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Annotation of Net2/vm/device_pager.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1990 University of Utah.
        !             3:  * Copyright (c) 1991 The Regents of the University of California.
        !             4:  * 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:  * 3. All advertising materials mentioning features or use of this software
        !            19:  *    must display the following acknowledgement:
        !            20:  *     This product includes software developed by the University of
        !            21:  *     California, Berkeley and its contributors.
        !            22:  * 4. Neither the name of the University nor the names of its contributors
        !            23:  *    may be used to endorse or promote products derived from this software
        !            24:  *    without specific prior written permission.
        !            25:  *
        !            26:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            27:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            28:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            29:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            30:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            31:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            32:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            33:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            34:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            35:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            36:  * SUCH DAMAGE.
        !            37:  *
        !            38:  *     @(#)device_pager.c      7.2 (Berkeley) 4/20/91
        !            39:  */
        !            40: 
        !            41: /*
        !            42:  * Page to/from special files.
        !            43:  */
        !            44: 
        !            45: #include "devpager.h"
        !            46: #if NDEVPAGER > 0
        !            47: 
        !            48: #include "param.h"
        !            49: #include "conf.h"
        !            50: #include "mman.h"
        !            51: #include "malloc.h"
        !            52: 
        !            53: #include "vm.h"
        !            54: #include "vm_page.h"
        !            55: #include "vm_kern.h"
        !            56: #include "device_pager.h"
        !            57: 
        !            58: queue_head_t   dev_pager_list; /* list of managed devices */
        !            59: 
        !            60: #ifdef DEBUG
        !            61: int    dpagerdebug = 0;
        !            62: #define        DDB_FOLLOW      0x01
        !            63: #define DDB_INIT       0x02
        !            64: #define DDB_ALLOC      0x04
        !            65: #define DDB_FAIL       0x08
        !            66: #endif
        !            67: 
        !            68: void
        !            69: dev_pager_init()
        !            70: {
        !            71: #ifdef DEBUG
        !            72:        if (dpagerdebug & DDB_FOLLOW)
        !            73:                printf("dev_pager_init()\n");
        !            74: #endif
        !            75:        queue_init(&dev_pager_list);
        !            76: }
        !            77: 
        !            78: vm_pager_t
        !            79: dev_pager_alloc(handle, size, prot)
        !            80:        caddr_t handle;
        !            81:        vm_size_t size;
        !            82:        vm_prot_t prot;
        !            83: {
        !            84:        dev_t dev;
        !            85:        vm_pager_t pager;
        !            86:        int (*mapfunc)(), nprot;
        !            87:        register vm_object_t object;
        !            88:        register vm_page_t page;
        !            89:        register dev_pager_t devp;
        !            90:        register int npages, off;
        !            91:        extern int nullop(), enodev();
        !            92: 
        !            93: 
        !            94: #ifdef DEBUG
        !            95:        if (dpagerdebug & DDB_FOLLOW)
        !            96:                printf("dev_pager_alloc(%x, %x, %x)\n", handle, size, prot);
        !            97: #endif
        !            98:        /*
        !            99:         * Pageout to device, should never happen.
        !           100:         */
        !           101:        if (handle == NULL)
        !           102:                panic("dev_pager_alloc called");
        !           103: 
        !           104:        /*
        !           105:         * Look it up, creating as necessary
        !           106:         */
        !           107:        pager = vm_pager_lookup(&dev_pager_list, handle);
        !           108:        if (pager == NULL) {
        !           109:                /*
        !           110:                 * Validation.  Make sure this device can be mapped
        !           111:                 * and that range to map is acceptible to device.
        !           112:                 */
        !           113:                dev = (dev_t)handle;
        !           114:                mapfunc = cdevsw[major(dev)].d_mmap;
        !           115:                if (!mapfunc || mapfunc == enodev || mapfunc == nullop)
        !           116:                        return(NULL);
        !           117:                nprot = 0;
        !           118:                if (prot & VM_PROT_READ)
        !           119:                        nprot |= PROT_READ;
        !           120:                if (prot & VM_PROT_WRITE)
        !           121:                        nprot |= PROT_WRITE;
        !           122:                if (prot & VM_PROT_EXECUTE)
        !           123:                        nprot |= PROT_EXEC;
        !           124:                npages = atop(round_page(size));
        !           125:                for (off = 0; npages--; off += PAGE_SIZE)
        !           126:                        if ((*mapfunc)(dev, off, nprot) == -1)
        !           127:                                return(NULL);
        !           128:                /*
        !           129:                 * Allocate and initialize pager structs
        !           130:                 */
        !           131:                pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK);
        !           132:                if (pager == NULL)
        !           133:                        return(NULL);
        !           134:                devp = (dev_pager_t)malloc(sizeof *devp, M_VMPGDATA, M_WAITOK);
        !           135:                if (devp == NULL) {
        !           136:                        free((caddr_t)pager, M_VMPAGER);
        !           137:                        return(NULL);
        !           138:                }
        !           139:                devp->devp_dev = dev;
        !           140:                devp->devp_npages = atop(round_page(size));
        !           141:                pager->pg_handle = handle;
        !           142:                pager->pg_ops = &devicepagerops;
        !           143:                pager->pg_type = PG_DEVICE;
        !           144:                pager->pg_data = (caddr_t)devp;
        !           145:                /*
        !           146:                 * Allocate object and vm_page structures to describe memory
        !           147:                 */
        !           148:                npages = devp->devp_npages;
        !           149:                object = devp->devp_object = vm_object_allocate(ptoa(npages));
        !           150:                vm_object_enter(object, pager);
        !           151:                vm_object_setpager(object, pager, (vm_offset_t)0, FALSE);
        !           152:                devp->devp_pages = (vm_page_t)
        !           153:                        kmem_alloc(kernel_map, npages*sizeof(struct vm_page));
        !           154:                off = 0;
        !           155:                for (page = devp->devp_pages;
        !           156:                     page < &devp->devp_pages[npages]; page++) {
        !           157:                        vm_object_lock(object);
        !           158:                        vm_page_init(page, object, off);
        !           159:                        page->phys_addr =
        !           160:                                pmap_phys_address((*mapfunc)(dev, off, nprot));
        !           161:                        page->wire_count = 1;
        !           162:                        page->fictitious = TRUE;
        !           163:                        PAGE_WAKEUP(page);
        !           164:                        vm_object_unlock(object);
        !           165:                        off += PAGE_SIZE;
        !           166:                }
        !           167:                /*
        !           168:                 * Finally, put it on the managed list so other can find it.
