/*
* 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 */
/**
* iser_start_rdma_unaligned_sg
*/
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;
}
/**
* iser_finalize_rdma_unaligned_sg
*/
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)
/**
* 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 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;
}
/**
* 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 *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);
}
}
/**
* iser_reg_rdma_mem - Registers memory intended for RDMA,
* obtaining rkey and va
*
* returns 0 on success, errno code on failure
*/
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, ®d_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;
}