IB/iser: Use pd->local_dma_lkey

[linux-2.6/btrfs-unstable.git] / drivers / infiniband / ulp / iser / iser_memory.c

/*
 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
 * Copyright (c) 2013-2014 Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/scatterlist.h>

#include "iscsi_iser.h"
static
int iser_fast_reg_fmr(struct iscsi_iser_task *iser_task,
                      struct iser_data_buf *mem,
                      struct iser_reg_resources *rsc,
                      struct iser_mem_reg *mem_reg);
static
int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
                     struct iser_data_buf *mem,
                     struct iser_reg_resources *rsc,
                     struct iser_mem_reg *mem_reg);

static struct iser_reg_ops fastreg_ops = {
        .alloc_reg_res  = iser_alloc_fastreg_pool,
        .free_reg_res   = iser_free_fastreg_pool,
        .reg_mem        = iser_fast_reg_mr,
        .unreg_mem      = iser_unreg_mem_fastreg,
        .reg_desc_get   = iser_reg_desc_get_fr,
        .reg_desc_put   = iser_reg_desc_put_fr,
};

static struct iser_reg_ops fmr_ops = {
        .alloc_reg_res  = iser_alloc_fmr_pool,
        .free_reg_res   = iser_free_fmr_pool,
        .reg_mem        = iser_fast_reg_fmr,
        .unreg_mem      = iser_unreg_mem_fmr,
        .reg_desc_get   = iser_reg_desc_get_fmr,
        .reg_desc_put   = iser_reg_desc_put_fmr,
};

int iser_assign_reg_ops(struct iser_device *device)
{
        struct ib_device_attr *dev_attr = &device->dev_attr;

        /* Assign function handles  - based on FMR support */
        if (device->ib_device->alloc_fmr && device->ib_device->dealloc_fmr &&
            device->ib_device->map_phys_fmr && device->ib_device->unmap_fmr) {
                iser_info("FMR supported, using FMR for registration\n");
                device->reg_ops = &fmr_ops;
        } else
        if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
                iser_info("FastReg supported, using FastReg for registration\n");
                device->reg_ops = &fastreg_ops;
        } else {
                iser_err("IB device does not support FMRs nor FastRegs, can't register memory\n");
                return -1;
        }

        return 0;
}

static void
iser_free_bounce_sg(struct iser_data_buf *data)
{
        struct scatterlist *sg;
        int count;

        for_each_sg(data->sg, sg, data->size, count)
                __free_page(sg_page(sg));

        kfree(data->sg);

        data->sg = data->orig_sg;
        data->size = data->orig_size;
        data->orig_sg = NULL;
        data->orig_size = 0;
}

static int
iser_alloc_bounce_sg(struct iser_data_buf *data)
{
        struct scatterlist *sg;
        struct page *page;
        unsigned long length = data->data_len;
        int i = 0, nents = DIV_ROUND_UP(length, PAGE_SIZE);

        sg = kcalloc(nents, sizeof(*sg), GFP_ATOMIC);
        if (!sg)
                goto err;

        sg_init_table(sg, nents);
        while (length) {
                u32 page_len = min_t(u32, length, PAGE_SIZE);

                page = alloc_page(GFP_ATOMIC);
                if (!page)
                        goto err;

                sg_set_page(&sg[i], page, page_len, 0);
                length -= page_len;
                i++;
        }

        data->orig_sg = data->sg;
        data->orig_size = data->size;
        data->sg = sg;
        data->size = nents;

        return 0;

err:
        for (; i > 0; i--)
                __free_page(sg_page(&sg[i - 1]));
        kfree(sg);

        return -ENOMEM;
}

static void
iser_copy_bounce(struct iser_data_buf *data, bool to_buffer)
{
        struct scatterlist *osg, *bsg = data->sg;
        void *oaddr, *baddr;
        unsigned int left = data->data_len;
        unsigned int bsg_off = 0;
        int i;

        for_each_sg(data->orig_sg, osg, data->orig_size, i) {
                unsigned int copy_len, osg_off = 0;

                oaddr = kmap_atomic(sg_page(osg)) + osg->offset;
                copy_len = min(left, osg->length);
                while (copy_len) {
                        unsigned int len = min(copy_len, bsg->length - bsg_off);

