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linux/drivers/s390/char/monreader.c
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop 
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00

650 lines
16 KiB
C
Raw Blame History

/*
* Character device driver for reading z/VM *MONITOR service records.
*
* Copyright IBM Corp. 2004, 2009
*
* Author: Gerald Schaefer <gerald.schaefer@de.ibm.com>
*/
#define KMSG_COMPONENT "monreader"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <net/iucv/iucv.h>
#include <asm/uaccess.h>
#include <asm/ebcdic.h>
#include <asm/extmem.h>
#define MON_COLLECT_SAMPLE 0x80
#define MON_COLLECT_EVENT 0x40
#define MON_SERVICE "*MONITOR"
#define MON_IN_USE 0x01
#define MON_MSGLIM 255
static char mon_dcss_name[9] = "MONDCSS\0";
struct mon_msg {
u32 pos;
u32 mca_offset;
struct iucv_message msg;
char msglim_reached;
char replied_msglim;
};
struct mon_private {
struct iucv_path *path;
struct mon_msg *msg_array[MON_MSGLIM];
unsigned int write_index;
unsigned int read_index;
atomic_t msglim_count;
atomic_t read_ready;
atomic_t iucv_connected;
atomic_t iucv_severed;
};
static unsigned long mon_in_use = 0;
static unsigned long mon_dcss_start;
static unsigned long mon_dcss_end;
static DECLARE_WAIT_QUEUE_HEAD(mon_read_wait_queue);
static DECLARE_WAIT_QUEUE_HEAD(mon_conn_wait_queue);
static u8 user_data_connect[16] = {
/* Version code, must be 0x01 for shared mode */
0x01,
/* what to collect */
MON_COLLECT_SAMPLE | MON_COLLECT_EVENT,
/* DCSS name in EBCDIC, 8 bytes padded with blanks */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};
static u8 user_data_sever[16] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};
static struct device *monreader_device;
/******************************************************************************
* helper functions *
*****************************************************************************/
/*
* Create the 8 bytes EBCDIC DCSS segment name from
* an ASCII name, incl. padding
*/
static void dcss_mkname(char *ascii_name, char *ebcdic_name)
{
int i;
for (i = 0; i < 8; i++) {
if (ascii_name[i] == '\0')
break;
ebcdic_name[i] = toupper(ascii_name[i]);
};
for (; i < 8; i++)
ebcdic_name[i] = ' ';
ASCEBC(ebcdic_name, 8);
}
static inline unsigned long mon_mca_start(struct mon_msg *monmsg)
{
return *(u32 *) &monmsg->msg.rmmsg;
}
static inline unsigned long mon_mca_end(struct mon_msg *monmsg)
{
return *(u32 *) &monmsg->msg.rmmsg[4];
}
static inline u8 mon_mca_type(struct mon_msg *monmsg, u8 index)
{
return *((u8 *) mon_mca_start(monmsg) + monmsg->mca_offset + index);
}
static inline u32 mon_mca_size(struct mon_msg *monmsg)
{
return mon_mca_end(monmsg) - mon_mca_start(monmsg) + 1;
}
static inline u32 mon_rec_start(struct mon_msg *monmsg)
{
return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 4));
}
static inline u32 mon_rec_end(struct mon_msg *monmsg)
{
return *((u32 *) (mon_mca_start(monmsg) + monmsg->mca_offset + 8));
}
static int mon_check_mca(struct mon_msg *monmsg)
{
if ((mon_rec_end(monmsg) <= mon_rec_start(monmsg)) ||
(mon_rec_start(monmsg) < mon_dcss_start) ||
(mon_rec_end(monmsg) > mon_dcss_end) ||
(mon_mca_type(monmsg, 0) == 0) ||
(mon_mca_size(monmsg) % 12 != 0) ||
(mon_mca_end(monmsg) <= mon_mca_start(monmsg)) ||
(mon_mca_end(monmsg) > mon_dcss_end) ||
(mon_mca_start(monmsg) < mon_dcss_start) ||
((mon_mca_type(monmsg, 1) == 0) && (mon_mca_type(monmsg, 2) == 0)))
return -EINVAL;
return 0;
}
static int mon_send_reply(struct mon_msg *monmsg,
struct mon_private *monpriv)
{
int rc;
rc = iucv_message_reply(monpriv->path, &monmsg->msg,
IUCV_IPRMDATA, NULL, 0);
atomic_dec(&monpriv->msglim_count);
if (likely(!monmsg->msglim_reached)) {
monmsg->pos = 0;
monmsg->mca_offset = 0;
monpriv->read_index = (monpriv->read_index + 1) %
MON_MSGLIM;
atomic_dec(&monpriv->read_ready);
} else
monmsg->replied_msglim = 1;
if (rc) {
