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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 1.12 2006/02/17 19:18:07 dillon Exp $
48 #ifndef _SYS_GLOBALDATA_H_
49 #include <sys/globaldata.h> /* curthread */
51 #ifndef _SYS_THREAD2_H_
52 #include <sys/thread2.h> /* crit_*() functions */
54 #ifndef _SYS_SPINLOCK2_H_
55 #include <sys/spinlock2.h> /* crit_*() functions */
61 #define BUF_LOCKINIT(bp) \
62 lockinit(&(bp)->b_lock, 0, buf_wmesg, 0, 0)
66 * Get a lock sleeping non-interruptably until it becomes available.
69 BUF_LOCK(struct buf *bp, int locktype)
73 spin_lock(&buftimespinlock);
74 bp->b_lock.lk_wmesg = buf_wmesg;
75 bp->b_lock.lk_prio = 0; /* tsleep flags */
76 /* bp->b_lock.lk_timo = 0; not necessary */
77 ret = lockmgr(&(bp)->b_lock, locktype | LK_INTERLOCK,
78 &buftimespinlock, curthread);
82 * Get a lock sleeping with specified interruptably and timeout.
85 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo)
89 spin_lock(&buftimespinlock);
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 | LK_INTERLOCK | LK_TIMELOCK,
94 &buftimespinlock, curthread);
98 * Release a lock. Only the acquiring process may free the lock unless
99 * it has been handed off to biodone.
102 BUF_UNLOCK(struct buf *bp)
104 lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread);
108 * When initiating asynchronous I/O, change ownership of the lock to the
109 * kernel. Once done, the lock may legally released by biodone. The
110 * original owning process can no longer acquire it recursively, but must
111 * wait until the I/O is completed and the lock has been freed by biodone.
114 BUF_KERNPROC(struct buf *bp)
116 struct thread *td = curthread;
118 if (bp->b_lock.lk_lockholder == td)
120 bp->b_lock.lk_lockholder = LK_KERNTHREAD;
123 * Find out the number of references to a lock.
125 * The non-blocking version should only be used for assertions in cases
126 * where the buffer is expected to be owned or otherwise data stable.
129 BUF_REFCNT(struct buf *bp)
131 return (lockcount(&(bp)->b_lock));
135 BUF_REFCNTNB(struct buf *bp)
137 return (lockcountnb(&(bp)->b_lock));
141 * Free a buffer lock.
143 #define BUF_LOCKFREE(bp) \
144 if (BUF_REFCNTNB(bp) > 0) \
145 panic("free locked buf")
148 bioq_init(struct bio_queue_head *head)
150 TAILQ_INIT(&head->queue);
151 head->last_blkno = 0;
152 head->insert_point = NULL;
153 head->switch_point = NULL;
157 bioq_insert_tail(struct bio_queue_head *head, struct bio *bio)
159 if ((bio->bio_buf->b_flags & B_ORDERED) != 0) {
160 head->insert_point = bio;
161 head->switch_point = NULL;
163 TAILQ_INSERT_TAIL(&head->queue, bio, bio_act);
167 bioq_remove(struct bio_queue_head *head, struct bio *bio)
169 if (bio == head->switch_point)
170 head->switch_point = TAILQ_NEXT(bio, bio_act);
171 if (bio == head->insert_point) {
172 head->insert_point = TAILQ_PREV(bio, bio_queue, bio_act);
173 if (head->insert_point == NULL)
174 head->last_blkno = 0;
175 } else if (bio == TAILQ_FIRST(&head->queue))
176 head->last_blkno = bio->bio_blkno;
177 TAILQ_REMOVE(&head->queue, bio, bio_act);
178 if (TAILQ_FIRST(&head->queue) == head->switch_point)
179 head->switch_point = NULL;
182 static __inline struct bio *
183 bioq_first(struct bio_queue_head *head)
185 return (TAILQ_FIRST(&head->queue));
190 #endif /* !_SYS_BUF2_H_ */