drivers/target/target_core_file.c - maze/linux - Git at Google

 /*******************************************************************************
  * Filename:  target_core_file.c
  *
  * This file contains the Storage Engine <-> FILEIO transport specific functions
  *
  * Copyright (c) 2005 PyX Technologies, Inc.
  * Copyright (c) 2005-2006 SBE, Inc.  All Rights Reserved.
  * Copyright (c) 2007-2010 Rising Tide Systems
  * Copyright (c) 2008-2010 Linux-iSCSI.org
  *
  * 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/version.h>
 #include <linux/string.h>
 #include <linux/parser.h>
 #include <linux/timer.h>
 #include <linux/blkdev.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_device.h>
 #include <target/target_core_transport.h>

 #include "target_core_file.h"

 #if 1
 #define DEBUG_FD_CACHE(x...) printk(x)
 #else
 #define DEBUG_FD_CACHE(x...)
 #endif

 #if 1
 #define DEBUG_FD_FUA(x...) printk(x)
 #else
 #define DEBUG_FD_FUA(x...)
 #endif

 static struct se_subsystem_api fileio_template;

 /*	fd_attach_hba(): (Part of se_subsystem_api_t template)
  *
  *
  */
 static int fd_attach_hba(struct se_hba *hba, u32 host_id)
 {
 	struct fd_host *fd_host;

 	fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
 	if (!(fd_host)) {
 		printk(KERN_ERR "Unable to allocate memory for struct fd_host\n");
 		return -1;
 	}

 	fd_host->fd_host_id = host_id;

 	atomic_set(&hba->left_queue_depth, FD_HBA_QUEUE_DEPTH);
 	atomic_set(&hba->max_queue_depth, FD_HBA_QUEUE_DEPTH);
 	hba->hba_ptr = (void *) fd_host;

 	printk(KERN_INFO "CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
 		" Target Core Stack %s\n", hba->hba_id, FD_VERSION,
 		TARGET_CORE_MOD_VERSION);
 	printk(KERN_INFO "CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic"
 		" Target Core with TCQ Depth: %d MaxSectors: %u\n",
 		hba->hba_id, fd_host->fd_host_id,
 		atomic_read(&hba->max_queue_depth), FD_MAX_SECTORS);

 	return 0;
 }

 static void fd_detach_hba(struct se_hba *hba)
 {
 	struct fd_host *fd_host = hba->hba_ptr;

 	printk(KERN_INFO "CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
 		" Target Core\n", hba->hba_id, fd_host->fd_host_id);

 	kfree(fd_host);
 	hba->hba_ptr = NULL;
 }

 static void *fd_allocate_virtdevice(struct se_hba *hba, const char *name)
 {
 	struct fd_dev *fd_dev;
 	struct fd_host *fd_host = (struct fd_host *) hba->hba_ptr;

 	fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
 	if (!(fd_dev)) {
 		printk(KERN_ERR "Unable to allocate memory for struct fd_dev\n");
 		return NULL;
 	}

 	fd_dev->fd_host = fd_host;

 	printk(KERN_INFO "FILEIO: Allocated fd_dev for %p\n", name);

 	return fd_dev;
 }

 /*	fd_create_virtdevice(): (Part of se_subsystem_api_t template)
  *
  *
  */
 static struct se_device *fd_create_virtdevice(
 	struct se_hba *hba,
 	struct se_subsystem_dev *se_dev,
 	void *p)
 {
 	char *dev_p = NULL;
 	struct se_device *dev;
 	struct se_dev_limits dev_limits;
 	struct queue_limits *limits;
 	struct fd_dev *fd_dev = (struct fd_dev *) p;
 	struct fd_host *fd_host = (struct fd_host *) hba->hba_ptr;
 	mm_segment_t old_fs;
 	struct file *file;
 	struct inode *inode = NULL;
 	int dev_flags = 0, flags;

 	memset(&dev_limits, 0, sizeof(struct se_dev_limits));

 	old_fs = get_fs();
 	set_fs(get_ds());
 	dev_p = getname(fd_dev->fd_dev_name);
 	set_fs(old_fs);

 	if (IS_ERR(dev_p)) {
 		printk(KERN_ERR "getname(%s) failed: %lu\n",
 			fd_dev->fd_dev_name, IS_ERR(dev_p));
 		goto fail;
 	}
 #if 0
 	if (di->no_create_file)
 		flags = O_RDWR | O_LARGEFILE;
 	else
 		flags = O_RDWR | O_CREAT | O_LARGEFILE;
 #else
 	flags = O_RDWR | O_CREAT | O_LARGEFILE;
 #endif
 /*	flags |= O_DIRECT; */
 	/*
 	 * If fd_buffered_io=1 has not been set explictly (the default),
 	 * use O_SYNC to force FILEIO writes to disk.
 	 */
 	if (!(fd_dev->fbd_flags & FDBD_USE_BUFFERED_IO))
 		flags |= O_SYNC;

 	file = filp_open(dev_p, flags, 0600);