                        baddr = kmap_atomic(sg_page(bsg)) + bsg->offset;
                        if (to_buffer)
                                memcpy(baddr + bsg_off, oaddr + osg_off, len);
                        else
                                memcpy(oaddr + osg_off, baddr + bsg_off, len);

                        kunmap_atomic(baddr - bsg->offset);
                        osg_off += len;
                        bsg_off += len;
                        copy_len -= len;

                        if (bsg_off >= bsg->length) {
                                bsg = sg_next(bsg);
                                bsg_off = 0;
                        }
                }
                kunmap_atomic(oaddr - osg->offset);
                left -= osg_off;
        }
}

static inline void
iser_copy_from_bounce(struct iser_data_buf *data)
{
        iser_copy_bounce(data, false);
}

static inline void
iser_copy_to_bounce(struct iser_data_buf *data)
{
        iser_copy_bounce(data, true);
}

struct iser_fr_desc *
iser_reg_desc_get_fr(struct ib_conn *ib_conn)
{
        struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
        struct iser_fr_desc *desc;
        unsigned long flags;

        spin_lock_irqsave(&fr_pool->lock, flags);
        desc = list_first_entry(&fr_pool->list,
                                struct iser_fr_desc, list);
        list_del(&desc->list);
        spin_unlock_irqrestore(&fr_pool->lock, flags);

        return desc;
}

void
iser_reg_desc_put_fr(struct ib_conn *ib_conn,
                     struct iser_fr_desc *desc)
{
        struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
        unsigned long flags;

        spin_lock_irqsave(&fr_pool->lock, flags);
        list_add(&desc->list, &fr_pool->list);
        spin_unlock_irqrestore(&fr_pool->lock, flags);
}

struct iser_fr_desc *
iser_reg_desc_get_fmr(struct ib_conn *ib_conn)
{
        struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;

        return list_first_entry(&fr_pool->list,
                                struct iser_fr_desc, list);
}

void
iser_reg_desc_put_fmr(struct ib_conn *ib_conn,
                      struct iser_fr_desc *desc)
{
}

/**
 * iser_start_rdma_unaligned_sg
 */
static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
                                        struct iser_data_buf *data,
                                        enum iser_data_dir cmd_dir)
{
        struct ib_device *dev = iser_task->iser_conn->ib_conn.device->ib_device;
        int rc;

        rc = iser_alloc_bounce_sg(data);
        if (rc) {
                iser_err("Failed to allocate bounce for data len %lu\n",
                         data->data_len);
                return rc;
        }

        if (cmd_dir == ISER_DIR_OUT)
                iser_copy_to_bounce(data);

        data->dma_nents = ib_dma_map_sg(dev, data->sg, data->size,
                                        (cmd_dir == ISER_DIR_OUT) ?
                                        DMA_TO_DEVICE : DMA_FROM_DEVICE);
        if (!data->dma_nents) {
                iser_err("Got dma_nents %d, something went wrong...\n",
                         data->dma_nents);
                rc = -ENOMEM;
                goto err;
        }

        return 0;
err:
        iser_free_bounce_sg(data);
        return rc;
}

/**
 * iser_finalize_rdma_unaligned_sg
 */

void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
                                     struct iser_data_buf *data,
                                     enum iser_data_dir cmd_dir)
{
        struct ib_device *dev = iser_task->iser_conn->ib_conn.device->ib_device;

        ib_dma_unmap_sg(dev, data->sg, data->size,
                        (cmd_dir == ISER_DIR_OUT) ?
                        DMA_TO_DEVICE : DMA_FROM_DEVICE);

        if (cmd_dir == ISER_DIR_IN)
                iser_copy_from_bounce(data);

        iser_free_bounce_sg(data);
}

#define IS_4K_ALIGNED(addr)     ((((unsigned long)addr) & ~MASK_4K) == 0)

/**
 * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
 * and returns the length of resulting physical address array (may be less than
 * the original due to possible compaction).
 *
 * we build a "page vec" under the assumption that the SG meets the RDMA
 * alignment requirements. Other then the first and last SG elements, all
 * the "internal" elements can be compacted into a list whose elements are
 * dma addresses of physical pages. The code supports also the weird case
 * where --few fragments of the same page-- are present in the SG as
 * consecutive elements. Also, it handles one entry SG.
 */

static int iser_sg_to_page_vec(struct iser_data_buf *data,
                               struct ib_device *ibdev, u64 *pages,
                               int *offset, int *data_size)
{
        struct scatterlist *sg, *sgl = data->sg;
        u64 start_addr, end_addr, page, chunk_start = 0;
        unsigned long total_sz = 0;
        unsigned int dma_len;
        int i, new_chunk, cur_page, last_ent = data->dma_nents - 1;

