2 * Copyright (C) 2006-2010 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/dlm.h>
19 #include <linux/dlm_device.h>
20 #include <linux/slab.h>
22 #include "dlm_internal.h"
23 #include "lockspace.h"
25 #include "lvb_table.h"
29 static const char name_prefix[] = "dlm";
30 static const struct file_operations device_fops;
31 static atomic_t dlm_monitor_opened;
32 static int dlm_monitor_unused = 1;
36 struct dlm_lock_params32 {
50 char lvb[DLM_USER_LVB_LEN];
54 struct dlm_write_request32 {
61 struct dlm_lock_params32 lock;
62 struct dlm_lspace_params lspace;
63 struct dlm_purge_params purge;
74 struct dlm_lock_result32 {
80 struct dlm_lksb32 lksb;
83 /* Offsets may be zero if no data is present */
87 static void compat_input(struct dlm_write_request *kb,
88 struct dlm_write_request32 *kb32,
91 kb->version[0] = kb32->version[0];
92 kb->version[1] = kb32->version[1];
93 kb->version[2] = kb32->version[2];
96 kb->is64bit = kb32->is64bit;
97 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
98 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
99 kb->i.lspace.flags = kb32->i.lspace.flags;
100 kb->i.lspace.minor = kb32->i.lspace.minor;
101 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
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, namelen);
123 static void compat_output(struct dlm_lock_result *res,
124 struct dlm_lock_result32 *res32)
126 res32->version[0] = res->version[0];
127 res32->version[1] = res->version[1];
128 res32->version[2] = res->version[2];
130 res32->user_astaddr = (__u32)(long)res->user_astaddr;
131 res32->user_astparam = (__u32)(long)res->user_astparam;
132 res32->user_lksb = (__u32)(long)res->user_lksb;
133 res32->bast_mode = res->bast_mode;
135 res32->lvb_offset = res->lvb_offset;
136 res32->length = res->length;
138 res32->lksb.sb_status = res->lksb.sb_status;
139 res32->lksb.sb_flags = res->lksb.sb_flags;
140 res32->lksb.sb_lkid = res->lksb.sb_lkid;
141 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
145 /* Figure out if this lock is at the end of its life and no longer
146 available for the application to use. The lkb still exists until
147 the final ast is read. A lock becomes EOL in three situations:
148 1. a noqueue request fails with EAGAIN
149 2. an unlock completes with EUNLOCK
150 3. a cancel of a waiting request completes with ECANCEL/EDEADLK
151 An EOL lock needs to be removed from the process's list of locks.
152 And we can't allow any new operation on an EOL lock. This is
153 not related to the lifetime of the lkb struct which is managed
154 entirely by refcount. */
156 static int lkb_is_endoflife(int mode, int status)
165 if (mode == DLM_LOCK_IV)
172 /* we could possibly check if the cancel of an orphan has resulted in the lkb
173 being removed and then remove that lkb from the orphans list and free it */
175 void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
176 int status, uint32_t sbflags, uint64_t seq)
179 struct dlm_user_args *ua;
180 struct dlm_user_proc *proc;
183 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
186 ls = lkb->lkb_resource->res_ls;
187 mutex_lock(&ls->ls_clear_proc_locks);
189 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
190 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
191 lkb->ua so we can't try to use it. This second check is necessary
192 for cases where a completion ast is received for an operation that
193 began before clear_proc_locks did its cancel/unlock. */
195 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
198 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
202 if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL)
205 if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status))
206 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
208 spin_lock(&proc->asts_spin);
210 rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq);
212 spin_unlock(&proc->asts_spin);
216 if (list_empty(&lkb->lkb_cb_list)) {
217 kref_get(&lkb->lkb_ref);
218 list_add_tail(&lkb->lkb_cb_list, &proc->asts);