 	if (IS_ERR(file) || !file || !file->f_dentry) {
 		printk(KERN_ERR "filp_open(%s) failed\n", dev_p);
 		goto fail;
 	}
 	fd_dev->fd_file = file;
 	/*
 	 * If using a block backend with this struct file, we extract
 	 * fd_dev->fd_[block,dev]_size from struct block_device.
 	 *
 	 * Otherwise, we use the passed fd_size= from configfs
 	 */
 	inode = file->f_mapping->host;
 	if (S_ISBLK(inode->i_mode)) {
 		struct request_queue *q;
 		/*
 		 * Setup the local scope queue_limits from struct request_queue->limits
 		 * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 		 */
 		q = bdev_get_queue(inode->i_bdev);
 		limits = &dev_limits.limits;
 		limits->logical_block_size = bdev_logical_block_size(inode->i_bdev);
 		limits->max_hw_sectors = queue_max_hw_sectors(q);
 		limits->max_sectors = queue_max_sectors(q);
 		/*
 		 * Determine the number of bytes from i_size_read() minus
 		 * one (1) logical sector from underlying struct block_device
 		 */
 		fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
 		fd_dev->fd_dev_size = (i_size_read(file->f_mapping->host) -
 				       fd_dev->fd_block_size);

 		printk(KERN_INFO "FILEIO: Using size: %llu bytes from struct"
 			" block_device blocks: %llu logical_block_size: %d\n",
 			fd_dev->fd_dev_size,
 			div_u64(fd_dev->fd_dev_size, fd_dev->fd_block_size),
 			fd_dev->fd_block_size);
 	} else {
 		if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
 			printk(KERN_ERR "FILEIO: Missing fd_dev_size="
 				" parameter, and no backing struct"
 				" block_device\n");
 			goto fail;
 		}

 		limits = &dev_limits.limits;
 		limits->logical_block_size = FD_BLOCKSIZE;
 		limits->max_hw_sectors = FD_MAX_SECTORS;
 		limits->max_sectors = FD_MAX_SECTORS;
 		fd_dev->fd_block_size = FD_BLOCKSIZE;
 	}

 	dev_limits.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
 	dev_limits.queue_depth = FD_DEVICE_QUEUE_DEPTH;

 	dev = transport_add_device_to_core_hba(hba, &fileio_template,
 				se_dev, dev_flags, (void *)fd_dev,
 				&dev_limits, "FILEIO", FD_VERSION);
 	if (!(dev))
 		goto fail;

 	fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
 	fd_dev->fd_queue_depth = dev->queue_depth;

 	printk(KERN_INFO "CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
 		" %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
 			fd_dev->fd_dev_name, fd_dev->fd_dev_size);

 	putname(dev_p);
 	return dev;
 fail:
 	if (fd_dev->fd_file) {
 		filp_close(fd_dev->fd_file, NULL);
 		fd_dev->fd_file = NULL;
 	}
 	putname(dev_p);
 	return NULL;
 }

 /*	fd_free_device(): (Part of se_subsystem_api_t template)
  *
  *
  */
 static void fd_free_device(void *p)
 {
 	struct fd_dev *fd_dev = (struct fd_dev *) p;

 	if (fd_dev->fd_file) {
 		filp_close(fd_dev->fd_file, NULL);
 		fd_dev->fd_file = NULL;
 	}

 	kfree(fd_dev);
 }

 static inline struct fd_request *FILE_REQ(struct se_task *task)
 {
 	return container_of(task, struct fd_request, fd_task);
 }


 static struct se_task *
 fd_alloc_task(struct se_cmd *cmd)
 {
 	struct fd_request *fd_req;

 	fd_req = kzalloc(sizeof(struct fd_request), GFP_KERNEL);
 	if (!(fd_req)) {
 		printk(KERN_ERR "Unable to allocate struct fd_request\n");
 		return NULL;
 	}

 	fd_req->fd_dev = SE_DEV(cmd)->dev_ptr;

 	return &fd_req->fd_task;
 }

 static int fd_do_readv(struct se_task *task)
 {
 	struct fd_request *req = FILE_REQ(task);
 	struct file *fd = req->fd_dev->fd_file;
 	struct scatterlist *sg = task->task_sg;
 	struct iovec *iov;
 	mm_segment_t old_fs;
 	loff_t pos = (task->task_lba * DEV_ATTRIB(task->se_dev)->block_size);
 	int ret = 0, i;

 	iov = kzalloc(sizeof(struct iovec) * task->task_sg_num, GFP_KERNEL);
 	if (!(iov)) {
 		printk(KERN_ERR "Unable to allocate fd_do_readv iov[]\n");
 		return -1;
 	}

 	for (i = 0; i < task->task_sg_num; i++) {
 		iov[i].iov_len = sg[i].length;
 		iov[i].iov_base = sg_virt(&sg[i]);
 	}

 	old_fs = get_fs();
 	set_fs(get_ds());
 	ret = vfs_readv(fd, &iov[0], task->task_sg_num, &pos);
 	set_fs(old_fs);

 	kfree(iov);
 	/*
 	 * Return zeros and GOOD status even if the READ did not return
 	 * the expected virt_size for struct file w/o a backing struct
 	 * block_device.
 	 */
 	if (S_ISBLK(fd->f_dentry->d_inode->i_mode)) {
 		if (ret < 0 || ret != task->task_size) {
 			printk(KERN_ERR "vfs_readv() returned %d,"
 				" expecting %d for S_ISBLK\n", ret,
 				(int)task->task_size);
 			return -1;
 		}
 	} else {
 		if (ret < 0) {
 			printk(KERN_ERR "vfs_readv() returned %d for non"
 				" S_ISBLK\n", ret);
 			return -1;
 		}
 	}

