[net-next-2.6.git] / fs / gfs2 / locking / dlm / plock.c

/*
 * Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/miscdevice.h>
#include <linux/lock_dlm_plock.h>
#include <linux/poll.h>

#include "lock_dlm.h"


static spinlock_t ops_lock;
static struct list_head send_list;
static struct list_head recv_list;
static wait_queue_head_t send_wq;
static wait_queue_head_t recv_wq;

struct plock_op {
	struct list_head list;
	int done;
	struct gdlm_plock_info info;
};

struct plock_xop {
	struct plock_op xop;
	void *callback;
	void *fl;
	void *file;
	struct file_lock flc;
};


static inline void set_version(struct gdlm_plock_info *info)
{
	info->version[0] = GDLM_PLOCK_VERSION_MAJOR;
	info->version[1] = GDLM_PLOCK_VERSION_MINOR;
	info->version[2] = GDLM_PLOCK_VERSION_PATCH;
}

static int check_version(struct gdlm_plock_info *info)
{
	if ((GDLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
	    (GDLM_PLOCK_VERSION_MINOR < info->version[1])) {
		log_error("plock device version mismatch: "
			  "kernel (%u.%u.%u), user (%u.%u.%u)",
			  GDLM_PLOCK_VERSION_MAJOR,
			  GDLM_PLOCK_VERSION_MINOR,
			  GDLM_PLOCK_VERSION_PATCH,
			  info->version[0],
			  info->version[1],
			  info->version[2]);
		return -EINVAL;
	}
	return 0;
}

static void send_op(struct plock_op *op)
{
	set_version(&op->info);
	INIT_LIST_HEAD(&op->list);
	spin_lock(&ops_lock);
	list_add_tail(&op->list, &send_list);
	spin_unlock(&ops_lock);
	wake_up(&send_wq);
}

int gdlm_plock(void *lockspace, struct lm_lockname *name,
	       struct file *file, int cmd, struct file_lock *fl)
{
	struct gdlm_ls *ls = lockspace;
	struct plock_op *op;
	struct plock_xop *xop;
	int rv;

	xop = kzalloc(sizeof(*xop), GFP_KERNEL);
	if (!xop)
		return -ENOMEM;

	op = &xop->xop;
	op->info.optype		= GDLM_PLOCK_OP_LOCK;
	op->info.pid		= fl->fl_pid;
	op->info.ex		= (fl->fl_type == F_WRLCK);
	op->info.wait		= IS_SETLKW(cmd);
	op->info.fsid		= ls->id;
	op->info.number		= name->ln_number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;
	op->info.owner		= (__u64)(long) fl->fl_owner;
	if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
		xop->callback	= fl->fl_lmops->fl_grant;
		locks_init_lock(&xop->flc);
		locks_copy_lock(&xop->flc, fl);
		xop->fl		= fl;
		xop->file	= file;
	} else
		xop->callback	= NULL;

	send_op(op);

	if (xop->callback == NULL)
		wait_event(recv_wq, (op->done != 0));
	else
		return -EINPROGRESS;

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		printk(KERN_INFO "plock op on list\n");
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	rv = op->info.rv;

	if (!rv) {
		if (posix_lock_file_wait(file, fl) < 0)
			log_error("gdlm_plock: vfs lock error %x,%llx",
				  name->ln_type,
				  (unsigned long long)name->ln_number);
	}

	kfree(xop);
	return rv;
}

/* Returns failure iff a succesful lock operation should be canceled */
static int gdlm_plock_callback(struct plock_op *op)
{
	struct file *file;
	struct file_lock *fl;
	struct file_lock *flc;
	int (*notify)(void *, void *, int) = NULL;
	struct plock_xop *xop = (struct plock_xop *)op;
	int rv = 0;

