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/*
* History:
* Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
* to allow user process control of SCSI devices.
* Development Sponsored by Killy Corp. NY NY
*
* Original driver (sg.c):
* Copyright (C) 1992 Lawrence Foard
* Version 2 and 3 extensions to driver:
* Copyright (C) 1998 - 2005 Douglas Gilbert
*
* Modified 19-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
*
* 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, or (at your option)
* any later version.
*
*/

static int sg_version_num = 30534; /* 2 digits for each component */
#define SG_VERSION_STR "3.5.34"

/*
* D. P. Gilbert (dgilbert@interlog.com, dougg@triode.net.au), notes:
* - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
* the kernel/module needs to be built with CONFIG_SCSI_LOGGING
* (otherwise the macros compile to empty statements).
*
*/
#include <linux/module.h>

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/aio.h>
#include <linux/errno.h>
#include <linux/mtio.h>
#include <linux/ioctl.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/moduleparam.h>
#include <linux/cdev.h>
#include <linux/idr.h>
#include <linux/seq_file.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/blktrace_api.h>
#include <linux/mutex.h>
#include <linux/ratelimit.h>

#include "scsi.h"
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/sg.h>

#include "scsi_logging.h"

#ifdef CONFIG_SCSI_PROC_FS
#include <linux/proc_fs.h>
static char *sg_version_date = "20061027";

static int sg_proc_init(void);
static void sg_proc_cleanup(void);
#endif

#define SG_ALLOW_DIO_DEF 0

#define SG_MAX_DEVS 32768

/*
* Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
* Then when using 32 bit integers x * m may overflow during the calculation.
* Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
* calculates the same, but prevents the overflow when both m and d
* are "small" numbers (like HZ and USER_HZ).
* Of course an overflow is inavoidable if the result of muldiv doesn't fit
* in 32 bits.
*/
#define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))

#define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)

int sg_big_buff = SG_DEF_RESERVED_SIZE;
/* N.B. This variable is readable and writeable via
/proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
of this size (or less if there is not enough memory) will be reserved
for use by this file descriptor. [Deprecated usage: this variable is also
readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
the kernel (i.e. it is not a module).] */
static int def_reserved_size = -1; /* picks up init parameter */
static int sg_allow_dio = SG_ALLOW_DIO_DEF;

static int scatter_elem_sz = SG_SCATTER_SZ;
static int scatter_elem_sz_prev = SG_SCATTER_SZ;

#define SG_SECTOR_SZ 512

static int sg_add(struct device *, struct class_interface *);
static void sg_remove(struct device *, struct class_interface *);

static DEFINE_SPINLOCK(sg_open_exclusive_lock);

static DEFINE_IDR(sg_index_idr);
static DEFINE_RWLOCK(sg_index_lock); /* Also used to lock
file descriptor list for device */

static struct class_interface sg_interface = {
.add_dev = sg_add,
.remove_dev = sg_remove,
};

typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
unsigned bufflen; /* Size of (aggregate) data buffer */
struct page **pages;
int page_order;
char dio_in_use; /* 0->indirect IO (or mmap), 1->dio */
unsigned char cmd_opcode; /* first byte of command */
} Sg_scatter_hold;

struct sg_device; /* forward declarations */
struct sg_fd;

typedef struct sg_request { /* SG_MAX_QUEUE requests outstanding per file */
struct sg_request *nextrp; /* NULL -> tail request (slist) */
struct sg_fd *parentfp; /* NULL -> not in use */
Sg_scatter_hold data; /* hold buffer, perhaps scatter list */
sg_io_hdr_t header; /* scsi command+info, see <scsi/sg.h> */
unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
char res_used; /* 1 -> using reserve buffer, 0 -> not ... */
char orphan; /* 1 -> drop on sight, 0 -> normal */
char sg_io_owned; /* 1 -> packet belongs to SG_IO */
/* done protected by rq_list_lock */
char done; /* 0->before bh, 1->before read, 2->read */
struct request *rq;
struct bio *bio;
struct execute_work ew;
} Sg_request;

typedef struct sg_fd { /* holds the state of a file descriptor */
/* sfd_siblings is protected by sg_index_lock */
struct list_head sfd_siblings;
struct sg_device *parentdp; /* owning device */
wait_queue_head_t read_wait; /* queue read until command done */
rwlock_t rq_list_lock; /* protect access to list in req_arr */
int timeout; /* defaults to SG_DEFAULT_TIMEOUT */
int timeout_user; /* defaults to SG_DEFAULT_TIMEOUT_USER */
Sg_scatter_hold reserve; /* buffer held for this file descriptor */
unsigned save_scat_len; /* original length of trunc. scat. element */
Sg_request *headrp; /* head of request slist, NULL->empty */
struct fasync_struct *async_qp; /* used by asynchronous notification */
Sg_request req_arr[SG_MAX_QUEUE]; /* used as singly-linked list */
char low_dma; /* as in parent but possibly overridden to 1 */
char force_packid; /* 1 -> pack_id input to read(), 0 -> ignored */
char cmd_q; /* 1 -> allow command queuing, 0 -> don't */
char next_cmd_len; /* 0 -> automatic (def), >0 -> use on next write() */
char keep_orphan; /* 0 -> drop orphan (def), 1 -> keep for read() */
char mmap_called; /* 0 -> mmap() never called on this fd */
struct kref f_ref;
struct execute_work ew;
} Sg_fd;

typedef struct sg_device { /* holds the state of each scsi generic device */
struct scsi_device *device;
wait_queue_head_t o_excl_wait; /* queue open() when O_EXCL in use */
int sg_tablesize; /* adapter's max scatter-gather table size */
u32 index; /* device index number */
/* sfds is protected by sg_index_lock */
struct list_head sfds;
volatile char detached; /* 0->attached, 1->detached pending removal */
/* exclude protected by sg_open_exclusive_lock */
char exclude; /* opened for exclusive access */
char sgdebug; /* 0->off, 1->sense, 9->dump dev, 10-> all devs */
struct gendisk *disk;
struct cdev * cdev; /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
struct kref d_ref;
} Sg_device;

/* tasklet or soft irq callback */
static void sg_rq_end_io(struct request *rq, int uptodate);
static int sg_start_req(Sg_request *srp, unsigned char *cmd);
static int sg_finish_rem_req(Sg_request * srp);
static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
Sg_request * srp);
static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
const char __user *buf, size_t count, int blocking,
int read_only, int sg_io_owned, Sg_request **o_srp);
static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
unsigned char *cmnd, int timeout, int blocking);
static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
static void sg_remove_scat(Sg_scatter_hold * schp);
static void sg_build_reserve(Sg_fd * sfp, int req_size);
static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev);
static void sg_remove_sfp(struct kref *);
static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
static Sg_request *sg_add_request(Sg_fd * sfp);
static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
static int sg_res_in_use(Sg_fd * sfp);
static Sg_device *sg_get_dev(int dev);
static void sg_put_dev(Sg_device *sdp);

#define SZ_SG_HEADER sizeof(struct sg_header)
#define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
#define SZ_SG_IOVEC sizeof(sg_iovec_t)
#define SZ_SG_REQ_INFO sizeof(sg_req_info_t)

static int sg_allow_access(struct file *filp, unsigned char *cmd)
{
struct sg_fd *sfp = filp->private_data;

if (sfp->parentdp->device->type == TYPE_SCANNER)
return 0;

return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
}

static int get_exclude(Sg_device *sdp)
{
unsigned long flags;
int ret;

spin_lock_irqsave(&sg_open_exclusive_lock, flags);
ret = sdp->exclude;
spin_unlock_irqrestore(&sg_open_exclusive_lock, flags);
return ret;
}

static int set_exclude(Sg_device *sdp, char val)
{
unsigned long flags;

spin_lock_irqsave(&sg_open_exclusive_lock, flags);
sdp->exclude = val;
spin_unlock_irqrestore(&sg_open_exclusive_lock, flags);
return val;
}

static int sfds_list_empty(Sg_device *sdp)
{
unsigned long flags;
int ret;

read_lock_irqsave(&sg_index_lock, flags);
ret = list_empty(&sdp->sfds);
read_unlock_irqrestore(&sg_index_lock, flags);
return ret;
}

static int
sg_open(struct inode *inode, struct file *filp)
{
int dev = iminor(inode);
int flags = filp->f_flags;
struct request_queue *q;
Sg_device *sdp;
Sg_fd *sfp;
int res;
int retval;

nonseekable_open(inode, filp);
SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
sdp = sg_get_dev(dev);
if (IS_ERR(sdp)) {
retval = PTR_ERR(sdp);
sdp = NULL;
goto sg_put;
}

