1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2006-2010 Red Hat, Inc. All rights reserved.
6 #include <linux/miscdevice.h>
7 #include <linux/init.h>
8 #include <linux/wait.h>
9 #include <linux/file.h>
11 #include <linux/poll.h>
12 #include <linux/signal.h>
13 #include <linux/spinlock.h>
14 #include <linux/dlm.h>
15 #include <linux/dlm_device.h>
16 #include <linux/slab.h>
17 #include <linux/sched/signal.h>
19 #include "dlm_internal.h"
20 #include "lockspace.h"
22 #include "lvb_table.h"
27 static const char name_prefix[] = "dlm";
28 static const struct file_operations device_fops;
29 static atomic_t dlm_monitor_opened;
30 static int dlm_monitor_unused = 1;
34 struct dlm_lock_params32 {
48 char lvb[DLM_USER_LVB_LEN];
52 struct dlm_write_request32 {
59 struct dlm_lock_params32 lock;
60 struct dlm_lspace_params lspace;
61 struct dlm_purge_params purge;
72 struct dlm_lock_result32 {
78 struct dlm_lksb32 lksb;
81 /* Offsets may be zero if no data is present */
85 static void compat_input(struct dlm_write_request *kb,
86 struct dlm_write_request32 *kb32,
89 kb->version[0] = kb32->version[0];
90 kb->version[1] = kb32->version[1];
91 kb->version[2] = kb32->version[2];
94 kb->is64bit = kb32->is64bit;
95 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
96 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
97 kb->i.lspace.flags = kb32->i.lspace.flags;
98 kb->i.lspace.minor = kb32->i.lspace.minor;
99 memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
100 } else if (kb->cmd == DLM_USER_PURGE) {
101 kb->i.purge.nodeid = kb32->i.purge.nodeid;
102 kb->i.purge.pid = kb32->i.purge.pid;
104 kb->i.lock.mode = kb32->i.lock.mode;
105 kb->i.lock.namelen = kb32->i.lock.namelen;
106 kb->i.lock.flags = kb32->i.lock.flags;
107 kb->i.lock.lkid = kb32->i.lock.lkid;
108 kb->i.lock.parent = kb32->i.lock.parent;
109 kb->i.lock.xid = kb32->i.lock.xid;
110 kb->i.lock.timeout = kb32->i.lock.timeout;
111 kb->i.lock.castparam = (__user void *)(long)kb32->i.lock.castparam;
112 kb->i.lock.castaddr = (__user void *)(long)kb32->i.lock.castaddr;
113 kb->i.lock.bastparam = (__user void *)(long)kb32->i.lock.bastparam;
114 kb->i.lock.bastaddr = (__user void *)(long)kb32->i.lock.bastaddr;
115 kb->i.lock.lksb = (__user void *)(long)kb32->i.lock.lksb;
116 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
117 memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
121 static void compat_output(struct dlm_lock_result *res,
122 struct dlm_lock_result32 *res32)
124 memset(res32, 0, sizeof(*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)(__force long)res->user_astaddr;
131 res32->user_astparam = (__u32)(__force long)res->user_astparam;
132 res32->user_lksb = (__u32)(__force 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 #ifdef CONFIG_DLM_DEPRECATED_API
255 pr_warn_once("========================================================\n"
256 "WARNING: the lkb timeout feature is being deprecated and\n"
257 " will be removed in v6.2!\n"
258 "========================================================\n");
261 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
265 ua->user_lksb = params->lksb;
266 ua->castparam = params->castparam;
267 ua->castaddr = params->castaddr;
268 ua->bastparam = params->bastparam;
269 ua->bastaddr = params->bastaddr;
270 ua->xid = params->xid;
272 if (params->flags & DLM_LKF_CONVERT) {
273 #ifdef CONFIG_DLM_DEPRECATED_API
274 error = dlm_user_convert(ls, ua,
275 params->mode, params->flags,
276 params->lkid, params->lvb,
277 (unsigned long) params->timeout);
279 error = dlm_user_convert(ls, ua,
280 params->mode, params->flags,
281 params->lkid, params->lvb);
283 } else if (params->flags & DLM_LKF_ORPHAN) {
284 error = dlm_user_adopt_orphan(ls, ua,
285 params->mode, params->flags,
286 params->name, params->namelen,