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		printk(KERN_INFO "plock op on list\n");
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	/* check if the following 2 are still valid or make a copy */
	file = xop->file;
	flc = &xop->flc;
	fl = xop->fl;
	notify = xop->callback;

	if (op->info.rv) {
		notify(flc, NULL, op->info.rv);
		goto out;
	}

	/* got fs lock; bookkeep locally as well: */
	flc->fl_flags &= ~FL_SLEEP;
	if (posix_lock_file(file, flc, NULL)) {
		/*
		 * This can only happen in the case of kmalloc() failure.
		 * The filesystem's own lock is the authoritative lock,
		 * so a failure to get the lock locally is not a disaster.
		 * As long as GFS cannot reliably cancel locks (especially
		 * in a low-memory situation), we're better off ignoring
		 * this failure than trying to recover.
		 */
		log_error("gdlm_plock: vfs lock error file %p fl %p",
				file, fl);
	}

	rv = notify(flc, NULL, 0);
	if (rv) {
		/* XXX: We need to cancel the fs lock here: */
		printk("gfs2 lock granted after lock request failed;"
						" dangling lock!\n");
		goto out;
	}

out:
	kfree(xop);
	return rv;
}

int gdlm_punlock(void *lockspace, struct lm_lockname *name,
		 struct file *file, struct file_lock *fl)
{
	struct gdlm_ls *ls = lockspace;
	struct plock_op *op;
	int rv;

	op = kzalloc(sizeof(*op), GFP_KERNEL);
	if (!op)
		return -ENOMEM;

	if (posix_lock_file_wait(file, fl) < 0)
		log_error("gdlm_punlock: vfs unlock error %x,%llx",
			  name->ln_type, (unsigned long long)name->ln_number);

	op->info.optype		= GDLM_PLOCK_OP_UNLOCK;
	op->info.pid		= fl->fl_pid;
	op->info.fsid		= ls->id;
	op->info.number		= name->ln_number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;
	op->info.owner		= (__u64)(long) fl->fl_owner;

	send_op(op);
	wait_event(recv_wq, (op->done != 0));

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		printk(KERN_INFO "punlock op on list\n");
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	rv = op->info.rv;

	if (rv == -ENOENT)
		rv = 0;

	kfree(op);
	return rv;
}

int gdlm_plock_get(void *lockspace, struct lm_lockname *name,
		   struct file *file, struct file_lock *fl)
{
	struct gdlm_ls *ls = lockspace;
	struct plock_op *op;
	int rv;

	op = kzalloc(sizeof(*op), GFP_KERNEL);
	if (!op)
		return -ENOMEM;

	op->info.optype		= GDLM_PLOCK_OP_GET;
	op->info.pid		= fl->fl_pid;
	op->info.ex		= (fl->fl_type == F_WRLCK);
	op->info.fsid		= ls->id;
	op->info.number		= name->ln_number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;
	op->info.owner		= (__u64)(long) fl->fl_owner;

	send_op(op);
	wait_event(recv_wq, (op->done != 0));

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		printk(KERN_INFO "plock_get op on list\n");
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	rv = op->info.rv;

	fl->fl_type = F_UNLCK;
	if (rv == -ENOENT)
		rv = 0;
	else if (rv == 0 && op->info.pid != fl->fl_pid) {
		fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
		fl->fl_pid = op->info.pid;
		fl->fl_start = op->info.start;
		fl->fl_end = op->info.end;
	}

	kfree(op);
	return rv;
}

/* a read copies out one plock request from the send list */
static ssize_t dev_read(struct file *file, char __user *u, size_t count,
			loff_t *ppos)
{
	struct gdlm_plock_info info;
	struct plock_op *op = NULL;

	if (count < sizeof(info))
		return -EINVAL;

	spin_lock(&ops_lock);
	if (!list_empty(&send_list)) {
		op = list_entry(send_list.next, struct plock_op, list);
		list_move(&op->list, &recv_list);
		memcpy(&info, &op->info, sizeof(info));
	}
	spin_unlock(&ops_lock);

	if (!op)
		return -EAGAIN;

	if (copy_to_user(u, &info, sizeof(info)))
		return -EFAULT;
	return sizeof(info);
}