/* This driver's module count bumped by fops_get in <linux/fs.h> */
/* Prevent the device driver from vanishing while we sleep */
retval = scsi_device_get(sdp->device);
if (retval)
goto sg_put;

retval = scsi_autopm_get_device(sdp->device);
if (retval)
goto sdp_put;

if (!((flags & O_NONBLOCK) ||
scsi_block_when_processing_errors(sdp->device))) {
retval = -ENXIO;
/* we are in error recovery for this device */
goto error_out;
}

if (flags & O_EXCL) {
if (O_RDONLY == (flags & O_ACCMODE)) {
retval = -EPERM; /* Can't lock it with read only access */
goto error_out;
}
if (!sfds_list_empty(sdp) && (flags & O_NONBLOCK)) {
retval = -EBUSY;
goto error_out;
}
res = wait_event_interruptible(sdp->o_excl_wait,
((!sfds_list_empty(sdp) || get_exclude(sdp)) ? 0 : set_exclude(sdp, 1)));
if (res) {
retval = res; /* -ERESTARTSYS because signal hit process */
goto error_out;
}
} else if (get_exclude(sdp)) { /* some other fd has an exclusive lock on dev */
if (flags & O_NONBLOCK) {
retval = -EBUSY;
goto error_out;
}
res = wait_event_interruptible(sdp->o_excl_wait, !get_exclude(sdp));
if (res) {
retval = res; /* -ERESTARTSYS because signal hit process */
goto error_out;
}
}
if (sdp->detached) {
retval = -ENODEV;
goto error_out;
}
if (sfds_list_empty(sdp)) { /* no existing opens on this device */
sdp->sgdebug = 0;
q = sdp->device->request_queue;
sdp->sg_tablesize = queue_max_segments(q);
}
if ((sfp = sg_add_sfp(sdp, dev)))
filp->private_data = sfp;
else {
if (flags & O_EXCL) {
set_exclude(sdp, 0); /* undo if error */
wake_up_interruptible(&sdp->o_excl_wait);
}
retval = -ENOMEM;
goto error_out;
}
retval = 0;
error_out:
if (retval) {
scsi_autopm_put_device(sdp->device);
sdp_put:
scsi_device_put(sdp->device);
}
sg_put:
if (sdp)
sg_put_dev(sdp);
return retval;
}

/* Following function was formerly called 'sg_close' */
static int
sg_release(struct inode *inode, struct file *filp)
{
Sg_device *sdp;
Sg_fd *sfp;

if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));

set_exclude(sdp, 0);
wake_up_interruptible(&sdp->o_excl_wait);

scsi_autopm_put_device(sdp->device);
kref_put(&sfp->f_ref, sg_remove_sfp);
return 0;
}

static ssize_t
sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
{
Sg_device *sdp;
Sg_fd *sfp;
Sg_request *srp;
int req_pack_id = -1;
sg_io_hdr_t *hp;
struct sg_header *old_hdr = NULL;
int retval = 0;

if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_read: %s, count=%d\n",
sdp->disk->disk_name, (int) count));

if (!access_ok(VERIFY_WRITE, buf, count))
return -EFAULT;
if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
if (!old_hdr)
return -ENOMEM;
if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
retval = -EFAULT;
goto free_old_hdr;
}
if (old_hdr->reply_len < 0) {
if (count >= SZ_SG_IO_HDR) {
sg_io_hdr_t *new_hdr;
new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
if (!new_hdr) {
retval = -ENOMEM;
goto free_old_hdr;
}
retval =__copy_from_user
(new_hdr, buf, SZ_SG_IO_HDR);
req_pack_id = new_hdr->pack_id;
kfree(new_hdr);
if (retval) {
retval = -EFAULT;
goto free_old_hdr;
}
}
} else
req_pack_id = old_hdr->pack_id;
}
srp = sg_get_rq_mark(sfp, req_pack_id);
if (!srp) { /* now wait on packet to arrive */
if (sdp->detached) {
retval = -ENODEV;
goto free_old_hdr;
}
if (filp->f_flags & O_NONBLOCK) {
retval = -EAGAIN;
goto free_old_hdr;
}
retval = wait_event_interruptible(sfp->read_wait,
(sdp->detached ||
(srp = sg_get_rq_mark(sfp, req_pack_id))));
if (sdp->detached) {
retval = -ENODEV;
goto free_old_hdr;
}
if (retval) {
/* -ERESTARTSYS as signal hit process */
goto free_old_hdr;
}
}
if (srp->header.interface_id != '\0') {
retval = sg_new_read(sfp, buf, count, srp);
goto free_old_hdr;
}

hp = &srp->header;
if (old_hdr == NULL) {
old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
if (! old_hdr) {
retval = -ENOMEM;
goto free_old_hdr;
}
}
memset(old_hdr, 0, SZ_SG_HEADER);
old_hdr->reply_len = (int) hp->timeout;
old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
old_hdr->pack_id = hp->pack_id;
old_hdr->twelve_byte =
((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
old_hdr->target_status = hp->masked_status;
old_hdr->host_status = hp->host_status;
old_hdr->driver_status = hp->driver_status;
if ((CHECK_CONDITION & hp->masked_status) ||
(DRIVER_SENSE & hp->driver_status))
memcpy(old_hdr->sense_buffer, srp->sense_b,
sizeof (old_hdr->sense_buffer));
switch (hp->host_status) {
/* This setup of 'result' is for backward compatibility and is best
ignored by the user who should use target, host + driver status */
case DID_OK:
case DID_PASSTHROUGH:
case DID_SOFT_ERROR:
old_hdr->result = 0;
break;
case DID_NO_CONNECT:
case DID_BUS_BUSY:
case DID_TIME_OUT:
old_hdr->result = EBUSY;
break;
case DID_BAD_TARGET:
case DID_ABORT:
case DID_PARITY:
case DID_RESET:
case DID_BAD_INTR:
old_hdr->result = EIO;
break;
case DID_ERROR:
old_hdr->result = (srp->sense_b[0] == 0 &&
hp->masked_status == GOOD) ? 0 : EIO;
break;
default:
old_hdr->result = EIO;
break;
}

/* Now copy the result back to the user buffer. */
if (count >= SZ_SG_HEADER) {
if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
retval = -EFAULT;
goto free_old_hdr;
}
buf += SZ_SG_HEADER;
if (count > old_hdr->reply_len)
count = old_hdr->reply_len;
if (count > SZ_SG_HEADER) {
if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
retval = -EFAULT;
goto free_old_hdr;
}
}
} else
count = (old_hdr->result == 0) ? 0 : -EIO;
sg_finish_rem_req(srp);
retval = count;
free_old_hdr:
kfree(old_hdr);
return retval;
}

static ssize_t
sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
{
sg_io_hdr_t *hp = &srp->header;
int err = 0;
int len;

if (count < SZ_SG_IO_HDR) {
err = -EINVAL;
goto err_out;
}
hp->sb_len_wr = 0;
if ((hp->mx_sb_len > 0) && hp->sbp) {
if ((CHECK_CONDITION & hp->masked_status) ||
(DRIVER_SENSE & hp->driver_status)) {
int sb_len = SCSI_SENSE_BUFFERSIZE;
sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
len = 8 + (int) srp->sense_b[7]; /* Additional sense length field */
len = (len > sb_len) ? sb_len : len;
if (copy_to_user(hp->sbp, srp->sense_b, len)) {
err = -EFAULT;
goto err_out;
}
hp->sb_len_wr = len;
}
}
if (hp->masked_status || hp->host_status || hp->driver_status)
hp->info |= SG_INFO_CHECK;
if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
err = -EFAULT;
goto err_out;
}
err_out:
err = sg_finish_rem_req(srp);
return (0 == err) ? count : err;
}

static ssize_t
sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
{
int mxsize, cmd_size, k;
int input_size, blocking;
unsigned char opcode;
Sg_device *sdp;
Sg_fd *sfp;
Sg_request *srp;
struct sg_header old_hdr;
sg_io_hdr_t *hp;
unsigned char cmnd[MAX_COMMAND_SIZE];

if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
sdp->disk->disk_name, (int) count));
if (sdp->detached)
return -ENODEV;
if (!((filp->f_flags & O_NONBLOCK) ||
scsi_block_when_processing_errors(sdp->device)))
return -ENXIO;

if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT; /* protects following copy_from_user()s + get_user()s */
if (count < SZ_SG_HEADER)
return -EIO;
if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
return -EFAULT;
blocking = !(filp->f_flags & O_NONBLOCK);
if (old_hdr.reply_len < 0)
return sg_new_write(sfp, filp, buf, count,
blocking, 0, 0, NULL);
if (count < (SZ_SG_HEADER + 6))
return -EIO; /* The minimum scsi command length is 6 bytes. */

