FreeBSD/Linux Kernel Cross Reference
sys/sys/buf.h
1 /*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)buf.h 8.9 (Berkeley) 3/30/95
39 * $FreeBSD: src/sys/sys/buf.h,v 1.34.2.4 1999/09/05 08:21:58 peter Exp $
40 */
41
42 #ifndef _SYS_BUF_H_
43 #define _SYS_BUF_H_
44
45 #include <sys/queue.h>
46
47 #define NOLIST ((struct buf *)0x87654321)
48
49 struct buf;
50
51 struct iodone_chain {
52 long ic_prev_flags;
53 void (*ic_prev_iodone) __P((struct buf *));
54 void *ic_prev_iodone_chain;
55 struct {
56 long ia_long;
57 void *ia_ptr;
58 } ic_args[5];
59 };
60
61 /*
62 * The buffer header describes an I/O operation in the kernel.
63 */
64 struct buf {
65 LIST_ENTRY(buf) b_hash; /* Hash chain. */
66 LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */
67 TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
68 TAILQ_ENTRY(buf) b_act; /* Device driver queue when active. *new* */
69 struct proc *b_proc; /* Associated proc; NULL if kernel. */
70 long b_flags; /* B_* flags. */
71 unsigned short b_qindex; /* buffer queue index */
72 unsigned char b_usecount; /* buffer use count */
73 int b_error; /* Errno value. */
74 long b_bufsize; /* Allocated buffer size. */
75 long b_bcount; /* Valid bytes in buffer. */
76 long b_resid; /* Remaining I/O. */
77 dev_t b_dev; /* Device associated with buffer. */
78 struct {
79 caddr_t b_addr; /* Memory, superblocks, indirect etc. */
80 } b_un;
81 caddr_t b_kvabase; /* base kva for buffer */
82 int b_kvasize; /* size of kva for buffer */
83 void *b_saveaddr; /* Original b_addr for physio. */
84 daddr_t b_lblkno; /* Logical block number. */
85 daddr_t b_blkno; /* Underlying physical block number. */
86 /* Function to call upon completion. */
87 void (*b_iodone) __P((struct buf *));
88 /* For nested b_iodone's. */
89 struct iodone_chain *b_iodone_chain;
90 struct vnode *b_vp; /* Device vnode. */
91 int b_dirtyoff; /* Offset in buffer of dirty region. */
92 int b_dirtyend; /* Offset of end of dirty region. */
93 struct ucred *b_rcred; /* Read credentials reference. */
94 struct ucred *b_wcred; /* Write credentials reference. */
95 int b_validoff; /* Offset in buffer of valid region. */
96 int b_validend; /* Offset of end of valid region. */
97 daddr_t b_pblkno; /* physical block number */
98 caddr_t b_savekva; /* saved kva for transfer while bouncing */
99 void *b_driver1; /* for private use by the driver */
100 void *b_driver2; /* for private use by the driver */
101 void *b_spc;
102 union cluster_info {
103 TAILQ_HEAD(cluster_list_head, buf) cluster_head;
104 TAILQ_ENTRY(buf) cluster_entry;
105 } b_cluster;
106 struct vm_page *b_pages[btoc(MAXPHYS)];
107 int b_npages;
108 };
109
110 /* Device driver compatibility definitions. */
111 #define b_data b_un.b_addr /* b_un.b_addr is not changeable. */
112
113 /*
114 * These flags are kept in b_flags.
