rtkaio/sysdeps/unix/sysv/linux/klio_listio.c

   1 /* Enqueue and list of read or write requests.
   2    Copyright (C) 1997,1998,1999,2000,2001,2002,2003
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #include <kaio_misc.h>
  23
  24 #ifndef USE_KAIO
  25 #include <lio_listio.c>
  26 #else
  27
  28 #include <aio.h>
  29 #include <assert.h>
  30 #include <errno.h>
  31 #include <stdlib.h>
  32 #include <unistd.h>
  33
  34 #ifndef lio_listio
  35 #define LIO_OPCODE_BASE 0
  36 #endif
  37
  38 /* We need this special structure to handle asynchronous I/O.  */
  39 struct async_waitlist
  40   {
  41     int counter;
  42     struct sigevent sigev;
  43     struct waitlist list[0];
  44   };
  45
  46 int
  47 lio_listio (mode, list, nent, sig)
  48      int mode;
  49      struct aiocb *const list[];
  50      int nent;
  51      struct sigevent *sig;
  52 {
  53   struct sigevent defsigev;
  54   struct requestlist *requests[nent];
  55   int cnt;
  56   volatile int total = 0;
  57   int result = 0, op = 0;
  58   kctx_t kctx = KCTX_NONE;
  59
  60   /* Check arguments.  */
  61   if (mode != LIO_WAIT && mode != LIO_NOWAIT)
  62     {
  63       __set_errno (EINVAL);
  64       return -1;
  65     }
  66
  67   if (sig == NULL)
  68     {
  69       defsigev.sigev_notify = SIGEV_NONE;
  70       sig = &defsigev;
  71     }
  72
  73   /* Request the mutex.  */
  74   pthread_mutex_lock (&__aio_requests_mutex);
  75
  76   if (mode == LIO_WAIT && ! __have_no_kernel_aio && nent > 0)
  77     {
  78       int res;
  79       INTERNAL_SYSCALL_DECL (err);
  80
  81       kctx = 0;
  82       do
  83         res = INTERNAL_SYSCALL (io_setup, err, 2, nent, &kctx);
  84       while (INTERNAL_SYSCALL_ERROR_P (res, err)
  85              && INTERNAL_SYSCALL_ERRNO (res, err) == EINTR);
  86       if (INTERNAL_SYSCALL_ERROR_P (res, err))
  87         {
  88           kctx = KCTX_NONE;
  89           if (INTERNAL_SYSCALL_ERRNO (res, err) == ENOSYS)
  90             __have_no_kernel_aio = 1;
  91         }
  92     }
  93   else if (mode == LIO_NOWAIT)
  94     {
  95       op = LIO_KTHREAD;
  96       if (sig->sigev_notify != SIGEV_NONE)
  97         op = LIO_KTHREAD | LIO_KTHREAD_REQUIRED;
  98     }
  99   op |= LIO_OPCODE_BASE;
 100
 101   /* Now we can enqueue all requests.  Since we already acquired the
 102      mutex the enqueue function need not do this.  */
 103   for (cnt = 0; cnt < nent; ++cnt)
 104     if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
 105       {
 106         list[cnt]->aio_sigevent.sigev_notify = SIGEV_NONE;
 107         requests[cnt]
 108           = __aio_enqueue_request_ctx ((aiocb_union *) list[cnt],
 109                                        list[cnt]->aio_lio_opcode | op,
 110                                        kctx);
 111
 112         if (requests[cnt] != NULL)
 113           /* Successfully enqueued.  */
 114           ++total;
 115         else
 116           /* Signal that we've seen an error.  `errno' and the error code
 117              of the aiocb will tell more.  */
 118           result = -1;
 119       }
 120     else
 121       requests[cnt] = NULL;
 122
 123   if (total == 0)
 124     {
 125       /* We don't have anything to do except signalling if we work
 126          asynchronously.  */
 127
 128       if (kctx != KCTX_NONE)
 129         {
 130           INTERNAL_SYSCALL_DECL (err);
 131           INTERNAL_SYSCALL (io_destroy, err, 1, kctx);
 132         }
 133
 134       /* Release the mutex.  We do this before raising a signal since the
 135          signal handler might do a `siglongjmp' and then the mutex is
 136          locked forever.  */
 137       pthread_mutex_unlock (&__aio_requests_mutex);
 138
 139       if (mode == LIO_NOWAIT)
 140         {
 141 #ifdef BROKEN_THREAD_SIGNALS
 142           __aio_notify_only (sig,
 143                              sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0);
 144 #else
