xref: /illumos-gate/usr/src/uts/common/sys/uio.h (revision b4203d75)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2014 Garrett D'Amore <garrett@damore.org>
23  *
24  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
25  * Use is subject to license terms.
26  *
27  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
28  * Copyright (c) 2015, Joyent, Inc.  All rights reserved.
29  */
30 
31 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
32 /*	  All Rights Reserved	*/
33 
34 /*
35  * University Copyright- Copyright (c) 1982, 1986, 1988
36  * The Regents of the University of California
37  * All Rights Reserved
38  *
39  * University Acknowledgment- Portions of this document are derived from
40  * software developed by the University of California, Berkeley, and its
41  * contributors.
42  */
43 
44 #ifndef _SYS_UIO_H
45 #define	_SYS_UIO_H
46 
47 #include <sys/feature_tests.h>
48 
49 #ifdef	__cplusplus
50 extern "C" {
51 #endif
52 
53 #include <sys/types.h>
54 
55 /*
56  * I/O parameter information.  A uio structure describes the I/O which
57  * is to be performed by an operation.  Typically the data movement will
58  * be performed by a routine such as uiomove(), which updates the uio
59  * structure to reflect what was done.
60  */
61 
62 #if	defined(_XPG4_2)
63 typedef struct iovec {
64 	void	*iov_base;
65 	size_t	iov_len;
66 } iovec_t;
67 #else
68 typedef struct iovec {
69 	caddr_t	iov_base;
70 #if defined(_LP64)
71 	size_t	iov_len;
72 #else
73 	long	iov_len;
74 #endif
75 } iovec_t;
76 #endif	/* defined(_XPG4_2) */
77 
78 #if defined(_SYSCALL32)
79 
80 /* Kernel's view of user ILP32 iovec struct */
81 
82 typedef	struct iovec32 {
83 	caddr32_t	iov_base;
84 	int32_t		iov_len;
85 } iovec32_t;
86 
87 #endif	/* _SYSCALL32 */
88 
89 #if 	!defined(_XPG4_2) || defined(__EXTENSIONS__)
90 /*
91  * Segment flag values.
92  */
93 typedef enum uio_seg { UIO_USERSPACE, UIO_SYSSPACE, UIO_USERISPACE } uio_seg_t;
94 
95 typedef struct uio {
96 	iovec_t		*uio_iov;	/* pointer to array of iovecs */
97 	int		uio_iovcnt;	/* number of iovecs */
98 	lloff_t		_uio_offset;	/* file offset */
99 	uio_seg_t	uio_segflg;	/* address space (kernel or user) */
100 	uint16_t	uio_fmode;	/* file mode flags */
101 	uint16_t	uio_extflg;	/* extended flags */
102 	lloff_t		_uio_limit;	/* u-limit (maximum byte offset) */
103 	ssize_t		uio_resid;	/* residual count */
104 } uio_t;
105 
106 /*
107  * Extended uio_t uioa_t used for asynchronous uio.
108  *
109  * Note: UIOA_IOV_MAX is defined and used as it is in "fs/vncalls.c"
110  *	 as there isn't a formal definition of IOV_MAX for the kernel.
111  */
112 #define	UIOA_IOV_MAX	16
113 
114 typedef struct uioa_page_s {		/* locked uio_iov state */
115 	int	uioa_pfncnt;		/* count of pfn_t(s) in *uioa_ppp */
116 	void	**uioa_ppp;		/* page_t or pfn_t arrary */
117 	caddr_t	uioa_base;		/* address base */
118 	size_t	uioa_len;		/* span length */
119 } uioa_page_t;
120 
121 typedef struct uioa_s {
122 	iovec_t		*uio_iov;	/* pointer to array of iovecs */
123 	int		uio_iovcnt;	/* number of iovecs */
124 	lloff_t		_uio_offset;	/* file offset */
125 	uio_seg_t	uio_segflg;	/* address space (kernel or user) */
126 	uint16_t	uio_fmode;	/* file mode flags */
127 	uint16_t	uio_extflg;	/* extended flags */
128 	lloff_t		_uio_limit;	/* u-limit (maximum byte offset) */
129 	ssize_t		uio_resid;	/* residual count */
130 	/*
131 	 * uioa extended members.