        /* compute the offset of first element */
        *offset = (u64) sgl[0].offset & ~MASK_4K;

        new_chunk = 1;
        cur_page  = 0;
        for_each_sg(sgl, sg, data->dma_nents, i) {
                start_addr = ib_sg_dma_address(ibdev, sg);
                if (new_chunk)
                        chunk_start = start_addr;
                dma_len = ib_sg_dma_len(ibdev, sg);
                end_addr = start_addr + dma_len;
                total_sz += dma_len;

                /* collect page fragments until aligned or end of SG list */
                if (!IS_4K_ALIGNED(end_addr) && i < last_ent) {
                        new_chunk = 0;
                        continue;
                }
                new_chunk = 1;

                /* address of the first page in the contiguous chunk;
                   masking relevant for the very first SG entry,
                   which might be unaligned */
                page = chunk_start & MASK_4K;
                do {
                        pages[cur_page++] = page;
                        page += SIZE_4K;
                } while (page < end_addr);
        }

        *data_size = total_sz;
        iser_dbg("page_vec->data_size:%d cur_page %d\n",
                 *data_size, cur_page);
        return cur_page;
}


/**
 * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
 * for RDMA sub-list of a scatter-gather list of memory buffers, and  returns
 * the number of entries which are aligned correctly. Supports the case where
 * consecutive SG elements are actually fragments of the same physcial page.
 */
static int iser_data_buf_aligned_len(struct iser_data_buf *data,
                                     struct ib_device *ibdev,
                                     unsigned sg_tablesize)
{
        struct scatterlist *sg, *sgl, *next_sg = NULL;
        u64 start_addr, end_addr;
        int i, ret_len, start_check = 0;

        if (data->dma_nents == 1)
                return 1;

        sgl = data->sg;
        start_addr  = ib_sg_dma_address(ibdev, sgl);

        if (unlikely(sgl[0].offset &&
                     data->data_len >= sg_tablesize * PAGE_SIZE)) {
                iser_dbg("can't register length %lx with offset %x "
                         "fall to bounce buffer\n", data->data_len,
                         sgl[0].offset);
                return 0;
        }

        for_each_sg(sgl, sg, data->dma_nents, i) {
                if (start_check && !IS_4K_ALIGNED(start_addr))
                        break;

                next_sg = sg_next(sg);
                if (!next_sg)
                        break;

                end_addr    = start_addr + ib_sg_dma_len(ibdev, sg);
                start_addr  = ib_sg_dma_address(ibdev, next_sg);

                if (end_addr == start_addr) {
                        start_check = 0;
                        continue;
                } else
                        start_check = 1;

                if (!IS_4K_ALIGNED(end_addr))
                        break;
        }
        ret_len = (next_sg) ? i : i+1;

        if (unlikely(ret_len != data->dma_nents))
                iser_warn("rdma alignment violation (%d/%d aligned)\n",
                          ret_len, data->dma_nents);

        return ret_len;
}

static void iser_data_buf_dump(struct iser_data_buf *data,
                               struct ib_device *ibdev)
{
        struct scatterlist *sg;
        int i;

        for_each_sg(data->sg, sg, data->dma_nents, i)
                iser_dbg("sg[%d] dma_addr:0x%lX page:0x%p "
                         "off:0x%x sz:0x%x dma_len:0x%x\n",
                         i, (unsigned long)ib_sg_dma_address(ibdev, sg),
                         sg_page(sg), sg->offset,
                         sg->length, ib_sg_dma_len(ibdev, sg));
}

static void iser_dump_page_vec(struct iser_page_vec *page_vec)
{
        int i;

        iser_err("page vec length %d data size %d\n",
                 page_vec->length, page_vec->data_size);
        for (i = 0; i < page_vec->length; i++)
                iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
}

int iser_dma_map_task_data(struct iscsi_iser_task *iser_task,
                            struct iser_data_buf *data,
                            enum iser_data_dir iser_dir,
                            enum dma_data_direction dma_dir)
{
        struct ib_device *dev;

