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38 * @(#)buf.h 8.9 (Berkeley) 3/30/95
39 * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $
40 * $DragonFly: src/sys/sys/buf2.h,v 1.6 2003/08/20 07:31:21 rob Exp $
48 #ifndef _SYS_GLOBALDATA_H_
49 #include <sys/globaldata.h> /* curthread */
55 #define BUF_LOCKINIT(bp) \
56 lockinit(&(bp)->b_lock, 0, buf_wmesg, 0, 0)
60 * Get a lock sleeping non-interruptably until it becomes available.
62 static __inline int BUF_LOCK (struct buf *, int);
64 BUF_LOCK(struct buf *bp, int locktype)
69 lwkt_gettoken(&buftimetoken);
70 locktype |= LK_INTERLOCK;
71 bp->b_lock.lk_wmesg = buf_wmesg;
72 bp->b_lock.lk_prio = 0; /* tsleep flags */
73 /* bp->b_lock.lk_timo = 0; not necessary */
74 ret = lockmgr(&(bp)->b_lock, locktype, &buftimetoken, curthread);
79 * Get a lock sleeping with specified interruptably and timeout.
81 static __inline int BUF_TIMELOCK (struct buf *, int, char *, int, int);
83 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo)
88 lwkt_gettoken(&buftimetoken);
89 locktype |= LK_INTERLOCK | LK_TIMELOCK;
90 bp->b_lock.lk_wmesg = wmesg;
91 bp->b_lock.lk_prio = catch; /* tsleep flags */
92 bp->b_lock.lk_timo = timo;
93 ret = lockmgr(&(bp)->b_lock, (locktype), &buftimetoken, curthread);
98 * Release a lock. Only the acquiring process may free the lock unless
99 * it has been handed off to biodone.
101 static __inline void BUF_UNLOCK (struct buf *);
103 BUF_UNLOCK(struct buf *bp)
108 lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread);
113 * Free a buffer lock.
115 #define BUF_LOCKFREE(bp) \
116 if (BUF_REFCNT(bp) > 0) \
117 panic("free locked buf")
119 * When initiating asynchronous I/O, change ownership of the lock to the
120 * kernel. Once done, the lock may legally released by biodone. The
121 * original owning process can no longer acquire it recursively, but must
122 * wait until the I/O is completed and the lock has been freed by biodone.
124 static __inline void BUF_KERNPROC (struct buf *);
126 BUF_KERNPROC(struct buf *bp)
128 struct thread *td = curthread;
130 if (bp->b_lock.lk_lockholder == td)
132 bp->b_lock.lk_lockholder = LK_KERNTHREAD;
135 * Find out the number of references to a lock.
137 static __inline int BUF_REFCNT (struct buf *);
139 BUF_REFCNT(struct buf *bp)
144 ret = lockcount(&(bp)->b_lock);
150 bufq_init(struct buf_queue_head *head)
152 TAILQ_INIT(&head->queue);
153 head->last_pblkno = 0;
154 head->insert_point = NULL;
155 head->switch_point = NULL;
159 bufq_insert_tail(struct buf_queue_head *head, struct buf *bp)
161 if ((bp->b_flags & B_ORDERED) != 0) {
162 head->insert_point = bp;
163 head->switch_point = NULL;
165 TAILQ_INSERT_TAIL(&head->queue, bp, b_act);
169 bufq_remove(struct buf_queue_head *head, struct buf *bp)
171 if (bp == head->switch_point)
172 head->switch_point = TAILQ_NEXT(bp, b_act);
173 if (bp == head->insert_point) {
174 head->insert_point = TAILQ_PREV(bp, buf_queue, b_act);
175 if (head->insert_point == NULL)
176 head->last_pblkno = 0;
177 } else if (bp == TAILQ_FIRST(&head->queue))
178 head->last_pblkno = bp->b_pblkno;
179 TAILQ_REMOVE(&head->queue, bp, b_act);
180 if (TAILQ_FIRST(&head->queue) == head->switch_point)
181 head->switch_point = NULL;
184 static __inline struct buf *
185 bufq_first(struct buf_queue_head *head)
187 return (TAILQ_FIRST(&head->queue));
192 #endif /* !_SYS_BUF2_H_ */