forked from Minki/linux
IB/iser: iSER handling of memory for RDMA
This file contains the processing carried over an SG list associated with a SCSI command such that it can be registered with the IB verbs. The registration produces a network virtual address (VA) and a remote access key (RKEY or STAG in iSER spec notation) which are used by the target for its RDMA operation. Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
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1cfa0a75db
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6461f64ab5
401
drivers/infiniband/ulp/iser/iser_memory.c
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401
drivers/infiniband/ulp/iser/iser_memory.c
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/*
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* Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* $Id: iser_memory.c 6964 2006-05-07 11:11:43Z ogerlitz $
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <asm/io.h>
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#include <asm/scatterlist.h>
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#include <linux/scatterlist.h>
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#include "iscsi_iser.h"
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#define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */
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/**
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* Decrements the reference count for the
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* registered buffer & releases it
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*
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* returns 0 if released, 1 if deferred
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*/
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int iser_regd_buff_release(struct iser_regd_buf *regd_buf)
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{
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struct device *dma_device;
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if ((atomic_read(®d_buf->ref_count) == 0) ||
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atomic_dec_and_test(®d_buf->ref_count)) {
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/* if we used the dma mr, unreg is just NOP */
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if (regd_buf->reg.rkey != 0)
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iser_unreg_mem(®d_buf->reg);
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if (regd_buf->dma_addr) {
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dma_device = regd_buf->device->ib_device->dma_device;
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dma_unmap_single(dma_device,
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regd_buf->dma_addr,
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regd_buf->data_size,
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regd_buf->direction);
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}
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/* else this regd buf is associated with task which we */
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/* dma_unmap_single/sg later */
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return 0;
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} else {
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iser_dbg("Release deferred, regd.buff: 0x%p\n", regd_buf);
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return 1;
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}
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}
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/**
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* iser_reg_single - fills registered buffer descriptor with
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* registration information
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*/
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void iser_reg_single(struct iser_device *device,
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struct iser_regd_buf *regd_buf,
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enum dma_data_direction direction)
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{
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dma_addr_t dma_addr;
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dma_addr = dma_map_single(device->ib_device->dma_device,
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regd_buf->virt_addr,
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regd_buf->data_size, direction);
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BUG_ON(dma_mapping_error(dma_addr));
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regd_buf->reg.lkey = device->mr->lkey;
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regd_buf->reg.rkey = 0; /* indicate there's no need to unreg */
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regd_buf->reg.len = regd_buf->data_size;
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regd_buf->reg.va = dma_addr;
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regd_buf->dma_addr = dma_addr;
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regd_buf->direction = direction;
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}
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/**
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* iser_start_rdma_unaligned_sg
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*/
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int iser_start_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
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enum iser_data_dir cmd_dir)
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{
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int dma_nents;
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struct device *dma_device;
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char *mem = NULL;
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struct iser_data_buf *data = &iser_ctask->data[cmd_dir];
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unsigned long cmd_data_len = data->data_len;
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if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
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mem = (void *)__get_free_pages(GFP_NOIO,
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long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
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else
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mem = kmalloc(cmd_data_len, GFP_NOIO);
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if (mem == NULL) {
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iser_err("Failed to allocate mem size %d %d for copying sglist\n",
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data->size,(int)cmd_data_len);
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return -ENOMEM;
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}
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if (cmd_dir == ISER_DIR_OUT) {
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/* copy the unaligned sg the buffer which is used for RDMA */
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struct scatterlist *sg = (struct scatterlist *)data->buf;
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int i;
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char *p, *from;
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for (p = mem, i = 0; i < data->size; i++) {
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from = kmap_atomic(sg[i].page, KM_USER0);
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memcpy(p,
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from + sg[i].offset,
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sg[i].length);
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kunmap_atomic(from, KM_USER0);
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p += sg[i].length;
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}
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}
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sg_init_one(&iser_ctask->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
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iser_ctask->data_copy[cmd_dir].buf =
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&iser_ctask->data_copy[cmd_dir].sg_single;
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iser_ctask->data_copy[cmd_dir].size = 1;
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iser_ctask->data_copy[cmd_dir].copy_buf = mem;
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dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
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if (cmd_dir == ISER_DIR_OUT)
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dma_nents = dma_map_sg(dma_device,
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&iser_ctask->data_copy[cmd_dir].sg_single,