/* a write copies in one plock result that should match a plock_op
   on the recv list */
static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
			 loff_t *ppos)
{
	struct gdlm_plock_info info;
	struct plock_op *op;
	int found = 0;

	if (count != sizeof(info))
		return -EINVAL;

	if (copy_from_user(&info, u, sizeof(info)))
		return -EFAULT;

	if (check_version(&info))
		return -EINVAL;

	spin_lock(&ops_lock);
	list_for_each_entry(op, &recv_list, list) {
		if (op->info.fsid == info.fsid && op->info.number == info.number &&
		    op->info.owner == info.owner) {
			list_del_init(&op->list);
			found = 1;
			op->done = 1;
			memcpy(&op->info, &info, sizeof(info));
			break;
		}
	}
	spin_unlock(&ops_lock);

	if (found) {
		struct plock_xop *xop;
		xop = (struct plock_xop *)op;
		if (xop->callback)
			count = gdlm_plock_callback(op);
		else
			wake_up(&recv_wq);
	} else
		printk(KERN_INFO "gdlm dev_write no op %x %llx\n", info.fsid,
			(unsigned long long)info.number);
	return count;
}

static unsigned int dev_poll(struct file *file, poll_table *wait)
{
	poll_wait(file, &send_wq, wait);

	spin_lock(&ops_lock);
	if (!list_empty(&send_list)) {
		spin_unlock(&ops_lock);
		return POLLIN | POLLRDNORM;
	}
	spin_unlock(&ops_lock);
	return 0;
}

static const struct file_operations dev_fops = {
	.read    = dev_read,
	.write   = dev_write,
	.poll    = dev_poll,
	.owner   = THIS_MODULE
};

static struct miscdevice plock_dev_misc = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = GDLM_PLOCK_MISC_NAME,
	.fops = &dev_fops
};

int gdlm_plock_init(void)
{
	int rv;

	spin_lock_init(&ops_lock);
	INIT_LIST_HEAD(&send_list);
	INIT_LIST_HEAD(&recv_list);
	init_waitqueue_head(&send_wq);
	init_waitqueue_head(&recv_wq);

	rv = misc_register(&plock_dev_misc);
	if (rv)
		printk(KERN_INFO "gdlm_plock_init: misc_register failed %d",
		       rv);
	return rv;
}

