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![Nicholas Bellinger](/assets/img/avatar_default.png)
v2: Use correct target_core_stat.c 2006 copyright year v3: Drop extra unnessary legal verbage from header (hch) Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
470 lines
11 KiB
C
470 lines
11 KiB
C
/*******************************************************************************
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* Filename: target_core_rd.c
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*
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* This file contains the Storage Engine <-> Ramdisk transport
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* specific functions.
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*
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* (c) Copyright 2003-2012 RisingTide Systems LLC.
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*
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* Nicholas A. Bellinger <nab@kernel.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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******************************************************************************/
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#include <linux/string.h>
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#include <linux/parser.h>
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#include <linux/timer.h>
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#include <linux/blkdev.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_host.h>
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#include <target/target_core_base.h>
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#include <target/target_core_backend.h>
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#include "target_core_rd.h"
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static inline struct rd_dev *RD_DEV(struct se_device *dev)
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{
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return container_of(dev, struct rd_dev, dev);
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}
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/* rd_attach_hba(): (Part of se_subsystem_api_t template)
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*
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*
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*/
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static int rd_attach_hba(struct se_hba *hba, u32 host_id)
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{
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struct rd_host *rd_host;
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rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
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if (!rd_host) {
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pr_err("Unable to allocate memory for struct rd_host\n");
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return -ENOMEM;
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}
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rd_host->rd_host_id = host_id;
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hba->hba_ptr = rd_host;
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pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
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" Generic Target Core Stack %s\n", hba->hba_id,
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RD_HBA_VERSION, TARGET_CORE_MOD_VERSION);
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return 0;
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}
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static void rd_detach_hba(struct se_hba *hba)
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{
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struct rd_host *rd_host = hba->hba_ptr;
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pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
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" Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
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kfree(rd_host);
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hba->hba_ptr = NULL;
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}
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/* rd_release_device_space():
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*
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*
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*/
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static void rd_release_device_space(struct rd_dev *rd_dev)
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{
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u32 i, j, page_count = 0, sg_per_table;
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struct rd_dev_sg_table *sg_table;
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struct page *pg;
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struct scatterlist *sg;
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if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
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return;
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sg_table = rd_dev->sg_table_array;
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for (i = 0; i < rd_dev->sg_table_count; i++) {
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sg = sg_table[i].sg_table;
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sg_per_table = sg_table[i].rd_sg_count;
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for (j = 0; j < sg_per_table; j++) {
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pg = sg_page(&sg[j]);
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if (pg) {
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__free_page(pg);
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page_count++;
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}
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}
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kfree(sg);
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}
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pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
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" Device ID: %u, pages %u in %u tables total bytes %lu\n",
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rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
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rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
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kfree(sg_table);
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rd_dev->sg_table_array = NULL;
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rd_dev->sg_table_count = 0;
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}
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/* rd_build_device_space():
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*
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*
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*/
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static int rd_build_device_space(struct rd_dev *rd_dev)
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{
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u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed;
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u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
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sizeof(struct scatterlist));
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struct rd_dev_sg_table *sg_table;
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struct page *pg;
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struct scatterlist *sg;
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if (rd_dev->rd_page_count <= 0) {
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pr_err("Illegal page count: %u for Ramdisk device\n",
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rd_dev->rd_page_count);
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return -EINVAL;
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}
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total_sg_needed = rd_dev->rd_page_count;
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sg_tables = (total_sg_needed / max_sg_per_table) + 1;
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sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
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if (!sg_table) {
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pr_err("Unable to allocate memory for Ramdisk"
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" scatterlist tables\n");
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return -ENOMEM;
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}
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rd_dev->sg_table_array = sg_table;
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rd_dev->sg_table_count = sg_tables;
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while (total_sg_needed) {
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sg_per_table = (total_sg_needed > max_sg_per_table) ?
