/*
* 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 */
/**
* Decrements the reference count for the
* registered buffer & releases it
*
* returns 0 if released, 1 if deferred
*/
int iser_regd_buff_release(struct iser_regd_buf *regd_buf)
{
struct ib_device *dev;
if ((atomic_read(®d_buf->ref_count) == 0) ||
atomic_dec_and_test(®d_buf->ref_count)) {
/* if we used the dma mr, unreg is just NOP */
if (regd_buf->reg.is_fmr)
iser_unreg_mem(®d_buf->reg);
if (regd_buf->dma_addr) {
dev = regd_buf->device->ib_device;
ib_dma_unmap_single(dev,
regd_buf->dma_addr,
regd_buf->data_size,
regd_buf->direction);
}
/* else this regd buf is associated with task which we */
/* dma_unmap_single/sg later */
return 0;
} else {
iser_dbg("Release deferred, regd.buff: 0x%p\n", regd_buf);
return 1;
}
}
/**
* iser_reg_single - fills registered buffer descriptor with
* registration information
*/
void iser_reg_single(struct iser_device *device,
struct iser_regd_buf *regd_buf,
enum dma_data_direction direction)
{
u64 dma_addr;
dma_addr = ib_dma_map_single(device->ib_device,
regd_buf->virt_addr,
regd_buf->data_size, direction);
BUG_ON(ib_dma_mapping_error(device->ib_device, dma_addr));
regd_buf->reg.lkey = device->mr->lkey;
regd_buf->reg.len = regd_buf->data_size;
regd_buf->reg.va = dma_addr;
regd_buf->reg.is_fmr = 0;
regd_buf->dma_addr = dma_addr;
regd_buf->direction = direction;
}
/**
* 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_NOIO,
ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
else
mem = kmalloc(cmd_data_len, GFP_NOIO);
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), KM_USER0);
memcpy(p,
from + sg->offset,
sg->length);
kunmap_atomic(from, KM_USER0);
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), KM_SOFTIRQ0);
memcpy(to + sg->offset,
p,
sg->length);
kunmap_atomic(to, KM_SOFTIRQ0);
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;
}
/**
* 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 *sgl = (struct scatterlist *)data->buf;
struct scatterlist *sg;
u64 first_addr, last_addr, page;
int end_aligned;
unsigned int cur_page = 0;
unsigned long total_sz = 0;
int i;
/* compute the offset of first element */
page_vec->offset = (u64) sgl[0].offset & ~MASK_4K;
for_each_sg(sgl, sg, data->dma_nents, i) {
unsigned int dma_len = ib_sg_dma_len(ibdev, sg);
total_sz += dma_len;
first_addr = ib_sg_dma_address(ibdev, sg);
last_addr = first_addr + dma_len;
end_aligned = !(last_addr & ~MASK_4K);
/* continue to collect page fragments till aligned or SG ends */
while (!end_aligned && (i + 1 < data->dma_nents)) {
sg = sg_next(sg);
i++;
dma_len = ib_sg_dma_len(ibdev, sg);
total_sz += dma_len;
last_addr = ib_sg_dma_address(ibdev, sg) + dma_len;
end_aligned = !(last_addr & ~MASK_4K);
}
/* handle the 1st page in the 1st DMA element */
if (cur_page == 0) {
page = first_addr & MASK_4K;
page_vec->pages[cur_page] = page;
cur_page++;
page += SIZE_4K;
} else
page = first_addr;
for (; page < last_addr; page += SIZE_4K) {
page_vec->pages[cur_page] = page;
cur_page++;
}
}
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;
}
#define IS_4K_ALIGNED(addr) ((((unsigned long)addr) & ~MASK_4K) == 0)
/**
* 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 unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data,
struct ib_device *ibdev)
{
struct scatterlist *sgl, *sg;
u64 end_addr, next_addr;
int i, cnt;
unsigned int ret_len = 0;
sgl = (struct scatterlist *)data->buf;
cnt = 0;
for_each_sg(sgl, sg, data->dma_nents, i) {
/* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
"offset: %ld sz: %ld\n", i,
(unsigned long)sg_phys(sg),
(unsigned long)sg->offset,
(unsigned long)sg->length); */
end_addr = ib_sg_dma_address(ibdev, sg) +
ib_sg_dma_len(ibdev, sg);
/* iser_dbg("Checking sg iobuf end address "
"0x%08lX\n", end_addr); */
if (i + 1 < data->dma_nents) {
next_addr = ib_sg_dma_address(ibdev, sg_next(sg));
/* are i, i+1 fragments of the same page? */
if (end_addr == next_addr) {
cnt++;
continue;
} else if (!IS_4K_ALIGNED(end_addr)) {
ret_len = cnt + 1;
break;
}
}
cnt++;
}
if (i == data->dma_nents)
ret_len = cnt; /* loop ended */
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;
}
}
/* take a reference on this regd buf such that it will not be released *
* (eg in send dto completion) before we get the scsi response */
atomic_inc(®d_buf->ref_count);
return 0;
}
