Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / target / target_core_rd.c
diff --git a/kernel/drivers/target/target_core_rd.c b/kernel/drivers/target/target_core_rd.c
new file mode 100644 (file)
index 0000000..d16489b
--- /dev/null
@@ -0,0 +1,769 @@
+/*******************************************************************************
+ * Filename:  target_core_rd.c
+ *
+ * This file contains the Storage Engine <-> Ramdisk transport
+ * specific functions.
+ *
+ * (c) Copyright 2003-2013 Datera, Inc.
+ *
+ * Nicholas A. Bellinger <nab@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ ******************************************************************************/
+
+#include <linux/string.h>
+#include <linux/parser.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_backend.h>
+#include <target/target_core_backend_configfs.h>
+
+#include "target_core_rd.h"
+
+static inline struct rd_dev *RD_DEV(struct se_device *dev)
+{
+       return container_of(dev, struct rd_dev, dev);
+}
+
+/*     rd_attach_hba(): (Part of se_subsystem_api_t template)
+ *
+ *
+ */
+static int rd_attach_hba(struct se_hba *hba, u32 host_id)
+{
+       struct rd_host *rd_host;
+
+       rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
+       if (!rd_host) {
+               pr_err("Unable to allocate memory for struct rd_host\n");
+               return -ENOMEM;
+       }
+
+       rd_host->rd_host_id = host_id;
+
+       hba->hba_ptr = rd_host;
+
+       pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
+               " Generic Target Core Stack %s\n", hba->hba_id,
+               RD_HBA_VERSION, TARGET_CORE_MOD_VERSION);
+
+       return 0;
+}
+
+static void rd_detach_hba(struct se_hba *hba)
+{
+       struct rd_host *rd_host = hba->hba_ptr;
+
+       pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
+               " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
+
+       kfree(rd_host);
+       hba->hba_ptr = NULL;
+}
+
+static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
+                                u32 sg_table_count)
+{
+       struct page *pg;
+       struct scatterlist *sg;
+       u32 i, j, page_count = 0, sg_per_table;
+
+       for (i = 0; i < sg_table_count; i++) {
+               sg = sg_table[i].sg_table;
+               sg_per_table = sg_table[i].rd_sg_count;
+
+               for (j = 0; j < sg_per_table; j++) {
+                       pg = sg_page(&sg[j]);
+                       if (pg) {
+                               __free_page(pg);
+                               page_count++;
+                       }
+               }
+               kfree(sg);
+       }
+
+       kfree(sg_table);
+       return page_count;
+}
+
+static void rd_release_device_space(struct rd_dev *rd_dev)
+{
+       u32 page_count;
+
+       if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
+               return;
+
+       page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array,
+                                         rd_dev->sg_table_count);
+
+       pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
+               " Device ID: %u, pages %u in %u tables total bytes %lu\n",
+               rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
+               rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
+
+       rd_dev->sg_table_array = NULL;
+       rd_dev->sg_table_count = 0;
+}
+
+
+/*     rd_build_device_space():
+ *
+ *
+ */
+static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
+                                u32 total_sg_needed, unsigned char init_payload)
+{
+       u32 i = 0, j, page_offset = 0, sg_per_table;
+       u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
+                               sizeof(struct scatterlist));
+       struct page *pg;
+       struct scatterlist *sg;
+       unsigned char *p;
+
+       while (total_sg_needed) {
+               unsigned int chain_entry = 0;
+
+               sg_per_table = (total_sg_needed > max_sg_per_table) ?
