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