pr_err("Reading monitor data failed with rc=%i\n", rc);
return -EIO;
}
return 0;
}
static void mon_free_mem(struct mon_private *monpriv)
{
int i;
for (i = 0; i < MON_MSGLIM; i++)
if (monpriv->msg_array[i])
kfree(monpriv->msg_array[i]);
kfree(monpriv);
}
static struct mon_private *mon_alloc_mem(void)
{
int i;
struct mon_private *monpriv;
monpriv = kzalloc(sizeof(struct mon_private), GFP_KERNEL);
if (!monpriv)
return NULL;
for (i = 0; i < MON_MSGLIM; i++) {
monpriv->msg_array[i] = kzalloc(sizeof(struct mon_msg),
GFP_KERNEL);
if (!monpriv->msg_array[i]) {
mon_free_mem(monpriv);
return NULL;
}
}
return monpriv;
}
static inline void mon_next_mca(struct mon_msg *monmsg)
{
if (likely((mon_mca_size(monmsg) - monmsg->mca_offset) == 12))
return;
monmsg->mca_offset += 12;
monmsg->pos = 0;
}
static struct mon_msg *mon_next_message(struct mon_private *monpriv)
{
struct mon_msg *monmsg;
if (!atomic_read(&monpriv->read_ready))
return NULL;
monmsg = monpriv->msg_array[monpriv->read_index];
if (unlikely(monmsg->replied_msglim)) {
monmsg->replied_msglim = 0;
monmsg->msglim_reached = 0;
monmsg->pos = 0;
monmsg->mca_offset = 0;
monpriv->read_index = (monpriv->read_index + 1) %
MON_MSGLIM;
atomic_dec(&monpriv->read_ready);
return ERR_PTR(-EOVERFLOW);
}
return monmsg;
}
/******************************************************************************
* IUCV handler *
*****************************************************************************/
static void mon_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
{
struct mon_private *monpriv = path->private;
atomic_set(&monpriv->iucv_connected, 1);
wake_up(&mon_conn_wait_queue);
}
static void mon_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
{
struct mon_private *monpriv = path->private;
pr_err("z/VM *MONITOR system service disconnected with rc=%i\n",
ipuser[0]);
iucv_path_sever(path, NULL);
atomic_set(&monpriv->iucv_severed, 1);
wake_up(&mon_conn_wait_queue);
wake_up_interruptible(&mon_read_wait_queue);
}
static void mon_iucv_message_pending(struct iucv_path *path,
struct iucv_message *msg)
{
struct mon_private *monpriv = path->private;
memcpy(&monpriv->msg_array[monpriv->write_index]->msg,
msg, sizeof(*msg));
if (atomic_inc_return(&monpriv->msglim_count) == MON_MSGLIM) {
pr_warning("The read queue for monitor data is full\n");
monpriv->msg_array[monpriv->write_index]->msglim_reached = 1;
}
monpriv->write_index = (monpriv->write_index + 1) % MON_MSGLIM;
atomic_inc(&monpriv->read_ready);
wake_up_interruptible(&mon_read_wait_queue);
}
static struct iucv_handler monreader_iucv_handler = {
.path_complete = mon_iucv_path_complete,
.path_severed = mon_iucv_path_severed,
.message_pending = mon_iucv_message_pending,
};
/******************************************************************************
* file operations *
*****************************************************************************/
static int mon_open(struct inode *inode, struct file *filp)
{
struct mon_private *monpriv;
int rc;
/*
* only one user allowed
*/
rc = -EBUSY;
if (test_and_set_bit(MON_IN_USE, &mon_in_use))
goto out;
rc = -ENOMEM;
monpriv = mon_alloc_mem();
if (!monpriv)
goto out_use;
/*
* Connect to *MONITOR service
*/
monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
if (!monpriv->path)
goto out_priv;
rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
MON_SERVICE, NULL, user_data_connect, monpriv);
if (rc) {
pr_err("Connecting to the z/VM *MONITOR system service "
"failed with rc=%i\n", rc);
rc = -EIO;
goto out_path;
}
/*
* Wait for connection confirmation
*/
wait_event(mon_conn_wait_queue,
atomic_read(&monpriv->iucv_connected) ||
atomic_read(&monpriv->iucv_severed));
if (atomic_read(&monpriv->iucv_severed)) {
atomic_set(&monpriv->iucv_severed, 0);
atomic_set(&monpriv->iucv_connected, 0);
rc = -EIO;
goto out_path;
}
filp->private_data = monpriv;
dev_set_drvdata(monreader_device, monpriv);
return nonseekable_open(inode, filp);
