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 1.27 2008/08/22 08:47:56 swildner 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 int 36 physio(cdev_t dev, struct uio *uio, int ioflag) 37 { 38 int i; 39 int error; 40 int saflags; 41 int iolen; 42 int bcount; 43 int bounceit; 44 caddr_t ubase; 45 struct buf *bp; 46 47 bp = getpbuf_kva(NULL); 48 saflags = bp->b_flags; 49 error = 0; 50 51 /* XXX: sanity check */ 52 if (dev->si_iosize_max < PAGE_SIZE) { 53 kprintf("WARNING: %s si_iosize_max=%d, using MAXPHYS.\n", 54 devtoname(dev), dev->si_iosize_max); 55 dev->si_iosize_max = MAXPHYS; 56 } 57 58 /* Must be a real uio */ 59 KKASSERT(uio->uio_segflg != UIO_NOCOPY); 60 61 for (i = 0; i < uio->uio_iovcnt; i++) { 62 while (uio->uio_iov[i].iov_len) { 63 if (uio->uio_rw == UIO_READ) 64 bp->b_cmd = BUF_CMD_READ; 65 else 66 bp->b_cmd = BUF_CMD_WRITE; 67 bp->b_flags = saflags; 68 bcount = uio->uio_iov[i].iov_len; 69 70 reinitbufbio(bp); /* clear translation cache */ 71 bp->b_bio1.bio_offset = uio->uio_offset; 72 bp->b_bio1.bio_done = biodone_sync; 73 bp->b_bio1.bio_flags |= BIO_SYNC; 74 75 /* 76 * Setup for mapping the request into kernel memory. 77 * 78 * We can only write as much as fits in a pbuf, 79 * which is MAXPHYS, and no larger then the device's 80 * ability. 81 * 82 * If not using bounce pages the base address of the 83 * user mapping into the pbuf may be offset, further 84 * reducing how much will actually fit in the pbuf. 85 */ 86 if (bcount > dev->si_iosize_max) 87 bcount = dev->si_iosize_max; 88 89 ubase = uio->uio_iov[i].iov_base; 90 bounceit = (int)(((vm_offset_t)ubase) & 15); 91 iolen = ((vm_offset_t)ubase) & PAGE_MASK; 92 if (bounceit) { 93 if (bcount > bp->b_kvasize) 94 bcount = bp->b_kvasize; 95 } else { 96 if ((bcount + iolen) > bp->b_kvasize) { 97 bcount = bp->b_kvasize; 98 if (iolen != 0) 99 bcount -= PAGE_SIZE; 100 } 101 } 102 103 /* 104 * If we have to use a bounce buffer allocate kernel 105 * memory and copyin/copyout. Otherwise map the 106 * user buffer directly into kernel memory without 107 * copying. 108 */ 109 if (uio->uio_segflg == UIO_USERSPACE) { 110 if (bounceit) { 111 bp->b_data = bp->b_kvabase; 112 bp->b_bcount = bcount; 113 vm_hold_load_pages(bp, (vm_offset_t)bp->b_data, (vm_offset_t)bp->b_data + bcount); 114 if (uio->uio_rw == UIO_WRITE) { 115 error = copyin(ubase, bp->b_data, bcount); 116 if (error) { 117 vm_hold_free_pages(bp, (vm_offset_t)bp->b_data, (vm_offset_t)bp->b_data + bcount); 118 goto doerror; 119 } 120 } 121 } else if (vmapbuf(bp, ubase, bcount) < 0) { 122 error = EFAULT; 123 goto doerror; 124 } 125 } else { 126 bp->b_data = uio->uio_iov[i].iov_base; 127 bp->b_bcount = bcount; 128 } 129 dev_dstrategy(dev, &bp->b_bio1); 130 biowait(&bp->b_bio1, "physstr"); 131 132 iolen = bp->b_bcount - bp->b_resid; 133 if (uio->uio_segflg == UIO_USERSPACE) { 134 if (bounceit) { 135 if (uio->uio_rw == UIO_READ && iolen) { 136 error = copyout(bp->b_data, ubase, iolen); 137 if (error) { 138 bp->b_flags |= B_ERROR; 139 bp->b_error = error; 140 } 141 } 142 vm_hold_free_pages(bp, (vm_offset_t)bp->b_data, (vm_offset_t)bp->b_data + bcount); 143 } else { 144 vunmapbuf(bp); 145 } 146 } 147 if (iolen == 0 && !(bp->b_flags & B_ERROR)) 148 goto doerror; /* EOF */ 149 uio->uio_iov[i].iov_len -= iolen; 150 uio->uio_iov[i].iov_base = (char *)uio->uio_iov[i].iov_base + iolen; 151 uio->uio_resid -= iolen; 152 uio->uio_offset += iolen; 153 if (bp->b_flags & B_ERROR) { 154 error = bp->b_error; 155 goto doerror; 156 } 157 } 158 } 159 doerror: 160 relpbuf(bp, NULL); 161 return (error); 162 } 163 164 int 165 physread(struct dev_read_args *ap) 166 { 167 return(physio(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); 168 } 169 170 int 171 physwrite(struct dev_write_args *ap) 172 { 173 return(physio(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); 174 } 175 176