device_pager.c

Version: - FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
    1 /*-
    2  * Copyright (c) 1990 University of Utah.
    3  * Copyright (c) 1991, 1993
    4  *      The Regents of the University of California.  All rights reserved.
    5  *
    6  * This code is derived from software contributed to Berkeley by
    7  * the Systems Programming Group of the University of Utah Computer
    8  * Science Department.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)device_pager.c      8.1 (Berkeley) 6/11/93
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD$");
   39 
   40 #include <sys/param.h>
   41 #include <sys/systm.h>
   42 #include <sys/conf.h>
   43 #include <sys/lock.h>
   44 #include <sys/proc.h>
   45 #include <sys/mutex.h>
   46 #include <sys/mman.h>
   47 #include <sys/sx.h>
   48 
   49 #include <vm/vm.h>
   50 #include <vm/vm_object.h>
   51 #include <vm/vm_page.h>
   52 #include <vm/vm_pager.h>
   53 #include <vm/uma.h>
   54 
   55 static void dev_pager_init(void);
   56 static vm_object_t dev_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
   57                 vm_ooffset_t);
   58 static void dev_pager_dealloc(vm_object_t);
   59 static int dev_pager_getpages(vm_object_t, vm_page_t *, int, int);
   60 static void dev_pager_putpages(vm_object_t, vm_page_t *, int, 
   61                 boolean_t, int *);
   62 static boolean_t dev_pager_haspage(vm_object_t, vm_pindex_t, int *,
   63                 int *);
   64 
   65 /* list of device pager objects */
   66 static struct pagerlst dev_pager_object_list;
   67 /* protect list manipulation */
   68 static struct mtx dev_pager_mtx;
   69 
   70 
   71 static uma_zone_t fakepg_zone;
   72 
   73 static vm_page_t dev_pager_getfake(vm_paddr_t);
   74 static void dev_pager_putfake(vm_page_t);
   75 static void dev_pager_updatefake(vm_page_t, vm_paddr_t);
   76 
   77 struct pagerops devicepagerops = {
   78         .pgo_init =     dev_pager_init,
   79         .pgo_alloc =    dev_pager_alloc,
   80         .pgo_dealloc =  dev_pager_dealloc,
   81         .pgo_getpages = dev_pager_getpages,
   82         .pgo_putpages = dev_pager_putpages,
   83         .pgo_haspage =  dev_pager_haspage,
   84 };
   85 
   86 static void
   87 dev_pager_init()
   88 {
   89         TAILQ_INIT(&dev_pager_object_list);
   90         mtx_init(&dev_pager_mtx, "dev_pager list", NULL, MTX_DEF);
   91         fakepg_zone = uma_zcreate("DP fakepg", sizeof(struct vm_page),
   92             NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
   93             UMA_ZONE_NOFREE|UMA_ZONE_VM); 
   94 }
   95 
   96 /*
   97  * MPSAFE
   98  */
   99 static vm_object_t
  100 dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff)
  101 {
  102         struct cdev *dev;
  103         vm_object_t object, object1;
  104         vm_pindex_t pindex;
  105         unsigned int npages;
  106         vm_paddr_t paddr;
  107         vm_offset_t off;
  108         struct cdevsw *csw;
  109 
  110         /*
  111          * Offset should be page aligned.
  112          */
  113         if (foff & PAGE_MASK)
  114                 return (NULL);
  115 
  116         size = round_page(size);
  117         pindex = OFF_TO_IDX(foff + size);
  118 
  119         /*
  120          * Make sure this device can be mapped.
  121          */
  122         dev = handle;
  123         csw = dev_refthread(dev);
  124         if (csw == NULL)
  125                 return (NULL);
  126 
  127         /*
  128          * Check that the specified range of the device allows the desired
  129          * protection.
