freebsd-src/sys/dev/iser/iser_memory.c

/* $FreeBSD$ */
/*-
 * Copyright (c) 2015, Mellanox Technologies, Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "icl_iser.h"

static struct fast_reg_descriptor *
iser_reg_desc_get(struct ib_conn *ib_conn)
{
	struct fast_reg_descriptor *desc;

	mtx_lock(&ib_conn->lock);
	desc = list_first_entry(&ib_conn->fastreg.pool,
				struct fast_reg_descriptor, list);
	list_del(&desc->list);
	mtx_unlock(&ib_conn->lock);

	return (desc);
}

static void
iser_reg_desc_put(struct ib_conn *ib_conn,
		  struct fast_reg_descriptor *desc)
{
	mtx_lock(&ib_conn->lock);
	list_add(&desc->list, &ib_conn->fastreg.pool);
	mtx_unlock(&ib_conn->lock);
}

#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->sgl;
	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;

	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)
{
	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->sgl;
	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;

	return (ret_len);
}

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

	dev = iser_pdu->iser_conn->ib_conn.device->ib_device;
	ib_dma_unmap_sg(dev, data->sgl, 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->sgl;

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

	return (0);
}

/**
 * TODO: This should be a verb
 * iser_ib_inc_rkey - increments the key portion of the given rkey. Can be used
 * for calculating a new rkey for type 2 memory windows.
 * @rkey - the rkey to increment.
 */
static inline u32
iser_ib_inc_rkey(u32 rkey)
{
	const u32 mask = 0x000000ff;

	return (((rkey + 1) & mask) | (rkey & ~mask));
}

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

	memset(inv_wr, 0, sizeof(*inv_wr));
	inv_wr->opcode = IB_WR_LOCAL_INV;
	inv_wr->wr_id = ISER_FASTREG_LI_WRID;
	inv_wr->ex.invalidate_rkey = mr->rkey;

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

static int
iser_fast_reg_mr(struct icl_iser_pdu *iser_pdu,
		 struct iser_data_buf *mem,
		 struct iser_reg_resources *rsc,
		 struct iser_mem_reg *reg)
{
	struct ib_conn *ib_conn = &iser_pdu->iser_conn->ib_conn;
	struct iser_device *device = ib_conn->device;
	struct ib_send_wr fastreg_wr, inv_wr;
	struct ib_send_wr *bad_wr, *wr = NULL;
	int ret, offset, size, plen;

	/* if there a single dma entry, dma mr suffices */
	if (mem->dma_nents == 1)
		return iser_reg_dma(device, mem, reg);

	/* rsc is not null */
	plen = iser_sg_to_page_vec(mem, device->ib_device,
				   rsc->frpl->page_list,
				   &offset, &size);
	if (plen * SIZE_4K < size) {
		ISER_ERR("fast reg page_list too short to hold this SG");
		return (EINVAL);
	}

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

	/* Prepare FASTREG WR */
	memset(&fastreg_wr, 0, sizeof(fastreg_wr));
	fastreg_wr.wr_id = ISER_FASTREG_LI_WRID;
	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
	fastreg_wr.wr.fast_reg.iova_start = rsc->frpl->page_list[0] + offset;
	fastreg_wr.wr.fast_reg.page_list = rsc->frpl;
	fastreg_wr.wr.fast_reg.page_list_len = plen;
	fastreg_wr.wr.fast_reg.page_shift = SHIFT_4K;
	fastreg_wr.wr.fast_reg.length = size;
	fastreg_wr.wr.fast_reg.rkey = rsc->mr->rkey;
	fastreg_wr.wr.fast_reg.access_flags = (IB_ACCESS_LOCAL_WRITE  |
					       IB_ACCESS_REMOTE_WRITE |
					       IB_ACCESS_REMOTE_READ);

	if (!wr)
		wr = &fastreg_wr;
	else
		wr->next = &fastreg_wr;

	ret = ib_post_send(ib_conn->qp, wr, &bad_wr);
	if (ret) {
		ISER_ERR("fast registration failed, ret:%d", ret);
		return (ret);
	}
	rsc->mr_valid = 0;

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

	return (ret);
}

/**
 * iser_reg_rdma_mem - Registers memory intended for RDMA,
 * using Fast Registration WR (if possible) obtaining rkey and va
 *
 * returns 0 on success, errno code on failure
 */
int
iser_reg_rdma_mem(struct icl_iser_pdu *iser_pdu,
		  enum iser_data_dir cmd_dir)
{
	struct ib_conn *ib_conn = &iser_pdu->iser_conn->ib_conn;
	struct iser_device   *device = ib_conn->device;
	struct ib_device     *ibdev = device->ib_device;
	struct iser_data_buf *mem = &iser_pdu->data[cmd_dir];
	struct iser_mem_reg *mem_reg = &iser_pdu->rdma_reg[cmd_dir];
	struct fast_reg_descriptor *desc = NULL;
	int err, aligned_len;

	aligned_len = iser_data_buf_aligned_len(mem, ibdev);
	if (aligned_len != mem->dma_nents) {
		ISER_ERR("bounce buffer is not supported");
		return 1;
	}

	if (mem->dma_nents != 1) {
		desc = iser_reg_desc_get(ib_conn);
		mem_reg->mem_h = desc;
	}

	err = iser_fast_reg_mr(iser_pdu, mem, desc ? &desc->rsc : NULL,
				       mem_reg);
	if (err)
		goto err_reg;

	return (0);

err_reg:
	if (desc)
		iser_reg_desc_put(ib_conn, desc);

	return (err);
}

void
iser_unreg_rdma_mem(struct icl_iser_pdu *iser_pdu,
		    enum iser_data_dir cmd_dir)
{
	struct iser_mem_reg *reg = &iser_pdu->rdma_reg[cmd_dir];

	if (!reg->mem_h)
		return;

	iser_reg_desc_put(&iser_pdu->iser_conn->ib_conn,
			  reg->mem_h);
	reg->mem_h = NULL;
}

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

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

	data->dma_nents = ib_dma_map_sg(dev, data->sgl, data->size, dma_dir);
	if (data->dma_nents == 0) {
		ISER_ERR("dma_map_sg failed");
		return (EINVAL);
	}

	return (0);
}