 145           __aio_notify_only (sig);
 146 #endif
 147         }
 148
 149       return result;
 150     }
 151   else if (mode == LIO_WAIT)
 152     {
 153       pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 154       struct waitlist waitlist[nent];
 155       int oldstate;
 156       volatile int ktotal = 0;
 157
 158       total = 0;
 159       for (cnt = 0; cnt < nent; ++cnt)
 160         {
 161           assert (requests[cnt] == NULL || list[cnt] != NULL);
 162
 163           if (requests[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP)
 164             {
 165               if (requests[cnt]->kioctx != KCTX_NONE)
 166                 {
 167                   assert (requests[cnt]->kioctx == kctx);
 168                   waitlist[cnt].counterp = &ktotal;
 169                   ++ktotal;
 170                 }
 171               else
 172                 {
 173                   waitlist[cnt].counterp = &total;
 174                   ++total;
 175                 }
 176               waitlist[cnt].cond = &cond;
 177               waitlist[cnt].next = requests[cnt]->waiting;
 178               waitlist[cnt].sigevp = NULL;
 179 #ifdef BROKEN_THREAD_SIGNALS
 180               waitlist[cnt].caller_pid = 0;     /* Not needed.  */
 181 #endif
 182               requests[cnt]->waiting = &waitlist[cnt];
 183             }
 184         }
 185
 186       /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation
 187          points we must be careful.  We added entries to the waiting lists
 188          which we must remove.  So defer cancelation for now.  */
 189       pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate);
 190
 191       while (ktotal > 0)
 192         __aio_wait_for_events (kctx, NULL);
 193       while (total > 0)
 194         pthread_cond_wait (&cond, &__aio_requests_mutex);
 195
 196       /* Now it's time to restore the cancelation state.  */
 197       pthread_setcancelstate (oldstate, NULL);
 198
 199       if (kctx != KCTX_NONE)
 200         {
 201           INTERNAL_SYSCALL_DECL (err);
 202           INTERNAL_SYSCALL (io_destroy, err, 1, kctx);
 203         }
 204
 205       /* Release the conditional variable.  */
 206       if (pthread_cond_destroy (&cond) != 0)
 207         /* This must never happen.  */
 208         abort ();
 209     }
 210   else if (sig->sigev_notify != SIGEV_NONE)
 211     {
 212       struct async_waitlist *waitlist;
 213
 214       waitlist = (struct async_waitlist *)
 215         malloc (sizeof (struct async_waitlist)
 216                 + (nent * sizeof (struct waitlist)));
 217
 218       if (waitlist == NULL)
 219         {
 220           __set_errno (EAGAIN);
 221           result = -1;
 222         }
 223       else
 224         {
 225 #ifdef BROKEN_THREAD_SIGNALS
 226           pid_t caller_pid = sig->sigev_notify == SIGEV_SIGNAL ? getpid () : 0;
 227 #endif
 228           total = 0;
 229
 230           for (cnt = 0; cnt < nent; ++cnt)
 231             {
 232               assert (requests[cnt] == NULL || list[cnt] != NULL);
 233
 234               if (requests[cnt] != NULL
 235                   && list[cnt]->aio_lio_opcode != LIO_NOP)
 236                 {
 237                   waitlist->list[cnt].cond = NULL;
 238                   waitlist->list[cnt].next = requests[cnt]->waiting;
 239                   waitlist->list[cnt].counterp = &waitlist->counter;
 240                   waitlist->list[cnt].sigevp = &waitlist->sigev;
 241 #ifdef BROKEN_THREAD_SIGNALS
 242                   waitlist->list[cnt].caller_pid = caller_pid;
 243 #endif
 244                   requests[cnt]->waiting = &waitlist->list[cnt];
 245                   ++total;
 246                 }
 247             }
 248
 249           waitlist->counter = total;
 250           waitlist->sigev = *sig;
 251         }
 252     }
 253
 254   /* Release the mutex.  */
 255   pthread_mutex_unlock (&__aio_requests_mutex);
 256
 257   return result;
 258 }
 259 #endif