1 /****************************************************************************** 2 ******************************************************************************* 3 ** 4 ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. 5 ** Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. 6 ** 7 ** This copyrighted material is made available to anyone wishing to use, 8 ** modify, copy, or redistribute it subject to the terms and conditions 9 ** of the GNU General Public License v.2. 10 ** 11 ******************************************************************************* 12 ******************************************************************************/ 13 14 #include "dlm_internal.h" 15 #include "lock.h" 16 #include "user.h" 17 #include "ast.h" 18 19 #define WAKE_ASTS 0 20 21 static struct list_head ast_queue; 22 static spinlock_t ast_queue_lock; 23 static struct task_struct * astd_task; 24 static unsigned long astd_wakeflags; 25 static struct mutex astd_running; 26 27 28 void dlm_del_ast(struct dlm_lkb *lkb) 29 { 30 spin_lock(&ast_queue_lock); 31 if (lkb->lkb_ast_type & (AST_COMP | AST_BAST)) 32 list_del(&lkb->lkb_astqueue); 33 spin_unlock(&ast_queue_lock); 34 } 35 36 void dlm_add_ast(struct dlm_lkb *lkb, int type, int bastmode) 37 { 38 if (lkb->lkb_flags & DLM_IFL_USER) { 39 dlm_user_add_ast(lkb, type, bastmode); 40 return; 41 } 42 43 spin_lock(&ast_queue_lock); 44 if (!(lkb->lkb_ast_type & (AST_COMP | AST_BAST))) { 45 kref_get(&lkb->lkb_ref); 46 list_add_tail(&lkb->lkb_astqueue, &ast_queue); 47 } 48 lkb->lkb_ast_type |= type; 49 if (bastmode) 50 lkb->lkb_bastmode = bastmode; 51 spin_unlock(&ast_queue_lock); 52 53 set_bit(WAKE_ASTS, &astd_wakeflags); 54 wake_up_process(astd_task); 55 } 56 57 static void process_asts(void) 58 { 59 struct dlm_ls *ls = NULL; 60 struct dlm_rsb *r = NULL; 61 struct dlm_lkb *lkb; 62 void (*cast) (void *astparam); 63 void (*bast) (void *astparam, int mode); 64 int type = 0, bastmode; 65 66 repeat: 67 spin_lock(&ast_queue_lock); 68 list_for_each_entry(lkb, &ast_queue, lkb_astqueue) { 69 r = lkb->lkb_resource; 70 ls = r->res_ls; 71 72 if (dlm_locking_stopped(ls)) 73 continue; 74 75 list_del(&lkb->lkb_astqueue); 76 type = lkb->lkb_ast_type; 77 lkb->lkb_ast_type = 0; 78 bastmode = lkb->lkb_bastmode; 79 80 spin_unlock(&ast_queue_lock); 81 cast = lkb->lkb_astfn; 82 bast = lkb->lkb_bastfn; 83 84 if ((type & AST_COMP) && cast) 85 cast(lkb->lkb_astparam); 86 87 if ((type & AST_BAST) && bast) 88 bast(lkb->lkb_astparam, bastmode); 89 90 /* this removes the reference added by dlm_add_ast 91 and may result in the lkb being freed */ 92 dlm_put_lkb(lkb); 93 94 cond_resched(); 95 goto repeat; 96 } 97 spin_unlock(&ast_queue_lock); 98 } 99 100 static inline int no_asts(void) 101 { 102 int ret; 103 104 spin_lock(&ast_queue_lock); 105 ret = list_empty(&ast_queue); 106 spin_unlock(&ast_queue_lock); 107 return ret; 108 } 109 110 static int dlm_astd(void *data) 111 { 112 while (!kthread_should_stop()) { 113 set_current_state(TASK_INTERRUPTIBLE); 114 if (!test_bit(WAKE_ASTS, &astd_wakeflags)) 115 schedule(); 116 set_current_state(TASK_RUNNING); 117 118 mutex_lock(&astd_running); 119 if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags)) 120 process_asts(); 121 mutex_unlock(&astd_running); 122 } 123 return 0; 124 } 125 126 void dlm_astd_wake(void) 127 { 128 if (!no_asts()) { 129 set_bit(WAKE_ASTS, &astd_wakeflags); 130 wake_up_process(astd_task); 131 } 132 } 133 134 int dlm_astd_start(void) 135 { 136 struct task_struct *p; 137 int error = 0; 138 139 INIT_LIST_HEAD(&ast_queue); 140 spin_lock_init(&ast_queue_lock); 141 mutex_init(&astd_running); 142 143 p = kthread_run(dlm_astd, NULL, "dlm_astd"); 144 if (IS_ERR(p)) 145 error = PTR_ERR(p); 146 else 147 astd_task = p; 148 return error; 149 } 150 151 void dlm_astd_stop(void) 152 { 153 kthread_stop(astd_task); 154 } 155 156 void dlm_astd_suspend(void) 157 { 158 mutex_lock(&astd_running); 159 } 160 161 void dlm_astd_resume(void) 162 { 163 mutex_unlock(&astd_running); 164 } 165 166