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 * $FreeBSD$ 20 */ 21 22 #include <sys/param.h> 23 #include <sys/systm.h> 24 #include <sys/bio.h> 25 #include <sys/buf.h> 26 #include <sys/conf.h> 27 #include <sys/proc.h> 28 #include <sys/uio.h> 29 30 #include <vm/vm.h> 31 #include <vm/vm_extern.h> 32 33 static void 34 physwakeup(struct buf *bp) 35 { 36 wakeup(bp); 37 } 38 39 int 40 physio(dev_t dev, struct uio *uio, int ioflag) 41 { 42 int i; 43 int error; 44 int spl; 45 caddr_t sa; 46 u_int iolen; 47 struct buf *bp; 48 49 /* Keep the process UPAGES from being swapped. XXX: why ? */ 50 PHOLD(curproc); 51 52 bp = getpbuf(NULL); 53 sa = bp->b_data; 54 error = bp->b_error = 0; 55 56 /* XXX: sanity check */ 57 if(dev->si_iosize_max < PAGE_SIZE) { 58 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 59 devtoname(dev), dev->si_iosize_max); 60 dev->si_iosize_max = DFLTPHYS; 61 } 62 63 for (i = 0; i < uio->uio_iovcnt; i++) { 64 while (uio->uio_iov[i].iov_len) { 65 bp->b_flags = B_PHYS; 66 if (uio->uio_rw == UIO_READ) 67 bp->b_iocmd = BIO_READ; 68 else 69 bp->b_iocmd = BIO_WRITE; 70 bp->b_dev = dev; 71 bp->b_iodone = physwakeup; 72 bp->b_data = uio->uio_iov[i].iov_base; 73 bp->b_bcount = uio->uio_iov[i].iov_len; 74 bp->b_offset = uio->uio_offset; 75 bp->b_saveaddr = sa; 76 77 /* Don't exceed drivers iosize limit */ 78 if (bp->b_bcount > dev->si_iosize_max) 79 bp->b_bcount = dev->si_iosize_max; 80 81 /* 82 * Make sure the pbuf can map the request 83 * XXX: The pbuf has kvasize = MAXPHYS so a request 84 * XXX: larger than MAXPHYS - PAGE_SIZE must be 85 * XXX: page aligned or it will be fragmented. 86 */ 87 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK; 88 if ((bp->b_bcount + iolen) > bp->b_kvasize) { 89 bp->b_bcount = bp->b_kvasize; 90 if (iolen != 0) 91 bp->b_bcount -= PAGE_SIZE; 92 } 93 bp->b_bufsize = bp->b_bcount; 94 95 bp->b_blkno = btodb(bp->b_offset); 96 97 if (uio->uio_segflg == UIO_USERSPACE) { 98 /* 99 * Note that useracc() alone is not a 100 * sufficient test. vmapbuf() can still fail 101 * due to a smaller file mapped into a larger 102 * area of VM, or if userland races against 103 * vmapbuf() after the useracc() check. 104 */ 105 if (!useracc(bp->b_data, bp->b_bufsize, 106 bp->b_iocmd == BIO_READ ? 107 VM_PROT_WRITE : VM_PROT_READ)) { 108 error = EFAULT; 109 goto doerror; 110 } 111 if (vmapbuf(bp) < 0) { 112 error = EFAULT; 113 goto doerror; 114 } 115 } 116 117 DEV_STRATEGY(bp); 118 spl = splbio(); 119 while ((bp->b_flags & B_DONE) == 0) 120 tsleep(bp, PRIBIO, "physstr", 0); 121 splx(spl); 122 123 if (uio->uio_segflg == UIO_USERSPACE) 124 vunmapbuf(bp); 125 iolen = bp->b_bcount - bp->b_resid; 126 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR)) 127 goto doerror; /* EOF */ 128 uio->uio_iov[i].iov_len -= iolen; 129 uio->uio_iov[i].iov_base = 130 (char *)uio->uio_iov[i].iov_base + iolen; 131 uio->uio_resid -= iolen; 132 uio->uio_offset += iolen; 133 if( bp->b_ioflags & BIO_ERROR) { 134 error = bp->b_error; 135 goto doerror; 136 } 137 } 138 } 139 doerror: 140 relpbuf(bp, NULL); 141 PRELE(curproc); 142 return (error); 143 } 144