xref: /titanic_44/usr/src/uts/sun4/io/efcode/fc_physio.c (revision f169c0eae91b2ee787cf8d6dcf8edd9159d4c9e2)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright (c) 1999-2001 by Sun Microsystems, Inc.
24  * All rights reserved.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/types.h>
30 #include <sys/debug.h>
31 #include <sys/cmn_err.h>
32 #include <sys/kmem.h>
33 #include <sys/sysmacros.h>
34 #include <sys/buf.h>
35 #include <sys/user.h>
36 #include <sys/proc.h>
37 #include <sys/systm.h>
38 #include <sys/vmsystm.h>
39 #include <sys/mman.h>
40 #include <sys/vm.h>
41 #include <sys/ddi.h>
42 
43 #include <vm/as.h>
44 #include <vm/page.h>
45 
46 /*
47  * Prepare for raw I/O request - derived from default_physio()
48  * This is the 'setup' portion of physio, limited to dealing
49  * with unstructured access to a single range of user space addresses.
50  *
51  * This is quite limited in functionality compared to physio().
52  *
53  * 1. allocate and return buf header
54  * 2. lock down user pages and verify access protections
55  *
56  * Use B_READ (S_WRITE) for unstructured access. (We don't know the
57  * direction of the transfer, so use the safest.)
58  */
59 
60 int
61 fc_physio_setup(struct buf **bpp, void *io_base, size_t io_len)
62 {
63 	struct proc *procp;
64 	struct as *asp;
65 	int error = 0;
66 	page_t **pplist;
67 	struct buf *bp = *bpp;
68 
69 	bp = getrbuf(KM_SLEEP);
70 	bp->b_iodone = NULL;
71 	bp->b_resid = 0;
72 	*bpp = bp;
73 
74 	/* segflg *is always* UIO_USERSPACE for us */
75 	procp = ttoproc(curthread);
76 	asp = procp->p_as;
77 
78 	ASSERT(SEMA_HELD(&bp->b_sem));
79 
80 	bp->b_error = 0;
81 	bp->b_proc = procp;
82 
83 	bp->b_flags = B_BUSY | B_PHYS | B_READ;
84 	bp->b_edev = 0;
85 	bp->b_lblkno = 0;
86 
87 	/*
88 	 * Don't count on b_addr remaining untouched by the
89 	 * code below (it may be reset because someone does
90 	 * a bp_mapin on the buffer).
91 	 */
92 	bp->b_un.b_addr = io_base;
93 	bp->b_bcount = io_len;
94 
95 	error = as_pagelock(asp, &pplist, io_base, io_len, S_WRITE);
96 
97 	if (error != 0) {
98 		bp->b_flags |= B_ERROR;
99 		bp->b_error = error;
100 		bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS);
101 		freerbuf(bp);
102 		*bpp = NULL;
103 		return (error);
104 	}
105 
106 	bp->b_shadow = pplist;
107 	if (pplist != NULL) {
108 		bp->b_flags |= B_SHADOW;
109 	}
110 	return (0);
111 }
112 
113 /*
114  * unlock the pages and free the buf header, if we allocated it.
115  */
116 void
117 fc_physio_free(struct buf **bpp, void *io_base, size_t io_len)
118 {
119 	struct buf *bp = *bpp;
120 	page_t **pplist = NULL;
121 
122 	/*
123 	 * unlock the pages
124 	 */
125 
126 	if (bp->b_flags & B_SHADOW)
127 		pplist = bp->b_shadow;
128 
129 	as_pageunlock(bp->b_proc->p_as, pplist, io_base, io_len, S_WRITE);
130 
131 	bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_SHADOW);
132 
133 	freerbuf(bp);
134 	*bpp = NULL;
135 }
136