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 1.46.2.3 2003/05/29 06:15:35 alc Exp $ 20 * $DragonFly: src/sys/kern/kern_physio.c,v 1.5 2003/07/22 17:03:33 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 31 #include <vm/vm.h> 32 #include <vm/vm_extern.h> 33 34 static void 35 physwakeup(struct buf *bp) 36 { 37 wakeup((caddr_t) bp); 38 } 39 40 int 41 physio(dev_t dev, struct uio *uio, int ioflag) 42 { 43 int i; 44 int error; 45 int spl; 46 caddr_t sa; 47 off_t blockno; 48 u_int iolen; 49 struct buf *bp; 50 51 /* 52 * NOTE: we no longer have to PHOLD() the process, because the 53 * kernel stack / uarea cannot be swapped, and when it can be in 54 * the future it will only happen if the process is sleeping on 55 * a particular address. 56 */ 57 bp = getpbuf(NULL); 58 sa = bp->b_data; 59 error = 0; 60 61 /* XXX: sanity check */ 62 if(dev->si_iosize_max < PAGE_SIZE) { 63 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 64 devtoname(dev), dev->si_iosize_max); 65 dev->si_iosize_max = DFLTPHYS; 66 } 67 68 for (i = 0; i < uio->uio_iovcnt; i++) { 69 while (uio->uio_iov[i].iov_len) { 70 if (uio->uio_rw == UIO_READ) 71 bp->b_flags = B_PHYS | B_CALL | B_READ; 72 else 73 bp->b_flags = B_PHYS | B_CALL | B_WRITE; 74 bp->b_dev = dev; 75 bp->b_iodone = physwakeup; 76 bp->b_data = uio->uio_iov[i].iov_base; 77 bp->b_bcount = uio->uio_iov[i].iov_len; 78 bp->b_offset = uio->uio_offset; 79 bp->b_saveaddr = sa; 80 81 /* Don't exceed drivers iosize limit */ 82 if (bp->b_bcount > dev->si_iosize_max) 83 bp->b_bcount = dev->si_iosize_max; 84 85 /* 86 * Make sure the pbuf can map the request 87 * XXX: The pbuf has kvasize = MAXPHYS so a request 88 * XXX: larger than MAXPHYS - PAGE_SIZE must be 89 * XXX: page aligned or it will be fragmented. 90 */ 91 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK; 92 if ((bp->b_bcount + iolen) > bp->b_kvasize) { 93 bp->b_bcount = bp->b_kvasize; 94 if (iolen != 0) 95 bp->b_bcount -= PAGE_SIZE; 96 } 97 bp->b_bufsize = bp->b_bcount; 98 99 blockno = bp->b_offset >> DEV_BSHIFT; 100 if ((daddr_t)blockno != blockno) { 101 error = EINVAL; /* blockno overflow */ 102 goto doerror; 103 } 104 bp->b_blkno = blockno; 105 106 if (uio->uio_segflg == UIO_USERSPACE) 107 if (vmapbuf(bp) < 0) { 108 error = EFAULT; 109 goto doerror; 110 } 111 112 BUF_STRATEGY(bp, 0); 113 spl = splbio(); 114 while ((bp->b_flags & B_DONE) == 0) 115 tsleep((caddr_t)bp, 0, "physstr", 0); 116 splx(spl); 117 118 if (uio->uio_segflg == UIO_USERSPACE) 119 vunmapbuf(bp); 120 iolen = bp->b_bcount - bp->b_resid; 121 if (iolen == 0 && !(bp->b_flags & B_ERROR)) 122 goto doerror; /* EOF */ 123 uio->uio_iov[i].iov_len -= iolen; 124 uio->uio_iov[i].iov_base += iolen; 125 uio->uio_resid -= iolen; 126 uio->uio_offset += iolen; 127 if( bp->b_flags & B_ERROR) { 128 error = bp->b_error; 129 goto doerror; 130 } 131 } 132 } 133 doerror: 134 relpbuf(bp, NULL); 135 return (error); 136 } 137