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_run_callback(uint32_t ls_id,uint32_t lkb_id,int8_t mode,uint32_t flags,uint8_t sb_flags,int sb_status,struct dlm_lksb * lksb,void (* astfn)(void * astparam),void (* bastfn)(void * astparam,int mode),void * astparam,const char * res_name,size_t res_length)21 static void dlm_run_callback(uint32_t ls_id, uint32_t lkb_id, int8_t mode,
22 			     uint32_t flags, uint8_t sb_flags, int sb_status,
23 			     struct dlm_lksb *lksb,
24 			     void (*astfn)(void *astparam),
25 			     void (*bastfn)(void *astparam, int mode),
26 			     void *astparam, const char *res_name,
27 			     size_t res_length)
28 {
29 	if (flags & DLM_CB_BAST) {
30 		trace_dlm_bast(ls_id, lkb_id, mode, res_name, res_length);
31 		bastfn(astparam, mode);
32 	} else if (flags & DLM_CB_CAST) {
33 		trace_dlm_ast(ls_id, lkb_id, sb_status, sb_flags, res_name,
34 			      res_length);
35 		lksb->sb_status = sb_status;
36 		lksb->sb_flags = sb_flags;
37 		astfn(astparam);
38 	}
39 }
40 
dlm_do_callback(struct dlm_callback * cb)41 static void dlm_do_callback(struct dlm_callback *cb)
42 {
43 	dlm_run_callback(cb->ls_id, cb->lkb_id, cb->mode, cb->flags,
44 			 cb->sb_flags, cb->sb_status, cb->lkb_lksb,
45 			 cb->astfn, cb->bastfn, cb->astparam,
46 			 cb->res_name, cb->res_length);
47 	dlm_free_cb(cb);
48 }
49 
dlm_callback_work(struct work_struct * work)50 static void dlm_callback_work(struct work_struct *work)
51 {
52 	struct dlm_callback *cb = container_of(work, struct dlm_callback, work);
53 
54 	dlm_do_callback(cb);
55 }
56 
dlm_may_skip_callback(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags,int * copy_lvb)57 bool dlm_may_skip_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
58 			   int status, uint32_t sbflags, int *copy_lvb)
59 {
60 	struct dlm_rsb *rsb = lkb->lkb_resource;
61 	struct dlm_ls *ls = rsb->res_ls;
62 	int prev_mode;
63 
64 	if (copy_lvb)
65 		*copy_lvb = 0;
66 
67 	if (flags & DLM_CB_BAST) {
68 		/* if cb is a bast, it should be skipped if the blocking mode is
69 		 * compatible with the last granted mode
70 		 */
71 		if (lkb->lkb_last_cast_cb_mode != -1) {
72 			if (dlm_modes_compat(mode, lkb->lkb_last_cast_cb_mode)) {
73 				log_debug(ls, "skip %x bast mode %d for cast mode %d",
74 					  lkb->lkb_id, mode,
75 					  lkb->lkb_last_cast_cb_mode);
76 				return true;
77 			}
78 		}
79 
80 		/*
81 		 * Suppress some redundant basts here, do more on removal.
82 		 * Don't even add a bast if the callback just before it
83 		 * is a bast for the same mode or a more restrictive mode.
84 		 * (the addional > PR check is needed for PR/CW inversion)
85 		 */
86 		if (lkb->lkb_last_cb_mode != -1 &&
87 		    lkb->lkb_last_cb_flags & DLM_CB_BAST) {
88 			prev_mode = lkb->lkb_last_cb_mode;
89 
90 			if ((prev_mode == mode) ||
91 			    (prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
92 				log_debug(ls, "skip %x add bast mode %d for bast mode %d",
93 					  lkb->lkb_id, mode, prev_mode);
94 				return true;
95 			}
96 		}
97 
98 		lkb->lkb_last_bast_time = ktime_get();
99 		lkb->lkb_last_bast_cb_mode = mode;
100 	} else if (flags & DLM_CB_CAST) {
101 		if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
102 			prev_mode = lkb->lkb_last_cast_cb_mode;
103 
104 			if (!status && lkb->lkb_lksb->sb_lvbptr &&
105 			    dlm_lvb_operations[prev_mode + 1][mode + 1]) {
106 				if (copy_lvb)
107 					*copy_lvb = 1;
108 			}
109 		}
110 
111 		lkb->lkb_last_cast_cb_mode = mode;
112 		lkb->lkb_last_cast_time = ktime_get();
113 	}
114 
115 	lkb->lkb_last_cb_mode = mode;
116 	lkb->lkb_last_cb_flags = flags;
117 
118 	return false;
119 }
120 
dlm_get_cb(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags,struct dlm_callback ** cb)121 int dlm_get_cb(struct dlm_lkb *lkb, uint32_t flags, int mode,
122 	       int status, uint32_t sbflags,
123 	       struct dlm_callback **cb)
124 {
125 	struct dlm_rsb *rsb = lkb->lkb_resource;
126 	struct dlm_ls *ls = rsb->res_ls;
127 
128 	*cb = dlm_allocate_cb();
129 	if (WARN_ON_ONCE(!*cb))
130 		return -ENOMEM;
131 
132 	/* for tracing */
