kernel-ark/drivers/s390/char/tape_char.c
Arjan van de Ven d54b1fdb1d [PATCH] mark struct file_operations const 5
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:45 -08:00

497 lines
11 KiB
C

/*
* drivers/s390/char/tape_char.c
* character device frontend for tape device driver
*
* S390 and zSeries version
* Copyright IBM Corp. 2001,2006
* Author(s): Carsten Otte <cotte@de.ibm.com>
* Michael Holzheu <holzheu@de.ibm.com>
* Tuan Ngo-Anh <ngoanh@de.ibm.com>
* Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/mtio.h>
#include <asm/uaccess.h>
#define TAPE_DBF_AREA tape_core_dbf
#include "tape.h"
#include "tape_std.h"
#include "tape_class.h"
#define PRINTK_HEADER "TAPE_CHAR: "
#define TAPECHAR_MAJOR 0 /* get dynamic major */
/*
* file operation structure for tape character frontend
*/
static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
static int tapechar_open(struct inode *,struct file *);
static int tapechar_release(struct inode *,struct file *);
static int tapechar_ioctl(struct inode *, struct file *, unsigned int,
unsigned long);
static long tapechar_compat_ioctl(struct file *, unsigned int,
unsigned long);
static const struct file_operations tape_fops =
{
.owner = THIS_MODULE,
.read = tapechar_read,
.write = tapechar_write,
.ioctl = tapechar_ioctl,
.compat_ioctl = tapechar_compat_ioctl,
.open = tapechar_open,
.release = tapechar_release,
};
static int tapechar_major = TAPECHAR_MAJOR;
/*
* This function is called for every new tapedevice
*/
int
tapechar_setup_device(struct tape_device * device)
{
char device_name[20];
sprintf(device_name, "ntibm%i", device->first_minor / 2);
device->nt = register_tape_dev(
&device->cdev->dev,
MKDEV(tapechar_major, device->first_minor),
&tape_fops,
device_name,
"non-rewinding"
);
device_name[0] = 'r';
device->rt = register_tape_dev(
&device->cdev->dev,
MKDEV(tapechar_major, device->first_minor + 1),
&tape_fops,
device_name,
"rewinding"
);
return 0;
}
void
tapechar_cleanup_device(struct tape_device *device)
{
unregister_tape_dev(device->rt);
device->rt = NULL;
unregister_tape_dev(device->nt);
device->nt = NULL;
}
static int
tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
{
struct idal_buffer *new;
if (device->char_data.idal_buf != NULL &&
device->char_data.idal_buf->size == block_size)
return 0;
if (block_size > MAX_BLOCKSIZE) {
DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
block_size, MAX_BLOCKSIZE);
PRINT_ERR("Invalid blocksize (%zd> %d)\n",
block_size, MAX_BLOCKSIZE);
return -EINVAL;
}
/* The current idal buffer is not correct. Allocate a new one. */
new = idal_buffer_alloc(block_size, 0);
if (new == NULL)
return -ENOMEM;
if (device->char_data.idal_buf != NULL)
idal_buffer_free(device->char_data.idal_buf);
device->char_data.idal_buf = new;
return 0;
}
/*
* Tape device read function
*/
static ssize_t
tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
{
struct tape_device *device;
struct tape_request *request;
size_t block_size;
int rc;
DBF_EVENT(6, "TCHAR:read\n");
device = (struct tape_device *) filp->private_data;
/*
* If the tape isn't terminated yet, do it now. And since we then
* are at the end of the tape there wouldn't be anything to read
* anyways. So we return immediatly.