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1, DMA_TO_DEVICE);
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else
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dma_nents = dma_map_sg(dma_device,
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&iser_ctask->data_copy[cmd_dir].sg_single,
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1, DMA_FROM_DEVICE);
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BUG_ON(dma_nents == 0);
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iser_ctask->data_copy[cmd_dir].dma_nents = dma_nents;
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return 0;
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}
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/**
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* iser_finalize_rdma_unaligned_sg
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*/
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void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
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enum iser_data_dir cmd_dir)
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{
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struct device *dma_device;
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struct iser_data_buf *mem_copy;
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unsigned long cmd_data_len;
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dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
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mem_copy = &iser_ctask->data_copy[cmd_dir];
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if (cmd_dir == ISER_DIR_OUT)
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dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
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DMA_TO_DEVICE);
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else
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dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
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DMA_FROM_DEVICE);
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if (cmd_dir == ISER_DIR_IN) {
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char *mem;
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struct scatterlist *sg;
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unsigned char *p, *to;
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unsigned int sg_size;
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int i;
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/* copy back read RDMA to unaligned sg */
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mem = mem_copy->copy_buf;
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sg = (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
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sg_size = iser_ctask->data[ISER_DIR_IN].size;
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for (p = mem, i = 0; i < sg_size; i++){
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to = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
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memcpy(to + sg[i].offset,
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p,
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sg[i].length);
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kunmap_atomic(to, KM_SOFTIRQ0);
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p += sg[i].length;
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}
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}
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cmd_data_len = iser_ctask->data[cmd_dir].data_len;
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if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
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free_pages((unsigned long)mem_copy->copy_buf,
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long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
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else
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kfree(mem_copy->copy_buf);
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mem_copy->copy_buf = NULL;
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}
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/**
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* iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
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* and returns the length of resulting physical address array (may be less than
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* the original due to possible compaction).
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*
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* we build a "page vec" under the assumption that the SG meets the RDMA
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* alignment requirements. Other then the first and last SG elements, all
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* the "internal" elements can be compacted into a list whose elements are
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* dma addresses of physical pages. The code supports also the weird case
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* where --few fragments of the same page-- are present in the SG as
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* consecutive elements. Also, it handles one entry SG.
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*/
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static int iser_sg_to_page_vec(struct iser_data_buf *data,
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struct iser_page_vec *page_vec)
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{
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struct scatterlist *sg = (struct scatterlist *)data->buf;
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dma_addr_t first_addr, last_addr, page;
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int start_aligned, end_aligned;
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unsigned int cur_page = 0;
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unsigned long total_sz = 0;
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int i;
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/* compute the offset of first element */
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page_vec->offset = (u64) sg[0].offset;
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for (i = 0; i < data->dma_nents; i++) {
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total_sz += sg_dma_len(&sg[i]);
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first_addr = sg_dma_address(&sg[i]);
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last_addr = first_addr + sg_dma_len(&sg[i]);
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start_aligned = !(first_addr & ~PAGE_MASK);
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end_aligned = !(last_addr & ~PAGE_MASK);
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/* continue to collect page fragments till aligned or SG ends */
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while (!end_aligned && (i + 1 < data->dma_nents)) {
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i++;
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total_sz += sg_dma_len(&sg[i]);
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last_addr = sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]);
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end_aligned = !(last_addr & ~PAGE_MASK);
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}
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first_addr = first_addr & PAGE_MASK;
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for (page = first_addr; page < last_addr; page += PAGE_SIZE)
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page_vec->pages[cur_page++] = page;
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}
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page_vec->data_size = total_sz;
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iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
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return cur_page;
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}
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#define MASK_4K ((1UL << 12) - 1) /* 0xFFF */
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#define IS_4K_ALIGNED(addr) ((((unsigned long)addr) & MASK_4K) == 0)
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/**
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* iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
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* for RDMA sub-list of a scatter-gather list of memory buffers, and returns
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* the number of entries which are aligned correctly. Supports the case where
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* consecutive SG elements are actually fragments of the same physcial page.