  130          *
  131          * XXX assumes VM_PROT_* == PROT_*
  132          */
  133         npages = OFF_TO_IDX(size);
  134         for (off = foff; npages--; off += PAGE_SIZE)
  135                 if ((*csw->d_mmap)(dev, off, &paddr, (int)prot) != 0) {
  136                         dev_relthread(dev);
  137                         return (NULL);
  138                 }
  139 
  140         mtx_lock(&dev_pager_mtx);
  141 
  142         /*
  143          * Look up pager, creating as necessary.
  144          */
  145         object1 = NULL;
  146         object = vm_pager_object_lookup(&dev_pager_object_list, handle);
  147         if (object == NULL) {
  148                 /*
  149                  * Allocate object and associate it with the pager.  Initialize
  150                  * the object's pg_color based upon the physical address of the
  151                  * device's memory.
  152                  */
  153                 mtx_unlock(&dev_pager_mtx);
  154                 object1 = vm_object_allocate(OBJT_DEVICE, pindex);
  155                 object1->flags |= OBJ_COLORED;
  156                 object1->pg_color = atop(paddr) - OFF_TO_IDX(off - PAGE_SIZE);
  157                 mtx_lock(&dev_pager_mtx);
  158                 object = vm_pager_object_lookup(&dev_pager_object_list, handle);
  159                 if (object != NULL) {
  160                         /*
  161                          * We raced with other thread while allocating object.
  162                          */
  163                         if (pindex > object->size)
  164                                 object->size = pindex;
  165                 } else {
  166                         object = object1;
  167                         object1 = NULL;
  168                         object->handle = handle;
  169                         TAILQ_INIT(&object->un_pager.devp.devp_pglist);
  170                         TAILQ_INSERT_TAIL(&dev_pager_object_list, object,
  171                             pager_object_list);
  172                 }
  173         } else {
  174                 if (pindex > object->size)
  175                         object->size = pindex;
  176         }
  177         mtx_unlock(&dev_pager_mtx);
  178         dev_relthread(dev);
  179         vm_object_deallocate(object1);
  180         return (object);
  181 }
  182 
  183 static void
  184 dev_pager_dealloc(object)
  185         vm_object_t object;
  186 {
  187         vm_page_t m;
  188 
  189         VM_OBJECT_UNLOCK(object);
  190         mtx_lock(&dev_pager_mtx);
  191         TAILQ_REMOVE(&dev_pager_object_list, object, pager_object_list);
  192         mtx_unlock(&dev_pager_mtx);
  193         VM_OBJECT_LOCK(object);
  194         /*
  195          * Free up our fake pages.
  196          */
  197         while ((m = TAILQ_FIRST(&object->un_pager.devp.devp_pglist)) != 0) {
  198                 TAILQ_REMOVE(&object->un_pager.devp.devp_pglist, m, pageq);
  199                 dev_pager_putfake(m);
  200         }
  201 }
  202 
  203 static int
  204 dev_pager_getpages(object, m, count, reqpage)
  205         vm_object_t object;
  206         vm_page_t *m;
  207         int count;
  208         int reqpage;
  209 {
  210         vm_pindex_t offset;
  211         vm_paddr_t paddr;
  212         vm_page_t page;
  213         struct cdev *dev;
  214         int i, ret;
  215         int prot;
  216         struct cdevsw *csw;
  217         struct thread *td;
  218         struct file *fpop;
  219 
  220         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
  221         dev = object->handle;
  222         offset = m[reqpage]->pindex;
  223         VM_OBJECT_UNLOCK(object);
  224         csw = dev_refthread(dev);
  225         if (csw == NULL)
  226                 panic("dev_pager_getpage: no cdevsw");
  227         prot = PROT_READ;       /* XXX should pass in? */
  228 
  229         td = curthread;
  230         fpop = td->td_fpop;
  231         td->td_fpop = NULL;
  232         ret = (*csw->d_mmap)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot);
  233         KASSERT(ret == 0, ("dev_pager_getpage: map function returns error"));
  234         td->td_fpop = fpop;
  235         dev_relthread(dev);
  236 
  237         if ((m[reqpage]->flags & PG_FICTITIOUS) != 0) {
  238                 /*
  239                  * If the passed in reqpage page is a fake page, update it with
  240                  * the new physical address.
