ast.c

  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
 21static 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_flags, sb_status, res_name,
 34			      res_length);
 35		lksb->sb_status = sb_status;
 36		lksb->sb_flags = sb_flags;
 37		astfn(astparam);
 38	}
 39}
 40
 41static 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
 50static 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
 57bool 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
121int 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
147static 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
165void 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
202int 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
217void dlm_callback_stop(struct dlm_ls *ls)
218{
219	if (ls->ls_callback_wq)
220		destroy_workqueue(ls->ls_callback_wq);
221}
222
223void 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
238void 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
247more:
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