+                       max_sg_per_table : total_sg_needed;
+
+#ifdef CONFIG_ARCH_HAS_SG_CHAIN
+
+               /*
+                * Reserve extra element for chain entry
+                */
+               if (sg_per_table < total_sg_needed)
+                       chain_entry = 1;
+
+#endif /* CONFIG_ARCH_HAS_SG_CHAIN */
+
+               sg = kcalloc(sg_per_table + chain_entry, sizeof(*sg),
+                               GFP_KERNEL);
+               if (!sg) {
+                       pr_err("Unable to allocate scatterlist array"
+                               " for struct rd_dev\n");
+                       return -ENOMEM;
+               }
+
+               sg_init_table(sg, sg_per_table + chain_entry);
+
+#ifdef CONFIG_ARCH_HAS_SG_CHAIN
+
+               if (i > 0) {
+                       sg_chain(sg_table[i - 1].sg_table,
+                                max_sg_per_table + 1, sg);
+               }
+
+#endif /* CONFIG_ARCH_HAS_SG_CHAIN */
+
+               sg_table[i].sg_table = sg;
+               sg_table[i].rd_sg_count = sg_per_table;
+               sg_table[i].page_start_offset = page_offset;
+               sg_table[i++].page_end_offset = (page_offset + sg_per_table)
+                                               - 1;
+
+               for (j = 0; j < sg_per_table; j++) {
+                       pg = alloc_pages(GFP_KERNEL, 0);
+                       if (!pg) {
+                               pr_err("Unable to allocate scatterlist"
+                                       " pages for struct rd_dev_sg_table\n");
+                               return -ENOMEM;
+                       }
+                       sg_assign_page(&sg[j], pg);
+                       sg[j].length = PAGE_SIZE;
+
+                       p = kmap(pg);
+                       memset(p, init_payload, PAGE_SIZE);
+                       kunmap(pg);
+               }
+
+               page_offset += sg_per_table;
+               total_sg_needed -= sg_per_table;
+       }
+
+       return 0;
+}
+
+static int rd_build_device_space(struct rd_dev *rd_dev)
+{
+       struct rd_dev_sg_table *sg_table;
+       u32 sg_tables, total_sg_needed;
+       u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
+                               sizeof(struct scatterlist));
+       int rc;
+
+       if (rd_dev->rd_page_count <= 0) {
+               pr_err("Illegal page count: %u for Ramdisk device\n",
+                      rd_dev->rd_page_count);
+               return -EINVAL;
+       }
+
+       /* Don't need backing pages for NULLIO */
+       if (rd_dev->rd_flags & RDF_NULLIO)
+               return 0;
+
+       total_sg_needed = rd_dev->rd_page_count;
+
+       sg_tables = (total_sg_needed / max_sg_per_table) + 1;
+
+       sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
+       if (!sg_table) {
+               pr_err("Unable to allocate memory for Ramdisk"
+                      " scatterlist tables\n");
+               return -ENOMEM;
+       }
+
+       rd_dev->sg_table_array = sg_table;
+       rd_dev->sg_table_count = sg_tables;
+
+       rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00);
+       if (rc)
+               return rc;
+
+       pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
+                " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
+                rd_dev->rd_dev_id, rd_dev->rd_page_count,
+                rd_dev->sg_table_count);
+
+       return 0;
+}
+
+static void rd_release_prot_space(struct rd_dev *rd_dev)
+{
+       u32 page_count;
+
+       if (!rd_dev->sg_prot_array || !rd_dev->sg_prot_count)
+               return;
+
+       page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_prot_array,
+                                         rd_dev->sg_prot_count);
+
+       pr_debug("CORE_RD[%u] - Released protection space for Ramdisk"
+                " Device ID: %u, pages %u in %u tables total bytes %lu\n",
+                rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
+                rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
+
+       rd_dev->sg_prot_array = NULL;
+       rd_dev->sg_prot_count = 0;
+}
+
+static int rd_build_prot_space(struct rd_dev *rd_dev, int prot_length, int block_size)
+{
+       struct rd_dev_sg_table *sg_table;
+       u32 total_sg_needed, sg_tables;
+       u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
+                               sizeof(struct scatterlist));
+       int rc;
+
+       if (rd_dev->rd_flags & RDF_NULLIO)
+               return 0;
+       /*
+        * prot_length=8byte dif data
+        * tot sg needed = rd_page_count * (PGSZ/block_size) *
+        *                 (prot_length/block_size) + pad
+        * PGSZ canceled each other.