 	return 1;
 }

 static int fd_do_writev(struct se_task *task)
 {
 	struct fd_request *req = FILE_REQ(task);
 	struct file *fd = req->fd_dev->fd_file;
 	struct scatterlist *sg = task->task_sg;
 	struct iovec *iov;
 	mm_segment_t old_fs;
 	loff_t pos = (task->task_lba * DEV_ATTRIB(task->se_dev)->block_size);
 	int ret, i = 0;

 	iov = kzalloc(sizeof(struct iovec) * task->task_sg_num, GFP_KERNEL);
 	if (!(iov)) {
 		printk(KERN_ERR "Unable to allocate fd_do_writev iov[]\n");
 		return -1;
 	}

 	for (i = 0; i < task->task_sg_num; i++) {
 		iov[i].iov_len = sg[i].length;
 		iov[i].iov_base = sg_virt(&sg[i]);
 	}

 	old_fs = get_fs();
 	set_fs(get_ds());
 	ret = vfs_writev(fd, &iov[0], task->task_sg_num, &pos);
 	set_fs(old_fs);

 	kfree(iov);

 	if (ret < 0 || ret != task->task_size) {
 		printk(KERN_ERR "vfs_writev() returned %d\n", ret);
 		return -1;
 	}

 	return 1;
 }

 static void fd_emulate_sync_cache(struct se_task *task)
 {
 	struct se_cmd *cmd = TASK_CMD(task);
 	struct se_device *dev = cmd->se_dev;
 	struct fd_dev *fd_dev = dev->dev_ptr;
 	int immed = (cmd->t_task->t_task_cdb[1] & 0x2);
 	loff_t start, end;
 	int ret;

 	/*
 	 * If the Immediate bit is set, queue up the GOOD response
 	 * for this SYNCHRONIZE_CACHE op
 	 */
 	if (immed)
 		transport_complete_sync_cache(cmd, 1);

 	/*
 	 * Determine if we will be flushing the entire device.
 	 */
 	if (cmd->t_task->t_task_lba == 0 && cmd->data_length == 0) {
 		start = 0;
 		end = LLONG_MAX;
 	} else {
 		start = cmd->t_task->t_task_lba * DEV_ATTRIB(dev)->block_size;
 		if (cmd->data_length)
 			end = start + cmd->data_length;
 		else
 			end = LLONG_MAX;
 	}

 	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 	if (ret != 0)
 		printk(KERN_ERR "FILEIO: vfs_fsync_range() failed: %d\n", ret);

 	if (!immed)
 		transport_complete_sync_cache(cmd, ret == 0);
 }

 /*
  * Tell TCM Core that we are capable of WriteCache emulation for
  * an underlying struct se_device.
  */
 static int fd_emulated_write_cache(struct se_device *dev)
 {
 	return 1;
 }

 static int fd_emulated_dpo(struct se_device *dev)
 {
 	return 0;
 }
 /*
  * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
  * for TYPE_DISK.
  */
 static int fd_emulated_fua_write(struct se_device *dev)
 {
 	return 1;
 }

 static int fd_emulated_fua_read(struct se_device *dev)
 {
 	return 0;
 }

 /*
  * WRITE Force Unit Access (FUA) emulation on a per struct se_task
  * LBA range basis..
  */
 static void fd_emulate_write_fua(struct se_cmd *cmd, struct se_task *task)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct fd_dev *fd_dev = dev->dev_ptr;
 	loff_t start = task->task_lba * DEV_ATTRIB(dev)->block_size;
 	loff_t end = start + task->task_size;
 	int ret;

 	DEBUG_FD_CACHE("FILEIO: FUA WRITE LBA: %llu, bytes: %u\n",
 			task->task_lba, task->task_size);

 	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 	if (ret != 0)
 		printk(KERN_ERR "FILEIO: vfs_fsync_range() failed: %d\n", ret);
 }

 static int fd_do_task(struct se_task *task)
 {
 	struct se_cmd *cmd = task->task_se_cmd;
 	struct se_device *dev = cmd->se_dev;
 	int ret = 0;

 	/*
 	 * Call vectorized fileio functions to map struct scatterlist
 	 * physical memory addresses to struct iovec virtual memory.
 	 */
 	if (task->task_data_direction == DMA_FROM_DEVICE) {
 		ret = fd_do_readv(task);
 	} else {
 		ret = fd_do_writev(task);

 		if (ret > 0 &&
 		    DEV_ATTRIB(dev)->emulate_write_cache > 0 &&
 		    DEV_ATTRIB(dev)->emulate_fua_write > 0 &&
 		    T_TASK(cmd)->t_tasks_fua) {
 			/*
 			 * We might need to be a bit smarter here
 			 * and return some sense data to let the initiator
 			 * know the FUA WRITE cache sync failed..?
 			 */
 			fd_emulate_write_fua(cmd, task);
 		}

 	}

 	if (ret < 0)
 		return ret;
 	if (ret) {
 		task->task_scsi_status = GOOD;
 		transport_complete_task(task, 1);
 	}
 	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
 }