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max_sg_per_table : total_sg_needed;
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sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
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GFP_KERNEL);
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if (!sg) {
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pr_err("Unable to allocate scatterlist array"
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" for struct rd_dev\n");
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return -ENOMEM;
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}
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sg_init_table(sg, sg_per_table);
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sg_table[i].sg_table = sg;
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sg_table[i].rd_sg_count = sg_per_table;
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sg_table[i].page_start_offset = page_offset;
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sg_table[i++].page_end_offset = (page_offset + sg_per_table)
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- 1;
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for (j = 0; j < sg_per_table; j++) {
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pg = alloc_pages(GFP_KERNEL, 0);
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if (!pg) {
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pr_err("Unable to allocate scatterlist"
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" pages for struct rd_dev_sg_table\n");
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return -ENOMEM;
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}
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sg_assign_page(&sg[j], pg);
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sg[j].length = PAGE_SIZE;
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}
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page_offset += sg_per_table;
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total_sg_needed -= sg_per_table;
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}
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pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
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" %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
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rd_dev->rd_dev_id, rd_dev->rd_page_count,
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rd_dev->sg_table_count);
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return 0;
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}
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static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
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{
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struct rd_dev *rd_dev;
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struct rd_host *rd_host = hba->hba_ptr;
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rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
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if (!rd_dev) {
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pr_err("Unable to allocate memory for struct rd_dev\n");
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return NULL;
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}
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rd_dev->rd_host = rd_host;
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return &rd_dev->dev;
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}
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static int rd_configure_device(struct se_device *dev)
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{
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struct rd_dev *rd_dev = RD_DEV(dev);
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struct rd_host *rd_host = dev->se_hba->hba_ptr;
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int ret;
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if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
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pr_debug("Missing rd_pages= parameter\n");
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return -EINVAL;
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}
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ret = rd_build_device_space(rd_dev);
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if (ret < 0)
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goto fail;
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dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
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dev->dev_attrib.hw_max_sectors = UINT_MAX;
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dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
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rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
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pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
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" %u pages in %u tables, %lu total bytes\n",
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rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
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rd_dev->sg_table_count,
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(unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
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return 0;
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fail:
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rd_release_device_space(rd_dev);
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return ret;
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}
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static void rd_free_device(struct se_device *dev)
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{
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struct rd_dev *rd_dev = RD_DEV(dev);
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rd_release_device_space(rd_dev);
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kfree(rd_dev);
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}
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static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
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{
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u32 i;
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struct rd_dev_sg_table *sg_table;
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for (i = 0; i < rd_dev->sg_table_count; i++) {
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sg_table = &rd_dev->sg_table_array[i];
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if ((sg_table->page_start_offset <= page) &&
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(sg_table->page_end_offset >= page))
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return sg_table;
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}
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pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
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page);
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return NULL;
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}
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static sense_reason_t
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rd_execute_rw(struct se_cmd *cmd)
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{
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struct scatterlist *sgl = cmd->t_data_sg;
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u32 sgl_nents = cmd->t_data_nents;
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enum dma_data_direction data_direction = cmd->data_direction;
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struct se_device *se_dev = cmd->se_dev;
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struct rd_dev *dev = RD_DEV(se_dev);
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struct rd_dev_sg_table *table;
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struct scatterlist *rd_sg;
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struct sg_mapping_iter m;
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u32 rd_offset;
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u32 rd_size;
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u32 rd_page;
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u32 src_len;
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u64 tmp;
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tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
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rd_offset = do_div(tmp, PAGE_SIZE);
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rd_page = tmp;
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rd_size = cmd->data_length;
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table = rd_get_sg_table(dev, rd_page);
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if (!table)
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return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
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rd_sg = &table->sg_table[rd_page - table->page_start_offset];
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pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
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dev->rd_dev_id,
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data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
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cmd->t_task_lba, rd_size, rd_page, rd_offset);
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src_len = PAGE_SIZE - rd_offset;
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sg_miter_start(&m, sgl, sgl_nents,
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data_direction == DMA_FROM_DEVICE ?