+        */
+       total_sg_needed = (rd_dev->rd_page_count * prot_length / block_size) + 1;
+
+       sg_tables = (total_sg_needed / max_sg_per_table) + 1;
+
+       sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
+       if (!sg_table) {
+               pr_err("Unable to allocate memory for Ramdisk protection"
+                      " scatterlist tables\n");
+               return -ENOMEM;
+       }
+
+       rd_dev->sg_prot_array = sg_table;
+       rd_dev->sg_prot_count = sg_tables;
+
+       rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0xff);
+       if (rc)
+               return rc;
+
+       pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u prot space of"
+                " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
+                rd_dev->rd_dev_id, total_sg_needed, rd_dev->sg_prot_count);
+
+       return 0;
+}
+
+static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
+{
+       struct rd_dev *rd_dev;
+       struct rd_host *rd_host = hba->hba_ptr;
+
+       rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
+       if (!rd_dev) {
+               pr_err("Unable to allocate memory for struct rd_dev\n");
+               return NULL;
+       }
+
+       rd_dev->rd_host = rd_host;
+
+       return &rd_dev->dev;
+}
+
+static int rd_configure_device(struct se_device *dev)
+{
+       struct rd_dev *rd_dev = RD_DEV(dev);
+       struct rd_host *rd_host = dev->se_hba->hba_ptr;
+       int ret;
+
+       if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
+               pr_debug("Missing rd_pages= parameter\n");
+               return -EINVAL;
+       }
+
+       ret = rd_build_device_space(rd_dev);
+       if (ret < 0)
+               goto fail;
+
+       dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
+       dev->dev_attrib.hw_max_sectors = UINT_MAX;
+       dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
+
+       rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
+
+       pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
+               " %u pages in %u tables, %lu total bytes\n",
+               rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
+               rd_dev->sg_table_count,
+               (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
+
+       return 0;
+
+fail:
+       rd_release_device_space(rd_dev);
+       return ret;
+}
+
+static void rd_free_device(struct se_device *dev)
+{
+       struct rd_dev *rd_dev = RD_DEV(dev);
+
+       rd_release_device_space(rd_dev);
+       kfree(rd_dev);
+}
+
+static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
+{
+       struct rd_dev_sg_table *sg_table;
+       u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
+                               sizeof(struct scatterlist));
+
+       i = page / sg_per_table;
+       if (i < rd_dev->sg_table_count) {
+               sg_table = &rd_dev->sg_table_array[i];
+               if ((sg_table->page_start_offset <= page) &&
+                   (sg_table->page_end_offset >= page))
+                       return sg_table;
+       }
+
+       pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
+                       page);
+
+       return NULL;
+}
+
+static struct rd_dev_sg_table *rd_get_prot_table(struct rd_dev *rd_dev, u32 page)
+{
+       struct rd_dev_sg_table *sg_table;
+       u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
+                               sizeof(struct scatterlist));
+
+       i = page / sg_per_table;
+       if (i < rd_dev->sg_prot_count) {
+               sg_table = &rd_dev->sg_prot_array[i];
+               if ((sg_table->page_start_offset <= page) &&
+                    (sg_table->page_end_offset >= page))
+                       return sg_table;
+       }
+
+       pr_err("Unable to locate struct prot rd_dev_sg_table for page: %u\n",
+                       page);
+
+       return NULL;
+}
+
+typedef sense_reason_t (*dif_verify)(struct se_cmd *, sector_t, unsigned int,
+                                    unsigned int, struct scatterlist *, int);
+
+static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, dif_verify dif_verify)
+{
+       struct se_device *se_dev = cmd->se_dev;
+       struct rd_dev *dev = RD_DEV(se_dev);
+       struct rd_dev_sg_table *prot_table;
+       bool need_to_release = false;
+       struct scatterlist *prot_sg;
+       u32 sectors = cmd->data_length / se_dev->dev_attrib.block_size;
+       u32 prot_offset, prot_page;
+       u32 prot_npages __maybe_unused;
+       u64 tmp;
+       sense_reason_t rc = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       tmp = cmd->t_task_lba * se_dev->prot_length;
+       prot_offset = do_div(tmp, PAGE_SIZE);
+       prot_page = tmp;
+
+       prot_table = rd_get_prot_table(dev, prot_page);
+       if (!prot_table)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       prot_sg = &prot_table->sg_table[prot_page -
+                                       prot_table->page_start_offset];
+
+#ifndef CONFIG_ARCH_HAS_SG_CHAIN
+
+       prot_npages = DIV_ROUND_UP(prot_offset + sectors * se_dev->prot_length,
+                                  PAGE_SIZE);
+
+       /*
+        * Allocate temporaly contiguous scatterlist entries if prot pages
+        * straddles multiple scatterlist tables.