if (!(srp = sg_add_request(sfp))) {
SCSI_LOG_TIMEOUT(1, printk("sg_write: queue full\n"));
return -EDOM;
}
buf += SZ_SG_HEADER;
__get_user(opcode, buf);
if (sfp->next_cmd_len > 0) {
if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
sfp->next_cmd_len = 0;
sg_remove_request(sfp, srp);
return -EIO;
}
cmd_size = sfp->next_cmd_len;
sfp->next_cmd_len = 0; /* reset so only this write() effected */
} else {
cmd_size = COMMAND_SIZE(opcode); /* based on SCSI command group */
if ((opcode >= 0xc0) && old_hdr.twelve_byte)
cmd_size = 12;
}
SCSI_LOG_TIMEOUT(4, printk(
"sg_write: scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
/* Determine buffer size. */
input_size = count - cmd_size;
mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
mxsize -= SZ_SG_HEADER;
input_size -= SZ_SG_HEADER;
if (input_size < 0) {
sg_remove_request(sfp, srp);
return -EIO; /* User did not pass enough bytes for this command. */
}
hp = &srp->header;
hp->interface_id = '\0'; /* indicator of old interface tunnelled */
hp->cmd_len = (unsigned char) cmd_size;
hp->iovec_count = 0;
hp->mx_sb_len = 0;
if (input_size > 0)
hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
else
hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
hp->dxfer_len = mxsize;
if (hp->dxfer_direction == SG_DXFER_TO_DEV)
hp->dxferp = (char __user *)buf + cmd_size;
else
hp->dxferp = NULL;
hp->sbp = NULL;
hp->timeout = old_hdr.reply_len; /* structure abuse ... */
hp->flags = input_size; /* structure abuse ... */
hp->pack_id = old_hdr.pack_id;
hp->usr_ptr = NULL;
if (__copy_from_user(cmnd, buf, cmd_size))
return -EFAULT;
/*
* SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
* but is is possible that the app intended SG_DXFER_TO_DEV, because there
* is a non-zero input_size, so emit a warning.
*/
if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
static char cmd[TASK_COMM_LEN];
if (strcmp(current->comm, cmd)) {
printk_ratelimited(KERN_WARNING
"sg_write: data in/out %d/%d bytes "
"for SCSI command 0x%x-- guessing "
"data in;\n program %s not setting "
"count and/or reply_len properly\n",
old_hdr.reply_len - (int)SZ_SG_HEADER,
input_size, (unsigned int) cmnd[0],
current->comm);
strcpy(cmd, current->comm);
}
}
k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
return (k < 0) ? k : count;
}

static ssize_t
sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
size_t count, int blocking, int read_only, int sg_io_owned,
Sg_request **o_srp)
{
int k;
Sg_request *srp;
sg_io_hdr_t *hp;
unsigned char cmnd[MAX_COMMAND_SIZE];
int timeout;
unsigned long ul_timeout;

if (count < SZ_SG_IO_HDR)
return -EINVAL;
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT; /* protects following copy_from_user()s + get_user()s */

sfp->cmd_q = 1; /* when sg_io_hdr seen, set command queuing on */
if (!(srp = sg_add_request(sfp))) {
SCSI_LOG_TIMEOUT(1, printk("sg_new_write: queue full\n"));
return -EDOM;
}
srp->sg_io_owned = sg_io_owned;
hp = &srp->header;
if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
sg_remove_request(sfp, srp);
return -EFAULT;
}
if (hp->interface_id != 'S') {
sg_remove_request(sfp, srp);
return -ENOSYS;
}
if (hp->flags & SG_FLAG_MMAP_IO) {
if (hp->dxfer_len > sfp->reserve.bufflen) {
sg_remove_request(sfp, srp);
return -ENOMEM; /* MMAP_IO size must fit in reserve buffer */
}
if (hp->flags & SG_FLAG_DIRECT_IO) {
sg_remove_request(sfp, srp);
return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
}
if (sg_res_in_use(sfp)) {
sg_remove_request(sfp, srp);
return -EBUSY; /* reserve buffer already being used */
}
}
ul_timeout = msecs_to_jiffies(srp->header.timeout);
timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
sg_remove_request(sfp, srp);
return -EMSGSIZE;
}
if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
sg_remove_request(sfp, srp);
return -EFAULT; /* protects following copy_from_user()s + get_user()s */
}
if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
sg_remove_request(sfp, srp);
return -EFAULT;
}
if (read_only && sg_allow_access(file, cmnd)) {
sg_remove_request(sfp, srp);
return -EPERM;
}
k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
if (k < 0)
return k;
if (o_srp)
*o_srp = srp;
return count;
}

static int
sg_common_write(Sg_fd * sfp, Sg_request * srp,
unsigned char *cmnd, int timeout, int blocking)
{
int k, data_dir;
Sg_device *sdp = sfp->parentdp;
sg_io_hdr_t *hp = &srp->header;

srp->data.cmd_opcode = cmnd[0]; /* hold opcode of command */
hp->status = 0;
hp->masked_status = 0;
hp->msg_status = 0;
hp->info = 0;
hp->host_status = 0;
hp->driver_status = 0;
hp->resid = 0;
SCSI_LOG_TIMEOUT(4, printk("sg_common_write: scsi opcode=0x%02x, cmd_size=%d\n",
(int) cmnd[0], (int) hp->cmd_len));

k = sg_start_req(srp, cmnd);
if (k) {
SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%d\n", k));
sg_finish_rem_req(srp);
return k; /* probably out of space --> ENOMEM */
}
if (sdp->detached) {
if (srp->bio)
blk_end_request_all(srp->rq, -EIO);
sg_finish_rem_req(srp);
return -ENODEV;
}

switch (hp->dxfer_direction) {
case SG_DXFER_TO_FROM_DEV:
case SG_DXFER_FROM_DEV:
data_dir = DMA_FROM_DEVICE;
break;
case SG_DXFER_TO_DEV:
data_dir = DMA_TO_DEVICE;
break;
case SG_DXFER_UNKNOWN:
data_dir = DMA_BIDIRECTIONAL;
break;
default:
data_dir = DMA_NONE;
break;
}
hp->duration = jiffies_to_msecs(jiffies);

srp->rq->timeout = timeout;
kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
srp->rq, 1, sg_rq_end_io);
return 0;
}

static int srp_done(Sg_fd *sfp, Sg_request *srp)
{
unsigned long flags;
int ret;

read_lock_irqsave(&sfp->rq_list_lock, flags);
ret = srp->done;
read_unlock_irqrestore(&sfp->rq_list_lock, flags);
return ret;
}

static long
sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
void __user *p = (void __user *)arg;
int __user *ip = p;
int result, val, read_only;
Sg_device *sdp;
Sg_fd *sfp;
Sg_request *srp;
unsigned long iflags;

if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
return -ENXIO;

SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
sdp->disk->disk_name, (int) cmd_in));
read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));

switch (cmd_in) {
case SG_IO:
if (sdp->detached)
return -ENODEV;
if (!scsi_block_when_processing_errors(sdp->device))
return -ENXIO;
if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
return -EFAULT;
result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
1, read_only, 1, &srp);
if (result < 0)
return result;
result = wait_event_interruptible(sfp->read_wait,
(srp_done(sfp, srp) || sdp->detached));
if (sdp->detached)
return -ENODEV;
write_lock_irq(&sfp->rq_list_lock);
if (srp->done) {
srp->done = 2;
write_unlock_irq(&sfp->rq_list_lock);
result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
return (result < 0) ? result : 0;
}
srp->orphan = 1;
write_unlock_irq(&sfp->rq_list_lock);
return result; /* -ERESTARTSYS because signal hit process */
case SG_SET_TIMEOUT:
result = get_user(val, ip);
if (result)
return result;
if (val < 0)
return -EIO;
if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
val = MULDIV (INT_MAX, USER_HZ, HZ);
sfp->timeout_user = val;
sfp->timeout = MULDIV (val, HZ, USER_HZ);

return 0;
case SG_GET_TIMEOUT: /* N.B. User receives timeout as return value */
/* strange ..., for backward compatibility */
return sfp->timeout_user;
case SG_SET_FORCE_LOW_DMA:
result = get_user(val, ip);
if (result)
return result;
if (val) {
sfp->low_dma = 1;
if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
val = (int) sfp->reserve.bufflen;
sg_remove_scat(&sfp->reserve);
sg_build_reserve(sfp, val);
}
} else {
if (sdp->detached)
return -ENODEV;
sfp->low_dma = sdp->device->host->unchecked_isa_dma;
}
return 0;
case SG_GET_LOW_DMA:
return put_user((int) sfp->low_dma, ip);
case SG_GET_SCSI_ID:
if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
return -EFAULT;
else {
sg_scsi_id_t __user *sg_idp = p;