  241                  */
  242                 VM_OBJECT_LOCK(object);
  243                 dev_pager_updatefake(m[reqpage], paddr);
  244                 if (count > 1) {
  245                         vm_page_lock_queues();
  246                         for (i = 0; i < count; i++) {
  247                                 if (i != reqpage)
  248                                         vm_page_free(m[i]);
  249                         }
  250                         vm_page_unlock_queues();
  251                 }
  252         } else {
  253                 /*
  254                  * Replace the passed in reqpage page with our own fake page and
  255                  * free up the all of the original pages.
  256                  */
  257                 page = dev_pager_getfake(paddr);
  258                 VM_OBJECT_LOCK(object);
  259                 TAILQ_INSERT_TAIL(&object->un_pager.devp.devp_pglist, page, pageq);
  260                 vm_page_lock_queues();
  261                 for (i = 0; i < count; i++)
  262                         vm_page_free(m[i]);
  263                 vm_page_unlock_queues();
  264                 vm_page_insert(page, object, offset);
  265                 m[reqpage] = page;
  266         }
  267 
  268         return (VM_PAGER_OK);
  269 }
  270 
  271 static void
  272 dev_pager_putpages(object, m, count, sync, rtvals)
  273         vm_object_t object;
  274         vm_page_t *m;
  275         int count;
  276         boolean_t sync;
  277         int *rtvals;
  278 {
  279         panic("dev_pager_putpage called");
  280 }
  281 
  282 static boolean_t
  283 dev_pager_haspage(object, pindex, before, after)
  284         vm_object_t object;
  285         vm_pindex_t pindex;
  286         int *before;
  287         int *after;
  288 {
  289         if (before != NULL)
  290                 *before = 0;
  291         if (after != NULL)
  292                 *after = 0;
  293         return (TRUE);
  294 }
  295 
  296 /*
  297  * Instantiate a fictitious page.  Unlike physical memory pages, only
  298  * the machine-independent fields must be initialized.
  299  */
  300 static vm_page_t
  301 dev_pager_getfake(paddr)
  302         vm_paddr_t paddr;
  303 {
  304         vm_page_t m;
  305 
  306         m = uma_zalloc(fakepg_zone, M_WAITOK);
  307 
  308         m->flags = PG_FICTITIOUS;
  309         m->oflags = VPO_BUSY;
  310         m->valid = VM_PAGE_BITS_ALL;
  311         m->dirty = 0;
  312         m->busy = 0;
  313         m->queue = PQ_NONE;
  314         m->object = NULL;
  315 
  316         m->wire_count = 1;
  317         m->hold_count = 0;
  318         m->phys_addr = paddr;
  319 
  320         return (m);
  321 }
  322 
  323 static void
  324 dev_pager_putfake(m)
  325         vm_page_t m;
  326 {
  327         if (!(m->flags & PG_FICTITIOUS))
  328                 panic("dev_pager_putfake: bad page");
  329         uma_zfree(fakepg_zone, m);
  330 }
  331 
  332 static void
  333 dev_pager_updatefake(m, paddr)
  334         vm_page_t m;
  335         vm_paddr_t paddr;
  336 {
  337         if (!(m->flags & PG_FICTITIOUS))
  338                 panic("dev_pager_updatefake: bad page");
  339         m->phys_addr = paddr;
  340         m->valid = VM_PAGE_BITS_ALL;
  341 }
Cache object: abf1f9e3e0528a0f5a287d8fe3b67cf7
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.
FreeBSD/Linux Kernel Cross Reference sys/vm/device_pager.c

FreeBSD/Linux Kernel Cross Reference
sys/vm/device_pager.c
