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 1.2 2003/06/17 04:28:41 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 30 #include <vm/vm.h> 31 #include <vm/vm_extern.h> 32 33 static void 34 physwakeup(struct buf *bp) 35 { 36 wakeup((caddr_t) 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 off_t blockno; 47 u_int iolen; 48 struct buf *bp; 49 50 /* Keep the process UPAGES from being swapped. XXX: why ? */ 51 PHOLD(curproc); 52 53 bp = getpbuf(NULL); 54 sa = bp->b_data; 55 error = 0; 56 57 /* XXX: sanity check */ 58 if(dev->si_iosize_max < PAGE_SIZE) { 59 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 60 devtoname(dev), dev->si_iosize_max); 61 dev->si_iosize_max = DFLTPHYS; 62 } 63 64 for (i = 0; i < uio->uio_iovcnt; i++) { 65 while (uio->uio_iov[i].iov_len) { 66 if (uio->uio_rw == UIO_READ) 67 bp->b_flags = B_PHYS | B_CALL | B_READ; 68 else 69 bp->b_flags = B_PHYS | B_CALL | B_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 blockno = bp->b_offset >> DEV_BSHIFT; 96 if ((daddr_t)blockno != blockno) { 97 error = EINVAL; /* blockno overflow */ 98 goto doerror; 99 } 100 bp->b_blkno = blockno; 101 102 if (uio->uio_segflg == UIO_USERSPACE) 103 if (vmapbuf(bp) < 0) { 104 error = EFAULT; 105 goto doerror; 106 } 107 108 BUF_STRATEGY(bp, 0); 109 spl = splbio(); 110 while ((bp->b_flags & B_DONE) == 0) 111 tsleep((caddr_t)bp, PRIBIO, "physstr", 0); 112 splx(spl); 113 114 if (uio->uio_segflg == UIO_USERSPACE) 115 vunmapbuf(bp); 116 iolen = bp->b_bcount - bp->b_resid; 117 if (iolen == 0 && !(bp->b_flags & B_ERROR)) 118 goto doerror; /* EOF */ 119 uio->uio_iov[i].iov_len -= iolen; 120 uio->uio_iov[i].iov_base += iolen; 121 uio->uio_resid -= iolen; 122 uio->uio_offset += iolen; 123 if( bp->b_flags & B_ERROR) { 124 error = bp->b_error; 125 goto doerror; 126 } 127 } 128 } 129 doerror: 130 relpbuf(bp, NULL); 131 PRELE(curproc); 132 return (error); 133 } 134