if (sdp->detached)
return -ENODEV;
__put_user((int) sdp->device->host->host_no,
&sg_idp->host_no);
__put_user((int) sdp->device->channel,
&sg_idp->channel);
__put_user((int) sdp->device->id, &sg_idp->scsi_id);
__put_user((int) sdp->device->lun, &sg_idp->lun);
__put_user((int) sdp->device->type, &sg_idp->scsi_type);
__put_user((short) sdp->device->host->cmd_per_lun,
&sg_idp->h_cmd_per_lun);
__put_user((short) sdp->device->queue_depth,
&sg_idp->d_queue_depth);
__put_user(0, &sg_idp->unused[0]);
__put_user(0, &sg_idp->unused[1]);
return 0;
}
case SG_SET_FORCE_PACK_ID:
result = get_user(val, ip);
if (result)
return result;
sfp->force_packid = val ? 1 : 0;
return 0;
case SG_GET_PACK_ID:
if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
return -EFAULT;
read_lock_irqsave(&sfp->rq_list_lock, iflags);
for (srp = sfp->headrp; srp; srp = srp->nextrp) {
if ((1 == srp->done) && (!srp->sg_io_owned)) {
read_unlock_irqrestore(&sfp->rq_list_lock,
iflags);
__put_user(srp->header.pack_id, ip);
return 0;
}
}
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
__put_user(-1, ip);
return 0;
case SG_GET_NUM_WAITING:
read_lock_irqsave(&sfp->rq_list_lock, iflags);
for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
if ((1 == srp->done) && (!srp->sg_io_owned))
++val;
}
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
return put_user(val, ip);
case SG_GET_SG_TABLESIZE:
return put_user(sdp->sg_tablesize, ip);
case SG_SET_RESERVED_SIZE:
result = get_user(val, ip);
if (result)
return result;
                if (val < 0)
                        return -EINVAL;
val = min_t(int, val,
queue_max_sectors(sdp->device->request_queue) * 512);
if (val != sfp->reserve.bufflen) {
if (sg_res_in_use(sfp) || sfp->mmap_called)
return -EBUSY;
sg_remove_scat(&sfp->reserve);
sg_build_reserve(sfp, val);
}
return 0;
case SG_GET_RESERVED_SIZE:
val = min_t(int, sfp->reserve.bufflen,
queue_max_sectors(sdp->device->request_queue) * 512);
return put_user(val, ip);
case SG_SET_COMMAND_Q:
result = get_user(val, ip);
if (result)
return result;
sfp->cmd_q = val ? 1 : 0;
return 0;
case SG_GET_COMMAND_Q:
return put_user((int) sfp->cmd_q, ip);
case SG_SET_KEEP_ORPHAN:
result = get_user(val, ip);
if (result)
return result;
sfp->keep_orphan = val;
return 0;
case SG_GET_KEEP_ORPHAN:
return put_user((int) sfp->keep_orphan, ip);
case SG_NEXT_CMD_LEN:
result = get_user(val, ip);
if (result)
return result;
sfp->next_cmd_len = (val > 0) ? val : 0;
return 0;
case SG_GET_VERSION_NUM:
return put_user(sg_version_num, ip);
case SG_GET_ACCESS_COUNT:
/* faked - we don't have a real access count anymore */
val = (sdp->device ? 1 : 0);
return put_user(val, ip);
case SG_GET_REQUEST_TABLE:
if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
return -EFAULT;
else {
sg_req_info_t *rinfo;
unsigned int ms;

rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
GFP_KERNEL);
if (!rinfo)
return -ENOMEM;
read_lock_irqsave(&sfp->rq_list_lock, iflags);
for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
++val, srp = srp ? srp->nextrp : srp) {
memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
if (srp) {
rinfo[val].req_state = srp->done + 1;
rinfo[val].problem =
srp->header.masked_status &
srp->header.host_status &
srp->header.driver_status;
if (srp->done)
rinfo[val].duration =
srp->header.duration;
else {
ms = jiffies_to_msecs(jiffies);
rinfo[val].duration =
(ms > srp->header.duration) ?
(ms - srp->header.duration) : 0;
}
rinfo[val].orphan = srp->orphan;
rinfo[val].sg_io_owned =
srp->sg_io_owned;
rinfo[val].pack_id =
srp->header.pack_id;
rinfo[val].usr_ptr =
srp->header.usr_ptr;
}
}
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
result = __copy_to_user(p, rinfo,
SZ_SG_REQ_INFO * SG_MAX_QUEUE);
result = result ? -EFAULT : 0;
kfree(rinfo);
return result;
}
case SG_EMULATED_HOST:
if (sdp->detached)
return -ENODEV;
return put_user(sdp->device->host->hostt->emulated, ip);
case SG_SCSI_RESET:
if (sdp->detached)
return -ENODEV;
if (filp->f_flags & O_NONBLOCK) {
if (scsi_host_in_recovery(sdp->device->host))
return -EBUSY;
} else if (!scsi_block_when_processing_errors(sdp->device))
return -EBUSY;
result = get_user(val, ip);
if (result)
return result;
if (SG_SCSI_RESET_NOTHING == val)
return 0;
switch (val) {
case SG_SCSI_RESET_DEVICE:
val = SCSI_TRY_RESET_DEVICE;
break;
case SG_SCSI_RESET_TARGET:
val = SCSI_TRY_RESET_TARGET;
break;
case SG_SCSI_RESET_BUS:
val = SCSI_TRY_RESET_BUS;
break;
case SG_SCSI_RESET_HOST:
val = SCSI_TRY_RESET_HOST;
break;
default:
return -EINVAL;
}
if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
return -EACCES;
return (scsi_reset_provider(sdp->device, val) ==
SUCCESS) ? 0 : -EIO;
case SCSI_IOCTL_SEND_COMMAND:
if (sdp->detached)
return -ENODEV;
if (read_only) {
unsigned char opcode = WRITE_6;
Scsi_Ioctl_Command __user *siocp = p;

if (copy_from_user(&opcode, siocp->data, 1))
return -EFAULT;
if (sg_allow_access(filp, &opcode))
return -EPERM;
}
return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
case SG_SET_DEBUG:
result = get_user(val, ip);
if (result)
return result;
sdp->sgdebug = (char) val;
return 0;
case SCSI_IOCTL_GET_IDLUN:
case SCSI_IOCTL_GET_BUS_NUMBER:
case SCSI_IOCTL_PROBE_HOST:
case SG_GET_TRANSFORM:
if (sdp->detached)
return -ENODEV;
return scsi_ioctl(sdp->device, cmd_in, p);
case BLKSECTGET:
return put_user(queue_max_sectors(sdp->device->request_queue) * 512,
ip);
case BLKTRACESETUP:
return blk_trace_setup(sdp->device->request_queue,
sdp->disk->disk_name,
MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
NULL,
(char *)arg);
case BLKTRACESTART:
return blk_trace_startstop(sdp->device->request_queue, 1);
case BLKTRACESTOP:
return blk_trace_startstop(sdp->device->request_queue, 0);
case BLKTRACETEARDOWN:
return blk_trace_remove(sdp->device->request_queue);
default:
if (read_only)
return -EPERM; /* don't know so take safe approach */
return scsi_ioctl(sdp->device, cmd_in, p);
}
}

#ifdef CONFIG_COMPAT
static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
Sg_device *sdp;
Sg_fd *sfp;
struct scsi_device *sdev;

if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
return -ENXIO;

sdev = sdp->device;
if (sdev->host->hostt->compat_ioctl) {
int ret;

ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);

return ret;
}

return -ENOIOCTLCMD;
}
#endif

static unsigned int
sg_poll(struct file *filp, poll_table * wait)
{
unsigned int res = 0;
Sg_device *sdp;
Sg_fd *sfp;
Sg_request *srp;
int count = 0;
unsigned long iflags;

sfp = filp->private_data;
if (!sfp)
return POLLERR;
sdp = sfp->parentdp;
if (!sdp)
return POLLERR;
poll_wait(filp, &sfp->read_wait, wait);
read_lock_irqsave(&sfp->rq_list_lock, iflags);
for (srp = sfp->headrp; srp; srp = srp->nextrp) {
/* if any read waiting, flag it */
if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
res = POLLIN | POLLRDNORM;
++count;
}
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);

if (sdp->detached)
res |= POLLHUP;
else if (!sfp->cmd_q) {
if (0 == count)
res |= POLLOUT | POLLWRNORM;
} else if (count < SG_MAX_QUEUE)
res |= POLLOUT | POLLWRNORM;
SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
sdp->disk->disk_name, (int) res));
return res;
}

static int
sg_fasync(int fd, struct file *filp, int mode)
{
Sg_device *sdp;
Sg_fd *sfp;

if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
sdp->disk->disk_name, mode));

return fasync_helper(fd, filp, mode, &sfp->async_qp);
}

static int
sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
Sg_fd *sfp;
unsigned long offset, len, sa;
Sg_scatter_hold *rsv_schp;
int k, length;

if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
return VM_FAULT_SIGBUS;
rsv_schp = &sfp->reserve;
offset = vmf->pgoff << PAGE_SHIFT;
if (offset >= rsv_schp->bufflen)
return VM_FAULT_SIGBUS;
SCSI_LOG_TIMEOUT(3, printk("sg_vma_fault: offset=%lu, scatg=%d\n",
offset, rsv_schp->k_use_sg));
sa = vma->vm_start;
length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
len = vma->vm_end - sa;
len = (len < length) ? len : length;
if (offset < len) {
struct page *page = nth_page(rsv_schp->pages[k],
offset >> PAGE_SHIFT);
get_page(page); /* increment page count */
vmf->page = page;
return 0; /* success */
}
sa += len;
offset -= len;
}