291 #ifdef CONFIG_DLM_DEPRECATED_API
292 error = dlm_user_request(ls, ua,
293 params->mode, params->flags,
294 params->name, params->namelen,
295 (unsigned long) params->timeout);
297 error = dlm_user_request(ls, ua,
298 params->mode, params->flags,
299 params->name, params->namelen);
302 error = ua->lksb.sb_lkid;
305 dlm_put_lockspace(ls);
309 static int device_user_unlock(struct dlm_user_proc *proc,
310 struct dlm_lock_params *params)
313 struct dlm_user_args *ua;
316 ls = dlm_find_lockspace_local(proc->lockspace);
320 ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
324 ua->user_lksb = params->lksb;
325 ua->castparam = params->castparam;
326 ua->castaddr = params->castaddr;
328 if (params->flags & DLM_LKF_CANCEL)
329 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
331 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
334 dlm_put_lockspace(ls);
338 static int device_user_deadlock(struct dlm_user_proc *proc,
339 struct dlm_lock_params *params)
344 ls = dlm_find_lockspace_local(proc->lockspace);
348 error = dlm_user_deadlock(ls, params->flags, params->lkid);
350 dlm_put_lockspace(ls);
354 static int dlm_device_register(struct dlm_ls *ls, char *name)
358 /* The device is already registered. This happens when the
359 lockspace is created multiple times from userspace. */
360 if (ls->ls_device.name)
364 len = strlen(name) + strlen(name_prefix) + 2;
365 ls->ls_device.name = kzalloc(len, GFP_NOFS);
366 if (!ls->ls_device.name)
369 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
371 ls->ls_device.fops = &device_fops;
372 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
374 error = misc_register(&ls->ls_device);
376 kfree(ls->ls_device.name);
377 /* this has to be set to NULL
378 * to avoid a double-free in dlm_device_deregister
380 ls->ls_device.name = NULL;
386 int dlm_device_deregister(struct dlm_ls *ls)
388 /* The device is not registered. This happens when the lockspace
389 was never used from userspace, or when device_create_lockspace()
390 calls dlm_release_lockspace() after the register fails. */
391 if (!ls->ls_device.name)
394 misc_deregister(&ls->ls_device);
395 kfree(ls->ls_device.name);
399 static int device_user_purge(struct dlm_user_proc *proc,
400 struct dlm_purge_params *params)
405 ls = dlm_find_lockspace_local(proc->lockspace);
409 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
411 dlm_put_lockspace(ls);
415 static int device_create_lockspace(struct dlm_lspace_params *params)
417 dlm_lockspace_t *lockspace;
421 if (!capable(CAP_SYS_ADMIN))
424 error = dlm_new_lockspace(params->name, dlm_config.ci_cluster_name, params->flags,
425 DLM_USER_LVB_LEN, NULL, NULL, NULL,
430 ls = dlm_find_lockspace_local(lockspace);
434 error = dlm_device_register(ls, params->name);
435 dlm_put_lockspace(ls);
438 dlm_release_lockspace(lockspace, 0);
440 error = ls->ls_device.minor;
445 static int device_remove_lockspace(struct dlm_lspace_params *params)
447 dlm_lockspace_t *lockspace;
449 int error, force = 0;
451 if (!capable(CAP_SYS_ADMIN))
454 ls = dlm_find_lockspace_device(params->minor);
458 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
461 lockspace = ls->ls_local_handle;
462 dlm_put_lockspace(ls);
464 /* The final dlm_release_lockspace waits for references to go to
465 zero, so all processes will need to close their device for the
466 ls before the release will proceed. release also calls the
467 device_deregister above. Converting a positive return value
468 from release to zero means that userspace won't know when its
469 release was the final one, but it shouldn't need to know. */
471 error = dlm_release_lockspace(lockspace, force);
477 /* Check the user's version matches ours */
478 static int check_version(struct dlm_write_request *req)