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*/
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static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data)
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{
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struct scatterlist *sg;
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dma_addr_t end_addr, next_addr;
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int i, cnt;
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unsigned int ret_len = 0;
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sg = (struct scatterlist *)data->buf;
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for (cnt = 0, i = 0; i < data->dma_nents; i++, cnt++) {
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/* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
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"offset: %ld sz: %ld\n", i,
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(unsigned long)page_to_phys(sg[i].page),
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(unsigned long)sg[i].offset,
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(unsigned long)sg[i].length); */
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end_addr = sg_dma_address(&sg[i]) +
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sg_dma_len(&sg[i]);
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/* iser_dbg("Checking sg iobuf end address "
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"0x%08lX\n", end_addr); */
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if (i + 1 < data->dma_nents) {
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next_addr = sg_dma_address(&sg[i+1]);
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/* are i, i+1 fragments of the same page? */
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if (end_addr == next_addr)
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continue;
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else if (!IS_4K_ALIGNED(end_addr)) {
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ret_len = cnt + 1;
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break;
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}
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}
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}
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if (i == data->dma_nents)
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ret_len = cnt; /* loop ended */
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iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
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ret_len, data->dma_nents, data);
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return ret_len;
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}
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static void iser_data_buf_dump(struct iser_data_buf *data)
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{
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struct scatterlist *sg = (struct scatterlist *)data->buf;
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int i;
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for (i = 0; i < data->size; i++)
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iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
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"off:%d sz:%d dma_len:%d\n",
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i, (unsigned long)sg_dma_address(&sg[i]),
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sg[i].page, sg[i].offset,
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sg[i].length,sg_dma_len(&sg[i]));
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}
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static void iser_dump_page_vec(struct iser_page_vec *page_vec)
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{
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int i;
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iser_err("page vec length %d data size %d\n",
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page_vec->length, page_vec->data_size);
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for (i = 0; i < page_vec->length; i++)
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iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
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}
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static void iser_page_vec_build(struct iser_data_buf *data,
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struct iser_page_vec *page_vec)
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{
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int page_vec_len = 0;
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page_vec->length = 0;
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page_vec->offset = 0;
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iser_dbg("Translating sg sz: %d\n", data->dma_nents);
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page_vec_len = iser_sg_to_page_vec(data,page_vec);
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iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
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page_vec->length = page_vec_len;
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if (page_vec_len * PAGE_SIZE < page_vec->data_size) {
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iser_err("page_vec too short to hold this SG\n");
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iser_data_buf_dump(data);
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iser_dump_page_vec(page_vec);
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BUG();
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}
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}
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/**
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* iser_reg_rdma_mem - Registers memory intended for RDMA,
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* obtaining rkey and va
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*
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* returns 0 on success, errno code on failure
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*/
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int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask,
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enum iser_data_dir cmd_dir)
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{
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struct iser_conn *ib_conn = iser_ctask->iser_conn->ib_conn;
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struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];
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struct iser_regd_buf *regd_buf;
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int aligned_len;
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int err;
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regd_buf = &iser_ctask->rdma_regd[cmd_dir];
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aligned_len = iser_data_buf_aligned_len(mem);
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if (aligned_len != mem->size) {
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iser_err("rdma alignment violation %d/%d aligned\n",
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aligned_len, mem->size);
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iser_data_buf_dump(mem);
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/* allocate copy buf, if we are writing, copy the */
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/* unaligned scatterlist, dma map the copy */
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if (iser_start_rdma_unaligned_sg(iser_ctask, cmd_dir) != 0)
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return -ENOMEM;
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mem = &iser_ctask->data_copy[cmd_dir];
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}
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iser_page_vec_build(mem, ib_conn->page_vec);
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err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, ®d_buf->reg);
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if (err)
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return err;
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/* take a reference on this regd buf such that it will not be released *
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* (eg in send dto completion) before we get the scsi response */
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atomic_inc(®d_buf->ref_count);
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return 0;
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}
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