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 1.25 2007/08/21 17:26:45 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 struct buf *bp; 52 53 bp = getpbuf(NULL); 54 saflags = bp->b_flags; 55 error = 0; 56 57 /* XXX: sanity check */ 58 if(dev->si_iosize_max < PAGE_SIZE) { 59 kprintf("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 /* Must be a real uio */ 65 KKASSERT(uio->uio_segflg != UIO_NOCOPY); 66 67 /* Don't check block number overflow for D_MEM */ 68 if ((dev_dflags(dev) & D_TYPEMASK) == D_MEM) 69 chk_blockno = 0; 70 else 71 chk_blockno = 1; 72 73 for (i = 0; i < uio->uio_iovcnt; i++) { 74 while (uio->uio_iov[i].iov_len) { 75 if (uio->uio_rw == UIO_READ) 76 bp->b_cmd = BUF_CMD_READ; 77 else 78 bp->b_cmd = BUF_CMD_WRITE; 79 bp->b_flags = saflags; 80 bcount = uio->uio_iov[i].iov_len; 81 82 reinitbufbio(bp); /* clear translation cache */ 83 bp->b_bio1.bio_offset = uio->uio_offset; 84 bp->b_bio1.bio_done = physwakeup; 85 86 /* Don't exceed drivers iosize limit */ 87 if (bcount > dev->si_iosize_max) 88 bcount = dev->si_iosize_max; 89 90 /* 91 * Make sure the pbuf can map the request 92 * XXX: The pbuf has kvasize = MAXPHYS so a request 93 * XXX: larger than MAXPHYS - PAGE_SIZE must be 94 * XXX: page aligned or it will be fragmented. 95 */ 96 iolen = ((vm_offset_t) uio->uio_iov[i].iov_base) & 97 PAGE_MASK; 98 if ((bcount + iolen) > bp->b_kvasize) { 99 bcount = bp->b_kvasize; 100 if (iolen != 0) 101 bcount -= PAGE_SIZE; 102 } 103 if (uio->uio_segflg == UIO_USERSPACE) { 104 if (vmapbuf(bp, uio->uio_iov[i].iov_base, bcount) < 0) { 105 error = EFAULT; 106 goto doerror; 107 } 108 } else { 109 bp->b_data = uio->uio_iov[i].iov_base; 110 bp->b_bcount = bcount; 111 } 112 dev_dstrategy(dev, &bp->b_bio1); 113 crit_enter(); 114 while (bp->b_cmd != BUF_CMD_DONE) 115 tsleep(&bp->b_bio1, 0, "physstr", 0); 116 crit_exit(); 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 } 137 138 int 139 physread(struct dev_read_args *ap) 140 { 141 return(physio(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); 142 } 143 144 int 145 physwrite(struct dev_write_args *ap) 146 { 147 return(physio(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); 148 } 149 150