        !           169:                 */
        !           170:                queue_enter(&dev_pager_list, devp, dev_pager_t, devp_list);
        !           171: #ifdef DEBUG
        !           172:                if (dpagerdebug & DDB_ALLOC)
        !           173:                        printf("dev_pager_alloc: pages %d@%x\n",
        !           174:                               devp->devp_npages, devp->devp_pages);
        !           175: #endif
        !           176:        } else {
        !           177:                /*
        !           178:                 * vm_object_lookup() gains a reference and also
        !           179:                 * removes the object from the cache.
        !           180:                 */
        !           181:                devp = (dev_pager_t)pager->pg_data;
        !           182:                if (vm_object_lookup(pager) != devp->devp_object)
        !           183:                        panic("dev_pager_setup: bad object");
        !           184:        }
        !           185: #ifdef DEBUG
        !           186:        if (dpagerdebug & DDB_ALLOC) {
        !           187:                printf("dev_pager_alloc: pager %x devp %x object %x\n",
        !           188:                       pager, devp, object);
        !           189:                vm_object_print(object, FALSE);
        !           190:        }
        !           191: #endif
        !           192:        return(pager);
        !           193: 
        !           194: }
        !           195: 
        !           196: void
        !           197: dev_pager_dealloc(pager)
        !           198:        vm_pager_t pager;
        !           199: {
        !           200:        dev_pager_t devp = (dev_pager_t)pager->pg_data;
        !           201:        register vm_object_t object;
        !           202: 
        !           203: #ifdef DEBUG
        !           204:        if (dpagerdebug & DDB_FOLLOW)
        !           205:                printf("dev_pager_dealloc(%x)\n", pager);
        !           206: #endif
        !           207:        queue_remove(&dev_pager_list, devp, dev_pager_t, devp_list);
        !           208:        object = devp->devp_object;
        !           209: #ifdef DEBUG
        !           210:        if (dpagerdebug & DDB_ALLOC)
        !           211:                printf("dev_pager_dealloc: devp %x object %x pages %d@%x\n",
        !           212:                       devp, object, devp->devp_npages, devp->devp_pages);
        !           213: #endif
        !           214:        while (!queue_empty(&object->memq))
        !           215:                vm_page_remove((vm_page_t)queue_first(&object->memq));
        !           216:        kmem_free(kernel_map, devp->devp_pages,
        !           217:                  devp->devp_npages * sizeof(struct vm_page));
        !           218:        free((caddr_t)devp, M_VMPGDATA);
        !           219:        pager->pg_data = 0;
        !           220: }
        !           221: 
        !           222: dev_pager_getpage(pager, m, sync)
        !           223:        vm_pager_t pager;
        !           224:        vm_page_t m;
        !           225:        boolean_t sync;
        !           226: {
        !           227: #ifdef DEBUG
        !           228:        if (dpagerdebug & DDB_FOLLOW)
        !           229:                printf("dev_pager_getpage(%x, %x)\n", pager, m);
        !           230: #endif
        !           231:        return(VM_PAGER_BAD);
        !           232: }
        !           233: 
        !           234: dev_pager_putpage(pager, m, sync)
        !           235:        vm_pager_t pager;
        !           236:        vm_page_t m;
        !           237:        boolean_t sync;
        !           238: {
        !           239: #ifdef DEBUG
        !           240:        if (dpagerdebug & DDB_FOLLOW)
        !           241:                printf("dev_pager_putpage(%x, %x)\n", pager, m);
        !           242: #endif
        !           243:        if (pager == NULL)
        !           244:                return;
        !           245:        panic("dev_pager_putpage called");
        !           246: }
        !           247: 
        !           248: boolean_t
        !           249: dev_pager_haspage(pager, offset)
        !           250:        vm_pager_t pager;
        !           251:        vm_offset_t offset;
        !           252: {
        !           253: #ifdef DEBUG
        !           254:        if (dpagerdebug & DDB_FOLLOW)
        !           255:                printf("dev_pager_haspage(%x, %x)\n", pager, offset);
        !           256: #endif
        !           257:        return(TRUE);
        !           258: }
        !           259: #endif

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