 /*	fd_free_task(): (Part of se_subsystem_api_t template)
  *
  *
  */
 static void fd_free_task(struct se_task *task)
 {
 	struct fd_request *req = FILE_REQ(task);

 	kfree(req);
 }

 enum {
 	Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
 };

 static match_table_t tokens = {
 	{Opt_fd_dev_name, "fd_dev_name=%s"},
 	{Opt_fd_dev_size, "fd_dev_size=%s"},
 	{Opt_fd_buffered_io, "fd_buffered_id=%d"},
 	{Opt_err, NULL}
 };

 static ssize_t fd_set_configfs_dev_params(
 	struct se_hba *hba,
 	struct se_subsystem_dev *se_dev,
 	const char *page, ssize_t count)
 {
 	struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
 	char *orig, *ptr, *arg_p, *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, ",")) != NULL) {
 		if (!*ptr)
 			continue;

 		token = match_token(ptr, tokens, args);
 		switch (token) {
 		case Opt_fd_dev_name:
 			snprintf(fd_dev->fd_dev_name, FD_MAX_DEV_NAME,
 					"%s", match_strdup(&args[0]));
 			printk(KERN_INFO "FILEIO: Referencing Path: %s\n",
 					fd_dev->fd_dev_name);
 			fd_dev->fbd_flags |= FBDF_HAS_PATH;
 			break;
 		case Opt_fd_dev_size:
 			arg_p = match_strdup(&args[0]);
 			ret = strict_strtoull(arg_p, 0, &fd_dev->fd_dev_size);
 			if (ret < 0) {
 				printk(KERN_ERR "strict_strtoull() failed for"
 						" fd_dev_size=\n");
 				goto out;
 			}
 			printk(KERN_INFO "FILEIO: Referencing Size: %llu"
 					" bytes\n", fd_dev->fd_dev_size);
 			fd_dev->fbd_flags |= FBDF_HAS_SIZE;
 			break;
 		case Opt_fd_buffered_io:
 			match_int(args, &arg);
 			if (arg != 1) {
 				printk(KERN_ERR "bogus fd_buffered_io=%d value\n", arg);
 				ret = -EINVAL;
 				goto out;
 			}

 			printk(KERN_INFO "FILEIO: Using buffered I/O"
 				" operations for struct fd_dev\n");

 			fd_dev->fbd_flags |= FDBD_USE_BUFFERED_IO;
 			break;
 		default:
 			break;
 		}
 	}

 out:
 	kfree(orig);
 	return (!ret) ? count : ret;
 }

 static ssize_t fd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
 {
 	struct fd_dev *fd_dev = (struct fd_dev *) se_dev->se_dev_su_ptr;

 	if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
 		printk(KERN_ERR "Missing fd_dev_name=\n");
 		return -1;
 	}

 	return 0;
 }

 static ssize_t fd_show_configfs_dev_params(
 	struct se_hba *hba,
 	struct se_subsystem_dev *se_dev,
 	char *b)
 {
 	struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
 	ssize_t bl = 0;

 	bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
 	bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s\n",
 		fd_dev->fd_dev_name, fd_dev->fd_dev_size,
 		(fd_dev->fbd_flags & FDBD_USE_BUFFERED_IO) ?
 		"Buffered" : "Synchronous");
 	return bl;
 }

 /*	fd_get_cdb(): (Part of se_subsystem_api_t template)
  *
  *
  */
 static unsigned char *fd_get_cdb(struct se_task *task)
 {
 	struct fd_request *req = FILE_REQ(task);

 	return req->fd_scsi_cdb;
 }

 /*	fd_get_device_rev(): (Part of se_subsystem_api_t template)
  *
  *
  */
 static u32 fd_get_device_rev(struct se_device *dev)
 {
 	return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 }

 /*	fd_get_device_type(): (Part of se_subsystem_api_t template)
  *
  *
  */
 static u32 fd_get_device_type(struct se_device *dev)
 {
 	return TYPE_DISK;
 }

 static sector_t fd_get_blocks(struct se_device *dev)
 {
 	struct fd_dev *fd_dev = dev->dev_ptr;
 	unsigned long long blocks_long = div_u64(fd_dev->fd_dev_size,
 			DEV_ATTRIB(dev)->block_size);

 	return blocks_long;
 }

 static struct se_subsystem_api fileio_template = {
 	.name			= "fileio",
 	.owner			= THIS_MODULE,
 	.transport_type		= TRANSPORT_PLUGIN_VHBA_PDEV,
 	.attach_hba		= fd_attach_hba,
 	.detach_hba		= fd_detach_hba,
 	.allocate_virtdevice	= fd_allocate_virtdevice,
 	.create_virtdevice	= fd_create_virtdevice,
 	.free_device		= fd_free_device,
 	.dpo_emulated		= fd_emulated_dpo,
 	.fua_write_emulated	= fd_emulated_fua_write,
 	.fua_read_emulated	= fd_emulated_fua_read,
 	.write_cache_emulated	= fd_emulated_write_cache,
 	.alloc_task		= fd_alloc_task,
 	.do_task		= fd_do_task,
 	.do_sync_cache		= fd_emulate_sync_cache,
 	.free_task		= fd_free_task,
 	.check_configfs_dev_params = fd_check_configfs_dev_params,
 	.set_configfs_dev_params = fd_set_configfs_dev_params,
 	.show_configfs_dev_params = fd_show_configfs_dev_params,
 	.get_cdb		= fd_get_cdb,
 	.get_device_rev		= fd_get_device_rev,
 	.get_device_type	= fd_get_device_type,
 	.get_blocks		= fd_get_blocks,
 };

 static int __init fileio_module_init(void)
 {
 	return transport_subsystem_register(&fileio_template);
 }

 static void fileio_module_exit(void)
 {
 	transport_subsystem_release(&fileio_template);
 }

 MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 MODULE_LICENSE("GPL");

 module_init(fileio_module_init);
 module_exit(fileio_module_exit);
	/*******************************************************************************
	* Filename: target_core_file.c
	*
	* This file contains the Storage Engine <-> FILEIO transport specific functions
	*
	* Copyright (c) 2005 PyX Technologies, Inc.
	* Copyright (c) 2005-2006 SBE, Inc. All Rights Reserved.
	* Copyright (c) 2007-2010 Rising Tide Systems
	* Copyright (c) 2008-2010 Linux-iSCSI.org
	*
	* 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/version.h>
	#include <linux/string.h>
	#include <linux/parser.h>
	#include <linux/timer.h>
	#include <linux/blkdev.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_device.h>
	#include <target/target_core_transport.h>

	#include "target_core_file.h"

	#if 1
	#define DEBUG_FD_CACHE(x...) printk(x)
	#else
	#define DEBUG_FD_CACHE(x...)
	#endif

	#if 1
	#define DEBUG_FD_FUA(x...) printk(x)
	#else
	#define DEBUG_FD_FUA(x...)
	#endif

	static struct se_subsystem_api fileio_template;

	/* fd_attach_hba(): (Part of se_subsystem_api_t template)
	*
	*
	*/
	static int fd_attach_hba(struct se_hba *hba, u32 host_id)
	{
	struct fd_host *fd_host;

	fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
	if (!(fd_host)) {
	printk(KERN_ERR "Unable to allocate memory for struct fd_host\n");
	return -1;
	}

	fd_host->fd_host_id = host_id;

	atomic_set(&hba->left_queue_depth, FD_HBA_QUEUE_DEPTH);
	atomic_set(&hba->max_queue_depth, FD_HBA_QUEUE_DEPTH);
	hba->hba_ptr = (void *) fd_host;

	printk(KERN_INFO "CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
	" Target Core Stack %s\n", hba->hba_id, FD_VERSION,
	TARGET_CORE_MOD_VERSION);
	printk(KERN_INFO "CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic"
	" Target Core with TCQ Depth: %d MaxSectors: %u\n",
	hba->hba_id, fd_host->fd_host_id,
	atomic_read(&hba->max_queue_depth), FD_MAX_SECTORS);

	return 0;
	}

	static void fd_detach_hba(struct se_hba *hba)
	{
	struct fd_host *fd_host = hba->hba_ptr;

	printk(KERN_INFO "CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
	" Target Core\n", hba->hba_id, fd_host->fd_host_id);

	kfree(fd_host);
	hba->hba_ptr = NULL;
	}

	static void fd_allocate_virtdevice(struct se_hba hba, const char *name)
	{
	struct fd_dev *fd_dev;
	struct fd_host fd_host = (struct fd_host ) hba->hba_ptr;

	fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
	if (!(fd_dev)) {
	printk(KERN_ERR "Unable to allocate memory for struct fd_dev\n");
	return NULL;
	}

	fd_dev->fd_host = fd_host;

	printk(KERN_INFO "FILEIO: Allocated fd_dev for %p\n", name);

	return fd_dev;
	}

	/* fd_create_virtdevice(): (Part of se_subsystem_api_t template)
	*
	*
	*/
	static struct se_device *fd_create_virtdevice(
	struct se_hba *hba,
	struct se_subsystem_dev *se_dev,
	void *p)
	{
	char *dev_p = NULL;
	struct se_device *dev;
	struct se_dev_limits dev_limits;
	struct queue_limits *limits;
	struct fd_dev fd_dev = (struct fd_dev ) p;
	struct fd_host fd_host = (struct fd_host ) hba->hba_ptr;
	mm_segment_t old_fs;
	struct file *file;
	struct inode *inode = NULL;
	int dev_flags = 0, flags;

	memset(&dev_limits, 0, sizeof(struct se_dev_limits));

	old_fs = get_fs();
	set_fs(get_ds());
	dev_p = getname(fd_dev->fd_dev_name);
	set_fs(old_fs);

	if (IS_ERR(dev_p)) {
	printk(KERN_ERR "getname(%s) failed: %lu\n",
	fd_dev->fd_dev_name, IS_ERR(dev_p));
	goto fail;
	}
	#if 0
	if (di->no_create_file)
	flags = O_RDWR \| O_LARGEFILE;
	else
	flags = O_RDWR \| O_CREAT \| O_LARGEFILE;
	#else
	flags = O_RDWR \| O_CREAT \| O_LARGEFILE;
	#endif
	/* flags \|= O_DIRECT; */
	/*
	* If fd_buffered_io=1 has not been set explictly (the default),
	* use O_SYNC to force FILEIO writes to disk.
	*/
	if (!(fd_dev->fbd_flags & FDBD_USE_BUFFERED_IO))
	flags \|= O_SYNC;

	file = filp_open(dev_p, flags, 0600);