*/
if(device->required_tapemarks) {
return tape_std_terminate_write(device);
}
/* Find out block size to use */
if (device->char_data.block_size != 0) {
if (count < device->char_data.block_size) {
DBF_EVENT(3, "TCHAR:read smaller than block "
"size was requested\n");
return -EINVAL;
}
block_size = device->char_data.block_size;
} else {
block_size = count;
}
rc = tapechar_check_idalbuffer(device, block_size);
if (rc)
return rc;
#ifdef CONFIG_S390_TAPE_BLOCK
/* Changes position. */
device->blk_data.medium_changed = 1;
#endif
DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
/* Let the discipline build the ccw chain. */
request = device->discipline->read_block(device, block_size);
if (IS_ERR(request))
return PTR_ERR(request);
/* Execute it. */
rc = tape_do_io(device, request);
if (rc == 0) {
rc = block_size - request->rescnt;
DBF_EVENT(6, "TCHAR:rbytes: %x\n", rc);
filp->f_pos += rc;
/* Copy data from idal buffer to user space. */
if (idal_buffer_to_user(device->char_data.idal_buf,
data, rc) != 0)
rc = -EFAULT;
}
tape_free_request(request);
return rc;
}
/*
* Tape device write function
*/
static ssize_t
tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
{
struct tape_device *device;
struct tape_request *request;
size_t block_size;
size_t written;
int nblocks;
int i, rc;
DBF_EVENT(6, "TCHAR:write\n");
device = (struct tape_device *) filp->private_data;
/* Find out block size and number of blocks */
if (device->char_data.block_size != 0) {
if (count < device->char_data.block_size) {
DBF_EVENT(3, "TCHAR:write smaller than block "
"size was requested\n");
return -EINVAL;
}
block_size = device->char_data.block_size;
nblocks = count / block_size;
} else {
block_size = count;
nblocks = 1;
}
rc = tapechar_check_idalbuffer(device, block_size);
if (rc)
return rc;
#ifdef CONFIG_S390_TAPE_BLOCK
/* Changes position. */
device->blk_data.medium_changed = 1;
#endif
DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
/* Let the discipline build the ccw chain. */
request = device->discipline->write_block(device, block_size);
if (IS_ERR(request))
return PTR_ERR(request);
rc = 0;
written = 0;
for (i = 0; i < nblocks; i++) {
/* Copy data from user space to idal buffer. */
if (idal_buffer_from_user(device->char_data.idal_buf,
data, block_size)) {
rc = -EFAULT;
break;
}
rc = tape_do_io(device, request);
if (rc)
break;
DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
block_size - request->rescnt);
filp->f_pos += block_size - request->rescnt;
written += block_size - request->rescnt;
if (request->rescnt != 0)
break;
data += block_size;
}
tape_free_request(request);
if (rc == -ENOSPC) {
/*
* Ok, the device has no more space. It has NOT written
* the block.
*/
if (device->discipline->process_eov)
device->discipline->process_eov(device);
if (written > 0)
rc = 0;
}
/*
* After doing a write we always need two tapemarks to correctly
* terminate the tape (one to terminate the file, the second to
* flag the end of recorded data.
* Since process_eov positions the tape in front of the written
* tapemark it doesn't hurt to write two marks again.
*/
if (!rc)
device->required_tapemarks = 2;
return rc ? rc : written;
}
/*
* Character frontend tape device open function.
*/
static int
tapechar_open (struct inode *inode, struct file *filp)
{
struct tape_device *device;
int minor, rc;
DBF_EVENT(6, "TCHAR:open: %i:%i\n",
imajor(filp->f_path.dentry->d_inode),
iminor(filp->f_path.dentry->d_inode));
if (imajor(filp->f_path.dentry->d_inode) != tapechar_major)
return -ENODEV;
minor = iminor(filp->f_path.dentry->d_inode);
device = tape_get_device(minor / TAPE_MINORS_PER_DEV);
if (IS_ERR(device)) {
DBF_EVENT(3, "TCHAR:open: tape_get_device() failed\n");
return PTR_ERR(device);
}
rc = tape_open(device);
if (rc == 0) {
filp->private_data = device;
return nonseekable_open(inode, filp);
}
tape_put_device(device);
return rc;
}
/*
* Character frontend tape device release function.
*/
static int
tapechar_release(struct inode *inode, struct file *filp)
{
struct tape_device *device;
DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
device = (struct tape_device *) filp->private_data;
/*
* If this is the rewinding tape minor then rewind. In that case we
* write all required tapemarks. Otherwise only one to terminate the
* file.
