sys/dev/dmover/dmover_session.c

   1 /*      $NetBSD: dmover_session.c,v 1.4 2007/03/12 19:56:19 ad Exp $    */
   2
   3 /*
   4  * Copyright (c) 2002 Wasabi Systems, Inc.
   5  * All rights reserved.
   6  *
   7  * Written by Jason R. Thorpe for Wasabi Systems, Inc.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed for the NetBSD Project by
  20  *      Wasabi Systems, Inc.
  21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
  22  *    or promote products derived from this software without specific prior
  23  *    written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
  26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
  29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  35  * POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 /*
  39  * dmover_session.c: Session management functions for dmover-api.
  40  */
  41
  42 #include <sys/cdefs.h>
  43 __KERNEL_RCSID(0, "$NetBSD: dmover_session.c,v 1.4 2007/03/12 19:56:19 ad Exp $");
  44
  45 #include <sys/param.h>
  46 #include <sys/simplelock.h>
  47 #include <sys/pool.h>
  48 #include <sys/systm.h>
  49 #include <sys/malloc.h>
  50
  51 #include <dev/dmover/dmovervar.h>
  52
  53 struct pool dmover_session_pool;
  54
  55 static int initialized;
  56 static struct simplelock initialized_slock = SIMPLELOCK_INITIALIZER;
  57
  58 void
  59 dmover_session_initialize(void)
  60 {
  61
  62         simple_lock(&initialized_slock);
  63         if (__predict_true(initialized == 0)) {
  64                 pool_init(&dmover_session_pool, sizeof(struct dmover_session),
  65                     0, 0, 0, "dmses", &pool_allocator_nointr, IPL_NONE);
  66                 initialized = 1;
  67         }
  68         simple_unlock(&initialized_slock);
  69 }
  70
  71 /*
  72  * dmover_session_create:       [client interface function]
  73  *
  74  *      Create a dmover session.
  75  */
  76 int
  77 dmover_session_create(const char *type, struct dmover_session **dsesp)
  78 {
  79         struct dmover_session *dses;
  80         int error;
  81
  82         if (__predict_false(initialized == 0)) {
  83                 simple_lock(&initialized_slock);
  84                 error = initialized ? 0 : ENXIO;
  85                 simple_unlock(&initialized_slock);
  86
  87                 if (error)
  88                         return (error);
  89         }
  90
  91         dses = pool_get(&dmover_session_pool, PR_NOWAIT);
  92         if (__predict_false(dses == NULL))
  93                 return (ENOMEM);
  94
  95         /* Allocate a back-end to the session. */
  96         error = dmover_backend_alloc(dses, type);
  97         if (__predict_false(error)) {
  98                 pool_put(&dmover_session_pool, dses);
  99                 return (error);
 100         }
 101
 102         TAILQ_INIT(&dses->__dses_pendreqs);
 103         dses->__dses_npendreqs = 0;
 104
 105         *dsesp = dses;
 106         return (0);
 107 }
 108
 109 /*
 110  * dmover_session_destroy:      [client interface function]
 111  *
 112  *      Tear down a dmover session.
 113  */
 114 void
 115 dmover_session_destroy(struct dmover_session *dses)
 116 {
 117
 118 #ifdef DIAGNOSTIC
 119         if (__predict_false(initialized == 0)) {
 120                 int croak;
 121
 122                 simple_lock(&initialized_slock);
 123                 croak = (initialized == 0);
 124                 simple_unlock(&initialized_slock);
 125
 126                 if (croak)
 127                         panic("dmover_session_destroy: not initialized");
 128         }
 129 #endif
 130
 131         /* XXX */
 132         if (dses->__dses_npendreqs)
 133                 panic("dmover_session_destroy");
 134
 135         dmover_backend_release(dses);
 136         pool_put(&dmover_session_pool, dses);
 137 }