1 // SPDX-License-Identifier: GPL-2.0-only
2 /******************************************************************************
3 *******************************************************************************
4 **
5 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
6 ** Copyright (C) 2004-2010 Red Hat, Inc. All rights reserved.
7 **
8 **
9 *******************************************************************************
10 ******************************************************************************/
11
12 #include <trace/events/dlm.h>
13
14 #include "dlm_internal.h"
15 #include "lvb_table.h"
16 #include "memory.h"
17 #include "lock.h"
18 #include "user.h"
19 #include "ast.h"
20
dlm_release_callback(struct kref * ref)21 void dlm_release_callback(struct kref *ref)
22 {
23 struct dlm_callback *cb = container_of(ref, struct dlm_callback, ref);
24
25 dlm_free_cb(cb);
26 }
27
dlm_callback_set_last_ptr(struct dlm_callback ** from,struct dlm_callback * to)28 void dlm_callback_set_last_ptr(struct dlm_callback **from,
29 struct dlm_callback *to)
30 {
31 if (*from)
32 kref_put(&(*from)->ref, dlm_release_callback);
33
34 if (to)
35 kref_get(&to->ref);
36
37 *from = to;
38 }
39
dlm_enqueue_lkb_callback(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags)40 int dlm_enqueue_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
41 int status, uint32_t sbflags)
42 {
43 struct dlm_ls *ls = lkb->lkb_resource->res_ls;
44 int rv = DLM_ENQUEUE_CALLBACK_SUCCESS;
45 struct dlm_callback *cb;
46 int copy_lvb = 0;
47 int prev_mode;
48
49 if (flags & DLM_CB_BAST) {
50 /* if cb is a bast, it should be skipped if the blocking mode is
51 * compatible with the last granted mode
52 */
53 if (lkb->lkb_last_cast) {
54 if (dlm_modes_compat(mode, lkb->lkb_last_cast->mode)) {
55 log_debug(ls, "skip %x bast mode %d for cast mode %d",
56 lkb->lkb_id, mode,
57 lkb->lkb_last_cast->mode);
58 goto out;
59 }
60 }
61
62 /*
63 * Suppress some redundant basts here, do more on removal.
64 * Don't even add a bast if the callback just before it
65 * is a bast for the same mode or a more restrictive mode.
66 * (the addional > PR check is needed for PR/CW inversion)
67 */
68 if (lkb->lkb_last_cb && lkb->lkb_last_cb->flags & DLM_CB_BAST) {
69 prev_mode = lkb->lkb_last_cb->mode;
70
71 if ((prev_mode == mode) ||
72 (prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
73 log_debug(ls, "skip %x add bast mode %d for bast mode %d",
74 lkb->lkb_id, mode, prev_mode);
75 goto out;
76 }
77 }
78 } else if (flags & DLM_CB_CAST) {
79 if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
80 if (lkb->lkb_last_cast)
81 prev_mode = lkb->lkb_last_cb->mode;
82 else
83 prev_mode = -1;
84
85 if (!status && lkb->lkb_lksb->sb_lvbptr &&
86 dlm_lvb_operations[prev_mode + 1][mode + 1])
87 copy_lvb = 1;
88 }
89 }
90
91 cb = dlm_allocate_cb();
92 if (!cb) {
93 rv = DLM_ENQUEUE_CALLBACK_FAILURE;
94 goto out;
95 }
96
97 cb->flags = flags;
98 cb->mode = mode;
99 cb->sb_status = status;
100 cb->sb_flags = (sbflags & 0x000000FF);
101 cb->copy_lvb = copy_lvb;
102 kref_init(&cb->ref);
103 if (!test_and_set_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags))
104 rv = DLM_ENQUEUE_CALLBACK_NEED_SCHED;
105
106 list_add_tail(&cb->list, &lkb->lkb_callbacks);
107
108 if (flags & DLM_CB_CAST)
109 dlm_callback_set_last_ptr(&lkb->lkb_last_cast, cb);
110
111 dlm_callback_set_last_ptr(&lkb->lkb_last_cb, cb);
112
113 out:
114 return rv;
115 }
116
dlm_dequeue_lkb_callback(struct dlm_lkb * lkb,struct dlm_callback ** cb)117 int dlm_dequeue_lkb_callback(struct dlm_lkb *lkb, struct dlm_callback **cb)
118 {
119 /* oldest undelivered cb is callbacks first entry */
120 *cb = list_first_entry_or_null(&lkb->lkb_callbacks,
121 struct dlm_callback, list);
122 if (!*cb)
123 return DLM_DEQUEUE_CALLBACK_EMPTY;
124
125 /* remove it from callbacks so shift others down */
126 list_del(&(*cb)->list);
127 if (list_empty(&lkb->lkb_callbacks))
128 return DLM_DEQUEUE_CALLBACK_LAST;
129
130 return DLM_DEQUEUE_CALLBACK_SUCCESS;
131 }
132
dlm_add_cb(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags)133 void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
134 uint32_t sbflags)