115 */
116 #define B_AGE 0x00000001 /* Move to age queue when I/O done. */
117 #define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */
118 #define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
119 #define B_BAD 0x00000008 /* Bad block revectoring in progress. */
120 #define B_BUSY 0x00000010 /* I/O in progress. */
121 #define B_CACHE 0x00000020 /* Bread found us in the cache. */
122 #define B_CALL 0x00000040 /* Call b_iodone from biodone. */
123 #define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
124 #define B_DIRTY 0x00000100 /* Dirty page to be pushed out async. */
125 #define B_DONE 0x00000200 /* I/O completed. */
126 #define B_EINTR 0x00000400 /* I/O was interrupted */
127 #define B_ERROR 0x00000800 /* I/O error occurred. */
128 #define B_GATHERED 0x00001000 /* LFS: already in a segment. */
129 #define B_INVAL 0x00002000 /* Does not contain valid info. */
130 #define B_LOCKED 0x00004000 /* Locked in core (not reusable). */
131 #define B_NOCACHE 0x00008000 /* Do not cache block after use. */
132 #define B_MALLOC 0x00010000 /* malloced b_data */
133 #define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
134 #define B_PHYS 0x00040000 /* I/O to user memory. */
135 #define B_RAW 0x00080000 /* Set by physio for raw transfers. */
136 #define B_READ 0x00100000 /* Read buffer. */
137 #define B_TAPE 0x00200000 /* Magnetic tape I/O. */
138 #define B_RELBUF 0x00400000 /* Release VMIO buffer. */
139 #define B_WANTED 0x00800000 /* Process wants this buffer. */
140 #define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
141 #define B_WRITEINPROG 0x01000000 /* Write in progress. */
142 #define B_XXX 0x02000000 /* Debugging flag. */
143 #define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */
144 #define B_ORDERED 0x08000000 /* Must guarantee I/O ordering */
145 #define B_VMIO 0x20000000 /* VMIO flag */
146 #define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
147 #define B_BOUNCE 0x80000000 /* bounce buffer flag */
148
149 typedef struct buf_queue_head {
150 TAILQ_HEAD(buf_queue, buf) queue;
151 struct buf *insert_point;
152 struct buf *switch_point;
153 } buf_queue_head, *buf_queue_head_t;
154
155 static __inline void bufq_init __P((buf_queue_head *head));
156
157 static __inline void bufq_insert_tail __P((buf_queue_head *head,
158 struct buf *bp));
159
160 static __inline void bufq_remove __P((buf_queue_head *head,
161 struct buf *bp));
162
163 static __inline struct buf *bufq_first __P((buf_queue_head *head));
164
165 static __inline void
166 bufq_init(buf_queue_head *head)
167 {
168 TAILQ_INIT(&head->queue);
169 head->insert_point = NULL;
170 head->switch_point = NULL;
171 }
172
173 static __inline void
174 bufq_insert_tail(buf_queue_head *head, struct buf *bp)
175 {
176 if ((bp->b_flags & B_ORDERED) != 0) {
177 head->insert_point = bp;
178 head->switch_point = NULL;
179 }
180 TAILQ_INSERT_TAIL(&head->queue, bp, b_act);
181 }
182
183 static __inline void
184 bufq_remove(buf_queue_head *head, struct buf *bp)
185 {
186 if (bp == head->insert_point)
187 head->insert_point = TAILQ_PREV(bp, buf_queue, b_act);
188 if (bp == head->switch_point)
189 head->switch_point = TAILQ_NEXT(bp, b_act);
190 TAILQ_REMOVE(&head->queue, bp, b_act);
191 if (TAILQ_FIRST(&head->queue) == head->switch_point)
192 head->switch_point = NULL;
193 }
194
195 static __inline struct buf *
196 bufq_first(buf_queue_head *head)
197 {
198 return (TAILQ_FIRST(&head->queue));
199 }
200
201 /*
202 * number of buffer hash entries
203 */
204 #define BUFHSZ 512
205
206 /*
207 * buffer hash table calculation, originally by David Greenman
208 */
209 #define BUFHASH(vnp, bn) \
210 (&bufhashtbl[(((unsigned long)(vnp) >> 7)+(int)(bn)) % BUFHSZ])
211
212 /*
213 * Definitions for the buffer free lists.