480 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
481 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
482 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
484 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
485 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
487 task_pid_nr(current),
491 DLM_DEVICE_VERSION_MAJOR,
492 DLM_DEVICE_VERSION_MINOR,
493 DLM_DEVICE_VERSION_PATCH);
503 * dlm_user_request -> request_lock
504 * dlm_user_convert -> convert_lock
507 * dlm_user_unlock -> unlock_lock
508 * dlm_user_cancel -> cancel_lock
510 * device_create_lockspace
513 * device_remove_lockspace
514 * dlm_release_lockspace
517 /* a write to a lockspace device is a lock or unlock request, a write
518 to the control device is to create/remove a lockspace */
520 static ssize_t device_write(struct file *file, const char __user *buf,
521 size_t count, loff_t *ppos)
523 struct dlm_user_proc *proc = file->private_data;
524 struct dlm_write_request *kbuf;
528 if (count < sizeof(struct dlm_write_request32))
530 if (count < sizeof(struct dlm_write_request))
535 * can't compare against COMPAT/dlm_write_request32 because
536 * we don't yet know if is64bit is zero
538 if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
541 kbuf = memdup_user_nul(buf, count);
543 return PTR_ERR(kbuf);
545 if (check_version(kbuf)) {
551 if (!kbuf->is64bit) {
552 struct dlm_write_request32 *k32buf;
555 if (count > sizeof(struct dlm_write_request32))
556 namelen = count - sizeof(struct dlm_write_request32);
558 k32buf = (struct dlm_write_request32 *)kbuf;
560 /* add 1 after namelen so that the name string is terminated */
561 kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
569 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
571 compat_input(kbuf, k32buf, namelen);
576 /* do we really need this? can a write happen after a close? */
577 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
578 (proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
589 log_print("no locking on control device");
592 error = device_user_lock(proc, &kbuf->i.lock);
595 case DLM_USER_UNLOCK:
597 log_print("no locking on control device");
600 error = device_user_unlock(proc, &kbuf->i.lock);
603 case DLM_USER_DEADLOCK:
605 log_print("no locking on control device");
608 error = device_user_deadlock(proc, &kbuf->i.lock);
611 case DLM_USER_CREATE_LOCKSPACE:
613 log_print("create/remove only on control device");
616 error = device_create_lockspace(&kbuf->i.lspace);
619 case DLM_USER_REMOVE_LOCKSPACE:
621 log_print("create/remove only on control device");
624 error = device_remove_lockspace(&kbuf->i.lspace);
629 log_print("no locking on control device");
632 error = device_user_purge(proc, &kbuf->i.purge);
636 log_print("Unknown command passed to DLM device : %d\n",
645 /* Every process that opens the lockspace device has its own "proc" structure
646 hanging off the open file that's used to keep track of locks owned by the
647 process and asts that need to be delivered to the process. */
649 static int device_open(struct inode *inode, struct file *file)
651 struct dlm_user_proc *proc;
654 ls = dlm_find_lockspace_device(iminor(inode));
658 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
660 dlm_put_lockspace(ls);
664 proc->lockspace = ls->ls_local_handle;
665 INIT_LIST_HEAD(&proc->asts);
666 INIT_LIST_HEAD(&proc->locks);
667 INIT_LIST_HEAD(&proc->unlocking);
668 spin_lock_init(&proc->asts_spin);
669 spin_lock_init(&proc->locks_spin);
670 init_waitqueue_head(&proc->wait);
671 file->private_data = proc;
676 static int device_close(struct inode *inode, struct file *file)
678 struct dlm_user_proc *proc = file->private_data;
681 ls = dlm_find_lockspace_local(proc->lockspace);
685 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