	if (IS_ERR(file) \|\| !file \|\| !file->f_dentry) {
	printk(KERN_ERR "filp_open(%s) failed\n", dev_p);
	goto fail;
	}
	fd_dev->fd_file = file;
	/*
	* If using a block backend with this struct file, we extract
	* fd_dev->fd_[block,dev]_size from struct block_device.
	*
	* Otherwise, we use the passed fd_size= from configfs
	*/
	inode = file->f_mapping->host;
	if (S_ISBLK(inode->i_mode)) {
	struct request_queue *q;
	/*
	* Setup the local scope queue_limits from struct request_queue->limits
	* to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
	*/
	q = bdev_get_queue(inode->i_bdev);
	limits = &dev_limits.limits;
	limits->logical_block_size = bdev_logical_block_size(inode->i_bdev);
	limits->max_hw_sectors = queue_max_hw_sectors(q);
	limits->max_sectors = queue_max_sectors(q);
	/*
	* Determine the number of bytes from i_size_read() minus
	* one (1) logical sector from underlying struct block_device
	*/
	fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
	fd_dev->fd_dev_size = (i_size_read(file->f_mapping->host) -
	fd_dev->fd_block_size);

	printk(KERN_INFO "FILEIO: Using size: %llu bytes from struct"
	" block_device blocks: %llu logical_block_size: %d\n",
	fd_dev->fd_dev_size,
	div_u64(fd_dev->fd_dev_size, fd_dev->fd_block_size),
	fd_dev->fd_block_size);
	} else {
	if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
	printk(KERN_ERR "FILEIO: Missing fd_dev_size="
	" parameter, and no backing struct"
	" block_device\n");
	goto fail;
	}

	limits = &dev_limits.limits;
	limits->logical_block_size = FD_BLOCKSIZE;
	limits->max_hw_sectors = FD_MAX_SECTORS;
	limits->max_sectors = FD_MAX_SECTORS;
	fd_dev->fd_block_size = FD_BLOCKSIZE;
	}

	dev_limits.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
	dev_limits.queue_depth = FD_DEVICE_QUEUE_DEPTH;

	dev = transport_add_device_to_core_hba(hba, &fileio_template,
	se_dev, dev_flags, (void *)fd_dev,
	&dev_limits, "FILEIO", FD_VERSION);
	if (!(dev))
	goto fail;

	fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
	fd_dev->fd_queue_depth = dev->queue_depth;

	printk(KERN_INFO "CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
	" %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
	fd_dev->fd_dev_name, fd_dev->fd_dev_size);

	putname(dev_p);
	return dev;
	fail:
	if (fd_dev->fd_file) {
	filp_close(fd_dev->fd_file, NULL);
	fd_dev->fd_file = NULL;
	}
	putname(dev_p);
	return NULL;
	}

	/* fd_free_device(): (Part of se_subsystem_api_t template)
	*
	*
	*/
	static void fd_free_device(void *p)
	{
	struct fd_dev fd_dev = (struct fd_dev ) p;

	if (fd_dev->fd_file) {
	filp_close(fd_dev->fd_file, NULL);
	fd_dev->fd_file = NULL;
	}

	kfree(fd_dev);
	}

	static inline struct fd_request FILE_REQ(struct se_task task)
	{
	return container_of(task, struct fd_request, fd_task);
	}


	static struct se_task *
	fd_alloc_task(struct se_cmd *cmd)
	{
	struct fd_request *fd_req;

	fd_req = kzalloc(sizeof(struct fd_request), GFP_KERNEL);
	if (!(fd_req)) {
	printk(KERN_ERR "Unable to allocate struct fd_request\n");
	return NULL;
	}

	fd_req->fd_dev = SE_DEV(cmd)->dev_ptr;

	return &fd_req->fd_task;
	}

	static int fd_do_readv(struct se_task *task)
	{
	struct fd_request *req = FILE_REQ(task);
	struct file *fd = req->fd_dev->fd_file;
	struct scatterlist *sg = task->task_sg;
	struct iovec *iov;
	mm_segment_t old_fs;
	loff_t pos = (task->task_lba * DEV_ATTRIB(task->se_dev)->block_size);
	int ret = 0, i;

	iov = kzalloc(sizeof(struct iovec) * task->task_sg_num, GFP_KERNEL);
	if (!(iov)) {
	printk(KERN_ERR "Unable to allocate fd_do_readv iov[]\n");
	return -1;
	}

	for (i = 0; i < task->task_sg_num; i++) {
	iov[i].iov_len = sg[i].length;
	iov[i].iov_base = sg_virt(&sg[i]);
	}

	old_fs = get_fs();
	set_fs(get_ds());
	ret = vfs_readv(fd, &iov[0], task->task_sg_num, &pos);
	set_fs(old_fs);

	kfree(iov);
	/*
	* Return zeros and GOOD status even if the READ did not return
	* the expected virt_size for struct file w/o a backing struct
	* block_device.
	*/
	if (S_ISBLK(fd->f_dentry->d_inode->i_mode)) {
	if (ret < 0 \|\| ret != task->task_size) {
	printk(KERN_ERR "vfs_readv() returned %d,"
	" expecting %d for S_ISBLK\n", ret,
	(int)task->task_size);
	return -1;
	}
	} else {
	if (ret < 0) {
	printk(KERN_ERR "vfs_readv() returned %d for non"
	" S_ISBLK\n", ret);
	return -1;
	}
	}

