linux/drivers/target/target_core_file.c
Jörn Engel 8359cf43b9 target: remove useless casts
A reader should spend an extra moment whenever noticing a cast,
because either something special is going on that deserves extra
attention or, as is all too often the case, the code is wrong.

These casts, afaics, have all been useless.  They cast a foo* to a
foo*, cast a void* to the assigned type, cast a foo* to void*, before
assigning it to a void* variable, etc.

In a few cases I also removed an additional &...[0], which is equally
useless.

Lastly I added three FIXMEs where, to the best of my judgement, the
code appears to have a bug.  It would be good if someone could check
these.

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-12-14 11:28:07 +00:00

652 lines
16 KiB
C

/*******************************************************************************
* 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/string.h>
#include <linux/parser.h>
#include <linux/timer.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <target/target_core_base.h>
#include <target/target_core_backend.h>
#include "target_core_file.h"
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) {
pr_err("Unable to allocate memory for struct fd_host\n");
return -ENOMEM;
}
fd_host->fd_host_id = host_id;
hba->hba_ptr = fd_host;
pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
" Target Core Stack %s\n", hba->hba_id, FD_VERSION,
TARGET_CORE_MOD_VERSION);
pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic"
" MaxSectors: %u\n",
hba->hba_id, fd_host->fd_host_id, FD_MAX_SECTORS);
return 0;
}
static void fd_detach_hba(struct se_hba *hba)
{
struct fd_host *fd_host = hba->hba_ptr;
pr_debug("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 = hba->hba_ptr;
fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
if (!fd_dev) {
pr_err("Unable to allocate memory for struct fd_dev\n");
return NULL;
}
fd_dev->fd_host = fd_host;
pr_debug("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 = p;
struct fd_host *fd_host = hba->hba_ptr;
mm_segment_t old_fs;
struct file *file;
struct inode *inode = NULL;
int dev_flags = 0, flags, ret = -EINVAL;
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)) {
pr_err("getname(%s) failed: %lu\n",
fd_dev->fd_dev_name, IS_ERR(dev_p));
ret = PTR_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 explicitly (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)) {
pr_err("filp_open(%s) failed\n", dev_p);
ret = PTR_ERR(file);
goto fail;
}
if (!file || !file->f_dentry) {
pr_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);
pr_debug("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)) {
pr_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, 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;
pr_debug("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 ERR_PTR(ret);
}
/* fd_free_device(): (Part of se_subsystem_api_t template)
*
*
*/
static void fd_free_device(void *p)
{
struct fd_dev *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(unsigned char *cdb)
{
struct fd_request *fd_req;
fd_req = kzalloc(sizeof(struct fd_request), GFP_KERNEL);
if (!fd_req) {
pr_err("Unable to allocate struct fd_request\n");
return NULL;
}
return &fd_req->fd_task;
}
static int fd_do_readv(struct se_task *task)
{
struct fd_request *req = FILE_REQ(task);
struct se_device *se_dev = req->fd_task.task_se_cmd->se_dev;
struct fd_dev *dev = se_dev->dev_ptr;
struct file *fd = dev->fd_file;
struct scatterlist *sg = task->task_sg;
struct iovec *iov;
mm_segment_t old_fs;
loff_t pos = (task->task_lba *
se_dev->se_sub_dev->se_dev_attrib.block_size);
int ret = 0, i;
iov = kzalloc(sizeof(struct iovec) * task->task_sg_nents, GFP_KERNEL);
if (!iov) {
pr_err("Unable to allocate fd_do_readv iov[]\n");
return -ENOMEM;
}
for_each_sg(task->task_sg, sg, task->task_sg_nents, i) {
iov[i].iov_len = sg->length;
iov[i].iov_base = sg_virt(sg);
}
old_fs = get_fs();
set_fs(get_ds());
