iser_memory.c

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/*
 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. 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"

#define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */

static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
                    enum iser_data_dir cmd_dir)
{
    int dma_nents;
    struct ib_device *dev;
    char *mem = NULL;
    struct iser_data_buf *data = &iser_task->data[cmd_dir];
    unsigned long  cmd_data_len = data->data_len;

    if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
        mem = (void *)__get_free_pages(GFP_ATOMIC,
              ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
    else
        mem = kmalloc(cmd_data_len, GFP_ATOMIC);

    if (mem == NULL) {
        iser_err("Failed to allocate mem size %d %d for copying sglist\n",
             data->size,(int)cmd_data_len);
        return -ENOMEM;
    }

    if (cmd_dir == ISER_DIR_OUT) {
        /* copy the unaligned sg the buffer which is used for RDMA */
        struct scatterlist *sgl = (struct scatterlist *)data->buf;
        struct scatterlist *sg;
        int i;
        char *p, *from;

        p = mem;
        for_each_sg(sgl, sg, data->size, i) {
            from = kmap_atomic(sg_page(sg));
            memcpy(p,
                   from + sg->offset,
                   sg->length);
            kunmap_atomic(from);
            p += sg->length;
        }
    }

    sg_init_one(&iser_task->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
    iser_task->data_copy[cmd_dir].buf  =
        &iser_task->data_copy[cmd_dir].sg_single;
    iser_task->data_copy[cmd_dir].size = 1;

    iser_task->data_copy[cmd_dir].copy_buf  = mem;

    dev = iser_task->iser_conn->ib_conn->device->ib_device;
    dma_nents = ib_dma_map_sg(dev,
                  &iser_task->data_copy[cmd_dir].sg_single,
                  1,
                  (cmd_dir == ISER_DIR_OUT) ?
                  DMA_TO_DEVICE : DMA_FROM_DEVICE);
    BUG_ON(dma_nents == 0);

    iser_task->data_copy[cmd_dir].dma_nents = dma_nents;
    return 0;
}

void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
                     enum iser_data_dir         cmd_dir)
{
    struct ib_device *dev;
    struct iser_data_buf *mem_copy;
    unsigned long  cmd_data_len;

    dev = iser_task->iser_conn->ib_conn->device->ib_device;
    mem_copy = &iser_task->data_copy[cmd_dir];

    ib_dma_unmap_sg(dev, &mem_copy->sg_single, 1,
            (cmd_dir == ISER_DIR_OUT) ?
            DMA_TO_DEVICE : DMA_FROM_DEVICE);

    if (cmd_dir == ISER_DIR_IN) {
        char *mem;
        struct scatterlist *sgl, *sg;
        unsigned char *p, *to;
        unsigned int sg_size;
        int i;

        /* copy back read RDMA to unaligned sg */
        mem = mem_copy->copy_buf;

        sgl = (struct scatterlist *)iser_task->data[ISER_DIR_IN].buf;
        sg_size = iser_task->data[ISER_DIR_IN].size;

        p = mem;
        for_each_sg(sgl, sg, sg_size, i) {
            to = kmap_atomic(sg_page(sg));
            memcpy(to + sg->offset,
                   p,
                   sg->length);
            kunmap_atomic(to);
            p += sg->length;
        }
    }

    cmd_data_len = iser_task->data[cmd_dir].data_len;

    if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
        free_pages((unsigned long)mem_copy->copy_buf,
               ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
    else
        kfree(mem_copy->copy_buf);

    mem_copy->copy_buf = NULL;
}

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

static int iser_sg_to_page_vec(struct iser_data_buf *data,
                   struct iser_page_vec *page_vec,
                   struct ib_device *ibdev)
{
    struct scatterlist *sg, *sgl = (struct scatterlist *)data->buf;
    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 */
    page_vec->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 {
            page_vec->pages[cur_page++] = page;
            page += SIZE_4K;
        } while (page < end_addr);
    }

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


static int iser_data_buf_aligned_len(struct iser_data_buf *data,
                      struct ib_device *ibdev)
{
    struct scatterlist *sgl, *sg, *next_sg = NULL;
    u64 start_addr, end_addr;
    int i, ret_len, start_check = 0;

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

    sgl = (struct scatterlist *)data->buf;
    start_addr  = ib_sg_dma_address(ibdev, sgl);