687 dlm_clear_proc_locks(ls, proc);
689 /* at this point no more lkb's should exist for this lockspace,
690 so there's no chance of dlm_user_add_ast() being called and
691 looking for lkb->ua->proc */
694 file->private_data = NULL;
696 dlm_put_lockspace(ls);
697 dlm_put_lockspace(ls); /* for the find in device_open() */
699 /* FIXME: AUTOFREE: if this ls is no longer used do
700 device_remove_lockspace() */
705 static int copy_result_to_user(struct dlm_user_args *ua, int compat,
706 uint32_t flags, int mode, int copy_lvb,
707 char __user *buf, size_t count)
710 struct dlm_lock_result32 result32;
712 struct dlm_lock_result result;
718 memset(&result, 0, sizeof(struct dlm_lock_result));
719 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
720 result.version[1] = DLM_DEVICE_VERSION_MINOR;
721 result.version[2] = DLM_DEVICE_VERSION_PATCH;
722 memcpy(&result.lksb, &ua->lksb, offsetof(struct dlm_lksb, sb_lvbptr));
723 result.user_lksb = ua->user_lksb;
725 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
726 in a conversion unless the conversion is successful. See code
727 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
728 notes that a new blocking AST address and parameter are set even if
729 the conversion fails, so maybe we should just do that. */
731 if (flags & DLM_CB_BAST) {
732 result.user_astaddr = ua->bastaddr;
733 result.user_astparam = ua->bastparam;
734 result.bast_mode = mode;
736 result.user_astaddr = ua->castaddr;
737 result.user_astparam = ua->castparam;
742 len = sizeof(struct dlm_lock_result32);
745 len = sizeof(struct dlm_lock_result);
748 /* copy lvb to userspace if there is one, it's been updated, and
749 the user buffer has space for it */
751 if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
752 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
758 result.lvb_offset = len;
759 len += DLM_USER_LVB_LEN;
766 compat_output(&result, &result32);
767 resultptr = &result32;
771 if (copy_to_user(buf, resultptr, struct_len))
779 static int copy_version_to_user(char __user *buf, size_t count)
781 struct dlm_device_version ver;
783 memset(&ver, 0, sizeof(struct dlm_device_version));
784 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
785 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
786 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
788 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
790 return sizeof(struct dlm_device_version);
793 /* a read returns a single ast described in a struct dlm_lock_result */
795 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
798 struct dlm_user_proc *proc = file->private_data;
800 DECLARE_WAITQUEUE(wait, current);
801 struct dlm_callback cb;
802 int rv, resid, copy_lvb = 0;
803 int old_mode, new_mode;
805 if (count == sizeof(struct dlm_device_version)) {
806 rv = copy_version_to_user(buf, count);
811 log_print("non-version read from control device %zu", count);
816 if (count < sizeof(struct dlm_lock_result32))
818 if (count < sizeof(struct dlm_lock_result))
824 /* do we really need this? can a read happen after a close? */
825 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
828 spin_lock(&proc->asts_spin);
829 if (list_empty(&proc->asts)) {
830 if (file->f_flags & O_NONBLOCK) {
831 spin_unlock(&proc->asts_spin);
835 add_wait_queue(&proc->wait, &wait);
838 set_current_state(TASK_INTERRUPTIBLE);
839 if (list_empty(&proc->asts) && !signal_pending(current)) {
840 spin_unlock(&proc->asts_spin);
842 spin_lock(&proc->asts_spin);
845 set_current_state(TASK_RUNNING);
846 remove_wait_queue(&proc->wait, &wait);
848 if (signal_pending(current)) {
849 spin_unlock(&proc->asts_spin);
854 /* if we empty lkb_callbacks, we don't want to unlock the spinlock
855 without removing lkb_cb_list; so empty lkb_cb_list is always
