dev:    device to unmap from
 * @state:      DMA IOVA state
 * @mapped_len: number of bytes to unmap
 * @map:        peer-to-peer mapping type
 *
 * Returns %false if the callers need to manually unmap every DMA segment
 * mapped using @iter or %true if no work is left to be done.
 */
static inline bool blk_rq_dma_unmap(struct request *req, struct device *dma_dev,
                struct dma_iova_state *state, size_t mapped_len,
                enum pci_p2pdma_map_type map)
{
        if (map == PCI_P2PDMA_MAP_BUS_ADDR)
                return true;

        if (dma_use_iova(state)) {
                unsigned int attrs = 0;

                if (map == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE)
                        attrs |= DMA_ATTR_MMIO;

                dma_iova_destroy(dma_dev, state, mapped_len, rq_dma_dir(req),
                                 attrs);
                return true;
        }

        return !dma_need_unmap(dma_dev);
}
#endif /* BLK_MQ_DMA_H */