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SG_MITER_TO_SG : SG_MITER_FROM_SG);
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while (rd_size) {
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u32 len;
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void *rd_addr;
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sg_miter_next(&m);
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len = min((u32)m.length, src_len);
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m.consumed = len;
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rd_addr = sg_virt(rd_sg) + rd_offset;
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if (data_direction == DMA_FROM_DEVICE)
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memcpy(m.addr, rd_addr, len);
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else
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memcpy(rd_addr, m.addr, len);
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rd_size -= len;
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if (!rd_size)
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continue;
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src_len -= len;
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if (src_len) {
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rd_offset += len;
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continue;
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}
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/* rd page completed, next one please */
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rd_page++;
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rd_offset = 0;
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src_len = PAGE_SIZE;
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if (rd_page <= table->page_end_offset) {
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rd_sg++;
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continue;
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}
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table = rd_get_sg_table(dev, rd_page);
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if (!table) {
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sg_miter_stop(&m);
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return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
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}
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/* since we increment, the first sg entry is correct */
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rd_sg = table->sg_table;
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}
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sg_miter_stop(&m);
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target_complete_cmd(cmd, SAM_STAT_GOOD);
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return 0;
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}
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enum {
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Opt_rd_pages, Opt_err
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};
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static match_table_t tokens = {
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{Opt_rd_pages, "rd_pages=%d"},
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{Opt_err, NULL}
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};
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static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
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const char *page, ssize_t count)
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{
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struct rd_dev *rd_dev = RD_DEV(dev);
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char *orig, *ptr, *opts;
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substring_t args[MAX_OPT_ARGS];
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int ret = 0, arg, token;
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opts = kstrdup(page, GFP_KERNEL);
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if (!opts)
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return -ENOMEM;
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orig = opts;
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while ((ptr = strsep(&opts, ",\n")) != NULL) {
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if (!*ptr)
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continue;
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token = match_token(ptr, tokens, args);
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switch (token) {
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case Opt_rd_pages:
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match_int(args, &arg);
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rd_dev->rd_page_count = arg;
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pr_debug("RAMDISK: Referencing Page"
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" Count: %u\n", rd_dev->rd_page_count);
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rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
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break;
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default:
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break;
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}
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}
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kfree(orig);
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return (!ret) ? count : ret;
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}
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static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
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{
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struct rd_dev *rd_dev = RD_DEV(dev);
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ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
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rd_dev->rd_dev_id);
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bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu"
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" SG_table_count: %u\n", rd_dev->rd_page_count,
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PAGE_SIZE, rd_dev->sg_table_count);
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return bl;
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}
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static sector_t rd_get_blocks(struct se_device *dev)
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{
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struct rd_dev *rd_dev = RD_DEV(dev);
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unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
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dev->dev_attrib.block_size) - 1;
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return blocks_long;
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}
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static struct sbc_ops rd_sbc_ops = {
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.execute_rw = rd_execute_rw,
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};
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static sense_reason_t
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rd_parse_cdb(struct se_cmd *cmd)
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{
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return sbc_parse_cdb(cmd, &rd_sbc_ops);
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}
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static struct se_subsystem_api rd_mcp_template = {
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.name = "rd_mcp",
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.inquiry_prod = "RAMDISK-MCP",
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.inquiry_rev = RD_MCP_VERSION,
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.transport_type = TRANSPORT_PLUGIN_VHBA_VDEV,
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.attach_hba = rd_attach_hba,
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.detach_hba = rd_detach_hba,
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.alloc_device = rd_alloc_device,
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.configure_device = rd_configure_device,
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.free_device = rd_free_device,
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.parse_cdb = rd_parse_cdb,
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.set_configfs_dev_params = rd_set_configfs_dev_params,
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.show_configfs_dev_params = rd_show_configfs_dev_params,
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.get_device_type = sbc_get_device_type,
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.get_blocks = rd_get_blocks,
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};
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int __init rd_module_init(void)
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{
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int ret;
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ret = transport_subsystem_register(&rd_mcp_template);
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if (ret < 0) {
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return ret;
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}
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return 0;
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}
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void rd_module_exit(void)
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{
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transport_subsystem_release(&rd_mcp_template);
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}
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