219 wake_up_interruptible(&proc->wait);
221 spin_unlock(&proc->asts_spin);
223 if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
224 /* N.B. spin_lock locks_spin, not asts_spin */
225 spin_lock(&proc->locks_spin);
226 if (!list_empty(&lkb->lkb_ownqueue)) {
227 list_del_init(&lkb->lkb_ownqueue);
230 spin_unlock(&proc->locks_spin);
233 mutex_unlock(&ls->ls_clear_proc_locks);
236 static int device_user_lock(struct dlm_user_proc *proc,
237 struct dlm_lock_params *params)
240 struct dlm_user_args *ua;
244 ls = dlm_find_lockspace_local(proc->lockspace);
248 if (!params->castaddr || !params->lksb) {
253 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
257 ua->user_lksb = params->lksb;
258 ua->castparam = params->castparam;
259 ua->castaddr = params->castaddr;
260 ua->bastparam = params->bastparam;
261 ua->bastaddr = params->bastaddr;
262 ua->xid = params->xid;
264 if (params->flags & DLM_LKF_CONVERT) {
265 error = dlm_user_convert(ls, ua,
266 params->mode, params->flags,
267 params->lkid, params->lvb,
268 (unsigned long) params->timeout);
269 } else if (params->flags & DLM_LKF_ORPHAN) {
270 error = dlm_user_adopt_orphan(ls, ua,
271 params->mode, params->flags,
272 params->name, params->namelen,
273 (unsigned long) params->timeout,
278 error = dlm_user_request(ls, ua,
279 params->mode, params->flags,
280 params->name, params->namelen,
281 (unsigned long) params->timeout);
283 error = ua->lksb.sb_lkid;
286 dlm_put_lockspace(ls);
290 static int device_user_unlock(struct dlm_user_proc *proc,
291 struct dlm_lock_params *params)
294 struct dlm_user_args *ua;
297 ls = dlm_find_lockspace_local(proc->lockspace);
301 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
305 ua->user_lksb = params->lksb;
306 ua->castparam = params->castparam;
307 ua->castaddr = params->castaddr;
309 if (params->flags & DLM_LKF_CANCEL)
310 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
312 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
315 dlm_put_lockspace(ls);
319 static int device_user_deadlock(struct dlm_user_proc *proc,
320 struct dlm_lock_params *params)
325 ls = dlm_find_lockspace_local(proc->lockspace);
329 error = dlm_user_deadlock(ls, params->flags, params->lkid);
331 dlm_put_lockspace(ls);
335 static int dlm_device_register(struct dlm_ls *ls, char *name)
339 /* The device is already registered. This happens when the
340 lockspace is created multiple times from userspace. */
341 if (ls->ls_device.name)
345 len = strlen(name) + strlen(name_prefix) + 2;
346 ls->ls_device.name = kzalloc(len, GFP_NOFS);
347 if (!ls->ls_device.name)
350 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
352 ls->ls_device.fops = &device_fops;
353 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
355 error = misc_register(&ls->ls_device);
357 kfree(ls->ls_device.name);
358 /* this has to be set to NULL
359 * to avoid a double-free in dlm_device_deregister
361 ls->ls_device.name = NULL;
367 int dlm_device_deregister(struct dlm_ls *ls)
369 /* The device is not registered. This happens when the lockspace
370 was never used from userspace, or when device_create_lockspace()
371 calls dlm_release_lockspace() after the register fails. */
372 if (!ls->ls_device.name)
375 misc_deregister(&ls->ls_device);
376 kfree(ls->ls_device.name);
380 static int device_user_purge(struct dlm_user_proc *proc,
381 struct dlm_purge_params *params)
386 ls = dlm_find_lockspace_local(proc->lockspace);
390 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
392 dlm_put_lockspace(ls);
396 static int device_create_lockspace(struct dlm_lspace_params *params)
398 dlm_lockspace_t *lockspace;
402 if (!capable(CAP_SYS_ADMIN))
405 error = dlm_new_lockspace(params->name, NULL, params->flags,
406 DLM_USER_LVB_LEN, NULL, NULL, NULL,
411 ls = dlm_find_lockspace_local(lockspace);
415 error = dlm_device_register(ls, params->name);
416 dlm_put_lockspace(ls);
419 dlm_release_lockspace(lockspace, 0);
421 error = ls->ls_device.minor;