135 {
136 struct dlm_ls *ls = lkb->lkb_resource->res_ls;
137 int rv;
138
139 if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
140 dlm_user_add_ast(lkb, flags, mode, status, sbflags);
141 return;
142 }
143
144 spin_lock(&lkb->lkb_cb_lock);
145 rv = dlm_enqueue_lkb_callback(lkb, flags, mode, status, sbflags);
146 switch (rv) {
147 case DLM_ENQUEUE_CALLBACK_NEED_SCHED:
148 kref_get(&lkb->lkb_ref);
149
150 spin_lock(&ls->ls_cb_lock);
151 if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
152 list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
153 } else {
154 queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
155 }
156 spin_unlock(&ls->ls_cb_lock);
157 break;
158 case DLM_ENQUEUE_CALLBACK_FAILURE:
159 WARN_ON_ONCE(1);
160 break;
161 case DLM_ENQUEUE_CALLBACK_SUCCESS:
162 break;
163 default:
164 WARN_ON_ONCE(1);
165 break;
166 }
167 spin_unlock(&lkb->lkb_cb_lock);
168 }
169
dlm_callback_work(struct work_struct * work)170 void dlm_callback_work(struct work_struct *work)
171 {
172 struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
173 struct dlm_ls *ls = lkb->lkb_resource->res_ls;
174 void (*castfn) (void *astparam);
175 void (*bastfn) (void *astparam, int mode);
176 struct dlm_callback *cb;
177 int rv;
178
179 spin_lock(&lkb->lkb_cb_lock);
180 rv = dlm_dequeue_lkb_callback(lkb, &cb);
181 if (WARN_ON_ONCE(rv == DLM_DEQUEUE_CALLBACK_EMPTY)) {
182 clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
183 spin_unlock(&lkb->lkb_cb_lock);
184 goto out;
185 }
186 spin_unlock(&lkb->lkb_cb_lock);
187
188 for (;;) {
189 castfn = lkb->lkb_astfn;
190 bastfn = lkb->lkb_bastfn;
191
192 if (cb->flags & DLM_CB_BAST) {
193 trace_dlm_bast(ls, lkb, cb->mode);
194 lkb->lkb_last_bast_time = ktime_get();
195 lkb->lkb_last_bast_mode = cb->mode;
196 bastfn(lkb->lkb_astparam, cb->mode);
197 } else if (cb->flags & DLM_CB_CAST) {
198 lkb->lkb_lksb->sb_status = cb->sb_status;
199 lkb->lkb_lksb->sb_flags = cb->sb_flags;
200 trace_dlm_ast(ls, lkb);
201 lkb->lkb_last_cast_time = ktime_get();
202 castfn(lkb->lkb_astparam);
203 }
204
205 kref_put(&cb->ref, dlm_release_callback);
206
207 spin_lock(&lkb->lkb_cb_lock);
208 rv = dlm_dequeue_lkb_callback(lkb, &cb);
209 if (rv == DLM_DEQUEUE_CALLBACK_EMPTY) {
210 clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
211 spin_unlock(&lkb->lkb_cb_lock);
212 break;
213 }
214 spin_unlock(&lkb->lkb_cb_lock);
215 }
216
217 out:
218 /* undo kref_get from dlm_add_callback, may cause lkb to be freed */
219 dlm_put_lkb(lkb);
220 }
221
dlm_callback_start(struct dlm_ls * ls)222 int dlm_callback_start(struct dlm_ls *ls)
223 {
224 ls->ls_callback_wq = alloc_workqueue("dlm_callback",
225 WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
226 if (!ls->ls_callback_wq) {
227 log_print("can't start dlm_callback workqueue");
228 return -ENOMEM;
229 }
230 return 0;
231 }
232
dlm_callback_stop(struct dlm_ls * ls)233 void dlm_callback_stop(struct dlm_ls *ls)
234 {
235 if (ls->ls_callback_wq)
236 destroy_workqueue(ls->ls_callback_wq);
237 }
238
dlm_callback_suspend(struct dlm_ls * ls)239 void dlm_callback_suspend(struct dlm_ls *ls)
240 {
241 if (ls->ls_callback_wq) {
242 spin_lock(&ls->ls_cb_lock);
243 set_bit(LSFL_CB_DELAY, &ls->ls_flags);
244 spin_unlock(&ls->ls_cb_lock);
245
246 flush_workqueue(ls->ls_callback_wq);
247 }
248 }
249
250 #define MAX_CB_QUEUE 25
251
dlm_callback_resume(struct dlm_ls * ls)252 void dlm_callback_resume(struct dlm_ls *ls)
253 {
254 struct dlm_lkb *lkb, *safe;
255 int count = 0, sum = 0;
256 bool empty;
257
258 if (!ls->ls_callback_wq)
259 return;
260
261 more:
262 spin_lock(&ls->ls_cb_lock);
263 list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
264 list_del_init(&lkb->lkb_cb_list);
265 queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
266 count++;
267 if (count == MAX_CB_QUEUE)
268 break;
269 }
270 empty = list_empty(&ls->ls_cb_delay);
271 if (empty)
272 clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
273 spin_unlock(&ls->ls_cb_lock);
274
275 sum += count;
276 if (!empty) {
277 count = 0;
278 cond_resched();
279 goto more;
280 }
281
282 if (sum)
283 log_rinfo(ls, "%s %d", __func__, sum);
284 }
285
286