return VM_FAULT_SIGBUS;
}

static const struct vm_operations_struct sg_mmap_vm_ops = {
.fault = sg_vma_fault,
};

static int
sg_mmap(struct file *filp, struct vm_area_struct *vma)
{
Sg_fd *sfp;
unsigned long req_sz, len, sa;
Sg_scatter_hold *rsv_schp;
int k, length;

if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
return -ENXIO;
req_sz = vma->vm_end - vma->vm_start;
SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
(void *) vma->vm_start, (int) req_sz));
if (vma->vm_pgoff)
return -EINVAL; /* want no offset */
rsv_schp = &sfp->reserve;
if (req_sz > rsv_schp->bufflen)
return -ENOMEM; /* cannot map more than reserved buffer */

sa = vma->vm_start;
length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
len = vma->vm_end - sa;
len = (len < length) ? len : length;
sa += len;
}

sfp->mmap_called = 1;
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_private_data = sfp;
vma->vm_ops = &sg_mmap_vm_ops;
return 0;
}

static void sg_rq_end_io_usercontext(struct work_struct *work)
{
struct sg_request *srp = container_of(work, struct sg_request, ew.work);
struct sg_fd *sfp = srp->parentfp;

sg_finish_rem_req(srp);
kref_put(&sfp->f_ref, sg_remove_sfp);
}

/*
* This function is a "bottom half" handler that is called by the mid
* level when a command is completed (or has failed).
*/
static void sg_rq_end_io(struct request *rq, int uptodate)
{
struct sg_request *srp = rq->end_io_data;
Sg_device *sdp;
Sg_fd *sfp;
unsigned long iflags;
unsigned int ms;
char *sense;
int result, resid, done = 1;

if (WARN_ON(srp->done != 0))
return;

sfp = srp->parentfp;
if (WARN_ON(sfp == NULL))
return;

sdp = sfp->parentdp;
if (unlikely(sdp->detached))
printk(KERN_INFO "sg_rq_end_io: device detached\n");

sense = rq->sense;
result = rq->errors;
resid = rq->resid_len;

SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
sdp->disk->disk_name, srp->header.pack_id, result));
srp->header.resid = resid;
ms = jiffies_to_msecs(jiffies);
srp->header.duration = (ms > srp->header.duration) ?
(ms - srp->header.duration) : 0;
if (0 != result) {
struct scsi_sense_hdr sshdr;

srp->header.status = 0xff & result;
srp->header.masked_status = status_byte(result);
srp->header.msg_status = msg_byte(result);
srp->header.host_status = host_byte(result);
srp->header.driver_status = driver_byte(result);
if ((sdp->sgdebug > 0) &&
((CHECK_CONDITION == srp->header.masked_status) ||
(COMMAND_TERMINATED == srp->header.masked_status)))
__scsi_print_sense("sg_cmd_done", sense,
SCSI_SENSE_BUFFERSIZE);

/* Following if statement is a patch supplied by Eric Youngdale */
if (driver_byte(result) != 0
&& scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
&& !scsi_sense_is_deferred(&sshdr)
&& sshdr.sense_key == UNIT_ATTENTION
&& sdp->device->removable) {
/* Detected possible disc change. Set the bit - this */
/* may be used if there are filesystems using this device */
sdp->device->changed = 1;
}
}
/* Rely on write phase to clean out srp status values, so no "else" */

write_lock_irqsave(&sfp->rq_list_lock, iflags);
if (unlikely(srp->orphan)) {
if (sfp->keep_orphan)
srp->sg_io_owned = 0;
else
done = 0;
}
srp->done = done;
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);

if (likely(done)) {
/* Now wake up any sg_read() that is waiting for this
* packet.
*/
wake_up_interruptible(&sfp->read_wait);
kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
kref_put(&sfp->f_ref, sg_remove_sfp);
} else {
INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
schedule_work(&srp->ew.work);
}
}

static const struct file_operations sg_fops = {
.owner = THIS_MODULE,
.read = sg_read,
.write = sg_write,
.poll = sg_poll,
.unlocked_ioctl = sg_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = sg_compat_ioctl,
#endif
.open = sg_open,
.mmap = sg_mmap,
.release = sg_release,
.fasync = sg_fasync,
.llseek = no_llseek,
};

static struct class *sg_sysfs_class;

static int sg_sysfs_valid = 0;

static Sg_device *sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
{
struct request_queue *q = scsidp->request_queue;
Sg_device *sdp;
unsigned long iflags;
int error;
u32 k;

sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
if (!sdp) {
printk(KERN_WARNING "kmalloc Sg_device failure\n");
return ERR_PTR(-ENOMEM);
}

idr_preload(GFP_KERNEL);
write_lock_irqsave(&sg_index_lock, iflags);

error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
if (error < 0) {
if (error == -ENOSPC) {
sdev_printk(KERN_WARNING, scsidp,
"Unable to attach sg device type=%d, minor number exceeds %d\n",
scsidp->type, SG_MAX_DEVS - 1);
error = -ENODEV;
} else {
printk(KERN_WARNING
"idr allocation Sg_device failure: %d\n", error);
}
goto out_unlock;
}
k = error;

SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
sprintf(disk->disk_name, "sg%d", k);
disk->first_minor = k;
sdp->disk = disk;
sdp->device = scsidp;
INIT_LIST_HEAD(&sdp->sfds);
init_waitqueue_head(&sdp->o_excl_wait);
sdp->sg_tablesize = queue_max_segments(q);
sdp->index = k;
kref_init(&sdp->d_ref);
error = 0;

out_unlock:
write_unlock_irqrestore(&sg_index_lock, iflags);
idr_preload_end();

if (error) {
kfree(sdp);
return ERR_PTR(error);
}
return sdp;
}

static int
sg_add(struct device *cl_dev, struct class_interface *cl_intf)
{
struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
struct gendisk *disk;
Sg_device *sdp = NULL;
struct cdev * cdev = NULL;
int error;
unsigned long iflags;

disk = alloc_disk(1);
if (!disk) {
printk(KERN_WARNING "alloc_disk failed\n");
return -ENOMEM;
}
disk->major = SCSI_GENERIC_MAJOR;

error = -ENOMEM;
cdev = cdev_alloc();
if (!cdev) {
printk(KERN_WARNING "cdev_alloc failed\n");
goto out;
}
cdev->owner = THIS_MODULE;
cdev->ops = &sg_fops;

sdp = sg_alloc(disk, scsidp);
if (IS_ERR(sdp)) {
printk(KERN_WARNING "sg_alloc failed\n");
error = PTR_ERR(sdp);
goto out;
}

error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
if (error)
goto cdev_add_err;

sdp->cdev = cdev;
if (sg_sysfs_valid) {
struct device *sg_class_member;

sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
MKDEV(SCSI_GENERIC_MAJOR,
sdp->index),
sdp, "%s", disk->disk_name);
if (IS_ERR(sg_class_member)) {
printk(KERN_ERR "sg_add: "
"device_create failed\n");
error = PTR_ERR(sg_class_member);
goto cdev_add_err;
}
error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
&sg_class_member->kobj, "generic");
if (error)
printk(KERN_ERR "sg_add: unable to make symlink "
"'generic' back to sg%d\n", sdp->index);
} else
printk(KERN_WARNING "sg_add: sg_sys Invalid\n");

sdev_printk(KERN_NOTICE, scsidp,
"Attached scsi generic sg%d type %d\n", sdp->index,
scsidp->type);

dev_set_drvdata(cl_dev, sdp);

return 0;

cdev_add_err:
write_lock_irqsave(&sg_index_lock, iflags);
idr_remove(&sg_index_idr, sdp->index);
write_unlock_irqrestore(&sg_index_lock, iflags);
kfree(sdp);

out:
put_disk(disk);
if (cdev)
cdev_del(cdev);
return error;
}

static void sg_device_destroy(struct kref *kref)
{
struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
unsigned long flags;

/* CAUTION! Note that the device can still be found via idr_find()
* even though the refcount is 0. Therefore, do idr_remove() BEFORE
* any other cleanup.
*/

write_lock_irqsave(&sg_index_lock, flags);
idr_remove(&sg_index_idr, sdp->index);
write_unlock_irqrestore(&sg_index_lock, flags);

SCSI_LOG_TIMEOUT(3,
printk("sg_device_destroy: %s\n",
sdp->disk->disk_name));

put_disk(sdp->disk);
kfree(sdp);
}

static void sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
{
struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
Sg_device *sdp = dev_get_drvdata(cl_dev);
unsigned long iflags;
Sg_fd *sfp;

if (!sdp || sdp->detached)
return;