132 	 */
133 	uint32_t	uioa_state;	/* state of asynch i/o */
134 	ssize_t		uioa_mbytes;	/* bytes that have been uioamove()ed */
135 	uioa_page_t	*uioa_lcur;	/* pointer into uioa_locked[] */
136 	void		**uioa_lppp;	/* pointer into lcur->uioa_ppp[] */
137 	void		*uioa_hwst[4];	/* opaque hardware state */
138 	uioa_page_t	uioa_locked[UIOA_IOV_MAX]; /* Per iov locked pages */
139 } uioa_t;
140 
141 /*
142  * uio extensions
143  *
144  * PSARC 2009/478: Copy Reduction Interfaces
145  */
146 typedef enum xuio_type {
147 	UIOTYPE_ASYNCIO,
148 	UIOTYPE_ZEROCOPY
149 } xuio_type_t;
150 
151 typedef struct xuio {
152 	uio_t xu_uio;		/* Embedded UIO structure */
153 
154 	/* Extended uio fields */
155 	enum xuio_type xu_type;	/* What kind of uio structure? */
156 	union {
157 		/* Async I/O Support, intend to replace uioa_t. */
158 		struct {
159 			uint32_t xu_a_state;	/* state of async i/o */
160 			/* bytes that have been uioamove()ed */
161 			ssize_t xu_a_mbytes;
162 			uioa_page_t *xu_a_lcur;	/* pointer into uioa_locked[] */
163 			/* pointer into lcur->uioa_ppp[] */
164 			void **xu_a_lppp;
165 			void *xu_a_hwst[4];	/* opaque hardware state */
166 			/* Per iov locked pages */
167 			uioa_page_t xu_a_locked[UIOA_IOV_MAX];
168 		} xu_aio;
169 
170 		/*
171 		 * Copy Reduction Support -- facilate loaning / returning of
172 		 * filesystem cache buffers.
173 		 */
174 		struct {
175 			int xu_zc_rw;	/* read or write buffer */
176 			void *xu_zc_priv;	/* fs specific */
177 		} xu_zc;
178 	} xu_ext;
179 } xuio_t;
180 
181 #define	XUIO_XUZC_PRIV(xuio)    xuio->xu_ext.xu_zc.xu_zc_priv
182 #define	XUIO_XUZC_RW(xuio)	xuio->xu_ext.xu_zc.xu_zc_rw
183 
184 #define	UIOA_ALLOC	0x0001		/* allocated but not yet initialized */
185 #define	UIOA_INIT	0x0002		/* initialized but not yet enabled */
186 #define	UIOA_ENABLED	0x0004		/* enabled, asynch i/o active */
187 #define	UIOA_FINI	0x0008		/* finished waiting for uioafini() */
188 
189 #define	UIOA_CLR	(~0x000F)	/* clear mutually exclusive bits */
190 
191 #define	UIOA_POLL	0x0010		/* need dcopy_poll() */
192 
193 #define	uio_loffset	_uio_offset._f
194 #if !defined(_LP64)
195 #define	uio_offset	_uio_offset._p._l
196 #else
197 #define	uio_offset	uio_loffset
198 #endif
199 
200 #define	uio_llimit	_uio_limit._f
201 #if !defined(_LP64)
202 #define	uio_limit	_uio_limit._p._l
203 #else
204 #define	uio_limit	uio_llimit
205 #endif
206 
207 /*
208  * I/O direction.
209  */
210 typedef enum uio_rw { UIO_READ, UIO_WRITE } uio_rw_t;
211 
212 /*
213  * uio_extflg: extended flags
214  *
215  * NOTE: This flag will be used in uiomove to determine if non-temporal
216  * access, ie, access bypassing caches, should be used.  Filesystems that
217  * don't initialize this field could experience suboptimal performance due to
218  * the random data the field contains.
219  *
220  * NOTE: This flag is also used by uioasync callers to pass an extended
221  * uio_t (uioa_t), to uioasync enabled consumers. Unlike above all
222  * consumers of a uioa_t require the uio_extflg to be initialized.
