// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
/* Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. */

#include <linux/export.h>
#include <rdma/iter.h>

void __rdma_block_iter_start(struct ib_block_iter *biter,
                             struct scatterlist *sglist, unsigned int nents,
                             unsigned long pgsz)
{
        memset(biter, 0, sizeof(struct ib_block_iter));
        biter->__sg = sglist;
        biter->__sg_nents = nents;

        /* Driver provides best block size to use */
        biter->__pg_bit = __fls(pgsz);
}
EXPORT_SYMBOL(__rdma_block_iter_start);

bool __rdma_block_iter_next(struct ib_block_iter *biter)
{
        dma_addr_t block_offset;
        dma_addr_t delta;

        if (!biter->__sg_nents || !biter->__sg)
                return false;

        biter->__dma_addr = sg_dma_address(biter->__sg) + biter->__sg_advance;
        block_offset = biter->__dma_addr & (BIT_ULL(biter->__pg_bit) - 1);
        delta = BIT_ULL(biter->__pg_bit) - block_offset;

        while (biter->__sg_nents && biter->__sg &&
               sg_dma_len(biter->__sg) - biter->__sg_advance <= delta) {
                delta -= sg_dma_len(biter->__sg) - biter->__sg_advance;
                biter->__sg_advance = 0;
                biter->__sg = sg_next(biter->__sg);
                biter->__sg_nents--;
        }
        biter->__sg_advance += delta;

        return true;
}
EXPORT_SYMBOL(__rdma_block_iter_next);