*/
if ((iminor(inode) & 1) != 0) {
if (device->required_tapemarks)
tape_std_terminate_write(device);
tape_mtop(device, MTREW, 1);
} else {
if (device->required_tapemarks > 1) {
if (tape_mtop(device, MTWEOF, 1) == 0)
device->required_tapemarks--;
}
}
if (device->char_data.idal_buf != NULL) {
idal_buffer_free(device->char_data.idal_buf);
device->char_data.idal_buf = NULL;
}
tape_release(device);
filp->private_data = tape_put_device(device);
return 0;
}
/*
* Tape device io controls.
*/
static int
tapechar_ioctl(struct inode *inp, struct file *filp,
unsigned int no, unsigned long data)
{
struct tape_device *device;
int rc;
DBF_EVENT(6, "TCHAR:ioct\n");
device = (struct tape_device *) filp->private_data;
if (no == MTIOCTOP) {
struct mtop op;
if (copy_from_user(&op, (char __user *) data, sizeof(op)) != 0)
return -EFAULT;
if (op.mt_count < 0)
return -EINVAL;
/*
* Operations that change tape position should write final
* tapemarks.
*/
switch (op.mt_op) {
case MTFSF:
case MTBSF:
case MTFSR:
case MTBSR:
case MTREW:
case MTOFFL:
case MTEOM:
case MTRETEN:
case MTBSFM:
case MTFSFM:
case MTSEEK:
#ifdef CONFIG_S390_TAPE_BLOCK
device->blk_data.medium_changed = 1;
#endif
if (device->required_tapemarks)
tape_std_terminate_write(device);
default:
;
}
rc = tape_mtop(device, op.mt_op, op.mt_count);
if (op.mt_op == MTWEOF && rc == 0) {
if (op.mt_count > device->required_tapemarks)
device->required_tapemarks = 0;
else
device->required_tapemarks -= op.mt_count;
}
return rc;
}
if (no == MTIOCPOS) {
/* MTIOCPOS: query the tape position. */
struct mtpos pos;
rc = tape_mtop(device, MTTELL, 1);
if (rc < 0)
return rc;
pos.mt_blkno = rc;
if (copy_to_user((char __user *) data, &pos, sizeof(pos)) != 0)
return -EFAULT;
return 0;
}
if (no == MTIOCGET) {
/* MTIOCGET: query the tape drive status. */
struct mtget get;
memset(&get, 0, sizeof(get));
get.mt_type = MT_ISUNKNOWN;
get.mt_resid = 0 /* device->devstat.rescnt */;
get.mt_dsreg = device->tape_state;
/* FIXME: mt_gstat, mt_erreg, mt_fileno */
get.mt_gstat = 0;
get.mt_erreg = 0;
get.mt_fileno = 0;
get.mt_gstat = device->tape_generic_status;
if (device->medium_state == MS_LOADED) {
rc = tape_mtop(device, MTTELL, 1);
if (rc < 0)
return rc;
if (rc == 0)
get.mt_gstat |= GMT_BOT(~0);
get.mt_blkno = rc;
}
if (copy_to_user((char __user *) data, &get, sizeof(get)) != 0)
return -EFAULT;
return 0;
}
/* Try the discipline ioctl function. */
if (device->discipline->ioctl_fn == NULL)
return -EINVAL;
return device->discipline->ioctl_fn(device, no, data);
}
static long
tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
{
struct tape_device *device = filp->private_data;
int rval = -ENOIOCTLCMD;
if (device->discipline->ioctl_fn) {
lock_kernel();
rval = device->discipline->ioctl_fn(device, no, data);
unlock_kernel();
if (rval == -EINVAL)
rval = -ENOIOCTLCMD;
}
return rval;
}
/*
* Initialize character device frontend.
*/
int
tapechar_init (void)
{
dev_t dev;
if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
return -1;
tapechar_major = MAJOR(dev);
PRINT_INFO("tape gets major %d for character devices\n", MAJOR(dev));
return 0;
}
/*
* cleanup
*/
void
tapechar_exit(void)
{
PRINT_INFO("tape releases major %d for character devices\n",
tapechar_major);
unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
}