module/spl/spl-thread.c

   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         } while (1);
 159 }
 160 EXPORT_SYMBOL(spl_kthread_create);