sys/kern/kern_sfbuf.c

   1 /*
   2  * Copyright (c) 1998 David Greenman.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  */
  25
  26 #include <sys/param.h>
  27 #include <sys/types.h>
  28 #include <sys/systm.h>
  29 #include <sys/kernel.h>
  30 #include <sys/malloc.h>
  31 #include <sys/sfbuf.h>
  32 #include <sys/refcount.h>
  33 #include <sys/objcache.h>
  34
  35 #include <cpu/lwbuf.h>
  36
  37 #include <vm/vm.h>
  38 #include <vm/vm_extern.h>
  39 #include <vm/vm_kern.h>
  40 #include <vm/vm_page.h>
  41 #include <vm/pmap.h>
  42
  43 static void sf_buf_init(void *arg);
  44 SYSINIT(sock_sf, SI_BOOT2_MACHDEP, SI_ORDER_ANY, sf_buf_init, NULL);
  45
  46 static struct objcache *sf_buf_cache;
  47
  48 MALLOC_DEFINE(M_SFBUF, "sfbuf", "Sendfile buffer structures");
  49 static struct objcache_malloc_args sf_buf_malloc_args = {
  50         sizeof(struct sf_buf),
  51         M_SFBUF
  52 };
  53
  54
  55 static boolean_t
  56 sf_buf_cache_ctor(void *obj, void *pdata, int ocflags)
  57 {
  58         struct sf_buf *sf = (struct sf_buf *)obj;
  59
  60         sf->lwbuf = NULL;
  61         refcount_init(&sf->ref, 0);
  62
  63         return (TRUE);
  64 }
  65
  66 /*
  67  * Init objcache of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
  68  */
  69 static void
  70 sf_buf_init(void *arg)
  71 {
  72         sf_buf_cache = objcache_create("sf_buf", 0, 0,
  73                 sf_buf_cache_ctor, NULL, NULL,
  74                 objcache_malloc_alloc, objcache_malloc_free,
  75                 &sf_buf_malloc_args);
  76 }
  77
  78 /*
  79  * Acquire an sf_buf reference for a vm_page.
  80  */
  81 struct sf_buf *
  82 sf_buf_alloc(struct vm_page *m)
  83 {
  84         struct sf_buf *sf;
  85
  86         if ((sf = objcache_get(sf_buf_cache, M_WAITOK)) == NULL)
  87                 goto done;
  88
  89         if ((sf->lwbuf = lwbuf_alloc(m, &sf->lwbuf_cache)) == NULL) {
  90                 objcache_put(sf_buf_cache, sf);
  91                 sf = NULL;
  92                 goto done;
  93         }
  94
  95         /*
  96          * Force invalidation of the TLB entry on all CPU's
  97          */
  98         lwbuf_set_global(sf->lwbuf);
  99
 100         refcount_init(&sf->ref, 1);
 101
 102 done:
 103         return (sf);
 104 }
 105
 106 void
 107 sf_buf_ref(void *arg)
 108 {
 109         struct sf_buf *sf = arg;
 110
 111         refcount_acquire(&sf->ref);
 112 }
 113
 114 /*
 115  * Detach mapped page and release resources back to the system.
 116  *
 117  * Returns non-zero (TRUE) if this was the last release of the sfbuf.
 118  *
 119  * (matching the same API that refcount_release() uses to reduce confusion)
 120  */
 121 int
 122 sf_buf_free(void *arg)
 123 {
 124         struct sf_buf *sf = arg;
 125
 126         if (refcount_release(&sf->ref)) {
 127                 lwbuf_free(sf->lwbuf);
 128                 objcache_put(sf_buf_cache, sf);
 129                 return (1);
 130         }
 131         return (0);
 132 }