1.\" 2.\" Copyright (c) 2005 The DragonFly Project. All rights reserved. 3.\" 4.\" This code is derived from software contributed to The DragonFly Project 5.\" by Hiten Pandya <hmp@backplane.com>. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in 15.\" the documentation and/or other materials provided with the 16.\" distribution. 17.\" 3. Neither the name of The DragonFly Project nor the names of its 18.\" contributors may be used to endorse or promote products derived 19.\" from this software without specific, prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23.\" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24.\" FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25.\" COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26.\" INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31.\" OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" $NetBSD: physio.9,v 1.2 1996/11/11 00:05:12 lukem Exp $ 35.\" 36.\" Copyright (c) 1996 The NetBSD Foundation, Inc. 37.\" All rights reserved. 38.\" 39.\" This code is derived from software contributed to The NetBSD Foundation 40.\" by Paul Kranenburg. 41.\" 42.\" Redistribution and use in source and binary forms, with or without 43.\" modification, are permitted provided that the following conditions 44.\" are met: 45.\" 1. Redistributions of source code must retain the above copyright 46.\" notice, this list of conditions and the following disclaimer. 47.\" 2. Redistributions in binary form must reproduce the above copyright 48.\" notice, this list of conditions and the following disclaimer in the 49.\" documentation and/or other materials provided with the distribution. 50.\" 3. All advertising materials mentioning features or use of this software 51.\" must display the following acknowledgement: 52.\" This product includes software developed by the NetBSD 53.\" Foundation, Inc. and its contributors. 54.\" 4. Neither the name of The NetBSD Foundation nor the names of its 55.\" contributors may be used to endorse or promote products derived 56.\" from this software without specific prior written permission. 57.\" 58.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 59.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 60.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 61.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 62.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 63.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 64.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 65.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 66.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 67.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 68.\" POSSIBILITY OF SUCH DAMAGE. 69.\" 70.\" $FreeBSD: src/share/man/man9/physio.9,v 1.6.2.4 2001/12/17 11:30:18 ru Exp $ 71.\" $DragonFly: src/share/man/man9/physio.9,v 1.5 2008/11/09 10:59:14 swildner Exp $ 72.\" 73.Dd November 9, 2008 74.Dt PHYSIO 9 75.Os 76.Sh NAME 77.Nm physread , 78.Nm physwrite 79.Nd initiate I/O on raw devices 80.Sh SYNOPSIS 81.In sys/buf.h 82.In sys/device.h 83.Ft int 84.Fn physread "struct dev_read_args *ap" 85.Ft int 86.Fn physwrite "struct dev_write_args *ap" 87.Sh DESCRIPTION 88.Fn Physread 89and 90.Fn physwrite 91are helper functions typically called from character device read and write 92routines to start I/O on a user process buffer. 93They will call the 94.Fn dev_dstrategy 95routine one or more times depending on the size of transfer which is 96described by the 97.Fa ap 98argument. 99.Pp 100The maximum amount of data transferable in one iteration of the 101.Fn physread 102and 103.Fn physwrite 104functions is determined by the maximum I/O size supported by the device 105.Fa dev , 106otherwise the value of 107.Dv DFLTPHYS 108is used. 109Until the I/O operation is complete, the calling process or thread is 110put to sleep with the wait message set to 111.Ql "physstr" . 112.Pp 113The 114.Fn physread 115and 116.Fn physwrite 117functions always await the completion of the entire requested transfer 118before returning, unless an error condition is detected earlier. 119.Pp 120The 121.Fa ap 122argument is a pointer to a 123.Vt dev_read_args 124or 125.Vt dev_write_args 126structure, as passed to 127.Nm d_read 128or 129.Nm d_write . 130.Sh RETURN VALUES 131If successful 132.Fn physread 133and 134.Fn physwrite 135will return 0. 136.Pp 137The 138.Va errno 139value 140.Er EFAULT 141will be returned if the address range described by 142.Fa uio 143is not accessible by the calling process or thread. 144.Pp 145Note that the actual transfer size may be less than requested by 146.Fa ap 147if the device signals an 148.Dq end of file 149condition. 150.Sh SEE ALSO 151.Xr read 2 , 152.Xr write 2 , 153.Xr uio 9 154