void gdlm_plock_exit(void)
{
	if (misc_deregister(&plock_dev_misc) < 0)
		printk(KERN_INFO "gdlm_plock_exit: misc_deregister failed");
}
Commit	Line	Data
869d81df DT	1	/*
	2	* Copyright (C) 2005 Red Hat, Inc. All rights reserved.
	3	*
	4	* This copyrighted material is made available to anyone wishing to use,
	5	* modify, copy, or redistribute it subject to the terms and conditions
e9fc2aa0	6	* of the GNU General Public License version 2.
869d81df DT	7	*/
	8
	9	#include <linux/miscdevice.h>
	10	#include <linux/lock_dlm_plock.h>
bd01f843	11	#include <linux/poll.h>
869d81df DT	12
	13	#include "lock_dlm.h"
	14
	15
	16	static spinlock_t ops_lock;
	17	static struct list_head send_list;
	18	static struct list_head recv_list;
	19	static wait_queue_head_t send_wq;
	20	static wait_queue_head_t recv_wq;
	21
	22	struct plock_op {
	23	struct list_head list;
	24	int done;
	25	struct gdlm_plock_info info;
	26	};
	27
586759f0 ME	28	struct plock_xop {
	29	struct plock_op xop;
	30	void *callback;
	31	void *fl;
	32	void *file;
	33	struct file_lock flc;
	34	};
	35
	36
869d81df DT	37	static inline void set_version(struct gdlm_plock_info *info)
	38	{
	39	info->version[0] = GDLM_PLOCK_VERSION_MAJOR;
	40	info->version[1] = GDLM_PLOCK_VERSION_MINOR;
	41	info->version[2] = GDLM_PLOCK_VERSION_PATCH;
	42	}
	43
	44	static int check_version(struct gdlm_plock_info *info)
	45	{
	46	if ((GDLM_PLOCK_VERSION_MAJOR != info->version[0]) \|\|
	47	(GDLM_PLOCK_VERSION_MINOR < info->version[1])) {
	48	log_error("plock device version mismatch: "
	49	"kernel (%u.%u.%u), user (%u.%u.%u)",
	50	GDLM_PLOCK_VERSION_MAJOR,
	51	GDLM_PLOCK_VERSION_MINOR,
	52	GDLM_PLOCK_VERSION_PATCH,
	53	info->version[0],
	54	info->version[1],
	55	info->version[2]);
	56	return -EINVAL;
	57	}
	58	return 0;
	59	}
	60
	61	static void send_op(struct plock_op *op)
	62	{
	63	set_version(&op->info);
	64	INIT_LIST_HEAD(&op->list);
	65	spin_lock(&ops_lock);
	66	list_add_tail(&op->list, &send_list);
	67	spin_unlock(&ops_lock);
	68	wake_up(&send_wq);
	69	}
	70
9b47c11d	71	int gdlm_plock(void lockspace, struct lm_lockname name,
869d81df DT	72	struct file file, int cmd, struct file_lock fl)
869d81df DT	73	{
9b47c11d	74	struct gdlm_ls *ls = lockspace;
869d81df	75	struct plock_op *op;
586759f0	76	struct plock_xop *xop;
869d81df DT	77	int rv;
869d81df DT	78
586759f0 ME	79	xop = kzalloc(sizeof(*xop), GFP_KERNEL);
586759f0 ME	80	if (!xop)
869d81df DT	81	return -ENOMEM;
869d81df DT	82
586759f0	83	op = &xop->xop;
869d81df	84	op->info.optype = GDLM_PLOCK_OP_LOCK;
3a2a9c96	85	op->info.pid = fl->fl_pid;
869d81df DT	86	op->info.ex = (fl->fl_type == F_WRLCK);
	87	op->info.wait = IS_SETLKW(cmd);
	88	op->info.fsid = ls->id;
	89	op->info.number = name->ln_number;
	90	op->info.start = fl->fl_start;
	91	op->info.end = fl->fl_end;
de9b75d3	92	op->info.owner = (__u64)(long) fl->fl_owner;
586759f0 ME	93	if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
	94	xop->callback = fl->fl_lmops->fl_grant;
	95	locks_init_lock(&xop->flc);
	96	locks_copy_lock(&xop->flc, fl);
	97	xop->fl = fl;
	98	xop->file = file;
	99	} else
	100	xop->callback = NULL;
869d81df DT	101
869d81df DT	102	send_op(op);
586759f0 ME	103
	104	if (xop->callback == NULL)
	105	wait_event(recv_wq, (op->done != 0));
	106	else
	107	return -EINPROGRESS;
869d81df DT	108
	109	spin_lock(&ops_lock);
	110	if (!list_empty(&op->list)) {
d92a8d48	111	printk(KERN_INFO "plock op on list\n");
869d81df DT	112	list_del(&op->list);
	113	}
	114	spin_unlock(&ops_lock);
	115
	116	rv = op->info.rv;
	117
	118	if (!rv) {
	119	if (posix_lock_file_wait(file, fl) < 0)
	120	log_error("gdlm_plock: vfs lock error %x,%llx",
9229f013 DT	121	name->ln_type,
9229f013 DT	122	(unsigned long long)name->ln_number);
869d81df DT	123	}