	return 1;
	}

	static int fd_do_writev(struct se_task *task)
	{
	struct fd_request *req = FILE_REQ(task);
	struct file *fd = req->fd_dev->fd_file;
	struct scatterlist *sg = task->task_sg;
	struct iovec *iov;
	mm_segment_t old_fs;
	loff_t pos = (task->task_lba * DEV_ATTRIB(task->se_dev)->block_size);
	int ret, i = 0;

	iov = kzalloc(sizeof(struct iovec) * task->task_sg_num, GFP_KERNEL);
	if (!(iov)) {
	printk(KERN_ERR "Unable to allocate fd_do_writev iov[]\n");
	return -1;
	}

	for (i = 0; i < task->task_sg_num; i++) {
	iov[i].iov_len = sg[i].length;
	iov[i].iov_base = sg_virt(&sg[i]);
	}

	old_fs = get_fs();
	set_fs(get_ds());
	ret = vfs_writev(fd, &iov[0], task->task_sg_num, &pos);
	set_fs(old_fs);

	kfree(iov);

	if (ret < 0 \|\| ret != task->task_size) {
	printk(KERN_ERR "vfs_writev() returned %d\n", ret);
	return -1;
	}

	return 1;
	}

	static void fd_emulate_sync_cache(struct se_task *task)
	{
	struct se_cmd *cmd = TASK_CMD(task);
	struct se_device *dev = cmd->se_dev;
	struct fd_dev *fd_dev = dev->dev_ptr;
	int immed = (cmd->t_task->t_task_cdb[1] & 0x2);
	loff_t start, end;
	int ret;

	/*
	* If the Immediate bit is set, queue up the GOOD response
	* for this SYNCHRONIZE_CACHE op
	*/
	if (immed)
	transport_complete_sync_cache(cmd, 1);

	/*
	* Determine if we will be flushing the entire device.
	*/
	if (cmd->t_task->t_task_lba == 0 && cmd->data_length == 0) {
	start = 0;
	end = LLONG_MAX;
	} else {
	start = cmd->t_task->t_task_lba * DEV_ATTRIB(dev)->block_size;
	if (cmd->data_length)
	end = start + cmd->data_length;
	else
	end = LLONG_MAX;
	}

	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
	if (ret != 0)
	printk(KERN_ERR "FILEIO: vfs_fsync_range() failed: %d\n", ret);

	if (!immed)
	transport_complete_sync_cache(cmd, ret == 0);
	}

	/*
	* Tell TCM Core that we are capable of WriteCache emulation for
	* an underlying struct se_device.
	*/
	static int fd_emulated_write_cache(struct se_device *dev)
	{
	return 1;
	}

	static int fd_emulated_dpo(struct se_device *dev)
	{
	return 0;
	}
	/*
	* Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
	* for TYPE_DISK.
	*/
	static int fd_emulated_fua_write(struct se_device *dev)
	{
	return 1;
	}

	static int fd_emulated_fua_read(struct se_device *dev)
	{
	return 0;
	}

	/*
	* WRITE Force Unit Access (FUA) emulation on a per struct se_task
	* LBA range basis..
	*/
	static void fd_emulate_write_fua(struct se_cmd cmd, struct se_task task)
	{
	struct se_device *dev = cmd->se_dev;
	struct fd_dev *fd_dev = dev->dev_ptr;
	loff_t start = task->task_lba * DEV_ATTRIB(dev)->block_size;
	loff_t end = start + task->task_size;
	int ret;

	DEBUG_FD_CACHE("FILEIO: FUA WRITE LBA: %llu, bytes: %u\n",
	task->task_lba, task->task_size);

	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
	if (ret != 0)
	printk(KERN_ERR "FILEIO: vfs_fsync_range() failed: %d\n", ret);
	}

	static int fd_do_task(struct se_task *task)
	{
	struct se_cmd *cmd = task->task_se_cmd;
	struct se_device *dev = cmd->se_dev;
	int ret = 0;

	/*
	* Call vectorized fileio functions to map struct scatterlist
	* physical memory addresses to struct iovec virtual memory.
	*/
	if (task->task_data_direction == DMA_FROM_DEVICE) {
	ret = fd_do_readv(task);
	} else {
	ret = fd_do_writev(task);

	if (ret > 0 &&
	DEV_ATTRIB(dev)->emulate_write_cache > 0 &&
	DEV_ATTRIB(dev)->emulate_fua_write > 0 &&
	T_TASK(cmd)->t_tasks_fua) {
	/*
	* We might need to be a bit smarter here
	* and return some sense data to let the initiator
	* know the FUA WRITE cache sync failed..?
	*/
	fd_emulate_write_fua(cmd, task);
	}

	}

	if (ret < 0)
	return ret;
	if (ret) {
	task->task_scsi_status = GOOD;
	transport_complete_task(task, 1);
	}
	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
	}