        iser_task->dir[iser_dir] = 1;
        dev = iser_task->iser_conn->ib_conn.device->ib_device;

        data->dma_nents = ib_dma_map_sg(dev, data->sg, data->size, dma_dir);
        if (data->dma_nents == 0) {
                iser_err("dma_map_sg failed!!!\n");
                return -EINVAL;
        }
        return 0;
}

void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
                              struct iser_data_buf *data,
                              enum dma_data_direction dir)
{
        struct ib_device *dev;

        dev = iser_task->iser_conn->ib_conn.device->ib_device;
        ib_dma_unmap_sg(dev, data->sg, data->size, dir);
}

static int
iser_reg_dma(struct iser_device *device, struct iser_data_buf *mem,
             struct iser_mem_reg *reg)
{
        struct scatterlist *sg = mem->sg;

        reg->sge.lkey = device->pd->local_dma_lkey;
        reg->rkey = device->mr->rkey;
        reg->sge.addr = ib_sg_dma_address(device->ib_device, &sg[0]);
        reg->sge.length = ib_sg_dma_len(device->ib_device, &sg[0]);

        iser_dbg("Single DMA entry: lkey=0x%x, rkey=0x%x, addr=0x%llx,"
                 " length=0x%x\n", reg->sge.lkey, reg->rkey,
                 reg->sge.addr, reg->sge.length);

        return 0;
}

static int fall_to_bounce_buf(struct iscsi_iser_task *iser_task,
                              struct iser_data_buf *mem,
                              enum iser_data_dir cmd_dir)
{
        struct iscsi_conn *iscsi_conn = iser_task->iser_conn->iscsi_conn;
        struct iser_device *device = iser_task->iser_conn->ib_conn.device;

        iscsi_conn->fmr_unalign_cnt++;

        if (iser_debug_level > 0)
                iser_data_buf_dump(mem, device->ib_device);

        /* unmap the command data before accessing it */
        iser_dma_unmap_task_data(iser_task, mem,
                                 (cmd_dir == ISER_DIR_OUT) ?
                                 DMA_TO_DEVICE : DMA_FROM_DEVICE);

        /* allocate copy buf, if we are writing, copy the */
        /* unaligned scatterlist, dma map the copy        */
        if (iser_start_rdma_unaligned_sg(iser_task, mem, cmd_dir) != 0)
                return -ENOMEM;

        return 0;
}

/**
 * iser_reg_page_vec - Register physical memory
 *
 * returns: 0 on success, errno code on failure
 */
static
int iser_fast_reg_fmr(struct iscsi_iser_task *iser_task,
                      struct iser_data_buf *mem,
                      struct iser_reg_resources *rsc,
                      struct iser_mem_reg *reg)
{
        struct ib_conn *ib_conn = &iser_task->iser_conn->ib_conn;
        struct iser_device *device = ib_conn->device;
        struct iser_page_vec *page_vec = rsc->page_vec;
        struct ib_fmr_pool *fmr_pool = rsc->fmr_pool;
        struct ib_pool_fmr *fmr;
        int ret, plen;

        plen = iser_sg_to_page_vec(mem, device->ib_device,
                                   page_vec->pages,
                                   &page_vec->offset,
                                   &page_vec->data_size);
        page_vec->length = plen;
        if (plen * SIZE_4K < page_vec->data_size) {
                iser_err("page vec too short to hold this SG\n");
                iser_data_buf_dump(mem, device->ib_device);
                iser_dump_page_vec(page_vec);
                return -EINVAL;
        }

        fmr  = ib_fmr_pool_map_phys(fmr_pool,
                                    page_vec->pages,
                                    page_vec->length,
                                    page_vec->pages[0]);
        if (IS_ERR(fmr)) {
                ret = PTR_ERR(fmr);
                iser_err("ib_fmr_pool_map_phys failed: %d\n", ret);
                return ret;
        }

        reg->sge.lkey = fmr->fmr->lkey;
        reg->rkey = fmr->fmr->rkey;
        reg->sge.addr = page_vec->pages[0] + page_vec->offset;
        reg->sge.length = page_vec->data_size;
        reg->mem_h = fmr;

        iser_dbg("fmr reg: lkey=0x%x, rkey=0x%x, addr=0x%llx,"
                 " length=0x%x\n", reg->sge.lkey, reg->rkey,
                 reg->sge.addr, reg->sge.length);

        return 0;
}

/**
 * Unregister (previosuly registered using FMR) memory.
 * If memory is non-FMR does nothing.
 */
void iser_unreg_mem_fmr(struct iscsi_iser_task *iser_task,
                        enum iser_data_dir cmd_dir)
{
        struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];
        int ret;

        if (!reg->mem_h)
                return;

        iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n", reg->mem_h);

        ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);
        if (ret)
                iser_err("ib_fmr_pool_unmap failed %d\n", ret);

        reg->mem_h = NULL;
}

void iser_unreg_mem_fastreg(struct iscsi_iser_task *iser_task,
                            enum iser_data_dir cmd_dir)
{
        struct iser_device *device = iser_task->iser_conn->ib_conn.device;
        struct iser_mem_reg *reg = &iser_task->rdma_reg[cmd_dir];

        if (!reg->mem_h)
                return;

        device->reg_ops->reg_desc_put(&iser_task->iser_conn->ib_conn,
                                     reg->mem_h);
        reg->mem_h = NULL;
}

static void
iser_set_dif_domain(struct scsi_cmnd *sc, struct ib_sig_attrs *sig_attrs,
                    struct ib_sig_domain *domain)
{
        domain->sig_type = IB_SIG_TYPE_T10_DIF;
        domain->sig.dif.pi_interval = scsi_prot_interval(sc);
        domain->sig.dif.ref_tag = scsi_prot_ref_tag(sc);
        /*
         * At the moment we hard code those, but in the future
         * we will take them from sc.
         */
        domain->sig.dif.apptag_check_mask = 0xffff;
        domain->sig.dif.app_escape = true;
        domain->sig.dif.ref_escape = true;
        if (sc->prot_flags & SCSI_PROT_REF_INCREMENT)
                domain->sig.dif.ref_remap = true;
};

static int
iser_set_sig_attrs(struct scsi_cmnd *sc, struct ib_sig_attrs *sig_attrs)
{
        switch (scsi_get_prot_op(sc)) {
        case SCSI_PROT_WRITE_INSERT:
        case SCSI_PROT_READ_STRIP:
                sig_attrs->mem.sig_type = IB_SIG_TYPE_NONE;
                iser_set_dif_domain(sc, sig_attrs, &sig_attrs->wire);
                sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
                break;
        case SCSI_PROT_READ_INSERT:
        case SCSI_PROT_WRITE_STRIP:
                sig_attrs->wire.sig_type = IB_SIG_TYPE_NONE;
                iser_set_dif_domain(sc, sig_attrs, &sig_attrs->mem);
                sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
                                                IB_T10DIF_CSUM : IB_T10DIF_CRC;
                break;
        case SCSI_PROT_READ_PASS:
        case SCSI_PROT_WRITE_PASS:
                iser_set_dif_domain(sc, sig_attrs, &sig_attrs->wire);
                sig_attrs->wire.sig.dif.bg_type = IB_T10DIF_CRC;
                iser_set_dif_domain(sc, sig_attrs, &sig_attrs->mem);
                sig_attrs->mem.sig.dif.bg_type = sc->prot_flags & SCSI_PROT_IP_CHECKSUM ?
                                                IB_T10DIF_CSUM : IB_T10DIF_CRC;
                break;
        default:
                iser_err("Unsupported PI operation %d\n",
                         scsi_get_prot_op(sc));
                return -EINVAL;
        }

        return 0;
}

static inline void
iser_set_prot_checks(struct scsi_cmnd *sc, u8 *mask)
{
        *mask = 0;
        if (sc->prot_flags & SCSI_PROT_REF_CHECK)
                *mask |= ISER_CHECK_REFTAG;
        if (sc->prot_flags & SCSI_PROT_GUARD_CHECK)
                *mask |= ISER_CHECK_GUARD;
}

static void
iser_inv_rkey(struct ib_send_wr *inv_wr, struct ib_mr *mr)
{
        u32 rkey;

        inv_wr->opcode = IB_WR_LOCAL_INV;
        inv_wr->wr_id = ISER_FASTREG_LI_WRID;
        inv_wr->ex.invalidate_rkey = mr->rkey;
        inv_wr->send_flags = 0;
        inv_wr->num_sge = 0;