869d81df DT	124
586759f0 ME	125	kfree(xop);
	126	return rv;
	127	}
	128
	129	/* Returns failure iff a succesful lock operation should be canceled */
	130	static int gdlm_plock_callback(struct plock_op *op)
	131	{
	132	struct file *file;
	133	struct file_lock *fl;
	134	struct file_lock *flc;
	135	int (notify)(void , void *, int) = NULL;
	136	struct plock_xop xop = (struct plock_xop )op;
	137	int rv = 0;
	138
	139	spin_lock(&ops_lock);
	140	if (!list_empty(&op->list)) {
	141	printk(KERN_INFO "plock op on list\n");
	142	list_del(&op->list);
	143	}
	144	spin_unlock(&ops_lock);
	145
	146	/* check if the following 2 are still valid or make a copy */
	147	file = xop->file;
	148	flc = &xop->flc;
	149	fl = xop->fl;
	150	notify = xop->callback;
	151
	152	if (op->info.rv) {
	153	notify(flc, NULL, op->info.rv);
	154	goto out;
	155	}
	156
	157	/* got fs lock; bookkeep locally as well: */
	158	flc->fl_flags &= ~FL_SLEEP;
	159	if (posix_lock_file(file, flc, NULL)) {
	160	/*
	161	* This can only happen in the case of kmalloc() failure.
	162	* The filesystem's own lock is the authoritative lock,
	163	* so a failure to get the lock locally is not a disaster.
	164	* As long as GFS cannot reliably cancel locks (especially
	165	* in a low-memory situation), we're better off ignoring
	166	* this failure than trying to recover.
	167	*/
	168	log_error("gdlm_plock: vfs lock error file %p fl %p",
	169	file, fl);
	170	}
	171
	172	rv = notify(flc, NULL, 0);
	173	if (rv) {
	174	/* XXX: We need to cancel the fs lock here: */
	175	printk("gfs2 lock granted after lock request failed;"
	176	" dangling lock!\n");
	177	goto out;
	178	}
	179
	180	out:
	181	kfree(xop);
869d81df DT	182	return rv;
	183	}
	184
9b47c11d	185	int gdlm_punlock(void lockspace, struct lm_lockname name,
869d81df DT	186	struct file file, struct file_lock fl)
869d81df DT	187	{
9b47c11d	188	struct gdlm_ls *ls = lockspace;
869d81df DT	189	struct plock_op *op;
	190	int rv;
	191
	192	op = kzalloc(sizeof(*op), GFP_KERNEL);
	193	if (!op)
	194	return -ENOMEM;
	195
	196	if (posix_lock_file_wait(file, fl) < 0)
	197	log_error("gdlm_punlock: vfs unlock error %x,%llx",
9229f013	198	name->ln_type, (unsigned long long)name->ln_number);
869d81df DT	199
869d81df DT	200	op->info.optype = GDLM_PLOCK_OP_UNLOCK;
3a2a9c96	201	op->info.pid = fl->fl_pid;
869d81df DT	202	op->info.fsid = ls->id;
	203	op->info.number = name->ln_number;
	204	op->info.start = fl->fl_start;
	205	op->info.end = fl->fl_end;
de9b75d3	206	op->info.owner = (__u64)(long) fl->fl_owner;
869d81df DT	207
	208	send_op(op);
	209	wait_event(recv_wq, (op->done != 0));
	210
	211	spin_lock(&ops_lock);
	212	if (!list_empty(&op->list)) {
d92a8d48	213	printk(KERN_INFO "punlock op on list\n");
869d81df DT	214	list_del(&op->list);
	215	}
	216	spin_unlock(&ops_lock);
	217
	218	rv = op->info.rv;
	219
586759f0 ME	220	if (rv == -ENOENT)
	221	rv = 0;
	222
869d81df DT	223	kfree(op);
	224	return rv;
	225	}
	226
9b47c11d	227	int gdlm_plock_get(void lockspace, struct lm_lockname name,
869d81df DT	228	struct file file, struct file_lock fl)
869d81df DT	229	{
9b47c11d	230	struct gdlm_ls *ls = lockspace;
869d81df DT	231	struct plock_op *op;
	232	int rv;
	233
	234	op = kzalloc(sizeof(*op), GFP_KERNEL);
	235	if (!op)
	236	return -ENOMEM;
	237
	238	op->info.optype = GDLM_PLOCK_OP_GET;
3a2a9c96	239	op->info.pid = fl->fl_pid;
869d81df DT	240	op->info.ex = (fl->fl_type == F_WRLCK);
	241	op->info.fsid = ls->id;
	242	op->info.number = name->ln_number;
	243	op->info.start = fl->fl_start;
	244	op->info.end = fl->fl_end;
d88101d4	245	op->info.owner = (__u64)(long) fl->fl_owner;
586759f0	246
869d81df DT	247	send_op(op);
	248	wait_event(recv_wq, (op->done != 0));
	249
	250	spin_lock(&ops_lock);
