1 /* 2 * Copyright (c) 1994 John S. Dyson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Absolutely no warranty of function or purpose is made by the author 15 * John S. Dyson. 16 * 4. Modifications may be freely made to this file if the above conditions 17 * are met. 18 * 19 * $FreeBSD: src/sys/kern/kern_physio.c,v 1.46.2.4 2003/11/14 09:51:47 simokawa Exp $ 20 * $DragonFly: src/sys/kern/kern_physio.c,v 1.26 2008/08/10 20:03:14 dillon Exp $ 21 */ 22 23 #include <sys/param.h> 24 #include <sys/systm.h> 25 #include <sys/buf.h> 26 #include <sys/conf.h> 27 #include <sys/proc.h> 28 #include <sys/uio.h> 29 #include <sys/device.h> 30 #include <sys/thread2.h> 31 32 #include <vm/vm.h> 33 #include <vm/vm_extern.h> 34 35 static void 36 physwakeup(struct bio *bio) 37 { 38 bio->bio_buf->b_cmd = BUF_CMD_DONE; 39 wakeup(bio); 40 } 41 42 static int 43 physio(cdev_t dev, struct uio *uio, int ioflag) 44 { 45 int i; 46 int error; 47 int chk_blockno; 48 int saflags; 49 int iolen; 50 int bcount; 51 int bounceit; 52 caddr_t ubase; 53 struct buf *bp; 54 55 bp = getpbuf(NULL); 56 saflags = bp->b_flags; 57 error = 0; 58 59 /* XXX: sanity check */ 60 if (dev->si_iosize_max < PAGE_SIZE) { 61 kprintf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 62 devtoname(dev), dev->si_iosize_max); 63 dev->si_iosize_max = DFLTPHYS; 64 } 65 66 /* Must be a real uio */ 67 KKASSERT(uio->uio_segflg != UIO_NOCOPY); 68 69 /* Don't check block number overflow for D_MEM */ 70 if ((dev_dflags(dev) & D_TYPEMASK) == D_MEM) 71 chk_blockno = 0; 72 else 73 chk_blockno = 1; 74 75 for (i = 0; i < uio->uio_iovcnt; i++) { 76 while (uio->uio_iov[i].iov_len) { 77 if (uio->uio_rw == UIO_READ) 78 bp->b_cmd = BUF_CMD_READ; 79 else 80 bp->b_cmd = BUF_CMD_WRITE; 81 bp->b_flags = saflags; 82 bcount = uio->uio_iov[i].iov_len; 83 84 reinitbufbio(bp); /* clear translation cache */ 85 bp->b_bio1.bio_offset = uio->uio_offset; 86 bp->b_bio1.bio_done = physwakeup; 87 88 /* 89 * Setup for mapping the request into kernel memory. 90 * 91 * We can only write as much as fits in a pbuf, 92 * which is MAXPHYS, and no larger then the device's 93 * ability. 94 * 95 * If not using bounce pages the base address of the 96 * user mapping into the pbuf may be offset, further 97 * reducing how much will actually fit in the pbuf. 98 */ 99 if (bcount > dev->si_iosize_max) 100 bcount = dev->si_iosize_max; 101 102 ubase = uio->uio_iov[i].iov_base; 103 bounceit = (int)(((vm_offset_t)ubase) & 15); 104 iolen = ((vm_offset_t)ubase) & PAGE_MASK; 105 if (bounceit) { 106 if (bcount > bp->b_kvasize) 107 bcount = bp->b_kvasize; 108 } else { 109 if ((bcount + iolen) > bp->b_kvasize) { 110 bcount = bp->b_kvasize; 111 if (iolen != 0) 112 bcount -= PAGE_SIZE; 113 } 114 } 115 116 /* 117 * If we have to use a bounce buffer allocate kernel 118 * memory and copyin/copyout. Otherwise map the 119 * user buffer directly into kernel memory without 120 * copying. 121 */ 122 if (uio->uio_segflg == UIO_USERSPACE) { 123 if (bounceit) { 124 bp->b_data = bp->b_kvabase; 125 bp->b_bcount = bcount; 126 vm_hold_load_pages(bp, (vm_offset_t)bp->b_data, (vm_offset_t)bp->b_data + bcount); 127 if (uio->uio_rw == UIO_WRITE) { 128 error = copyin(ubase, bp->b_data, bcount); 129 if (error) { 130 vm_hold_free_pages(bp, (vm_offset_t)bp->b_data, (vm_offset_t)bp->b_data + bcount); 131 goto doerror; 132 } 133 } 134 } else if (vmapbuf(bp, ubase, bcount) < 0) { 135 error = EFAULT; 136 goto doerror; 137 } 138 } else { 139 bp->b_data = uio->uio_iov[i].iov_base; 140 bp->b_bcount = bcount; 141 } 142 dev_dstrategy(dev, &bp->b_bio1); 143 crit_enter(); 144 while (bp->b_cmd != BUF_CMD_DONE) 145 tsleep(&bp->b_bio1, 0, "physstr", 0); 146 crit_exit(); 147 148 iolen = bp->b_bcount - bp->b_resid; 149 if (uio->uio_segflg == UIO_USERSPACE) { 150 if (bounceit) { 151 if (uio->uio_rw == UIO_READ && iolen) { 152 error = copyout(bp->b_data, ubase, iolen); 153 if (error) { 154 bp->b_flags |= B_ERROR; 155 bp->b_error = error; 156 } 157 } 158 vm_hold_free_pages(bp, (vm_offset_t)bp->b_data, (vm_offset_t)bp->b_data + bcount); 159 } else { 160 vunmapbuf(bp); 161 } 162 } 163 if (iolen == 0 && !(bp->b_flags & B_ERROR)) 164 goto doerror; /* EOF */ 165 uio->uio_iov[i].iov_len -= iolen; 166 uio->uio_iov[i].iov_base += iolen; 167 uio->uio_resid -= iolen; 168 uio->uio_offset += iolen; 169 if (bp->b_flags & B_ERROR) { 170 error = bp->b_error; 171 goto doerror; 172 } 173 } 174 } 175 doerror: 176 relpbuf(bp, NULL); 177 return (error); 178 } 179 180 int 181 physread(struct dev_read_args *ap) 182 { 183 return(physio(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); 184 } 185 186 int 187 physwrite(struct dev_write_args *ap) 188 { 189 return(physio(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); 190 } 191 192