133 	(*cb)->lkb_id = lkb->lkb_id;
134 	(*cb)->ls_id = ls->ls_global_id;
135 	memcpy((*cb)->res_name, rsb->res_name, rsb->res_length);
136 	(*cb)->res_length = rsb->res_length;
137 
138 	(*cb)->flags = flags;
139 	(*cb)->mode = mode;
140 	(*cb)->sb_status = status;
141 	(*cb)->sb_flags = (sbflags & 0x000000FF);
142 	(*cb)->lkb_lksb = lkb->lkb_lksb;
143 
144 	return 0;
145 }
146 
dlm_get_queue_cb(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags,struct dlm_callback ** cb)147 static int dlm_get_queue_cb(struct dlm_lkb *lkb, uint32_t flags, int mode,
148 			    int status, uint32_t sbflags,
149 			    struct dlm_callback **cb)
150 {
151 	int rv;
152 
153 	rv = dlm_get_cb(lkb, flags, mode, status, sbflags, cb);
154 	if (rv)
155 		return rv;
156 
157 	(*cb)->astfn = lkb->lkb_astfn;
158 	(*cb)->bastfn = lkb->lkb_bastfn;
159 	(*cb)->astparam = lkb->lkb_astparam;
160 	INIT_WORK(&(*cb)->work, dlm_callback_work);
161 
162 	return 0;
163 }
164 
dlm_add_cb(struct dlm_lkb * lkb,uint32_t flags,int mode,int status,uint32_t sbflags)165 void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
166 		uint32_t sbflags)
167 {
168 	struct dlm_rsb *rsb = lkb->lkb_resource;
169 	struct dlm_ls *ls = rsb->res_ls;
170 	struct dlm_callback *cb;
171 	int rv;
172 
173 	if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
174 		dlm_user_add_ast(lkb, flags, mode, status, sbflags);
175 		return;
176 	}
177 
178 	if (dlm_may_skip_callback(lkb, flags, mode, status, sbflags, NULL))
179 		return;
180 
181 	spin_lock_bh(&ls->ls_cb_lock);
182 	if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
183 		rv = dlm_get_queue_cb(lkb, flags, mode, status, sbflags, &cb);
184 		if (!rv)
185 			list_add(&cb->list, &ls->ls_cb_delay);
186 	} else {
187 		if (test_bit(LSFL_SOFTIRQ, &ls->ls_flags)) {
188 			dlm_run_callback(ls->ls_global_id, lkb->lkb_id, mode, flags,
189 					 sbflags, status, lkb->lkb_lksb,
190 					 lkb->lkb_astfn, lkb->lkb_bastfn,
191 					 lkb->lkb_astparam, rsb->res_name,
192 					 rsb->res_length);
193 		} else {
194 			rv = dlm_get_queue_cb(lkb, flags, mode, status, sbflags, &cb);
195 			if (!rv)
196 				queue_work(ls->ls_callback_wq, &cb->work);
197 		}
198 	}
199 	spin_unlock_bh(&ls->ls_cb_lock);
200 }
201 
dlm_callback_start(struct dlm_ls * ls)202 int dlm_callback_start(struct dlm_ls *ls)
203 {
204 	if (!test_bit(LSFL_FS, &ls->ls_flags) ||
205 	    test_bit(LSFL_SOFTIRQ, &ls->ls_flags))
206 		return 0;
207 
208 	ls->ls_callback_wq = alloc_ordered_workqueue("dlm_callback",
209 						     WQ_HIGHPRI | WQ_MEM_RECLAIM);
210 	if (!ls->ls_callback_wq) {
211 		log_print("can't start dlm_callback workqueue");
212 		return -ENOMEM;
213 	}
214 	return 0;
215 }
216 
dlm_callback_stop(struct dlm_ls * ls)217 void dlm_callback_stop(struct dlm_ls *ls)
218 {
219 	if (ls->ls_callback_wq)
220 		destroy_workqueue(ls->ls_callback_wq);
221 }
222 
dlm_callback_suspend(struct dlm_ls * ls)223 void dlm_callback_suspend(struct dlm_ls *ls)
224 {
225 	if (!test_bit(LSFL_FS, &ls->ls_flags))
226 		return;
227 
228 	spin_lock_bh(&ls->ls_cb_lock);
229 	set_bit(LSFL_CB_DELAY, &ls->ls_flags);
230 	spin_unlock_bh(&ls->ls_cb_lock);
231 
232 	if (ls->ls_callback_wq)
233 		flush_workqueue(ls->ls_callback_wq);
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_callback *cb, *safe;
241 	int count = 0, sum = 0;
242 	bool empty;
243 
244 	if (!test_bit(LSFL_FS, &ls->ls_flags))
245 		return;
246 
247 more:
248 	spin_lock_bh(&ls->ls_cb_lock);
249 	list_for_each_entry_safe(cb, safe, &ls->ls_cb_delay, list) {
250 		list_del(&cb->list);
251 		if (test_bit(LSFL_SOFTIRQ, &ls->ls_flags))
252 			dlm_do_callback(cb);
253 		else
254 			queue_work(ls->ls_callback_wq, &cb->work);
255 
256 		count++;
257 		if (count == MAX_CB_QUEUE)
258 			break;
259 	}
260 	empty = list_empty(&ls->ls_cb_delay);
261 	if (empty)
262 		clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
263 	spin_unlock_bh(&ls->ls_cb_lock);
264 
265 	sum += count;
266 	if (!empty) {
267 		count = 0;
268 		cond_resched();
269 		goto more;
270 	}
271 
272 	if (sum)
273 		log_rinfo(ls, "%s %d", __func__, sum);
274 }
275 
276