426 static int device_remove_lockspace(struct dlm_lspace_params *params)
428 dlm_lockspace_t *lockspace;
430 int error, force = 0;
432 if (!capable(CAP_SYS_ADMIN))
435 ls = dlm_find_lockspace_device(params->minor);
439 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
442 lockspace = ls->ls_local_handle;
443 dlm_put_lockspace(ls);
445 /* The final dlm_release_lockspace waits for references to go to
446 zero, so all processes will need to close their device for the
447 ls before the release will proceed. release also calls the
448 device_deregister above. Converting a positive return value
449 from release to zero means that userspace won't know when its
450 release was the final one, but it shouldn't need to know. */
452 error = dlm_release_lockspace(lockspace, force);
458 /* Check the user's version matches ours */
459 static int check_version(struct dlm_write_request *req)
461 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
462 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
463 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
465 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
466 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
468 task_pid_nr(current),
472 DLM_DEVICE_VERSION_MAJOR,
473 DLM_DEVICE_VERSION_MINOR,
474 DLM_DEVICE_VERSION_PATCH);
484 * dlm_user_request -> request_lock
485 * dlm_user_convert -> convert_lock
488 * dlm_user_unlock -> unlock_lock
489 * dlm_user_cancel -> cancel_lock
491 * device_create_lockspace
494 * device_remove_lockspace
495 * dlm_release_lockspace
498 /* a write to a lockspace device is a lock or unlock request, a write
499 to the control device is to create/remove a lockspace */
501 static ssize_t device_write(struct file *file, const char __user *buf,
502 size_t count, loff_t *ppos)
504 struct dlm_user_proc *proc = file->private_data;
505 struct dlm_write_request *kbuf;
509 if (count < sizeof(struct dlm_write_request32))
511 if (count < sizeof(struct dlm_write_request))
516 * can't compare against COMPAT/dlm_write_request32 because
517 * we don't yet know if is64bit is zero
519 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
522 kbuf = kzalloc(count + 1, GFP_NOFS);
526 if (copy_from_user(kbuf, buf, count)) {
531 if (check_version(kbuf)) {
537 if (!kbuf->is64bit) {
538 struct dlm_write_request32 *k32buf;
541 if (count > sizeof(struct dlm_write_request32))
542 namelen = count - sizeof(struct dlm_write_request32);
544 k32buf = (struct dlm_write_request32 *)kbuf;
546 /* add 1 after namelen so that the name string is terminated */
547 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
555 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
557 compat_input(kbuf, k32buf, namelen);
562 /* do we really need this? can a write happen after a close? */
563 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
564 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
575 log_print("no locking on control device");
578 error = device_user_lock(proc, &kbuf->i.lock);
581 case DLM_USER_UNLOCK:
583 log_print("no locking on control device");
586 error = device_user_unlock(proc, &kbuf->i.lock);
589 case DLM_USER_DEADLOCK:
591 log_print("no locking on control device");
594 error = device_user_deadlock(proc, &kbuf->i.lock);
597 case DLM_USER_CREATE_LOCKSPACE:
599 log_print("create/remove only on control device");
602 error = device_create_lockspace(&kbuf->i.lspace);
605 case DLM_USER_REMOVE_LOCKSPACE:
607 log_print("create/remove only on control device");
610 error = device_remove_lockspace(&kbuf->i.lspace);
615 log_print("no locking on control device");
618 error = device_user_purge(proc, &kbuf->i.purge);
622 log_print("Unknown command passed to DLM device : %d\n",
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;
640 ls = dlm_find_lockspace_device(iminor(inode));
644 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
646 dlm_put_lockspace(ls);
650 proc->lockspace = ls->ls_local_handle;
651 INIT_LIST_HEAD(&proc->asts);
