1/***********************************************************************
2*                                                                      *
3*               This software is part of the ast package               *
4*          Copyright (c) 1985-2012 AT&T Intellectual Property          *
5*                      and is licensed under the                       *
6*                 Eclipse Public License, Version 1.0                  *
7*                    by AT&T Intellectual Property                     *
8*                                                                      *
9*                A copy of the License is available at                 *
10*          http://www.eclipse.org/org/documents/epl-v10.html           *
11*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
12*                                                                      *
13*              Information and Software Systems Research               *
14*                            AT&T Research                             *
15*                           Florham Park NJ                            *
16*                                                                      *
17*                 Glenn Fowler <gsf@research.att.com>                  *
18*                  David Korn <dgk@research.att.com>                   *
19*                   Phong Vo <kpv@research.att.com>                    *
20*                                                                      *
21***********************************************************************/
22#include	"sfdchdr.h"
23
24/*	Discipline to turn on direct IO capability.
25**	This currently only works for XFS on SGI's.
26**
27**	Written by Kiem-Phong Vo, kpv@research.att.com, 03/18/1998.
28*/
29
30#ifndef FDIRECT
31#undef F_DIOINFO
32#endif
33
34typedef struct _direct_s
35{	Sfdisc_t	disc;	/* Sfio discipline	*/
36	int		cntl;	/* file control flags	*/
37#ifdef F_DIOINFO
38	struct dioattr	dio;	/* direct IO params	*/
39#endif
40} Direct_t;
41
42/* convert a pointer to an int */
43#define P2I(p)	(Sfulong_t)((char*)(p) - (char*)0)
44
45#if __STD_C
46static ssize_t diordwr(Sfio_t* f, Void_t* buf, size_t n, Direct_t* di, int type)
47#else
48static ssize_t diordwr(f, buf, n, di, type)
49Sfio_t*		f;
50Void_t*		buf;
51size_t		n;
52Direct_t*	di;
53int		type;
54#endif
55{
56	size_t	rw, done;
57	ssize_t	rv;
58
59	done = 0;	/* amount processed by direct IO */
60	rv = 0;
61
62#ifdef F_DIOINFO
63	if((P2I(buf)%di->dio.d_mem) == 0 &&
64	   (f->here%di->dio.d_miniosz) == 0 && n >= di->dio.d_miniosz )
65	{	/* direct IO ok, make sure we're in the right mode */
66		if(!(di->cntl & FDIRECT) )
67		{	di->cntl |= FDIRECT;
68			(void)fcntl(f->file, F_SETFL, di->cntl);
69		}
70
71		for(rw = (n/di->dio.d_miniosz)*di->dio.d_miniosz;; )
72		{	size_t	io;
73
74			if((io = rw) > di->dio.d_maxiosz )
75				io = di->dio.d_maxiosz;
76			if(type == SF_READ)
77				rv = read(f->file,buf,io);
78			else	rv = write(f->file,buf,io);
79
80			if(rv > 0)
81			{	rw -= rv; done += rv;
82				buf = (Void_t*)((char*)buf + rv);
83			}
84
85			if(rv < io || rw < di->dio.d_miniosz)
86				break;
87		}
88	}
89
90	if(done < n && (di->cntl & FDIRECT) )
91	{	/* turn off directIO for remaining IO operation */
92		di->cntl &= ~FDIRECT;
93		(void)fcntl(f->file, F_SETFL, di->cntl);
94	}
95#endif /*F_DIOINFO*/
96
97	if((rw = n-done) > 0 &&
98	   (rv = type == SF_READ ? read(f->file,buf,rw) : write(f->file,buf,rw)) > 0 )
99		done += rv;
100
101	return done ? done : rv;
102}
103
104#if __STD_C
105static ssize_t dioread(Sfio_t* f, Void_t* buf, size_t n, Sfdisc_t* disc)
106#else
107static ssize_t dioread(f, buf, n, disc)
108Sfio_t*		f;
109Void_t*		buf;
110size_t		n;
111Sfdisc_t*	disc;
112#endif
113{
114	return diordwr(f, buf, n, (Direct_t*)disc, SF_READ);
115}
116
117#if __STD_C
118static ssize_t diowrite(Sfio_t* f, const Void_t* buf, size_t n, Sfdisc_t* disc)
119#else
120static ssize_t diowrite(f, buf, n, disc)
121Sfio_t*		f;
122Void_t*		buf;
123size_t		n;
124Sfdisc_t*	disc;
125#endif
126{
127	return diordwr(f, (Void_t*)buf, n, (Direct_t*)disc, SF_WRITE);
128}
129
130#if __STD_C
131static int dioexcept(Sfio_t* f, int type, Void_t* data, Sfdisc_t* disc)
132#else
133static int dioexcept(f,type,data,disc)
134Sfio_t*		f;
135int		type;
136Void_t*		data;
137Sfdisc_t*	disc;
138#endif
139{
140	Direct_t*	di = (Direct_t*)disc;
141
142	if(type == SF_FINAL || type == SF_DPOP)
143	{
144#ifdef F_DIOINFO
145		if(di->cntl&FDIRECT)
146		{	di->cntl &= ~FDIRECT;
147			(void)fcntl(f->file,F_SETFL,di->cntl);
148		}
149#endif
150		free(disc);
151	}
152
153	return 0;
154}
155
156#if __STD_C
157int sfdcdio(Sfio_t* f, size_t bufsize)
158#else
159int sfdcdio(f, bufsize)
160Sfio_t*	f;
161size_t	bufsize;
162#endif
163{
164#ifndef F_DIOINFO
165	return -1;
166#else
167	int		cntl;
168	struct dioattr	dio;
169	Void_t*		buf;
170	Direct_t*	di;
171
172	if(f->extent < 0 || (f->flags&SF_STRING))
173		return -1;
174
175	if((cntl = fcntl(f->file,F_GETFL,0)) < 0)
176		return -1;
177
178	if(!(cntl&FDIRECT) )
179	{	cntl |= FDIRECT;
180		if(fcntl(f->file,F_SETFL,cntl) < 0)
181			return -1;
182	}
183
184	if(fcntl(f->file,F_DIOINFO,&dio) < 0)
185		goto no_direct;
186
187	if(bufsize > 0)
188		bufsize = (bufsize/dio.d_miniosz)*dio.d_miniosz;
189	if(bufsize <= 0)
190		bufsize = dio.d_miniosz*64;
191	if(bufsize > dio.d_maxiosz)
192		bufsize = dio.d_maxiosz;
193
194	if(!(di = (Direct_t*)malloc(sizeof(Direct_t))) )
195		goto no_direct;
196
197	if(!(buf = (Void_t*)memalign(dio.d_mem,bufsize)) )
198	{	free(di);
199		goto no_direct;
200	}
201
202	sfsetbuf(f,buf,bufsize);
203	if(sfsetbuf(f,buf,0) == buf)
204		sfset(f,SF_MALLOC,1);
205	else
206	{	free(buf);
207		free(di);
208		goto no_direct;
209	}
210
211	di->disc.readf = dioread;
212	di->disc.writef = diowrite;
213	di->disc.seekf = NIL(Sfseek_f);
214	di->disc.exceptf = dioexcept;
215	di->cntl = cntl;
216	di->dio = dio;
217
218	if(sfdisc(f,(Sfdisc_t*)di) != (Sfdisc_t*)di)
219	{	free(di);
220	no_direct:
221		cntl &= ~FDIRECT;
222		(void)fcntl(f->file,F_SETFL,cntl);
223		return -1;
224	}
225
226	return 0;
227
228#endif /*F_DIOINFO*/
229}
230