214 */
215 #define BUFFER_QUEUES 6 /* number of free buffer queues */
216
217 extern LIST_HEAD(bufhashhdr, buf) bufhashtbl[BUFHSZ], invalhash;
218 extern TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES];
219
220 #define QUEUE_NONE 0 /* on no queue */
221 #define QUEUE_LOCKED 1 /* locked buffers */
222 #define QUEUE_LRU 2 /* useful buffers */
223 #define QUEUE_VMIO 3 /* VMIO buffers */
224 #define QUEUE_AGE 4 /* not-useful buffers */
225 #define QUEUE_EMPTY 5 /* empty buffer headers*/
226
227 /*
228 * Zero out the buffer's data area.
229 */
230 #define clrbuf(bp) { \
231 bzero((bp)->b_data, (u_int)(bp)->b_bcount); \
232 (bp)->b_resid = 0; \
233 }
234
235 /* Flags to low-level allocation routines. */
236 #define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */
237 #define B_SYNC 0x02 /* Do all allocations synchronously. */
238
239 #ifdef KERNEL
240 extern int nbuf; /* The number of buffer headers */
241 extern struct buf *buf; /* The buffer headers. */
242 extern char *buffers; /* The buffer contents. */
243 extern int bufpages; /* Number of memory pages in the buffer pool. */
244 extern struct buf *swbuf; /* Swap I/O buffer headers. */
245 extern int nswbuf; /* Number of swap I/O buffer headers. */
246 extern TAILQ_HEAD(swqueue, buf) bswlist;
247
248 void bufinit __P((void));
249 void bremfree __P((struct buf *));
250 int bread __P((struct vnode *, daddr_t, int,
251 struct ucred *, struct buf **));
252 int breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int,
253 struct ucred *, struct buf **));
254 int bwrite __P((struct buf *));
255 void bdwrite __P((struct buf *));
256 void bawrite __P((struct buf *));
257 int bowrite __P((struct buf *));
258 void brelse __P((struct buf *));
259 void bqrelse __P((struct buf *));
260 int vfs_bio_awrite __P((struct buf *));
261 struct buf * getpbuf __P((void));
262 struct buf *incore __P((struct vnode *, daddr_t));
263 struct buf *gbincore __P((struct vnode *, daddr_t));
264 int inmem __P((struct vnode *, daddr_t));
265 struct buf *getblk __P((struct vnode *, daddr_t, int, int, int));
266 struct buf *geteblk __P((int));
267 int allocbuf __P((struct buf *, int));
268 int biowait __P((struct buf *));
269 void biodone __P((struct buf *));
270
271 void cluster_callback __P((struct buf *));
272 int cluster_read __P((struct vnode *, u_quad_t, daddr_t, long,
273 struct ucred *, struct buf **));
274 int cluster_wbuild __P((struct vnode *, long, daddr_t, int));
275 void cluster_write __P((struct buf *, u_quad_t));
276 int physio __P((void (*)(struct buf *), struct buf *, dev_t,
277 int, u_int (*)(struct buf *), struct uio *));
278 u_int minphys __P((struct buf *));
279 void vfs_bio_clrbuf __P((struct buf *));
280 void vfs_busy_pages __P((struct buf *, int clear_modify));
281 void vfs_unbusy_pages(struct buf *);
282 void vwakeup __P((struct buf *));
283 void vmapbuf __P((struct buf *));
284 void vunmapbuf __P((struct buf *));
285 void relpbuf __P((struct buf *));
286 void brelvp __P((struct buf *));
287 void bgetvp __P((struct vnode *, struct buf *));
288 void pbgetvp __P((struct vnode *, struct buf *));
289 void pbrelvp __P((struct buf *));
290 void reassignbuf __P((struct buf *, struct vnode *));
291 struct buf *trypbuf __P((void));
292 void vm_bounce_alloc __P((struct buf *));
293 void vm_bounce_free __P((struct buf *));
294 vm_offset_t vm_bounce_kva_alloc __P((int));
295 void vm_bounce_kva_alloc_free __P((vm_offset_t, int));
296 #endif /* KERNEL */
297
298 #endif /* !_SYS_BUF_H_ */
Cache object: b5433aa04aec23c6383d056ff68f6ac1
|