652 INIT_LIST_HEAD(&proc->locks);
653 INIT_LIST_HEAD(&proc->unlocking);
654 spin_lock_init(&proc->asts_spin);
655 spin_lock_init(&proc->locks_spin);
656 init_waitqueue_head(&proc->wait);
657 file->private_data = proc;
662 static int device_close(struct inode *inode, struct file *file)
664 struct dlm_user_proc *proc = file->private_data;
667 ls = dlm_find_lockspace_local(proc->lockspace);
671 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
673 dlm_clear_proc_locks(ls, proc);
675 /* at this point no more lkb's should exist for this lockspace,
676 so there's no chance of dlm_user_add_ast() being called and
677 looking for lkb->ua->proc */
680 file->private_data = NULL;
682 dlm_put_lockspace(ls);
683 dlm_put_lockspace(ls); /* for the find in device_open() */
685 /* FIXME: AUTOFREE: if this ls is no longer used do
686 device_remove_lockspace() */
691 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
692 uint32_t flags, int mode, int copy_lvb,
693 char __user *buf, size_t count)
696 struct dlm_lock_result32 result32;
698 struct dlm_lock_result result;
704 memset(&result, 0, sizeof(struct dlm_lock_result));
705 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
706 result.version[1] = DLM_DEVICE_VERSION_MINOR;
707 result.version[2] = DLM_DEVICE_VERSION_PATCH;
708 memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr));
709 result.user_lksb = ua->user_lksb;
711 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
712 in a conversion unless the conversion is successful. See code
713 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
714 notes that a new blocking AST address and parameter are set even if
715 the conversion fails, so maybe we should just do that. */
717 if (flags & DLM_CB_BAST) {
718 result.user_astaddr = ua->bastaddr;
719 result.user_astparam = ua->bastparam;
720 result.bast_mode = mode;
722 result.user_astaddr = ua->castaddr;
723 result.user_astparam = ua->castparam;
728 len = sizeof(struct dlm_lock_result32);
731 len = sizeof(struct dlm_lock_result);
734 /* copy lvb to userspace if there is one, it's been updated, and
735 the user buffer has space for it */
737 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
738 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
744 result.lvb_offset = len;
745 len += DLM_USER_LVB_LEN;
752 compat_output(&result, &result32);
753 resultptr = &result32;
757 if (copy_to_user(buf, resultptr, struct_len))
765 static int copy_version_to_user(char __user *buf, size_t count)
767 struct dlm_device_version ver;
769 memset(&ver, 0, sizeof(struct dlm_device_version));
770 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
771 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
772 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
774 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
776 return sizeof(struct dlm_device_version);
779 /* a read returns a single ast described in a struct dlm_lock_result */
781 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
784 struct dlm_user_proc *proc = file->private_data;
786 DECLARE_WAITQUEUE(wait, current);
787 struct dlm_callback cb;
788 int rv, resid, copy_lvb = 0;
789 int old_mode, new_mode;
791 if (count == sizeof(struct dlm_device_version)) {
792 rv = copy_version_to_user(buf, count);
797 log_print("non-version read from control device %zu", count);
802 if (count < sizeof(struct dlm_lock_result32))
804 if (count < sizeof(struct dlm_lock_result))
810 /* do we really need this? can a read happen after a close? */
811 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
814 spin_lock(&proc->asts_spin);
815 if (list_empty(&proc->asts)) {
816 if (file->f_flags & O_NONBLOCK) {
817 spin_unlock(&proc->asts_spin);
821 add_wait_queue(&proc->wait, &wait);
824 set_current_state(TASK_INTERRUPTIBLE);
825 if (list_empty(&proc->asts) && !signal_pending(current)) {
826 spin_unlock(&proc->asts_spin);
828 spin_lock(&proc->asts_spin);
831 set_current_state(TASK_RUNNING);
832 remove_wait_queue(&proc->wait, &wait);