	251	if (!list_empty(&op->list)) {
d92a8d48	252	printk(KERN_INFO "plock_get op on list\n");
869d81df DT	253	list_del(&op->list);
	254	}
	255	spin_unlock(&ops_lock);
	256
	257	rv = op->info.rv;
	258
586759f0 ME	259	fl->fl_type = F_UNLCK;
	260	if (rv == -ENOENT)
	261	rv = 0;
	262	else if (rv == 0 && op->info.pid != fl->fl_pid) {
869d81df DT	263	fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
	264	fl->fl_pid = op->info.pid;
	265	fl->fl_start = op->info.start;
	266	fl->fl_end = op->info.end;
	267	}
	268
	269	kfree(op);
	270	return rv;
	271	}
	272
	273	/* a read copies out one plock request from the send list */
	274	static ssize_t dev_read(struct file file, char __user u, size_t count,
	275	loff_t *ppos)
	276	{
	277	struct gdlm_plock_info info;
	278	struct plock_op *op = NULL;
	279
	280	if (count < sizeof(info))
	281	return -EINVAL;
	282
	283	spin_lock(&ops_lock);
	284	if (!list_empty(&send_list)) {
	285	op = list_entry(send_list.next, struct plock_op, list);
	286	list_move(&op->list, &recv_list);
	287	memcpy(&info, &op->info, sizeof(info));
	288	}
	289	spin_unlock(&ops_lock);
	290
	291	if (!op)
	292	return -EAGAIN;
	293
	294	if (copy_to_user(u, &info, sizeof(info)))
	295	return -EFAULT;
	296	return sizeof(info);
	297	}
	298
	299	/* a write copies in one plock result that should match a plock_op
	300	on the recv list */
	301	static ssize_t dev_write(struct file file, const char __user u, size_t count,
	302	loff_t *ppos)
	303	{
	304	struct gdlm_plock_info info;
	305	struct plock_op *op;
	306	int found = 0;
	307
	308	if (count != sizeof(info))
	309	return -EINVAL;
	310
	311	if (copy_from_user(&info, u, sizeof(info)))
	312	return -EFAULT;
	313
	314	if (check_version(&info))
	315	return -EINVAL;
	316
	317	spin_lock(&ops_lock);
	318	list_for_each_entry(op, &recv_list, list) {
9b47c11d	319	if (op->info.fsid == info.fsid && op->info.number == info.number &&
08eac93a	320	op->info.owner == info.owner) {
869d81df DT	321	list_del_init(&op->list);
	322	found = 1;
	323	op->done = 1;
	324	memcpy(&op->info, &info, sizeof(info));
	325	break;
	326	}
	327	}
	328	spin_unlock(&ops_lock);
	329
586759f0 ME	330	if (found) {
	331	struct plock_xop *xop;
	332	xop = (struct plock_xop *)op;
	333	if (xop->callback)
	334	count = gdlm_plock_callback(op);
	335	else
	336	wake_up(&recv_wq);
	337	} else
d92a8d48	338	printk(KERN_INFO "gdlm dev_write no op %x %llx\n", info.fsid,
9229f013	339	(unsigned long long)info.number);
869d81df DT	340	return count;
	341	}
	342
	343	static unsigned int dev_poll(struct file file, poll_table wait)
	344	{
	345	poll_wait(file, &send_wq, wait);
	346
	347	spin_lock(&ops_lock);
	348	if (!list_empty(&send_list)) {
	349	spin_unlock(&ops_lock);
	350	return POLLIN \| POLLRDNORM;
	351	}
	352	spin_unlock(&ops_lock);
	353	return 0;
	354	}
	355
00977a59	356	static const struct file_operations dev_fops = {
869d81df DT	357	.read = dev_read,
	358	.write = dev_write,
	359	.poll = dev_poll,
	360	.owner = THIS_MODULE
	361	};
	362
	363	static struct miscdevice plock_dev_misc = {
	364	.minor = MISC_DYNAMIC_MINOR,
	365	.name = GDLM_PLOCK_MISC_NAME,
	366	.fops = &dev_fops
	367	};
	368
	369	int gdlm_plock_init(void)
	370	{
	371	int rv;
	372
	373	spin_lock_init(&ops_lock);
	374	INIT_LIST_HEAD(&send_list);
	375	INIT_LIST_HEAD(&recv_list);
	376	init_waitqueue_head(&send_wq);
	377	init_waitqueue_head(&recv_wq);
	378
	379	rv = misc_register(&plock_dev_misc);
	380	if (rv)
d92a8d48 SW	381	printk(KERN_INFO "gdlm_plock_init: misc_register failed %d",
d92a8d48 SW	382	rv);
869d81df DT	383	return rv;
	384	}
	385
	386	void gdlm_plock_exit(void)
	387	{
	388	if (misc_deregister(&plock_dev_misc) < 0)
d92a8d48	389	printk(KERN_INFO "gdlm_plock_exit: misc_deregister failed");
869d81df DT	390	}
869d81df DT	391