2 * Copyright (C) 2006-2008 Red Hat, Inc. All rights reserved.
4 * This copyrighted material is made available to anyone wishing to use,
5 * modify, copy, or redistribute it subject to the terms and conditions
6 * of the GNU General Public License v.2.
9 #include <linux/miscdevice.h>
10 #include <linux/init.h>
11 #include <linux/wait.h>
12 #include <linux/module.h>
13 #include <linux/file.h>
15 #include <linux/poll.h>
16 #include <linux/signal.h>
17 #include <linux/spinlock.h>
18 #include <linux/smp_lock.h>
19 #include <linux/dlm.h>
20 #include <linux/dlm_device.h>
22 #include "dlm_internal.h"
23 #include "lockspace.h"
25 #include "lvb_table.h"
28 static const char name_prefix[] = "dlm";
29 static const struct file_operations device_fops;
30 static atomic_t dlm_monitor_opened;
31 static int dlm_monitor_unused = 1;
35 struct dlm_lock_params32 {
49 char lvb[DLM_USER_LVB_LEN];
53 struct dlm_write_request32 {
60 struct dlm_lock_params32 lock;
61 struct dlm_lspace_params lspace;
62 struct dlm_purge_params purge;
73 struct dlm_lock_result32 {
79 struct dlm_lksb32 lksb;
82 /* Offsets may be zero if no data is present */
86 static void compat_input(struct dlm_write_request *kb,
87 struct dlm_write_request32 *kb32,
90 kb->version[0] = kb32->version[0];
91 kb->version[1] = kb32->version[1];
92 kb->version[2] = kb32->version[2];
95 kb->is64bit = kb32->is64bit;
96 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
97 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
98 kb->i.lspace.flags = kb32->i.lspace.flags;
99 kb->i.lspace.minor = kb32->i.lspace.minor;
100 memcpy(kb->i.lspace.name, kb32->i.lspace.name, count -
101 offsetof(struct dlm_write_request32, i.lspace.name));
102 } else if (kb->cmd == DLM_USER_PURGE) {
103 kb->i.purge.nodeid = kb32->i.purge.nodeid;
104 kb->i.purge.pid = kb32->i.purge.pid;
106 kb->i.lock.mode = kb32->i.lock.mode;
107 kb->i.lock.namelen = kb32->i.lock.namelen;
108 kb->i.lock.flags = kb32->i.lock.flags;
109 kb->i.lock.lkid = kb32->i.lock.lkid;
110 kb->i.lock.parent = kb32->i.lock.parent;
111 kb->i.lock.xid = kb32->i.lock.xid;
112 kb->i.lock.timeout = kb32->i.lock.timeout;
113 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
114 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
115 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
116 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
117 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
118 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
119 memcpy(kb->i.lock.name, kb32->i.lock.name, count -
120 offsetof(struct dlm_write_request32, i.lock.name));
124 static void compat_output(struct dlm_lock_result *res,
125 struct dlm_lock_result32 *res32)
127 res32->version[0] = res->version[0];
128 res32->version[1] = res->version[1];
129 res32->version[2] = res->version[2];
131 res32->user_astaddr = (__u32)(long)res->user_astaddr;
132 res32->user_astparam = (__u32)(long)res->user_astparam;
133 res32->user_lksb = (__u32)(long)res->user_lksb;
134 res32->bast_mode = res->bast_mode;
136 res32->lvb_offset = res->lvb_offset;
137 res32->length = res->length;
139 res32->lksb.sb_status = res->lksb.sb_status;
140 res32->lksb.sb_flags = res->lksb.sb_flags;
141 res32->lksb.sb_lkid = res->lksb.sb_lkid;
142 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
146 /* Figure out if this lock is at the end of its life and no longer
147 available for the application to use. The lkb still exists until
148 the final ast is read. A lock becomes EOL in three situations:
149 1. a noqueue request fails with EAGAIN
150 2. an unlock completes with EUNLOCK
151 3. a cancel of a waiting request completes with ECANCEL/EDEADLK
152 An EOL lock needs to be removed from the process's list of locks.
153 And we can't allow any new operation on an EOL lock. This is
154 not related to the lifetime of the lkb struct which is managed
155 entirely by refcount. */
157 static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type)
165 if (lkb->lkb_grmode == DLM_LOCK_IV)
169 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV)
176 /* we could possibly check if the cancel of an orphan has resulted in the lkb
177 being removed and then remove that lkb from the orphans list and free it */
179 void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
182 struct dlm_user_args *ua;
183 struct dlm_user_proc *proc;
184 int eol = 0, ast_type;
186 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
189 ls = lkb->lkb_resource->res_ls;
190 mutex_lock(&ls->ls_clear_proc_locks);
192 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
193 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
194 lkb->ua so we can't try to use it. This second check is necessary
195 for cases where a completion ast is received for an operation that
196 began before clear_proc_locks did its cancel/unlock. */
198 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
201 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
205 if (type == AST_BAST && ua->bastaddr == NULL)
208 spin_lock(&proc->asts_spin);
210 ast_type = lkb->lkb_ast_type;
211 lkb->lkb_ast_type |= type;
214 kref_get(&lkb->lkb_ref);
215 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
216 wake_up_interruptible(&proc->wait);
218 if (type == AST_COMP && (ast_type & AST_COMP))
219 log_debug(ls, "ast overlap %x status %x %x",
220 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
222 eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
224 lkb->lkb_ast_type &= ~AST_BAST;
225 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
228 /* We want to copy the lvb to userspace when the completion
229 ast is read if the status is 0, the lock has an lvb and
230 lvb_ops says we should. We could probably have set_lvb_lock()
231 set update_user_lvb instead and not need old_mode */
233 if ((lkb->lkb_ast_type & AST_COMP) &&
234 (lkb->lkb_lksb->sb_status == 0) &&
235 lkb->lkb_lksb->sb_lvbptr &&
236 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
237 ua->update_user_lvb = 1;
239 ua->update_user_lvb = 0;
241 spin_unlock(&proc->asts_spin);
244 spin_lock(&proc->locks_spin);
245 if (!list_empty(&lkb->lkb_ownqueue)) {
246 list_del_init(&lkb->lkb_ownqueue);
249 spin_unlock(&proc->locks_spin);
252 mutex_unlock(&ls->ls_clear_proc_locks);
255 static int device_user_lock(struct dlm_user_proc *proc,
256 struct dlm_lock_params *params)
259 struct dlm_user_args *ua;
262 ls = dlm_find_lockspace_local(proc->lockspace);
266 if (!params->castaddr || !params->lksb) {
271 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
275 ua->user_lksb = params->lksb;
276 ua->castparam = params->castparam;
277 ua->castaddr = params->castaddr;
278 ua->bastparam = params->bastparam;
279 ua->bastaddr = params->bastaddr;
280 ua->xid = params->xid;
282 if (params->flags & DLM_LKF_CONVERT)
283 error = dlm_user_convert(ls, ua,
284 params->mode, params->flags,
285 params->lkid, params->lvb,
286 (unsigned long) params->timeout);
288 error = dlm_user_request(ls, ua,
289 params->mode, params->flags,
290 params->name, params->namelen,
291 (unsigned long) params->timeout);
293 error = ua->lksb.sb_lkid;
296 dlm_put_lockspace(ls);
300 static int device_user_unlock(struct dlm_user_proc *proc,
301 struct dlm_lock_params *params)
304 struct dlm_user_args *ua;
307 ls = dlm_find_lockspace_local(proc->lockspace);
311 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
315 ua->user_lksb = params->lksb;
316 ua->castparam = params->castparam;
317 ua->castaddr = params->castaddr;
319 if (params->flags & DLM_LKF_CANCEL)
320 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
322 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
325 dlm_put_lockspace(ls);
329 static int device_user_deadlock(struct dlm_user_proc *proc,
330 struct dlm_lock_params *params)
335 ls = dlm_find_lockspace_local(proc->lockspace);
339 error = dlm_user_deadlock(ls, params->flags, params->lkid);
341 dlm_put_lockspace(ls);