834 if (signal_pending(current)) {
835 spin_unlock(&proc->asts_spin);
840 /* if we empty lkb_callbacks, we don't want to unlock the spinlock
841 without removing lkb_cb_list; so empty lkb_cb_list is always
842 consistent with empty lkb_callbacks */
844 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
846 /* rem_lkb_callback sets a new lkb_last_cast */
847 old_mode = lkb->lkb_last_cast.mode;
849 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
851 /* this shouldn't happen; lkb should have been removed from
852 list when resid was zero */
853 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
854 list_del_init(&lkb->lkb_cb_list);
855 spin_unlock(&proc->asts_spin);
856 /* removes ref for proc->asts, may cause lkb to be freed */
861 list_del_init(&lkb->lkb_cb_list);
862 spin_unlock(&proc->asts_spin);
864 if (cb.flags & DLM_CB_SKIP) {
865 /* removes ref for proc->asts, may cause lkb to be freed */
871 if (cb.flags & DLM_CB_CAST) {
874 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
875 dlm_lvb_operations[old_mode + 1][new_mode + 1])
878 lkb->lkb_lksb->sb_status = cb.sb_status;
879 lkb->lkb_lksb->sb_flags = cb.sb_flags;
882 rv = copy_result_to_user(lkb->lkb_ua,
883 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
884 cb.flags, cb.mode, copy_lvb, buf, count);
886 /* removes ref for proc->asts, may cause lkb to be freed */
893 static unsigned int device_poll(struct file *file, poll_table *wait)
895 struct dlm_user_proc *proc = file->private_data;
897 poll_wait(file, &proc->wait, wait);
899 spin_lock(&proc->asts_spin);
900 if (!list_empty(&proc->asts)) {
901 spin_unlock(&proc->asts_spin);
902 return POLLIN | POLLRDNORM;
904 spin_unlock(&proc->asts_spin);
908 int dlm_user_daemon_available(void)
910 /* dlm_controld hasn't started (or, has started, but not
911 properly populated configfs) */
913 if (!dlm_our_nodeid())
916 /* This is to deal with versions of dlm_controld that don't
917 know about the monitor device. We assume that if the
918 dlm_controld was started (above), but the monitor device
919 was never opened, that it's an old version. dlm_controld
920 should open the monitor device before populating configfs. */
922 if (dlm_monitor_unused)
925 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
928 static int ctl_device_open(struct inode *inode, struct file *file)
930 file->private_data = NULL;
934 static int ctl_device_close(struct inode *inode, struct file *file)
939 static int monitor_device_open(struct inode *inode, struct file *file)
941 atomic_inc(&dlm_monitor_opened);
942 dlm_monitor_unused = 0;
946 static int monitor_device_close(struct inode *inode, struct file *file)
948 if (atomic_dec_and_test(&dlm_monitor_opened))
949 dlm_stop_lockspaces();
953 static const struct file_operations device_fops = {
955 .release = device_close,
957 .write = device_write,
959 .owner = THIS_MODULE,
960 .llseek = noop_llseek,
963 static const struct file_operations ctl_device_fops = {
964 .open = ctl_device_open,
965 .release = ctl_device_close,
967 .write = device_write,
968 .owner = THIS_MODULE,
969 .llseek = noop_llseek,
972 static struct miscdevice ctl_device = {
973 .name = "dlm-control",
974 .fops = &ctl_device_fops,
975 .minor = MISC_DYNAMIC_MINOR,
978 static const struct file_operations monitor_device_fops = {
979 .open = monitor_device_open,
980 .release = monitor_device_close,
981 .owner = THIS_MODULE,
982 .llseek = noop_llseek,
985 static struct miscdevice monitor_device = {
986 .name = "dlm-monitor",
987 .fops = &monitor_device_fops,
988 .minor = MISC_DYNAMIC_MINOR,
991 int __init dlm_user_init(void)
995 atomic_set(&dlm_monitor_opened, 0);
997 error = misc_register(&ctl_device);
999 log_print("misc_register failed for control device");
1003 error = misc_register(&monitor_device);
1005 log_print("misc_register failed for monitor device");
1006 misc_deregister(&ctl_device);
1012 void dlm_user_exit(void)
1014 misc_deregister(&ctl_device);
1015 misc_deregister(&monitor_device);