        rkey = ib_inc_rkey(mr->rkey);
        ib_update_fast_reg_key(mr, rkey);
}

static int
iser_reg_sig_mr(struct iscsi_iser_task *iser_task,
                struct iser_pi_context *pi_ctx,
                struct iser_mem_reg *data_reg,
                struct iser_mem_reg *prot_reg,
                struct iser_mem_reg *sig_reg)
{
        struct iser_tx_desc *tx_desc = &iser_task->desc;
        struct ib_sig_attrs *sig_attrs = &tx_desc->sig_attrs;
        struct ib_send_wr *wr;
        int ret;

        memset(sig_attrs, 0, sizeof(*sig_attrs));
        ret = iser_set_sig_attrs(iser_task->sc, sig_attrs);
        if (ret)
                goto err;

        iser_set_prot_checks(iser_task->sc, &sig_attrs->check_mask);

        if (!pi_ctx->sig_mr_valid) {
                wr = iser_tx_next_wr(tx_desc);
                iser_inv_rkey(wr, pi_ctx->sig_mr);
        }

        wr = iser_tx_next_wr(tx_desc);
        wr->opcode = IB_WR_REG_SIG_MR;
        wr->wr_id = ISER_FASTREG_LI_WRID;
        wr->sg_list = &data_reg->sge;
        wr->num_sge = 1;
        wr->send_flags = 0;
        wr->wr.sig_handover.sig_attrs = sig_attrs;
        wr->wr.sig_handover.sig_mr = pi_ctx->sig_mr;
        if (scsi_prot_sg_count(iser_task->sc))
                wr->wr.sig_handover.prot = &prot_reg->sge;
        else
                wr->wr.sig_handover.prot = NULL;
        wr->wr.sig_handover.access_flags = IB_ACCESS_LOCAL_WRITE |
                                           IB_ACCESS_REMOTE_READ |
                                           IB_ACCESS_REMOTE_WRITE;
        pi_ctx->sig_mr_valid = 0;

        sig_reg->sge.lkey = pi_ctx->sig_mr->lkey;
        sig_reg->rkey = pi_ctx->sig_mr->rkey;
        sig_reg->sge.addr = 0;
        sig_reg->sge.length = scsi_transfer_length(iser_task->sc);

        iser_dbg("sig reg: lkey: 0x%x, rkey: 0x%x, addr: 0x%llx, length: %u\n",
                 sig_reg->sge.lkey, sig_reg->rkey, sig_reg->sge.addr,
                 sig_reg->sge.length);
err:
        return ret;
}

static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
                            struct iser_data_buf *mem,
                            struct iser_reg_resources *rsc,
                            struct iser_mem_reg *reg)
{
        struct ib_conn *ib_conn = &iser_task->iser_conn->ib_conn;
        struct iser_device *device = ib_conn->device;
        struct ib_mr *mr = rsc->mr;
        struct ib_fast_reg_page_list *frpl = rsc->frpl;
        struct iser_tx_desc *tx_desc = &iser_task->desc;
        struct ib_send_wr *wr;
        int offset, size, plen;

        plen = iser_sg_to_page_vec(mem, device->ib_device, frpl->page_list,
                                   &offset, &size);
        if (plen * SIZE_4K < size) {
                iser_err("fast reg page_list too short to hold this SG\n");
                return -EINVAL;
        }

        if (!rsc->mr_valid) {
                wr = iser_tx_next_wr(tx_desc);
                iser_inv_rkey(wr, mr);
        }

        wr = iser_tx_next_wr(tx_desc);
        wr->opcode = IB_WR_FAST_REG_MR;
        wr->wr_id = ISER_FASTREG_LI_WRID;
        wr->send_flags = 0;
        wr->wr.fast_reg.iova_start = frpl->page_list[0] + offset;
        wr->wr.fast_reg.page_list = frpl;
        wr->wr.fast_reg.page_list_len = plen;
        wr->wr.fast_reg.page_shift = SHIFT_4K;
        wr->wr.fast_reg.length = size;
        wr->wr.fast_reg.rkey = mr->rkey;
        wr->wr.fast_reg.access_flags = (IB_ACCESS_LOCAL_WRITE  |
                                        IB_ACCESS_REMOTE_WRITE |
                                        IB_ACCESS_REMOTE_READ);
        rsc->mr_valid = 0;