+        */
+       if (prot_table->page_end_offset < prot_page + prot_npages - 1) {
+               int i;
+
+               prot_sg = kcalloc(prot_npages, sizeof(*prot_sg), GFP_KERNEL);
+               if (!prot_sg)
+                       return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+               need_to_release = true;
+               sg_init_table(prot_sg, prot_npages);
+
+               for (i = 0; i < prot_npages; i++) {
+                       if (prot_page + i > prot_table->page_end_offset) {
+                               prot_table = rd_get_prot_table(dev,
+                                                               prot_page + i);
+                               if (!prot_table) {
+                                       kfree(prot_sg);
+                                       return rc;
+                               }
+                               sg_unmark_end(&prot_sg[i - 1]);
+                       }
+                       prot_sg[i] = prot_table->sg_table[prot_page + i -
+                                               prot_table->page_start_offset];
+               }
+       }
+
+#endif /* !CONFIG_ARCH_HAS_SG_CHAIN */
+
+       rc = dif_verify(cmd, cmd->t_task_lba, sectors, 0, prot_sg, prot_offset);
+       if (need_to_release)
+               kfree(prot_sg);
+
+       return rc;
+}
+
+static sense_reason_t
+rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
+             enum dma_data_direction data_direction)
+{
+       struct se_device *se_dev = cmd->se_dev;
+       struct rd_dev *dev = RD_DEV(se_dev);
+       struct rd_dev_sg_table *table;
+       struct scatterlist *rd_sg;
+       struct sg_mapping_iter m;
+       u32 rd_offset;
+       u32 rd_size;
+       u32 rd_page;
+       u32 src_len;
+       u64 tmp;
+       sense_reason_t rc;
+
+       if (dev->rd_flags & RDF_NULLIO) {
+               target_complete_cmd(cmd, SAM_STAT_GOOD);
+               return 0;
+       }
+
+       tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
+       rd_offset = do_div(tmp, PAGE_SIZE);
+       rd_page = tmp;
+       rd_size = cmd->data_length;
+
+       table = rd_get_sg_table(dev, rd_page);
+       if (!table)
+               return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+       rd_sg = &table->sg_table[rd_page - table->page_start_offset];
+
+       pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
+                       dev->rd_dev_id,
+                       data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
+                       cmd->t_task_lba, rd_size, rd_page, rd_offset);
+
+       if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
+           data_direction == DMA_TO_DEVICE) {
+               rc = rd_do_prot_rw(cmd, sbc_dif_verify_write);
+               if (rc)
+                       return rc;
+       }
+
+       src_len = PAGE_SIZE - rd_offset;
+       sg_miter_start(&m, sgl, sgl_nents,
+                       data_direction == DMA_FROM_DEVICE ?