out_path:
iucv_path_free(monpriv->path);
out_priv:
mon_free_mem(monpriv);
out_use:
clear_bit(MON_IN_USE, &mon_in_use);
out:
return rc;
}
static int mon_close(struct inode *inode, struct file *filp)
{
int rc, i;
struct mon_private *monpriv = filp->private_data;
/*
* Close IUCV connection and unregister
*/
if (monpriv->path) {
rc = iucv_path_sever(monpriv->path, user_data_sever);
if (rc)
pr_warning("Disconnecting the z/VM *MONITOR system "
"service failed with rc=%i\n", rc);
iucv_path_free(monpriv->path);
}
atomic_set(&monpriv->iucv_severed, 0);
atomic_set(&monpriv->iucv_connected, 0);
atomic_set(&monpriv->read_ready, 0);
atomic_set(&monpriv->msglim_count, 0);
monpriv->write_index = 0;
monpriv->read_index = 0;
dev_set_drvdata(monreader_device, NULL);
for (i = 0; i < MON_MSGLIM; i++)
kfree(monpriv->msg_array[i]);
kfree(monpriv);
clear_bit(MON_IN_USE, &mon_in_use);
return 0;
}
static ssize_t mon_read(struct file *filp, char __user *data,
size_t count, loff_t *ppos)
{
struct mon_private *monpriv = filp->private_data;
struct mon_msg *monmsg;
int ret;
u32 mce_start;
monmsg = mon_next_message(monpriv);
if (IS_ERR(monmsg))
return PTR_ERR(monmsg);
if (!monmsg) {
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible(mon_read_wait_queue,
atomic_read(&monpriv->read_ready) ||
atomic_read(&monpriv->iucv_severed));
if (ret)
return ret;
if (unlikely(atomic_read(&monpriv->iucv_severed)))
return -EIO;
monmsg = monpriv->msg_array[monpriv->read_index];
}
if (!monmsg->pos)
monmsg->pos = mon_mca_start(monmsg) + monmsg->mca_offset;
if (mon_check_mca(monmsg))
goto reply;
/* read monitor control element (12 bytes) first */
mce_start = mon_mca_start(monmsg) + monmsg->mca_offset;
if ((monmsg->pos >= mce_start) && (monmsg->pos < mce_start + 12)) {
count = min(count, (size_t) mce_start + 12 - monmsg->pos);
ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
count);
if (ret)
return -EFAULT;
monmsg->pos += count;
if (monmsg->pos == mce_start + 12)
monmsg->pos = mon_rec_start(monmsg);
goto out_copy;
}
/* read records */
if (monmsg->pos <= mon_rec_end(monmsg)) {
count = min(count, (size_t) mon_rec_end(monmsg) - monmsg->pos
+ 1);
ret = copy_to_user(data, (void *) (unsigned long) monmsg->pos,
count);
if (ret)
return -EFAULT;
monmsg->pos += count;
if (monmsg->pos > mon_rec_end(monmsg))
mon_next_mca(monmsg);
goto out_copy;
}
reply:
ret = mon_send_reply(monmsg, monpriv);
return ret;
out_copy:
*ppos += count;
return count;
}
static unsigned int mon_poll(struct file *filp, struct poll_table_struct *p)
{
struct mon_private *monpriv = filp->private_data;
poll_wait(filp, &mon_read_wait_queue, p);
if (unlikely(atomic_read(&monpriv->iucv_severed)))
return POLLERR;
if (atomic_read(&monpriv->read_ready))
return POLLIN | POLLRDNORM;
return 0;
}
static const struct file_operations mon_fops = {
.owner = THIS_MODULE,
.open = &mon_open,
.release = &mon_close,
.read = &mon_read,
.poll = &mon_poll,
.llseek = noop_llseek,
};
static struct miscdevice mon_dev = {
.name = "monreader",
.fops = &mon_fops,
.minor = MISC_DYNAMIC_MINOR,
};
/******************************************************************************
* suspend / resume *
*****************************************************************************/
static int monreader_freeze(struct device *dev)
{
struct mon_private *monpriv = dev_get_drvdata(dev);
int rc;
if (!monpriv)
return 0;
if (monpriv->path) {
rc = iucv_path_sever(monpriv->path, user_data_sever);
if (rc)
pr_warning("Disconnecting the z/VM *MONITOR system "
"service failed with rc=%i\n", rc);
iucv_path_free(monpriv->path);
}
atomic_set(&monpriv->iucv_severed, 0);
atomic_set(&monpriv->iucv_connected, 0);
atomic_set(&monpriv->read_ready, 0);
atomic_set(&monpriv->msglim_count, 0);
monpriv->write_index = 0;
monpriv->read_index = 0;
monpriv->path = NULL;
return 0;
}
static int monreader_thaw(struct device *dev)
{