345 static int dlm_device_register(struct dlm_ls *ls, char *name)
349 /* The device is already registered. This happens when the
350 lockspace is created multiple times from userspace. */
351 if (ls->ls_device.name)
355 len = strlen(name) + strlen(name_prefix) + 2;
356 ls->ls_device.name = kzalloc(len, GFP_KERNEL);
357 if (!ls->ls_device.name)
360 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
362 ls->ls_device.fops = &device_fops;
363 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
365 error = misc_register(&ls->ls_device);
367 kfree(ls->ls_device.name);
373 int dlm_device_deregister(struct dlm_ls *ls)
377 /* The device is not registered. This happens when the lockspace
378 was never used from userspace, or when device_create_lockspace()
379 calls dlm_release_lockspace() after the register fails. */
380 if (!ls->ls_device.name)
383 error = misc_deregister(&ls->ls_device);
385 kfree(ls->ls_device.name);
389 static int device_user_purge(struct dlm_user_proc *proc,
390 struct dlm_purge_params *params)
395 ls = dlm_find_lockspace_local(proc->lockspace);
399 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
401 dlm_put_lockspace(ls);
405 static int device_create_lockspace(struct dlm_lspace_params *params)
407 dlm_lockspace_t *lockspace;
411 if (!capable(CAP_SYS_ADMIN))
414 error = dlm_new_lockspace(params->name, strlen(params->name),
415 &lockspace, params->flags, DLM_USER_LVB_LEN);
419 ls = dlm_find_lockspace_local(lockspace);
423 error = dlm_device_register(ls, params->name);
424 dlm_put_lockspace(ls);
427 dlm_release_lockspace(lockspace, 0);
429 error = ls->ls_device.minor;
434 static int device_remove_lockspace(struct dlm_lspace_params *params)
436 dlm_lockspace_t *lockspace;
438 int error, force = 0;
440 if (!capable(CAP_SYS_ADMIN))
443 ls = dlm_find_lockspace_device(params->minor);
447 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
450 lockspace = ls->ls_local_handle;
451 dlm_put_lockspace(ls);
453 /* The final dlm_release_lockspace waits for references to go to
454 zero, so all processes will need to close their device for the
455 ls before the release will proceed. release also calls the
456 device_deregister above. Converting a positive return value
457 from release to zero means that userspace won't know when its
458 release was the final one, but it shouldn't need to know. */
460 error = dlm_release_lockspace(lockspace, force);
466 /* Check the user's version matches ours */
467 static int check_version(struct dlm_write_request *req)
469 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
470 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
471 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
473 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
474 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
476 task_pid_nr(current),
480 DLM_DEVICE_VERSION_MAJOR,
481 DLM_DEVICE_VERSION_MINOR,
482 DLM_DEVICE_VERSION_PATCH);
492 * dlm_user_request -> request_lock
493 * dlm_user_convert -> convert_lock
496 * dlm_user_unlock -> unlock_lock
497 * dlm_user_cancel -> cancel_lock
499 * device_create_lockspace
502 * device_remove_lockspace
503 * dlm_release_lockspace
506 /* a write to a lockspace device is a lock or unlock request, a write
507 to the control device is to create/remove a lockspace */
509 static ssize_t device_write(struct file *file, const char __user *buf,
510 size_t count, loff_t *ppos)
512 struct dlm_user_proc *proc = file->private_data;
513 struct dlm_write_request *kbuf;
514 sigset_t tmpsig, allsigs;
518 if (count < sizeof(struct dlm_write_request32))
520 if (count < sizeof(struct dlm_write_request))
524 kbuf = kzalloc(count + 1, GFP_KERNEL);
528 if (copy_from_user(kbuf, buf, count)) {
533 if (check_version(kbuf)) {
539 if (!kbuf->is64bit) {
540 struct dlm_write_request32 *k32buf;
541 k32buf = (struct dlm_write_request32 *)kbuf;
542 kbuf = kmalloc(count + 1 + (sizeof(struct dlm_write_request) -
543 sizeof(struct dlm_write_request32)), GFP_KERNEL);
550 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
551 compat_input(kbuf, k32buf, count + 1);
556 /* do we really need this? can a write happen after a close? */
557 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
558 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
563 sigfillset(&allsigs);
564 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
572 log_print("no locking on control device");