        reg->sge.lkey = mr->lkey;
        reg->rkey = mr->rkey;
        reg->sge.addr = frpl->page_list[0] + offset;
        reg->sge.length = size;

        iser_dbg("fast reg: lkey=0x%x, rkey=0x%x, addr=0x%llx,"
                 " length=0x%x\n", reg->sge.lkey, reg->rkey,
                 reg->sge.addr, reg->sge.length);

        return 0;
}

static int
iser_handle_unaligned_buf(struct iscsi_iser_task *task,
                          struct iser_data_buf *mem,
                          enum iser_data_dir dir)
{
        struct iser_conn *iser_conn = task->iser_conn;
        struct iser_device *device = iser_conn->ib_conn.device;
        int err, aligned_len;

        aligned_len = iser_data_buf_aligned_len(mem, device->ib_device,
                                                iser_conn->scsi_sg_tablesize);
        if (aligned_len != mem->dma_nents) {
                err = fall_to_bounce_buf(task, mem, dir);
                if (err)
                        return err;
        }

        return 0;
}

static int
iser_reg_prot_sg(struct iscsi_iser_task *task,
                 struct iser_data_buf *mem,
                 struct iser_fr_desc *desc,
                 struct iser_mem_reg *reg)
{
        struct iser_device *device = task->iser_conn->ib_conn.device;

        if (mem->dma_nents == 1)
                return iser_reg_dma(device, mem, reg);

        return device->reg_ops->reg_mem(task, mem, &desc->pi_ctx->rsc, reg);
}

static int
iser_reg_data_sg(struct iscsi_iser_task *task,
                 struct iser_data_buf *mem,
                 struct iser_fr_desc *desc,
                 struct iser_mem_reg *reg)
{
        struct iser_device *device = task->iser_conn->ib_conn.device;

        if (mem->dma_nents == 1)
                return iser_reg_dma(device, mem, reg);

        return device->reg_ops->reg_mem(task, mem, &desc->rsc, reg);
}

int iser_reg_rdma_mem(struct iscsi_iser_task *task,
                      enum iser_data_dir dir)
{
        struct ib_conn *ib_conn = &task->iser_conn->ib_conn;
        struct iser_device *device = ib_conn->device;
        struct iser_data_buf *mem = &task->data[dir];
        struct iser_mem_reg *reg = &task->rdma_reg[dir];
        struct iser_mem_reg *data_reg;
        struct iser_fr_desc *desc = NULL;
        int err;

        err = iser_handle_unaligned_buf(task, mem, dir);
        if (unlikely(err))
                return err;

        if (mem->dma_nents != 1 ||
            scsi_get_prot_op(task->sc) != SCSI_PROT_NORMAL) {
                desc = device->reg_ops->reg_desc_get(ib_conn);
                reg->mem_h = desc;
        }

        if (scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL)
                data_reg = reg;
        else
                data_reg = &task->desc.data_reg;

        err = iser_reg_data_sg(task, mem, desc, data_reg);
        if (unlikely(err))
                goto err_reg;

        if (scsi_get_prot_op(task->sc) != SCSI_PROT_NORMAL) {
                struct iser_mem_reg *prot_reg = &task->desc.prot_reg;

                if (scsi_prot_sg_count(task->sc)) {
                        mem = &task->prot[dir];
                        err = iser_handle_unaligned_buf(task, mem, dir);
                        if (unlikely(err))
                                goto err_reg;

                        err = iser_reg_prot_sg(task, mem, desc, prot_reg);
                        if (unlikely(err))
                                goto err_reg;
                }

                err = iser_reg_sig_mr(task, desc->pi_ctx, data_reg,
                                      prot_reg, reg);
                if (unlikely(err))
                        goto err_reg;

                desc->pi_ctx->sig_protected = 1;
        }

        return 0;

err_reg:
        if (desc)
                device->reg_ops->reg_desc_put(ib_conn, desc);

        return err;
}

void iser_unreg_rdma_mem(struct iscsi_iser_task *task,
                         enum iser_data_dir dir)
{
        struct iser_device *device = task->iser_conn->ib_conn.device;

        device->reg_ops->unreg_mem(task, dir);
}