SCSI_LOG_TIMEOUT(3, printk("sg_remove: %s\n", sdp->disk->disk_name));

/* Need a write lock to set sdp->detached. */
write_lock_irqsave(&sg_index_lock, iflags);
sdp->detached = 1;
list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
wake_up_interruptible(&sfp->read_wait);
kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
}
write_unlock_irqrestore(&sg_index_lock, iflags);

sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
cdev_del(sdp->cdev);
sdp->cdev = NULL;

sg_put_dev(sdp);
}

module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
module_param_named(def_reserved_size, def_reserved_size, int,
S_IRUGO | S_IWUSR);
module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);

MODULE_AUTHOR("Douglas Gilbert");
MODULE_DESCRIPTION("SCSI generic (sg) driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(SG_VERSION_STR);
MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);

MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
                "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");

static int __init
init_sg(void)
{
int rc;

if (scatter_elem_sz < PAGE_SIZE) {
scatter_elem_sz = PAGE_SIZE;
scatter_elem_sz_prev = scatter_elem_sz;
}
if (def_reserved_size >= 0)
sg_big_buff = def_reserved_size;
else
def_reserved_size = sg_big_buff;

rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
SG_MAX_DEVS, "sg");
if (rc)
return rc;
        sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
        if ( IS_ERR(sg_sysfs_class) ) {
rc = PTR_ERR(sg_sysfs_class);
goto err_out;
        }
sg_sysfs_valid = 1;
rc = scsi_register_interface(&sg_interface);
if (0 == rc) {
#ifdef CONFIG_SCSI_PROC_FS
sg_proc_init();
#endif /* CONFIG_SCSI_PROC_FS */
return 0;
}
class_destroy(sg_sysfs_class);
err_out:
unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
return rc;
}

static void __exit
exit_sg(void)
{
#ifdef CONFIG_SCSI_PROC_FS
sg_proc_cleanup();
#endif /* CONFIG_SCSI_PROC_FS */
scsi_unregister_interface(&sg_interface);
class_destroy(sg_sysfs_class);
sg_sysfs_valid = 0;
unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
SG_MAX_DEVS);
idr_destroy(&sg_index_idr);
}

static int sg_start_req(Sg_request *srp, unsigned char *cmd)
{
int res;
struct request *rq;
Sg_fd *sfp = srp->parentfp;
sg_io_hdr_t *hp = &srp->header;
int dxfer_len = (int) hp->dxfer_len;
int dxfer_dir = hp->dxfer_direction;
unsigned int iov_count = hp->iovec_count;
Sg_scatter_hold *req_schp = &srp->data;
Sg_scatter_hold *rsv_schp = &sfp->reserve;
struct request_queue *q = sfp->parentdp->device->request_queue;
struct rq_map_data *md, map_data;
int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;

SCSI_LOG_TIMEOUT(4, printk(KERN_INFO "sg_start_req: dxfer_len=%d\n",
dxfer_len));

rq = blk_get_request(q, rw, GFP_ATOMIC);
if (!rq)
return -ENOMEM;

memcpy(rq->cmd, cmd, hp->cmd_len);

rq->cmd_len = hp->cmd_len;
rq->cmd_type = REQ_TYPE_BLOCK_PC;

srp->rq = rq;
rq->end_io_data = srp;
rq->sense = srp->sense_b;
rq->retries = SG_DEFAULT_RETRIES;

if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
return 0;

if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
!sfp->parentdp->device->host->unchecked_isa_dma &&
blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
md = NULL;
else
md = &map_data;

if (md) {
if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
sg_link_reserve(sfp, srp, dxfer_len);
else {
res = sg_build_indirect(req_schp, sfp, dxfer_len);
if (res)
return res;
}

md->pages = req_schp->pages;
md->page_order = req_schp->page_order;
md->nr_entries = req_schp->k_use_sg;
md->offset = 0;
md->null_mapped = hp->dxferp ? 0 : 1;
if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
md->from_user = 1;
else
md->from_user = 0;
}

if (iov_count) {
int len, size = sizeof(struct sg_iovec) * iov_count;
struct iovec *iov;

iov = memdup_user(hp->dxferp, size);
if (IS_ERR(iov))
return PTR_ERR(iov);

len = iov_length(iov, iov_count);
if (hp->dxfer_len < len) {
iov_count = iov_shorten(iov, iov_count, hp->dxfer_len);
len = hp->dxfer_len;
}

res = blk_rq_map_user_iov(q, rq, md, (struct sg_iovec *)iov,
iov_count,
len, GFP_ATOMIC);
kfree(iov);
} else
res = blk_rq_map_user(q, rq, md, hp->dxferp,
hp->dxfer_len, GFP_ATOMIC);

if (!res) {
srp->bio = rq->bio;

if (!md) {
req_schp->dio_in_use = 1;
hp->info |= SG_INFO_DIRECT_IO;
}
}
return res;
}

static int sg_finish_rem_req(Sg_request * srp)
{
int ret = 0;

Sg_fd *sfp = srp->parentfp;
Sg_scatter_hold *req_schp = &srp->data;

SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
if (srp->rq) {
if (srp->bio)
ret = blk_rq_unmap_user(srp->bio);

blk_put_request(srp->rq);
}

if (srp->res_used)
sg_unlink_reserve(sfp, srp);
else
sg_remove_scat(req_schp);

sg_remove_request(sfp, srp);

return ret;
}

static int
sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
{
int sg_bufflen = tablesize * sizeof(struct page *);
gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;

schp->pages = kzalloc(sg_bufflen, gfp_flags);
if (!schp->pages)
return -ENOMEM;
schp->sglist_len = sg_bufflen;
return tablesize; /* number of scat_gath elements allocated */
}

static int
sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
{
int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
int sg_tablesize = sfp->parentdp->sg_tablesize;
int blk_size = buff_size, order;
gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;

if (blk_size < 0)
return -EFAULT;
if (0 == blk_size)
++blk_size; /* don't know why */
/* round request up to next highest SG_SECTOR_SZ byte boundary */
blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
buff_size, blk_size));

/* N.B. ret_sz carried into this block ... */
mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
if (mx_sc_elems < 0)
return mx_sc_elems; /* most likely -ENOMEM */

num = scatter_elem_sz;
if (unlikely(num != scatter_elem_sz_prev)) {
if (num < PAGE_SIZE) {
scatter_elem_sz = PAGE_SIZE;
scatter_elem_sz_prev = PAGE_SIZE;
} else
scatter_elem_sz_prev = num;
}

if (sfp->low_dma)
gfp_mask |= GFP_DMA;

if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
gfp_mask |= __GFP_ZERO;

order = get_order(num);
retry:
ret_sz = 1 << (PAGE_SHIFT + order);

for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
k++, rem_sz -= ret_sz) {

num = (rem_sz > scatter_elem_sz_prev) ?
scatter_elem_sz_prev : rem_sz;

schp->pages[k] = alloc_pages(gfp_mask, order);
if (!schp->pages[k])
goto out;

if (num == scatter_elem_sz_prev) {
if (unlikely(ret_sz > scatter_elem_sz_prev)) {
scatter_elem_sz = ret_sz;
scatter_elem_sz_prev = ret_sz;
}
}

SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k=%d, num=%d, "
"ret_sz=%d\n", k, num, ret_sz));
} /* end of for loop */

schp->page_order = order;
schp->k_use_sg = k;
SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, "
"rem_sz=%d\n", k, rem_sz));

schp->bufflen = blk_size;
if (rem_sz > 0) /* must have failed */
return -ENOMEM;
return 0;
out:
for (i = 0; i < k; i++)
__free_pages(schp->pages[i], order);

if (--order >= 0)
goto retry;

return -ENOMEM;
}

static void
sg_remove_scat(Sg_scatter_hold * schp)
{
SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
if (schp->pages && schp->sglist_len > 0) {
if (!schp->dio_in_use) {
int k;

for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
SCSI_LOG_TIMEOUT(5, printk(
"sg_remove_scat: k=%d, pg=0x%p\n",
k, schp->pages[k]));
__free_pages(schp->pages[k], schp->page_order);
}

kfree(schp->pages);
}
}
memset(schp, 0, sizeof (*schp));
}

static int
sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
{
Sg_scatter_hold *schp = &srp->data;
int k, num;

SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
num_read_xfer));
if ((!outp) || (num_read_xfer <= 0))
return 0;

num = 1 << (PAGE_SHIFT + schp->page_order);
for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
if (num > num_read_xfer) {
if (__copy_to_user(outp, page_address(schp->pages[k]),
num_read_xfer))
return -EFAULT;
break;
} else {
if (__copy_to_user(outp, page_address(schp->pages[k]),
num))
return -EFAULT;
num_read_xfer -= num;
if (num_read_xfer <= 0)
break;
outp += num;
}
}

return 0;
}

static void
sg_build_reserve(Sg_fd * sfp, int req_size)
{
Sg_scatter_hold *schp = &sfp->reserve;

SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
do {
if (req_size < PAGE_SIZE)
req_size = PAGE_SIZE;
if (0 == sg_build_indirect(schp, sfp, req_size))
return;
else
sg_remove_scat(schp);
req_size >>= 1; /* divide by 2 */
} while (req_size > (PAGE_SIZE / 2));
}

static void
sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
{
Sg_scatter_hold *req_schp = &srp->data;
Sg_scatter_hold *rsv_schp = &sfp->reserve;
int k, num, rem;

srp->res_used = 1;
SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
rem = size;

num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
for (k = 0; k < rsv_schp->k_use_sg; k++) {
if (rem <= num) {
req_schp->k_use_sg = k + 1;
req_schp->sglist_len = rsv_schp->sglist_len;
req_schp->pages = rsv_schp->pages;

req_schp->bufflen = size;
req_schp->page_order = rsv_schp->page_order;
break;
} else
rem -= num;
}

if (k >= rsv_schp->k_use_sg)
SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
}

static void
sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
{
Sg_scatter_hold *req_schp = &srp->data;

SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
(int) req_schp->k_use_sg));
req_schp->k_use_sg = 0;
req_schp->bufflen = 0;
req_schp->pages = NULL;
req_schp->page_order = 0;
req_schp->sglist_len = 0;
sfp->save_scat_len = 0;
srp->res_used = 0;
}

static Sg_request *
sg_get_rq_mark(Sg_fd * sfp, int pack_id)
{
Sg_request *resp;
unsigned long iflags;

write_lock_irqsave(&sfp->rq_list_lock, iflags);
for (resp = sfp->headrp; resp; resp = resp->nextrp) {
/* look for requests that are ready + not SG_IO owned */
if ((1 == resp->done) && (!resp->sg_io_owned) &&
((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
resp->done = 2; /* guard against other readers */
break;
}
}
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
return resp;
}

/* always adds to end of list */
static Sg_request *
sg_add_request(Sg_fd * sfp)
{
int k;
unsigned long iflags;
Sg_request *resp;
Sg_request *rp = sfp->req_arr;

write_lock_irqsave(&sfp->rq_list_lock, iflags);
resp = sfp->headrp;
if (!resp) {
memset(rp, 0, sizeof (Sg_request));
rp->parentfp = sfp;
resp = rp;
sfp->headrp = resp;
} else {
if (0 == sfp->cmd_q)
resp = NULL; /* command queuing disallowed */
else {
for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
if (!rp->parentfp)
break;
}
if (k < SG_MAX_QUEUE) {
memset(rp, 0, sizeof (Sg_request));
rp->parentfp = sfp;
while (resp->nextrp)
resp = resp->nextrp;
resp->nextrp = rp;
resp = rp;
} else
resp = NULL;
}
}
if (resp) {
resp->nextrp = NULL;
resp->header.duration = jiffies_to_msecs(jiffies);
}
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
return resp;
}

/* Return of 1 for found; 0 for not found */
static int
sg_remove_request(Sg_fd * sfp, Sg_request * srp)
{
Sg_request *prev_rp;
Sg_request *rp;
unsigned long iflags;
int res = 0;

if ((!sfp) || (!srp) || (!sfp->headrp))
return res;
write_lock_irqsave(&sfp->rq_list_lock, iflags);
prev_rp = sfp->headrp;
if (srp == prev_rp) {
sfp->headrp = prev_rp->nextrp;
prev_rp->parentfp = NULL;
res = 1;
} else {
while ((rp = prev_rp->nextrp)) {
if (srp == rp) {
prev_rp->nextrp = rp->nextrp;
rp->parentfp = NULL;
res = 1;
break;
}
prev_rp = rp;
}
}
write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
return res;
}

static Sg_fd *
sg_add_sfp(Sg_device * sdp, int dev)
{
Sg_fd *sfp;
unsigned long iflags;
int bufflen;

sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
if (!sfp)
return NULL;

init_waitqueue_head(&sfp->read_wait);
rwlock_init(&sfp->rq_list_lock);

kref_init(&sfp->f_ref);
sfp->timeout = SG_DEFAULT_TIMEOUT;
sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
sfp->force_packid = SG_DEF_FORCE_PACK_ID;
sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
sdp->device->host->unchecked_isa_dma : 1;
sfp->cmd_q = SG_DEF_COMMAND_Q;
sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
sfp->parentdp = sdp;
write_lock_irqsave(&sg_index_lock, iflags);
list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
write_unlock_irqrestore(&sg_index_lock, iflags);
SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
if (unlikely(sg_big_buff != def_reserved_size))
sg_big_buff = def_reserved_size;

bufflen = min_t(int, sg_big_buff,
queue_max_sectors(sdp->device->request_queue) * 512);
sg_build_reserve(sfp, bufflen);
SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
sfp->reserve.bufflen, sfp->reserve.k_use_sg));

kref_get(&sdp->d_ref);
__module_get(THIS_MODULE);
return sfp;
}

static void sg_remove_sfp_usercontext(struct work_struct *work)
{
struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
struct sg_device *sdp = sfp->parentdp;

/* Cleanup any responses which were never read(). */
while (sfp->headrp)
sg_finish_rem_req(sfp->headrp);

if (sfp->reserve.bufflen > 0) {
SCSI_LOG_TIMEOUT(6,
printk("sg_remove_sfp: bufflen=%d, k_use_sg=%d\n",
(int) sfp->reserve.bufflen,
(int) sfp->reserve.k_use_sg));
sg_remove_scat(&sfp->reserve);
}

SCSI_LOG_TIMEOUT(6,
printk("sg_remove_sfp: %s, sfp=0x%p\n",
sdp->disk->disk_name,
sfp));
kfree(sfp);

scsi_device_put(sdp->device);
sg_put_dev(sdp);
module_put(THIS_MODULE);
}

static void sg_remove_sfp(struct kref *kref)
{
struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
struct sg_device *sdp = sfp->parentdp;
unsigned long iflags;

write_lock_irqsave(&sg_index_lock, iflags);
list_del(&sfp->sfd_siblings);
write_unlock_irqrestore(&sg_index_lock, iflags);
wake_up_interruptible(&sdp->o_excl_wait);

INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
schedule_work(&sfp->ew.work);
}

static int
sg_res_in_use(Sg_fd * sfp)
{
const Sg_request *srp;
unsigned long iflags;

read_lock_irqsave(&sfp->rq_list_lock, iflags);
for (srp = sfp->headrp; srp; srp = srp->nextrp)
if (srp->res_used)
break;
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
return srp ? 1 : 0;
}

#ifdef CONFIG_SCSI_PROC_FS
static int
sg_idr_max_id(int id, void *p, void *data)
{
int *k = data;

if (*k < id)
*k = id;

return 0;
}

static int
sg_last_dev(void)
{
int k = -1;
unsigned long iflags;

read_lock_irqsave(&sg_index_lock, iflags);
idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
read_unlock_irqrestore(&sg_index_lock, iflags);
return k + 1; /* origin 1 */
}
#endif

/* must be called with sg_index_lock held */
static Sg_device *sg_lookup_dev(int dev)
{
return idr_find(&sg_index_idr, dev);
}

static Sg_device *sg_get_dev(int dev)
{
struct sg_device *sdp;
unsigned long flags;

read_lock_irqsave(&sg_index_lock, flags);
sdp = sg_lookup_dev(dev);
if (!sdp)
sdp = ERR_PTR(-ENXIO);
else if (sdp->detached) {
/* If sdp->detached, then the refcount may already be 0, in
* which case it would be a bug to do kref_get().
*/
sdp = ERR_PTR(-ENODEV);
} else
kref_get(&sdp->d_ref);
read_unlock_irqrestore(&sg_index_lock, flags);

return sdp;
}

static void sg_put_dev(struct sg_device *sdp)
{
kref_put(&sdp->d_ref, sg_device_destroy);
}