ret = vfs_readv(fd, &iov[0], task->task_sg_nents, &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) {
pr_err("vfs_readv() returned %d,"
" expecting %d for S_ISBLK\n", ret,
(int)task->task_size);
return (ret < 0 ? ret : -EINVAL);
}
} else {
if (ret < 0) {
pr_err("vfs_readv() returned %d for non"
" S_ISBLK\n", ret);
return ret;
}
}
return 1;
}
static int fd_do_writev(struct se_task *task)
{
struct fd_request *req = FILE_REQ(task);
struct se_device *se_dev = req->fd_task.task_se_cmd->se_dev;
struct fd_dev *dev = se_dev->dev_ptr;
struct file *fd = dev->fd_file;
struct scatterlist *sg = task->task_sg;
struct iovec *iov;
mm_segment_t old_fs;
loff_t pos = (task->task_lba *
se_dev->se_sub_dev->se_dev_attrib.block_size);
int ret, i = 0;
iov = kzalloc(sizeof(struct iovec) * task->task_sg_nents, GFP_KERNEL);
if (!iov) {
pr_err("Unable to allocate fd_do_writev iov[]\n");
return -ENOMEM;
}
for_each_sg(task->task_sg, sg, task->task_sg_nents, i) {
iov[i].iov_len = sg->length;
iov[i].iov_base = sg_virt(sg);
}
old_fs = get_fs();
set_fs(get_ds());
ret = vfs_writev(fd, &iov[0], task->task_sg_nents, &pos);
set_fs(old_fs);
kfree(iov);
if (ret < 0 || ret != task->task_size) {
pr_err("vfs_writev() returned %d\n", ret);
return (ret < 0 ? ret : -EINVAL);
}
return 1;
}
static void fd_emulate_sync_cache(struct se_task *task)
{
struct se_cmd *cmd = task->task_se_cmd;
struct se_device *dev = cmd->se_dev;
struct fd_dev *fd_dev = dev->dev_ptr;
int immed = (cmd->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_lba == 0 && cmd->data_length == 0) {
start = 0;
end = LLONG_MAX;
} else {
start = cmd->t_task_lba * dev->se_sub_dev->se_dev_attrib.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)
pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
if (!immed)
transport_complete_sync_cache(cmd, ret == 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->se_sub_dev->se_dev_attrib.block_size;
loff_t end = start + task->task_size;
int ret;
pr_debug("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)
pr_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->se_sub_dev->se_dev_attrib.emulate_write_cache > 0 &&
dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
(cmd->se_cmd_flags & SCF_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) {
cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
return ret;
}
if (ret) {
task->task_scsi_status = GOOD;
transport_complete_task(task, 1);
}
return 0;
}
/* 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_io=%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, ",\n")) != NULL) {
if (!*ptr)
continue;
token = match_token(ptr, tokens, args);
switch (token) {
case Opt_fd_dev_name:
arg_p = match_strdup(&args[0]);
if (!arg_p) {
ret = -ENOMEM;
break;
}
snprintf(fd_dev->fd_dev_name, FD_MAX_DEV_NAME,
"%s", arg_p);
kfree(arg_p);
pr_debug("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]);
if (!arg_p) {
ret = -ENOMEM;
break;
}
ret = strict_strtoull(arg_p, 0, &fd_dev->fd_dev_size);
kfree(arg_p);
if (ret < 0) {
pr_err("strict_strtoull() failed for"
" fd_dev_size=\n");
goto out;
}
pr_debug("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) {
pr_err("bogus fd_buffered_io=%d value\n", arg);
ret = -EINVAL;
goto out;
}
pr_debug("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 = se_dev->se_dev_su_ptr;
if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
pr_err("Missing fd_dev_name=\n");
return -EINVAL;
}
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_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->se_sub_dev->se_dev_attrib.block_size);
return blocks_long;
}
static struct se_subsystem_api fileio_template = {
.name = "fileio",
.owner = THIS_MODULE,
.transport_type = TRANSPORT_PLUGIN_VHBA_PDEV,
.write_cache_emulated = 1,
.fua_write_emulated = 1,
.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,
.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_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);