	/* fd_free_task(): (Part of se_subsystem_api_t template)
	*
	*
	*/
	static void fd_free_task(struct se_task *task)
	{
	struct fd_request *req = FILE_REQ(task);

	kfree(req);
	}

	enum {
	Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
	};

	static match_table_t tokens = {
	{Opt_fd_dev_name, "fd_dev_name=%s"},
	{Opt_fd_dev_size, "fd_dev_size=%s"},
	{Opt_fd_buffered_io, "fd_buffered_id=%d"},
	{Opt_err, NULL}
	};

	static ssize_t fd_set_configfs_dev_params(
	struct se_hba *hba,
	struct se_subsystem_dev *se_dev,
	const char *page, ssize_t count)
	{
	struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
	char orig, ptr, arg_p, 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, ",")) != NULL) {
	if (!*ptr)
	continue;

	token = match_token(ptr, tokens, args);
	switch (token) {
	case Opt_fd_dev_name:
	snprintf(fd_dev->fd_dev_name, FD_MAX_DEV_NAME,
	"%s", match_strdup(&args[0]));
	printk(KERN_INFO "FILEIO: Referencing Path: %s\n",
	fd_dev->fd_dev_name);
	fd_dev->fbd_flags \|= FBDF_HAS_PATH;
	break;
	case Opt_fd_dev_size:
	arg_p = match_strdup(&args[0]);
	ret = strict_strtoull(arg_p, 0, &fd_dev->fd_dev_size);
	if (ret < 0) {
	printk(KERN_ERR "strict_strtoull() failed for"
	" fd_dev_size=\n");
	goto out;
	}
	printk(KERN_INFO "FILEIO: Referencing Size: %llu"
	" bytes\n", fd_dev->fd_dev_size);
	fd_dev->fbd_flags \|= FBDF_HAS_SIZE;
	break;
	case Opt_fd_buffered_io:
	match_int(args, &arg);
	if (arg != 1) {
	printk(KERN_ERR "bogus fd_buffered_io=%d value\n", arg);
	ret = -EINVAL;
	goto out;
	}

	printk(KERN_INFO "FILEIO: Using buffered I/O"
	" operations for struct fd_dev\n");

	fd_dev->fbd_flags \|= FDBD_USE_BUFFERED_IO;
	break;
	default:
	break;
	}
	}

	out:
	kfree(orig);
	return (!ret) ? count : ret;
	}

	static ssize_t fd_check_configfs_dev_params(struct se_hba hba, struct se_subsystem_dev se_dev)
	{
	struct fd_dev fd_dev = (struct fd_dev ) se_dev->se_dev_su_ptr;

	if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
	printk(KERN_ERR "Missing fd_dev_name=\n");
	return -1;
	}

	return 0;
	}

	static ssize_t fd_show_configfs_dev_params(
	struct se_hba *hba,
	struct se_subsystem_dev *se_dev,
	char *b)
	{
	struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
	ssize_t bl = 0;

	bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
	bl += sprintf(b + bl, " File: %s Size: %llu Mode: %s\n",
	fd_dev->fd_dev_name, fd_dev->fd_dev_size,
	(fd_dev->fbd_flags & FDBD_USE_BUFFERED_IO) ?
	"Buffered" : "Synchronous");
	return bl;
	}

	/* fd_get_cdb(): (Part of se_subsystem_api_t template)
	*
	*
	*/
	static unsigned char fd_get_cdb(struct se_task task)
	{
	struct fd_request *req = FILE_REQ(task);

	return req->fd_scsi_cdb;
	}

	/* fd_get_device_rev(): (Part of se_subsystem_api_t template)
	*
	*
	*/
	static u32 fd_get_device_rev(struct se_device *dev)
	{
	return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
	}

	/* fd_get_device_type(): (Part of se_subsystem_api_t template)
	*
	*
	*/
	static u32 fd_get_device_type(struct se_device *dev)
	{
	return TYPE_DISK;
	}

	static sector_t fd_get_blocks(struct se_device *dev)
	{
	struct fd_dev *fd_dev = dev->dev_ptr;
	unsigned long long blocks_long = div_u64(fd_dev->fd_dev_size,
	DEV_ATTRIB(dev)->block_size);

	return blocks_long;
	}

	static struct se_subsystem_api fileio_template = {
	.name = "fileio",
	.owner = THIS_MODULE,
	.transport_type = TRANSPORT_PLUGIN_VHBA_PDEV,
	.attach_hba = fd_attach_hba,
	.detach_hba = fd_detach_hba,
	.allocate_virtdevice = fd_allocate_virtdevice,
	.create_virtdevice = fd_create_virtdevice,
	.free_device = fd_free_device,
	.dpo_emulated = fd_emulated_dpo,
	.fua_write_emulated = fd_emulated_fua_write,
	.fua_read_emulated = fd_emulated_fua_read,
	.write_cache_emulated = fd_emulated_write_cache,
	.alloc_task = fd_alloc_task,
	.do_task = fd_do_task,
	.do_sync_cache = fd_emulate_sync_cache,
	.free_task = fd_free_task,
	.check_configfs_dev_params = fd_check_configfs_dev_params,
	.set_configfs_dev_params = fd_set_configfs_dev_params,
	.show_configfs_dev_params = fd_show_configfs_dev_params,
	.get_cdb = fd_get_cdb,
	.get_device_rev = fd_get_device_rev,
	.get_device_type = fd_get_device_type,
	.get_blocks = fd_get_blocks,
	};

	static int __init fileio_module_init(void)
	{
	return transport_subsystem_register(&fileio_template);
	}

	static void fileio_module_exit(void)
	{
	transport_subsystem_release(&fileio_template);
	}

	MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
	MODULE_AUTHOR("nab@Linux-iSCSI.org");
	MODULE_LICENSE("GPL");

	module_init(fileio_module_init);
	module_exit(fileio_module_exit);