575 error = device_user_lock(proc, &kbuf->i.lock);
578 case DLM_USER_UNLOCK:
580 log_print("no locking on control device");
583 error = device_user_unlock(proc, &kbuf->i.lock);
586 case DLM_USER_DEADLOCK:
588 log_print("no locking on control device");
591 error = device_user_deadlock(proc, &kbuf->i.lock);
594 case DLM_USER_CREATE_LOCKSPACE:
596 log_print("create/remove only on control device");
599 error = device_create_lockspace(&kbuf->i.lspace);
602 case DLM_USER_REMOVE_LOCKSPACE:
604 log_print("create/remove only on control device");
607 error = device_remove_lockspace(&kbuf->i.lspace);
612 log_print("no locking on control device");
615 error = device_user_purge(proc, &kbuf->i.purge);
619 log_print("Unknown command passed to DLM device : %d\n",
624 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
631 /* Every process that opens the lockspace device has its own "proc" structure
632 hanging off the open file that's used to keep track of locks owned by the
633 process and asts that need to be delivered to the process. */
635 static int device_open(struct inode *inode, struct file *file)
637 struct dlm_user_proc *proc;
641 ls = dlm_find_lockspace_device(iminor(inode));
647 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
649 dlm_put_lockspace(ls);
654 proc->lockspace = ls->ls_local_handle;
655 INIT_LIST_HEAD(&proc->asts);
656 INIT_LIST_HEAD(&proc->locks);
657 INIT_LIST_HEAD(&proc->unlocking);
658 spin_lock_init(&proc->asts_spin);
659 spin_lock_init(&proc->locks_spin);
660 init_waitqueue_head(&proc->wait);
661 file->private_data = proc;
667 static int device_close(struct inode *inode, struct file *file)
669 struct dlm_user_proc *proc = file->private_data;
671 sigset_t tmpsig, allsigs;
673 ls = dlm_find_lockspace_local(proc->lockspace);
677 sigfillset(&allsigs);
678 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
680 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
682 dlm_clear_proc_locks(ls, proc);
684 /* at this point no more lkb's should exist for this lockspace,
685 so there's no chance of dlm_user_add_ast() being called and
686 looking for lkb->ua->proc */
689 file->private_data = NULL;
691 dlm_put_lockspace(ls);
692 dlm_put_lockspace(ls); /* for the find in device_open() */
694 /* FIXME: AUTOFREE: if this ls is no longer used do
695 device_remove_lockspace() */
697 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
703 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
704 int bmode, char __user *buf, size_t count)
707 struct dlm_lock_result32 result32;
709 struct dlm_lock_result result;
715 memset(&result, 0, sizeof(struct dlm_lock_result));
716 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
717 result.version[1] = DLM_DEVICE_VERSION_MINOR;
718 result.version[2] = DLM_DEVICE_VERSION_PATCH;
719 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
720 result.user_lksb = ua->user_lksb;
722 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
723 in a conversion unless the conversion is successful. See code
724 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
725 notes that a new blocking AST address and parameter are set even if
726 the conversion fails, so maybe we should just do that. */
728 if (type == AST_BAST) {
729 result.user_astaddr = ua->bastaddr;
730 result.user_astparam = ua->bastparam;
731 result.bast_mode = bmode;
733 result.user_astaddr = ua->castaddr;
734 result.user_astparam = ua->castparam;
739 len = sizeof(struct dlm_lock_result32);
742 len = sizeof(struct dlm_lock_result);
745 /* copy lvb to userspace if there is one, it's been updated, and
746 the user buffer has space for it */
748 if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
749 count >= len + DLM_USER_LVB_LEN) {
750 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
756 result.lvb_offset = len;
757 len += DLM_USER_LVB_LEN;
764 compat_output(&result, &result32);
765 resultptr = &result32;
769 if (copy_to_user(buf, resultptr, struct_len))
777 static int copy_version_to_user(char __user *buf, size_t count)
779 struct dlm_device_version ver;
781 memset(&ver, 0, sizeof(struct dlm_device_version));
782 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
783 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
784 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
786 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
788 return sizeof(struct dlm_device_version);
