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 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 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 39 void dlm_purge_lkb_callbacks(struct dlm_lkb *lkb) 40 { 41 struct dlm_callback *cb, *safe; 42 43 list_for_each_entry_safe(cb, safe, &lkb->lkb_callbacks, list) { 44 list_del(&cb->list); 45 kref_put(&cb->ref, dlm_release_callback); 46 } 47 48 lkb->lkb_flags &= ~DLM_IFL_CB_PENDING; 49 50 /* invalidate */ 51 dlm_callback_set_last_ptr(&lkb->lkb_last_cast, NULL); 52 dlm_callback_set_last_ptr(&lkb->lkb_last_cb, NULL); 53 lkb->lkb_last_bast_mode = -1; 54 } 55 56 int dlm_enqueue_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode, 57 int status, uint32_t sbflags) 58 { 59 struct dlm_ls *ls = lkb->lkb_resource->res_ls; 60 int rv = DLM_ENQUEUE_CALLBACK_SUCCESS; 61 struct dlm_callback *cb; 62 int prev_mode; 63 64 if (flags & DLM_CB_BAST) { 65 /* if cb is a bast, it should be skipped if the blocking mode is 66 * compatible with the last granted mode 67 */ 68 if (lkb->lkb_last_cast) { 69 if (dlm_modes_compat(mode, lkb->lkb_last_cast->mode)) { 70 log_debug(ls, "skip %x bast mode %d for cast mode %d", 71 lkb->lkb_id, mode, 72 lkb->lkb_last_cast->mode); 73 goto out; 74 } 75 } 76 77 /* 78 * Suppress some redundant basts here, do more on removal. 79 * Don't even add a bast if the callback just before it 80 * is a bast for the same mode or a more restrictive mode. 81 * (the addional > PR check is needed for PR/CW inversion) 82 */ 83 if (lkb->lkb_last_cb && lkb->lkb_last_cb->flags & DLM_CB_BAST) { 84 prev_mode = lkb->lkb_last_cb->mode; 85 86 if ((prev_mode == mode) || 87 (prev_mode > mode && prev_mode > DLM_LOCK_PR)) { 88 log_debug(ls, "skip %x add bast mode %d for bast mode %d", 89 lkb->lkb_id, mode, prev_mode); 90 goto out; 91 } 92 } 93 } 94 95 cb = dlm_allocate_cb(); 96 if (!cb) { 97 rv = DLM_ENQUEUE_CALLBACK_FAILURE; 98 goto out; 99 } 100 101 cb->flags = flags; 102 cb->mode = mode; 103 cb->sb_status = status; 104 cb->sb_flags = (sbflags & 0x000000FF); 105 kref_init(&cb->ref); 106 if (!(lkb->lkb_flags & DLM_IFL_CB_PENDING)) { 107 lkb->lkb_flags |= DLM_IFL_CB_PENDING; 108 rv = DLM_ENQUEUE_CALLBACK_NEED_SCHED; 109 } 110 list_add_tail(&cb->list, &lkb->lkb_callbacks); 111 112 if (flags & DLM_CB_CAST) 113 dlm_callback_set_last_ptr(&lkb->lkb_last_cast, cb); 114 115 dlm_callback_set_last_ptr(&lkb->lkb_last_cb, cb); 116 117 out: 118 return rv; 119 } 120 121 int dlm_dequeue_lkb_callback(struct dlm_lkb *lkb, struct dlm_callback **cb) 122 { 123 /* oldest undelivered cb is callbacks first entry */ 124 *cb = list_first_entry_or_null(&lkb->lkb_callbacks, 125 struct dlm_callback, list); 126 if (!*cb) 127 return DLM_DEQUEUE_CALLBACK_EMPTY; 128 129 /* remove it from callbacks so shift others down */ 130 list_del(&(*cb)->list); 131 if (list_empty(&lkb->lkb_callbacks)) 132 return DLM_DEQUEUE_CALLBACK_LAST; 133 134 return DLM_DEQUEUE_CALLBACK_SUCCESS; 135 } 136 137 void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status, 138 uint32_t sbflags) 139 { 140 struct dlm_ls *ls = lkb->lkb_resource->res_ls; 141 int rv; 142 143 if (lkb->lkb_flags & DLM_IFL_USER) { 144 dlm_user_add_ast(lkb, flags, mode, status, sbflags); 145 return; 146 } 147 148 spin_lock(&lkb->lkb_cb_lock); 149 rv = dlm_enqueue_lkb_callback(lkb, flags, mode, status, sbflags); 150 switch (rv) { 151 case DLM_ENQUEUE_CALLBACK_NEED_SCHED: 152 kref_get(&lkb->lkb_ref); 