856 consistent with empty lkb_callbacks */
858 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
860 /* rem_lkb_callback sets a new lkb_last_cast */
861 old_mode = lkb->lkb_last_cast.mode;
863 rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
865 /* this shouldn't happen; lkb should have been removed from
866 list when resid was zero */
867 log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
868 list_del_init(&lkb->lkb_cb_list);
869 spin_unlock(&proc->asts_spin);
870 /* removes ref for proc->asts, may cause lkb to be freed */
875 list_del_init(&lkb->lkb_cb_list);
876 spin_unlock(&proc->asts_spin);
878 if (cb.flags & DLM_CB_SKIP) {
879 /* removes ref for proc->asts, may cause lkb to be freed */
885 if (cb.flags & DLM_CB_CAST) {
888 if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
889 dlm_lvb_operations[old_mode + 1][new_mode + 1])
892 lkb->lkb_lksb->sb_status = cb.sb_status;
893 lkb->lkb_lksb->sb_flags = cb.sb_flags;
896 rv = copy_result_to_user(lkb->lkb_ua,
897 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
898 cb.flags, cb.mode, copy_lvb, buf, count);
900 /* removes ref for proc->asts, may cause lkb to be freed */
907 static __poll_t device_poll(struct file *file, poll_table *wait)
909 struct dlm_user_proc *proc = file->private_data;
911 poll_wait(file, &proc->wait, wait);
913 spin_lock(&proc->asts_spin);
914 if (!list_empty(&proc->asts)) {
915 spin_unlock(&proc->asts_spin);
916 return EPOLLIN | EPOLLRDNORM;
918 spin_unlock(&proc->asts_spin);
922 int dlm_user_daemon_available(void)
924 /* dlm_controld hasn't started (or, has started, but not
925 properly populated configfs) */
927 if (!dlm_our_nodeid())
930 /* This is to deal with versions of dlm_controld that don't
931 know about the monitor device. We assume that if the
932 dlm_controld was started (above), but the monitor device
933 was never opened, that it's an old version. dlm_controld
934 should open the monitor device before populating configfs. */
936 if (dlm_monitor_unused)
939 return atomic_read(&dlm_monitor_opened) ? 1 : 0;
942 static int ctl_device_open(struct inode *inode, struct file *file)
944 file->private_data = NULL;
948 static int ctl_device_close(struct inode *inode, struct file *file)
953 static int monitor_device_open(struct inode *inode, struct file *file)
955 atomic_inc(&dlm_monitor_opened);
956 dlm_monitor_unused = 0;
960 static int monitor_device_close(struct inode *inode, struct file *file)
962 if (atomic_dec_and_test(&dlm_monitor_opened))
963 dlm_stop_lockspaces();
967 static const struct file_operations device_fops = {
969 .release = device_close,
971 .write = device_write,
973 .owner = THIS_MODULE,
974 .llseek = noop_llseek,
977 static const struct file_operations ctl_device_fops = {
978 .open = ctl_device_open,
979 .release = ctl_device_close,
981 .write = device_write,
982 .owner = THIS_MODULE,
983 .llseek = noop_llseek,
986 static struct miscdevice ctl_device = {
987 .name = "dlm-control",
988 .fops = &ctl_device_fops,
989 .minor = MISC_DYNAMIC_MINOR,
992 static const struct file_operations monitor_device_fops = {
993 .open = monitor_device_open,
994 .release = monitor_device_close,
995 .owner = THIS_MODULE,
996 .llseek = noop_llseek,
999 static struct miscdevice monitor_device = {
1000 .name = "dlm-monitor",
1001 .fops = &monitor_device_fops,
1002 .minor = MISC_DYNAMIC_MINOR,
1005 int __init dlm_user_init(void)
1009 atomic_set(&dlm_monitor_opened, 0);
1011 error = misc_register(&ctl_device);
1013 log_print("misc_register failed for control device");
1017 error = misc_register(&monitor_device);
1019 log_print("misc_register failed for monitor device");
1020 misc_deregister(&ctl_device);
1026 void dlm_user_exit(void)
1028 misc_deregister(&ctl_device);
1029 misc_deregister(&monitor_device);