791 /* a read returns a single ast described in a struct dlm_lock_result */
793 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
796 struct dlm_user_proc *proc = file->private_data;
798 DECLARE_WAITQUEUE(wait, current);
799 int error, type=0, bmode=0, removed = 0;
801 if (count == sizeof(struct dlm_device_version)) {
802 error = copy_version_to_user(buf, count);
807 log_print("non-version read from control device %zu", count);
812 if (count < sizeof(struct dlm_lock_result32))
814 if (count < sizeof(struct dlm_lock_result))
818 /* do we really need this? can a read happen after a close? */
819 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
822 spin_lock(&proc->asts_spin);
823 if (list_empty(&proc->asts)) {
824 if (file->f_flags & O_NONBLOCK) {
825 spin_unlock(&proc->asts_spin);
829 add_wait_queue(&proc->wait, &wait);
832 set_current_state(TASK_INTERRUPTIBLE);
833 if (list_empty(&proc->asts) && !signal_pending(current)) {
834 spin_unlock(&proc->asts_spin);
836 spin_lock(&proc->asts_spin);
839 set_current_state(TASK_RUNNING);
840 remove_wait_queue(&proc->wait, &wait);
842 if (signal_pending(current)) {
843 spin_unlock(&proc->asts_spin);
848 /* there may be both completion and blocking asts to return for
849 the lkb, don't remove lkb from asts list unless no asts remain */
851 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
853 if (lkb->lkb_ast_type & AST_COMP) {
854 lkb->lkb_ast_type &= ~AST_COMP;
856 } else if (lkb->lkb_ast_type & AST_BAST) {
857 lkb->lkb_ast_type &= ~AST_BAST;
859 bmode = lkb->lkb_bastmode;
862 if (!lkb->lkb_ast_type) {
863 list_del(&lkb->lkb_astqueue);
866 spin_unlock(&proc->asts_spin);
868 error = copy_result_to_user(lkb->lkb_ua,
869 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
870 type, bmode, buf, count);
872 /* removes reference for the proc->asts lists added by
873 dlm_user_add_ast() and may result in the lkb being freed */
880 static unsigned int device_poll(struct file *file, poll_table *wait)
882 struct dlm_user_proc *proc = file->private_data;
884 poll_wait(file, &proc->wait, wait);
886 spin_lock(&proc->asts_spin);
887 if (!list_empty(&proc->asts)) {
888 spin_unlock(&proc->asts_spin);
889 return POLLIN | POLLRDNORM;
891 spin_unlock(&proc->asts_spin);
895 int dlm_user_daemon_available(void)
897 /* dlm_controld hasn't started (or, has started, but not
898 properly populated configfs) */
900 if (!dlm_our_nodeid())
903 /* This is to deal with versions of dlm_controld that don't
904 know about the monitor device. We assume that if the
905 dlm_controld was started (above), but the monitor device
906 was never opened, that it's an old version. dlm_controld
907 should open the monitor device before populating configfs. */
909 if (dlm_monitor_unused)
912 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
915 static int ctl_device_open(struct inode *inode, struct file *file)
918 file->private_data = NULL;
922 static int ctl_device_close(struct inode *inode, struct file *file)
927 static int monitor_device_open(struct inode *inode, struct file *file)
929 atomic_inc(&dlm_monitor_opened);
930 dlm_monitor_unused = 0;
934 static int monitor_device_close(struct inode *inode, struct file *file)
936 if (atomic_dec_and_test(&dlm_monitor_opened))
937 dlm_stop_lockspaces();
941 static const struct file_operations device_fops = {
943 .release = device_close,
945 .write = device_write,
947 .owner = THIS_MODULE,
950 static const struct file_operations ctl_device_fops = {
951 .open = ctl_device_open,
952 .release = ctl_device_close,
954 .write = device_write,
955 .owner = THIS_MODULE,
958 static struct miscdevice ctl_device = {
959 .name = "dlm-control",
960 .fops = &ctl_device_fops,
961 .minor = MISC_DYNAMIC_MINOR,
964 static const struct file_operations monitor_device_fops = {
965 .open = monitor_device_open,
966 .release = monitor_device_close,
967 .owner = THIS_MODULE,
970 static struct miscdevice monitor_device = {
971 .name = "dlm-monitor",
972 .fops = &monitor_device_fops,
973 .minor = MISC_DYNAMIC_MINOR,
976 int __init dlm_user_init(void)
980 atomic_set(&dlm_monitor_opened, 0);
982 error = misc_register(&ctl_device);
984 log_print("misc_register failed for control device");
988 error = misc_register(&monitor_device);
990 log_print("misc_register failed for monitor device");
991 misc_deregister(&ctl_device);
997 void dlm_user_exit(void)
999 misc_deregister(&ctl_device);
1000 misc_deregister(&monitor_device);