#ifdef CONFIG_SCSI_PROC_FS

static struct proc_dir_entry *sg_proc_sgp = NULL;

static char sg_proc_sg_dirname[] = "scsi/sg";

static int sg_proc_seq_show_int(struct seq_file *s, void *v);

static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
size_t count, loff_t *off);
static const struct file_operations adio_fops = {
.owner = THIS_MODULE,
.open = sg_proc_single_open_adio,
.read = seq_read,
.llseek = seq_lseek,
.write = sg_proc_write_adio,
.release = single_release,
};

static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
static ssize_t sg_proc_write_dressz(struct file *filp,
const char __user *buffer, size_t count, loff_t *off);
static const struct file_operations dressz_fops = {
.owner = THIS_MODULE,
.open = sg_proc_single_open_dressz,
.read = seq_read,
.llseek = seq_lseek,
.write = sg_proc_write_dressz,
.release = single_release,
};

static int sg_proc_seq_show_version(struct seq_file *s, void *v);
static int sg_proc_single_open_version(struct inode *inode, struct file *file);
static const struct file_operations version_fops = {
.owner = THIS_MODULE,
.open = sg_proc_single_open_version,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};

static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
static const struct file_operations devhdr_fops = {
.owner = THIS_MODULE,
.open = sg_proc_single_open_devhdr,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};

static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
static int sg_proc_open_dev(struct inode *inode, struct file *file);
static void * dev_seq_start(struct seq_file *s, loff_t *pos);
static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
static void dev_seq_stop(struct seq_file *s, void *v);
static const struct file_operations dev_fops = {
.owner = THIS_MODULE,
.open = sg_proc_open_dev,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct seq_operations dev_seq_ops = {
.start = dev_seq_start,
.next = dev_seq_next,
.stop = dev_seq_stop,
.show = sg_proc_seq_show_dev,
};

static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
static const struct file_operations devstrs_fops = {
.owner = THIS_MODULE,
.open = sg_proc_open_devstrs,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct seq_operations devstrs_seq_ops = {
.start = dev_seq_start,
.next = dev_seq_next,
.stop = dev_seq_stop,
.show = sg_proc_seq_show_devstrs,
};

static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
static int sg_proc_open_debug(struct inode *inode, struct file *file);
static const struct file_operations debug_fops = {
.owner = THIS_MODULE,
.open = sg_proc_open_debug,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct seq_operations debug_seq_ops = {
.start = dev_seq_start,
.next = dev_seq_next,
.stop = dev_seq_stop,
.show = sg_proc_seq_show_debug,
};


struct sg_proc_leaf {
const char * name;
const struct file_operations * fops;
};

static const struct sg_proc_leaf sg_proc_leaf_arr[] = {
{"allow_dio", &adio_fops},
{"debug", &debug_fops},
{"def_reserved_size", &dressz_fops},
{"device_hdr", &devhdr_fops},
{"devices", &dev_fops},
{"device_strs", &devstrs_fops},
{"version", &version_fops}
};

static int
sg_proc_init(void)
{
int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
int k;

sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
if (!sg_proc_sgp)
return 1;
for (k = 0; k < num_leaves; ++k) {
const struct sg_proc_leaf *leaf = &sg_proc_leaf_arr[k];
umode_t mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
}
return 0;
}

static void
sg_proc_cleanup(void)
{
int k;
int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);

if (!sg_proc_sgp)
return;
for (k = 0; k < num_leaves; ++k)
remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
remove_proc_entry(sg_proc_sg_dirname, NULL);
}


static int sg_proc_seq_show_int(struct seq_file *s, void *v)
{
seq_printf(s, "%d\n", *((int *)s->private));
return 0;
}

static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
{
return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
}

static ssize_t
sg_proc_write_adio(struct file *filp, const char __user *buffer,
size_t count, loff_t *off)
{
int err;
unsigned long num;

if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
return -EACCES;
err = kstrtoul_from_user(buffer, count, 0, &num);
if (err)
return err;
sg_allow_dio = num ? 1 : 0;
return count;
}

static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
{
return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
}

static ssize_t
sg_proc_write_dressz(struct file *filp, const char __user *buffer,
size_t count, loff_t *off)
{
int err;
unsigned long k = ULONG_MAX;

if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
return -EACCES;

err = kstrtoul_from_user(buffer, count, 0, &k);
if (err)
return err;
if (k <= 1048576) { /* limit "big buff" to 1 MB */
sg_big_buff = k;
return count;
}
return -ERANGE;
}

static int sg_proc_seq_show_version(struct seq_file *s, void *v)
{
seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
sg_version_date);
return 0;
}

static int sg_proc_single_open_version(struct inode *inode, struct file *file)
{
return single_open(file, sg_proc_seq_show_version, NULL);
}

static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
{
seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
"online\n");
return 0;
}

static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
{
return single_open(file, sg_proc_seq_show_devhdr, NULL);
}

struct sg_proc_deviter {
loff_t index;
size_t max;
};

static void * dev_seq_start(struct seq_file *s, loff_t *pos)
{
struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);

s->private = it;
if (! it)
return NULL;

it->index = *pos;
it->max = sg_last_dev();
if (it->index >= it->max)
return NULL;
return it;
}

static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
struct sg_proc_deviter * it = s->private;

*pos = ++it->index;
return (it->index < it->max) ? it : NULL;
}

static void dev_seq_stop(struct seq_file *s, void *v)
{
kfree(s->private);
}

static int sg_proc_open_dev(struct inode *inode, struct file *file)
{
        return seq_open(file, &dev_seq_ops);
}

static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
{
struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
Sg_device *sdp;
struct scsi_device *scsidp;
unsigned long iflags;

read_lock_irqsave(&sg_index_lock, iflags);
sdp = it ? sg_lookup_dev(it->index) : NULL;
if (sdp && (scsidp = sdp->device) && (!sdp->detached))
seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
scsidp->host->host_no, scsidp->channel,
scsidp->id, scsidp->lun, (int) scsidp->type,
1,
(int) scsidp->queue_depth,
(int) scsidp->device_busy,
(int) scsi_device_online(scsidp));
else
seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}

static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
{
        return seq_open(file, &devstrs_seq_ops);
}

static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
{
struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
Sg_device *sdp;
struct scsi_device *scsidp;
unsigned long iflags;

read_lock_irqsave(&sg_index_lock, iflags);
sdp = it ? sg_lookup_dev(it->index) : NULL;
if (sdp && (scsidp = sdp->device) && (!sdp->detached))
seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
scsidp->vendor, scsidp->model, scsidp->rev);
else
seq_printf(s, "<no active device>\n");
read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}

/* must be called while holding sg_index_lock */
static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
{
int k, m, new_interface, blen, usg;
Sg_request *srp;
Sg_fd *fp;
const sg_io_hdr_t *hp;
const char * cp;
unsigned int ms;

k = 0;
list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
k++;
read_lock(&fp->rq_list_lock); /* irqs already disabled */
seq_printf(s, " FD(%d): timeout=%dms bufflen=%d "
"(res)sgat=%d low_dma=%d\n", k,
jiffies_to_msecs(fp->timeout),
fp->reserve.bufflen,
(int) fp->reserve.k_use_sg,
(int) fp->low_dma);
seq_printf(s, " cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
(int) fp->cmd_q, (int) fp->force_packid,
(int) fp->keep_orphan);
for (m = 0, srp = fp->headrp;
srp != NULL;
++m, srp = srp->nextrp) {
hp = &srp->header;
new_interface = (hp->interface_id == '\0') ? 0 : 1;
if (srp->res_used) {
if (new_interface &&
(SG_FLAG_MMAP_IO & hp->flags))
cp = " mmap>> ";
else
cp = " rb>> ";
} else {
if (SG_INFO_DIRECT_IO_MASK & hp->info)
cp = " dio>> ";
else
cp = " ";
}
seq_printf(s, cp);
blen = srp->data.bufflen;
usg = srp->data.k_use_sg;
seq_printf(s, srp->done ?
((1 == srp->done) ? "rcv:" : "fin:")
: "act:");
seq_printf(s, " id=%d blen=%d",
srp->header.pack_id, blen);
if (srp->done)
seq_printf(s, " dur=%d", hp->duration);
else {
ms = jiffies_to_msecs(jiffies);
seq_printf(s, " t_o/elap=%d/%d",
(new_interface ? hp->timeout :
jiffies_to_msecs(fp->timeout)),
(ms > hp->duration ? ms - hp->duration : 0));
}
seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
(int) srp->data.cmd_opcode);
}
if (0 == m)
seq_printf(s, " No requests active\n");
read_unlock(&fp->rq_list_lock);
}
}

static int sg_proc_open_debug(struct inode *inode, struct file *file)
{
        return seq_open(file, &debug_seq_ops);
}

static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
{
struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
Sg_device *sdp;
unsigned long iflags;

if (it && (0 == it->index)) {
seq_printf(s, "max_active_device=%d(origin 1)\n",
(int)it->max);
seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
}

read_lock_irqsave(&sg_index_lock, iflags);
sdp = it ? sg_lookup_dev(it->index) : NULL;
if (sdp && !list_empty(&sdp->sfds)) {
struct scsi_device *scsidp = sdp->device;

seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
if (sdp->detached)
seq_printf(s, "detached pending close ");
else
seq_printf
(s, "scsi%d chan=%d id=%d lun=%d em=%d",
scsidp->host->host_no,
scsidp->channel, scsidp->id,
scsidp->lun,
scsidp->host->hostt->emulated);
seq_printf(s, " sg_tablesize=%d excl=%d\n",
sdp->sg_tablesize, get_exclude(sdp));
sg_proc_debug_helper(s, sdp);
}
read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}

#endif /* CONFIG_SCSI_PROC_FS */

module_init(init_sg);
module_exit(exit_sg);
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