xref: /freebsd-src/sys/contrib/openzfs/module/os/linux/spl/spl-thread.c (revision 16d6b3b3da62aa5baaf3c66c8d4e6f8c8f70aeb7)
1 /*
2  *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
3  *  Copyright (C) 2007 The Regents of the University of California.
4  *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
5  *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
6  *  UCRL-CODE-235197
7  *
8  *  This file is part of the SPL, Solaris Porting Layer.
9  *  For details, see <http://zfsonlinux.org/>.
10  *
11  *  The SPL is free software; you can redistribute it and/or modify it
12  *  under the terms of the GNU General Public License as published by the
13  *  Free Software Foundation; either version 2 of the License, or (at your
14  *  option) any later version.
15  *
16  *  The SPL is distributed in the hope that it will be useful, but WITHOUT
17  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
19  *  for more details.
20  *
21  *  You should have received a copy of the GNU General Public License along
22  *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
23  *
24  *  Solaris Porting Layer (SPL) Thread Implementation.
25  */
26 
27 #include <sys/thread.h>
28 #include <sys/kmem.h>
29 #include <sys/tsd.h>
30 
31 /*
32  * Thread interfaces
33  */
34 typedef struct thread_priv_s {
35 	unsigned long tp_magic;		/* Magic */
36 	int tp_name_size;		/* Name size */
37 	char *tp_name;			/* Name (without _thread suffix) */
38 	void (*tp_func)(void *);	/* Registered function */
39 	void *tp_args;			/* Args to be passed to function */
40 	size_t tp_len;			/* Len to be passed to function */
41 	int tp_state;			/* State to start thread at */
42 	pri_t tp_pri;			/* Priority to start threat at */
43 } thread_priv_t;
44 
45 static int
46 thread_generic_wrapper(void *arg)
47 {
48 	thread_priv_t *tp = (thread_priv_t *)arg;
49 	void (*func)(void *);
50 	void *args;
51 
52 	ASSERT(tp->tp_magic == TP_MAGIC);
53 	func = tp->tp_func;
54 	args = tp->tp_args;
55 	set_current_state(tp->tp_state);
56 	set_user_nice((kthread_t *)current, PRIO_TO_NICE(tp->tp_pri));
57 	kmem_free(tp->tp_name, tp->tp_name_size);
58 	kmem_free(tp, sizeof (thread_priv_t));
59 
60 	if (func)
61 		func(args);
62 
63 	return (0);
64 }
65 
66 void
67 __thread_exit(void)
68 {
69 	tsd_exit();
70 	complete_and_exit(NULL, 0);
71 	/* Unreachable */
72 }
73 EXPORT_SYMBOL(__thread_exit);
74 
75 /*
76  * thread_create() may block forever if it cannot create a thread or
77  * allocate memory.  This is preferable to returning a NULL which Solaris
78  * style callers likely never check for... since it can't fail.
79  */
80 kthread_t *
81 __thread_create(caddr_t stk, size_t  stksize, thread_func_t func,
82     const char *name, void *args, size_t len, proc_t *pp, int state, pri_t pri)
83 {
84 	thread_priv_t *tp;
85 	struct task_struct *tsk;
86 	char *p;
87 
88 	/* Option pp is simply ignored */
89 	/* Variable stack size unsupported */
90 	ASSERT(stk == NULL);
91 
92 	tp = kmem_alloc(sizeof (thread_priv_t), KM_PUSHPAGE);
93 	if (tp == NULL)
94 		return (NULL);
95 
96 	tp->tp_magic = TP_MAGIC;
97 	tp->tp_name_size = strlen(name) + 1;
98 
99 	tp->tp_name = kmem_alloc(tp->tp_name_size, KM_PUSHPAGE);
100 	if (tp->tp_name == NULL) {
101 		kmem_free(tp, sizeof (thread_priv_t));
102 		return (NULL);
103 	}
104 
105 	strncpy(tp->tp_name, name, tp->tp_name_size);
106 
107 	/*
108 	 * Strip trailing "_thread" from passed name which will be the func
109 	 * name since the exposed API has no parameter for passing a name.
110 	 */
111 	p = strstr(tp->tp_name, "_thread");
112 	if (p)
113 		p[0] = '\0';
114 
115 	tp->tp_func  = func;
116 	tp->tp_args  = args;
117 	tp->tp_len   = len;
118 	tp->tp_state = state;
119 	tp->tp_pri   = pri;
120 
121 	tsk = spl_kthread_create(thread_generic_wrapper, (void *)tp,
122 	    "%s", tp->tp_name);
123 	if (IS_ERR(tsk))
124 		return (NULL);
125 
126 	wake_up_process(tsk);
127 	return ((kthread_t *)tsk);
128 }
129 EXPORT_SYMBOL(__thread_create);
130 
131 /*
132  * spl_kthread_create - Wrapper providing pre-3.13 semantics for
133  * kthread_create() in which it is not killable and less likely
134  * to return -ENOMEM.
135  */
136 struct task_struct *
137 spl_kthread_create(int (*func)(void *), void *data, const char namefmt[], ...)
138 {
139 	struct task_struct *tsk;
140 	va_list args;
141 	char name[TASK_COMM_LEN];
142 
143 	va_start(args, namefmt);
144 	vsnprintf(name, sizeof (name), namefmt, args);
145 	va_end(args);
146 	do {
147 		tsk = kthread_create(func, data, "%s", name);
148 		if (IS_ERR(tsk)) {
149 			if (signal_pending(current)) {
150 				clear_thread_flag(TIF_SIGPENDING);
151 				continue;
152 			}
153 			if (PTR_ERR(tsk) == -ENOMEM)
154 				continue;
155 			return (NULL);
156 		} else {
157 			return (tsk);
158 		}
159 	} while (1);
160 }
161 EXPORT_SYMBOL(spl_kthread_create);
162