153 154 spin_lock(&ls->ls_cb_lock); 155 if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) { 156 list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay); 157 } else { 158 queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work); 159 } 160 spin_unlock(&ls->ls_cb_lock); 161 break; 162 case DLM_ENQUEUE_CALLBACK_FAILURE: 163 WARN_ON_ONCE(1); 164 break; 165 case DLM_ENQUEUE_CALLBACK_SUCCESS: 166 break; 167 default: 168 WARN_ON_ONCE(1); 169 break; 170 } 171 spin_unlock(&lkb->lkb_cb_lock); 172 } 173 174 void dlm_callback_work(struct work_struct *work) 175 { 176 struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work); 177 struct dlm_ls *ls = lkb->lkb_resource->res_ls; 178 void (*castfn) (void *astparam); 179 void (*bastfn) (void *astparam, int mode); 180 struct dlm_callback *cb; 181 int rv; 182 183 spin_lock(&lkb->lkb_cb_lock); 184 rv = dlm_dequeue_lkb_callback(lkb, &cb); 185 spin_unlock(&lkb->lkb_cb_lock); 186 187 if (WARN_ON_ONCE(rv == DLM_DEQUEUE_CALLBACK_EMPTY)) 188 goto out; 189 190 for (;;) { 191 castfn = lkb->lkb_astfn; 192 bastfn = lkb->lkb_bastfn; 193 194 if (cb->flags & DLM_CB_BAST) { 195 trace_dlm_bast(ls, lkb, cb->mode); 196 lkb->lkb_last_bast_time = ktime_get(); 197 lkb->lkb_last_bast_mode = cb->mode; 198 bastfn(lkb->lkb_astparam, cb->mode); 199 } else if (cb->flags & DLM_CB_CAST) { 200 lkb->lkb_lksb->sb_status = cb->sb_status; 201 lkb->lkb_lksb->sb_flags = cb->sb_flags; 202 trace_dlm_ast(ls, lkb); 203 lkb->lkb_last_cast_time = ktime_get(); 204 castfn(lkb->lkb_astparam); 205 } 206 207 kref_put(&cb->ref, dlm_release_callback); 208 209 spin_lock(&lkb->lkb_cb_lock); 210 rv = dlm_dequeue_lkb_callback(lkb, &cb); 211 if (rv == DLM_DEQUEUE_CALLBACK_EMPTY) { 212 lkb->lkb_flags &= ~DLM_IFL_CB_PENDING; 213 spin_unlock(&lkb->lkb_cb_lock); 214 break; 215 } 216 spin_unlock(&lkb->lkb_cb_lock); 217 } 218 219 out: 220 /* undo kref_get from dlm_add_callback, may cause lkb to be freed */ 221 dlm_put_lkb(lkb); 222 } 223 224 int dlm_callback_start(struct dlm_ls *ls) 225 { 226 ls->ls_callback_wq = alloc_workqueue("dlm_callback", 227 WQ_HIGHPRI | WQ_MEM_RECLAIM, 0); 228 if (!ls->ls_callback_wq) { 229 log_print("can't start dlm_callback workqueue"); 230 return -ENOMEM; 231 } 232 return 0; 233 } 234 235 void dlm_callback_stop(struct dlm_ls *ls) 236 { 237 if (ls->ls_callback_wq) 238 destroy_workqueue(ls->ls_callback_wq); 239 } 240 241 void dlm_callback_suspend(struct dlm_ls *ls) 242 { 243 if (ls->ls_callback_wq) { 244 spin_lock(&ls->ls_cb_lock); 245 set_bit(LSFL_CB_DELAY, &ls->ls_flags); 246 spin_unlock(&ls->ls_cb_lock); 247 248 flush_workqueue(ls->ls_callback_wq); 249 } 250 } 251 252 #define MAX_CB_QUEUE 25 253 254 void dlm_callback_resume(struct dlm_ls *ls) 255 { 256 struct dlm_lkb *lkb, *safe; 257 int count = 0, sum = 0; 258 bool empty; 259 260 if (!ls->ls_callback_wq) 261 return; 262 263 more: 264 spin_lock(&ls->ls_cb_lock); 265 list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) { 266 list_del_init(&lkb->lkb_cb_list); 267 queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work); 268 count++; 269 if (count == MAX_CB_QUEUE) 270 break; 271 } 272 empty = list_empty(&ls->ls_cb_delay); 273 if (empty) 274 clear_bit(LSFL_CB_DELAY, &ls->ls_flags); 275 spin_unlock(&ls->ls_cb_lock); 276 277 sum += count; 278 if (!empty) { 279 count = 0; 280 cond_resched(); 281 goto more; 282 } 283 284 if (sum) 285 log_rinfo(ls, "%s %d", __func__, sum); 286 } 287 288