+                               SG_MITER_TO_SG : SG_MITER_FROM_SG);
+       while (rd_size) {
+               u32 len;
+               void *rd_addr;
+
+               sg_miter_next(&m);
+               if (!(u32)m.length) {
+                       pr_debug("RD[%u]: invalid sgl %p len %zu\n",
+                                dev->rd_dev_id, m.addr, m.length);
+                       sg_miter_stop(&m);
+                       return TCM_INCORRECT_AMOUNT_OF_DATA;
+               }
+               len = min((u32)m.length, src_len);
+               if (len > rd_size) {
+                       pr_debug("RD[%u]: size underrun page %d offset %d "
+                                "size %d\n", dev->rd_dev_id,
+                                rd_page, rd_offset, rd_size);
+                       len = rd_size;
+               }
+               m.consumed = len;
+
+               rd_addr = sg_virt(rd_sg) + rd_offset;
+
+               if (data_direction == DMA_FROM_DEVICE)
+                       memcpy(m.addr, rd_addr, len);
+               else
+                       memcpy(rd_addr, m.addr, len);
+
+               rd_size -= len;
+               if (!rd_size)
+                       continue;
+
+               src_len -= len;
+               if (src_len) {
+                       rd_offset += len;
+                       continue;
+               }
+
+               /* rd page completed, next one please */
+               rd_page++;
+               rd_offset = 0;
+               src_len = PAGE_SIZE;
+               if (rd_page <= table->page_end_offset) {
+                       rd_sg++;
+                       continue;
+               }
+
+               table = rd_get_sg_table(dev, rd_page);
+               if (!table) {
+                       sg_miter_stop(&m);
+                       return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+               }
+
+               /* since we increment, the first sg entry is correct */
+               rd_sg = table->sg_table;
+       }
+       sg_miter_stop(&m);
+
+       if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
+           data_direction == DMA_FROM_DEVICE) {
+               rc = rd_do_prot_rw(cmd, sbc_dif_verify_read);
+               if (rc)
+                       return rc;
+       }
+
+       target_complete_cmd(cmd, SAM_STAT_GOOD);
+       return 0;
+}
+
+enum {
+       Opt_rd_pages, Opt_rd_nullio, Opt_err
+};
+
+static match_table_t tokens = {
+       {Opt_rd_pages, "rd_pages=%d"},
+       {Opt_rd_nullio, "rd_nullio=%d"},
+       {Opt_err, NULL}
+};
+
+static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
+               const char *page, ssize_t count)
+{
+       struct rd_dev *rd_dev = RD_DEV(dev);
+       char *orig, *ptr, *opts;
+       substring_t args[MAX_OPT_ARGS];
+       int ret = 0, arg, token;
+
+       opts = kstrdup(page, GFP_KERNEL);
+       if (!opts)
+               return -ENOMEM;
+
+       orig = opts;
+
+       while ((ptr = strsep(&opts, ",\n")) != NULL) {
+               if (!*ptr)
+                       continue;
+
+               token = match_token(ptr, tokens, args);
+               switch (token) {
+               case Opt_rd_pages:
+                       match_int(args, &arg);
+                       rd_dev->rd_page_count = arg;
+                       pr_debug("RAMDISK: Referencing Page"
+                               " Count: %u\n", rd_dev->rd_page_count);
+                       rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
+                       break;
+               case Opt_rd_nullio:
+                       match_int(args, &arg);
+                       if (arg != 1)
+                               break;
+
+                       pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
+                       rd_dev->rd_flags |= RDF_NULLIO;
+                       break;
+               default:
+                       break;
+               }
+       }
+
+       kfree(orig);
+       return (!ret) ? count : ret;
+}
+
+static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
+{
+       struct rd_dev *rd_dev = RD_DEV(dev);
+