    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;
    iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
         ret_len, data->dma_nents, data);
    return ret_len;
}

static void iser_data_buf_dump(struct iser_data_buf *data,
                   struct ib_device *ibdev)
{
    struct scatterlist *sgl = (struct scatterlist *)data->buf;
    struct scatterlist *sg;
    int i;

    if (iser_debug_level == 0)
        return;

    for_each_sg(sgl, sg, data->dma_nents, i)
        iser_warn("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]);
}

static void iser_page_vec_build(struct iser_data_buf *data,
                struct iser_page_vec *page_vec,
                struct ib_device *ibdev)
{
    int page_vec_len = 0;

    page_vec->length = 0;
    page_vec->offset = 0;

    iser_dbg("Translating sg sz: %d\n", data->dma_nents);
    page_vec_len = iser_sg_to_page_vec(data, page_vec, ibdev);
    iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);

    page_vec->length = page_vec_len;

    if (page_vec_len * SIZE_4K < page_vec->data_size) {
        iser_err("page_vec too short to hold this SG\n");
        iser_data_buf_dump(data, ibdev);
        iser_dump_page_vec(page_vec);
        BUG();
    }
}

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->buf, 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 ib_device *dev;
    struct iser_data_buf *data;

    dev = iser_task->iser_conn->ib_conn->device->ib_device;

    if (iser_task->dir[ISER_DIR_IN]) {
        data = &iser_task->data[ISER_DIR_IN];
        ib_dma_unmap_sg(dev, data->buf, data->size, DMA_FROM_DEVICE);
    }

    if (iser_task->dir[ISER_DIR_OUT]) {
        data = &iser_task->data[ISER_DIR_OUT];
        ib_dma_unmap_sg(dev, data->buf, data->size, DMA_TO_DEVICE);
    }
}

int iser_reg_rdma_mem(struct iscsi_iser_task *iser_task,
              enum   iser_data_dir        cmd_dir)
{
    struct iscsi_conn    *iscsi_conn = iser_task->iser_conn->iscsi_conn;
    struct iser_conn     *ib_conn = iser_task->iser_conn->ib_conn;
    struct iser_device   *device = ib_conn->device;
    struct ib_device     *ibdev = device->ib_device;
    struct iser_data_buf *mem = &iser_task->data[cmd_dir];
    struct iser_regd_buf *regd_buf;
    int aligned_len;
    int err;
    int i;
    struct scatterlist *sg;

    regd_buf = &iser_task->rdma_regd[cmd_dir];

    aligned_len = iser_data_buf_aligned_len(mem, ibdev);
    if (aligned_len != mem->dma_nents) {
        iscsi_conn->fmr_unalign_cnt++;
        iser_warn("rdma alignment violation %d/%d aligned\n",
             aligned_len, mem->size);
        iser_data_buf_dump(mem, ibdev);

        /* unmap the command data before accessing it */
        iser_dma_unmap_task_data(iser_task);

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

    /* if there a single dma entry, FMR is not needed */
    if (mem->dma_nents == 1) {
        sg = (struct scatterlist *)mem->buf;

        regd_buf->reg.lkey = device->mr->lkey;
        regd_buf->reg.rkey = device->mr->rkey;
        regd_buf->reg.len  = ib_sg_dma_len(ibdev, &sg[0]);
        regd_buf->reg.va   = ib_sg_dma_address(ibdev, &sg[0]);
        regd_buf->reg.is_fmr = 0;

        iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X  "
             "va: 0x%08lX sz: %ld]\n",
             (unsigned int)regd_buf->reg.lkey,
             (unsigned int)regd_buf->reg.rkey,
             (unsigned long)regd_buf->reg.va,
             (unsigned long)regd_buf->reg.len);
    } else { /* use FMR for multiple dma entries */
        iser_page_vec_build(mem, ib_conn->page_vec, ibdev);
        err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, &regd_buf->reg);
        if (err) {
            iser_data_buf_dump(mem, ibdev);
            iser_err("mem->dma_nents = %d (dlength = 0x%x)\n",
                 mem->dma_nents,
                 ntoh24(iser_task->desc.iscsi_header.dlength));
            iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",
                 ib_conn->page_vec->data_size, ib_conn->page_vec->length,
                 ib_conn->page_vec->offset);
            for (i=0 ; i<ib_conn->page_vec->length ; i++)
                iser_err("page_vec[%d] = 0x%llx\n", i,
                     (unsigned long long) ib_conn->page_vec->pages[i]);
            return err;
        }
    }
    return 0;
}