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 LIST_HEAD(sf_buf_list, sf_buf);
  47
  48 static struct objcache *sf_buf_cache;
  49
  50 MALLOC_DEFINE(M_SFBUF, "sfbuf", "Sendfile buffer structures");
  51 struct objcache_malloc_args sf_buf_malloc_args = { sizeof(struct sf_buf), M_SFBUF };
  52
  53
  54 static boolean_t
  55 sf_buf_cache_ctor(void *obj, void *pdata, int ocflags)
  56 {
  57         struct sf_buf *sf = (struct sf_buf *)obj;
  58
  59         sf->lwbuf = NULL;
  60         refcount_init(&sf->ref, 0);
  61
  62         return (TRUE);
  63 }
  64
  65 /*
  66  * Init objcache of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
  67  */
  68 static void
  69 sf_buf_init(void *arg)
  70 {
  71         sf_buf_cache = objcache_create("sf_buf", 0, 0,
  72                 sf_buf_cache_ctor, NULL, NULL,
  73                 objcache_malloc_alloc, objcache_malloc_free,
  74                 &sf_buf_malloc_args);
  75 }
  76
  77 /*
  78  * Acquire an sf_buf reference for a vm_page.
  79  */
  80 struct sf_buf *
  81 sf_buf_alloc(struct vm_page *m)
  82 {
  83         struct sf_buf *sf;
  84
  85         if ((sf = objcache_get(sf_buf_cache, M_WAITOK)) == NULL)
  86                 goto done;
  87
  88         if ((sf->lwbuf = lwbuf_alloc(m, &sf->lwbuf_cache)) == NULL) {
  89                 objcache_put(sf_buf_cache, sf);
  90                 sf = NULL;
  91                 goto done;
  92         }
  93
  94         /*
  95          * Force invalidation of the TLB entry on all CPU's
  96          */
  97         lwbuf_set_global(sf->lwbuf);
  98
  99         refcount_init(&sf->ref, 1);
 100
 101 done:
 102         return (sf);
 103 }
 104
 105 void
 106 sf_buf_ref(void *arg)
 107 {
 108         struct sf_buf *sf = arg;
 109
 110         refcount_acquire(&sf->ref);
 111 }
 112
 113 /*
 114  * Detach mapped page and release resources back to the system.
 115  *
 116  * Returns non-zero (TRUE) if this was the last release of the sfbuf.
 117  *
 118  * (matching the same API that refcount_release() uses to reduce confusion)
 119  */
 120 int
 121 sf_buf_free(void *arg)
 122 {
 123         struct sf_buf *sf = arg;
 124
 125         if (refcount_release(&sf->ref)) {
 126                 lwbuf_free(sf->lwbuf);
 127                 objcache_put(sf_buf_cache, sf);
 128                 return (1);
 129         }
 130         return (0);
 131 }