+       ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
+                       rd_dev->rd_dev_id);
+       bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
+                       "  SG_table_count: %u  nullio: %d\n", rd_dev->rd_page_count,
+                       PAGE_SIZE, rd_dev->sg_table_count,
+                       !!(rd_dev->rd_flags & RDF_NULLIO));
+       return bl;
+}
+
+static sector_t rd_get_blocks(struct se_device *dev)
+{
+       struct rd_dev *rd_dev = RD_DEV(dev);
+
+       unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
+                       dev->dev_attrib.block_size) - 1;
+
+       return blocks_long;
+}
+
+static int rd_init_prot(struct se_device *dev)
+{
+       struct rd_dev *rd_dev = RD_DEV(dev);
+
+        if (!dev->dev_attrib.pi_prot_type)
+               return 0;
+
+       return rd_build_prot_space(rd_dev, dev->prot_length,
+                                  dev->dev_attrib.block_size);
+}
+
+static void rd_free_prot(struct se_device *dev)
+{
+       struct rd_dev *rd_dev = RD_DEV(dev);
+
+       rd_release_prot_space(rd_dev);
+}
+
+static struct sbc_ops rd_sbc_ops = {
+       .execute_rw             = rd_execute_rw,
+};
+
+static sense_reason_t
+rd_parse_cdb(struct se_cmd *cmd)
+{
+       return sbc_parse_cdb(cmd, &rd_sbc_ops);
+}
+
+DEF_TB_DEFAULT_ATTRIBS(rd_mcp);
+
+static struct configfs_attribute *rd_mcp_backend_dev_attrs[] = {
+       &rd_mcp_dev_attrib_emulate_model_alias.attr,
+       &rd_mcp_dev_attrib_emulate_dpo.attr,
+       &rd_mcp_dev_attrib_emulate_fua_write.attr,
+       &rd_mcp_dev_attrib_emulate_fua_read.attr,
+       &rd_mcp_dev_attrib_emulate_write_cache.attr,
+       &rd_mcp_dev_attrib_emulate_ua_intlck_ctrl.attr,
+       &rd_mcp_dev_attrib_emulate_tas.attr,
+       &rd_mcp_dev_attrib_emulate_tpu.attr,
+       &rd_mcp_dev_attrib_emulate_tpws.attr,
+       &rd_mcp_dev_attrib_emulate_caw.attr,
+       &rd_mcp_dev_attrib_emulate_3pc.attr,
+       &rd_mcp_dev_attrib_pi_prot_type.attr,
+       &rd_mcp_dev_attrib_hw_pi_prot_type.attr,
+       &rd_mcp_dev_attrib_pi_prot_format.attr,
+       &rd_mcp_dev_attrib_enforce_pr_isids.attr,
+       &rd_mcp_dev_attrib_is_nonrot.attr,
+       &rd_mcp_dev_attrib_emulate_rest_reord.attr,
+       &rd_mcp_dev_attrib_force_pr_aptpl.attr,
+       &rd_mcp_dev_attrib_hw_block_size.attr,
+       &rd_mcp_dev_attrib_block_size.attr,
+       &rd_mcp_dev_attrib_hw_max_sectors.attr,
+       &rd_mcp_dev_attrib_optimal_sectors.attr,
+       &rd_mcp_dev_attrib_hw_queue_depth.attr,
+       &rd_mcp_dev_attrib_queue_depth.attr,
+       &rd_mcp_dev_attrib_max_unmap_lba_count.attr,
+       &rd_mcp_dev_attrib_max_unmap_block_desc_count.attr,
+       &rd_mcp_dev_attrib_unmap_granularity.attr,
+       &rd_mcp_dev_attrib_unmap_granularity_alignment.attr,
+       &rd_mcp_dev_attrib_max_write_same_len.attr,
+       NULL,
+};
+
+static struct se_subsystem_api rd_mcp_template = {
+       .name                   = "rd_mcp",
+       .inquiry_prod           = "RAMDISK-MCP",
+       .inquiry_rev            = RD_MCP_VERSION,
+       .attach_hba             = rd_attach_hba,
+       .detach_hba             = rd_detach_hba,
+       .alloc_device           = rd_alloc_device,
+       .configure_device       = rd_configure_device,
+       .free_device            = rd_free_device,
+       .parse_cdb              = rd_parse_cdb,
+       .set_configfs_dev_params = rd_set_configfs_dev_params,
+       .show_configfs_dev_params = rd_show_configfs_dev_params,
+       .get_device_type        = sbc_get_device_type,
+       .get_blocks             = rd_get_blocks,
+       .init_prot              = rd_init_prot,
+       .free_prot              = rd_free_prot,
+};
+
+int __init rd_module_init(void)
+{
+       struct target_backend_cits *tbc = &rd_mcp_template.tb_cits;
+       int ret;
+
+       target_core_setup_sub_cits(&rd_mcp_template);
+       tbc->tb_dev_attrib_cit.ct_attrs = rd_mcp_backend_dev_attrs;
+
+       ret = transport_subsystem_register(&rd_mcp_template);
+       if (ret < 0) {
+               return ret;
+       }
+
+       return 0;
+}
+
+void rd_module_exit(void)
+{
+       transport_subsystem_release(&rd_mcp_template);
+}