struct mon_private *monpriv = dev_get_drvdata(dev);
int rc;
if (!monpriv)
return 0;
rc = -ENOMEM;
monpriv->path = iucv_path_alloc(MON_MSGLIM, IUCV_IPRMDATA, GFP_KERNEL);
if (!monpriv->path)
goto out;
rc = iucv_path_connect(monpriv->path, &monreader_iucv_handler,
MON_SERVICE, NULL, user_data_connect, monpriv);
if (rc) {
pr_err("Connecting to the z/VM *MONITOR system service "
"failed with rc=%i\n", rc);
goto out_path;
}
wait_event(mon_conn_wait_queue,
atomic_read(&monpriv->iucv_connected) ||
atomic_read(&monpriv->iucv_severed));
if (atomic_read(&monpriv->iucv_severed))
goto out_path;
return 0;
out_path:
rc = -EIO;
iucv_path_free(monpriv->path);
monpriv->path = NULL;
out:
atomic_set(&monpriv->iucv_severed, 1);
return rc;
}
static int monreader_restore(struct device *dev)
{
int rc;
segment_unload(mon_dcss_name);
rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
&mon_dcss_start, &mon_dcss_end);
if (rc < 0) {
segment_warning(rc, mon_dcss_name);
panic("fatal monreader resume error: no monitor dcss\n");
}
return monreader_thaw(dev);
}
static const struct dev_pm_ops monreader_pm_ops = {
.freeze = monreader_freeze,
.thaw = monreader_thaw,
.restore = monreader_restore,
};
static struct device_driver monreader_driver = {
.name = "monreader",
.bus = &iucv_bus,
.pm = &monreader_pm_ops,
};
/******************************************************************************
* module init/exit *
*****************************************************************************/
static int __init mon_init(void)
{
int rc;
if (!MACHINE_IS_VM) {
pr_err("The z/VM *MONITOR record device driver cannot be "
"loaded without z/VM\n");
return -ENODEV;
}
/*
* Register with IUCV and connect to *MONITOR service
*/
rc = iucv_register(&monreader_iucv_handler, 1);
if (rc) {
pr_err("The z/VM *MONITOR record device driver failed to "
"register with IUCV\n");
return rc;
}
rc = driver_register(&monreader_driver);
if (rc)
goto out_iucv;
monreader_device = kzalloc(sizeof(struct device), GFP_KERNEL);
if (!monreader_device)
goto out_driver;
dev_set_name(monreader_device, "monreader-dev");
monreader_device->bus = &iucv_bus;
monreader_device->parent = iucv_root;
monreader_device->driver = &monreader_driver;
monreader_device->release = (void (*)(struct device *))kfree;
rc = device_register(monreader_device);
if (rc) {
put_device(monreader_device);
goto out_driver;
}
rc = segment_type(mon_dcss_name);
if (rc < 0) {
segment_warning(rc, mon_dcss_name);
goto out_device;
}
if (rc != SEG_TYPE_SC) {
pr_err("The specified *MONITOR DCSS %s does not have the "
"required type SC\n", mon_dcss_name);
rc = -EINVAL;
goto out_device;
}
rc = segment_load(mon_dcss_name, SEGMENT_SHARED,
&mon_dcss_start, &mon_dcss_end);
if (rc < 0) {
segment_warning(rc, mon_dcss_name);
rc = -EINVAL;
goto out_device;
}
dcss_mkname(mon_dcss_name, &user_data_connect[8]);
/*
* misc_register() has to be the last action in module_init(), because
* file operations will be available right after this.
*/
rc = misc_register(&mon_dev);
if (rc < 0 )
goto out;
return 0;
out:
segment_unload(mon_dcss_name);
out_device:
device_unregister(monreader_device);
out_driver:
driver_unregister(&monreader_driver);
out_iucv:
iucv_unregister(&monreader_iucv_handler, 1);
return rc;
}
static void __exit mon_exit(void)
{
segment_unload(mon_dcss_name);
misc_deregister(&mon_dev);
device_unregister(monreader_device);
driver_unregister(&monreader_driver);
iucv_unregister(&monreader_iucv_handler, 1);
return;
}
module_init(mon_init);
module_exit(mon_exit);
module_param_string(mondcss, mon_dcss_name, 9, 0444);
MODULE_PARM_DESC(mondcss, "Name of DCSS segment to be used for *MONITOR "
"service, max. 8 chars. Default is MONDCSS");
MODULE_AUTHOR("Gerald Schaefer <geraldsc@de.ibm.com>");
MODULE_DESCRIPTION("Character device driver for reading z/VM "
"monitor service records.");
MODULE_LICENSE("GPL");
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