223  */
224 #define	UIO_COPY_DEFAULT	0x0000	/* no special options to copy */
225 #define	UIO_COPY_CACHED		0x0001	/* copy should not bypass caches */
226 
227 #define	UIO_ASYNC		0x0002	/* uio_t is really a uioa_t */
228 #define	UIO_XUIO		0x0004	/* Structure is xuio_t */
229 
230 /*
231  * Global uioasync capability shadow state.
232  */
233 typedef struct uioasync_s {
234 	boolean_t	enabled;	/* Is uioasync enabled? */
235 	size_t		mincnt;		/* Minimum byte count for use of */
236 } uioasync_t;
237 
238 #endif /* !defined(_XPG4_2) || defined(__EXTENSIONS__) */
239 
240 #if defined(_KERNEL) || defined(_FAKE_KERNEL)
241 
242 int	uiomove(void *, size_t, enum uio_rw, uio_t *);
243 void	uio_prefaultpages(ssize_t, uio_t *);
244 int	uiocopy(void *, size_t, enum uio_rw, uio_t *, size_t *);
245 int	ureadc(int, uio_t *);	/* should be errno_t in future */
246 int	uwritec(struct uio *);
247 void	uioskip(uio_t *, size_t);
248 int	uiodup(uio_t *, uio_t *, iovec_t *, int);
249 
250 int	uioamove(void *, size_t, enum uio_rw, uioa_t *);
251 int	uioainit(uio_t *, uioa_t *);
252 int	uioafini(uio_t *, uioa_t *);
253 extern	uioasync_t uioasync;
254 
255 #else	/* defined(_KERNEL) */
256 
257 extern ssize_t readv(int, const struct iovec *, int);
258 extern ssize_t writev(int, const struct iovec *, int);
259 
260 /*
261  * When in the large file compilation environment,
262  * map preadv/pwritev to their 64 bit offset versions
263  */
264 #if !defined(_LP64) && _FILE_OFFSET_BITS == 64
265 #ifdef __PRAGMA_REDEFINE_EXTNAME
266 #pragma	redefine_extname	preadv	preadv64
267 #pragma	redefine_extname	pwritev	pwritev64
268 #else /* __PRAGMA_REDEFINE_EXTNAME */
269 #define	preadv	preadv64
270 #define	pwritev	pwritev64
271 #endif /* __PRAGMA_REDEFINE_EXTNAME */
272 #endif /* !_LP64 && _FILE_OFFSET_BITS == 64 */
273 
274 /* In the LP64 compilation environment, the APIs are already large file */
275 #if defined(_LP64) && defined(_LARGEFILE64_SOURCE)
276 #ifdef  __PRAGMA_REDEFINE_EXTNAME
277 #pragma	redefine_extname	preadv64	preadv
278 #pragma	redefine_extname	pwritev64	pwritev
279 #else   /* __PRAGMA_REDEFINE_EXTNAME */
280 #define	preadv64	preadv
281 #define	pwritev64	pwritev
282 #endif  /* __PRAGMA_REDEFINE_EXTNAME */
283 #endif  /* _LP64 && _LARGEFILE64_SOURCE */
284 
285 extern ssize_t preadv(int, const struct iovec *, int, off_t);
286 extern ssize_t pwritev(int, const struct iovec *, int, off_t);
287 
288 /*
289  * preadv64 and pwritev64 should be defined when:
290  * - Using the transitional compilation environment, and not
291  *     the large file compilation environment.
292  */
293 #if defined(_LARGEFILE64_SOURCE) && !((_FILE_OFFSET_BITS == 64) && \
294 	!defined(__PRAGMA_REDEFINE_EXTNAME))
295 extern ssize_t preadv64(int, const struct iovec *, int, off64_t);
296 extern ssize_t pwritev64(int, const struct iovec *, int, off64_t);
297 #endif /* _LARGEFILE64_SOURCE */
298 
299 #endif	/* defined(_KERNEL) */
300 
301 #ifdef	__cplusplus
302 }
303 #endif
304 
305 #endif	/* _SYS_UIO_H */
306