blist: Import from FreeBSD

1 files changed, 104 insertions, 0 deletions

diff --git a/freebsd/sys/sys/blist.h b/freebsd/sys/sys/blist.h
new file mode 100644
index 00000000..f2e81ec8
--- /dev/null
+++ b/freebsd/sys/sys/blist.h
@@ -0,0 +1,104 @@
+/*-
+ * Copyright (c) 1998 Matthew Dillon.  All Rights Reserved.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+ * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Implements bitmap resource lists.
+ *
+ *	Usage:
+ *		blist = blist_create(blocks, flags)
+ *		(void)  blist_destroy(blist)
+ *		blkno = blist_alloc(blist, count)
+ *		(void)  blist_free(blist, blkno, count)
+ *		nblks = blist_fill(blist, blkno, count)
+ *		(void)  blist_resize(&blist, count, freeextra, flags)
+ *		
+ *
+ *	Notes:
+ *		on creation, the entire list is marked reserved.  You should
+ *		first blist_free() the sections you want to make available
+ *		for allocation before doing general blist_alloc()/free()
+ *		ops.
+ *
+ *		SWAPBLK_NONE is returned on failure.  This module is typically
+ *		capable of managing up to (2^31) blocks per blist, though
+ *		the memory utilization would be insane if you actually did
+ *		that.  Managing something like 512MB worth of 4K blocks 
+ *		eats around 32 KBytes of memory. 
+ *
+ * $FreeBSD$
+
+ */
+
+#ifndef _SYS_BLIST_H_
+#define _SYS_BLIST_H_
+
+typedef	u_int32_t	u_daddr_t;	/* unsigned disk address */
+
+/*
+ * note: currently use SWAPBLK_NONE as an absolute value rather then 
+ * a flag bit.
+ */
+
+#define SWAPBLK_MASK	((daddr_t)((u_daddr_t)-1 >> 1))		/* mask */
+#define SWAPBLK_NONE	((daddr_t)((u_daddr_t)SWAPBLK_MASK + 1))/* flag */
+
+/*
+ * blmeta and bl_bitmap_t MUST be a power of 2 in size.
+ */
+
+typedef struct blmeta {
+	union {
+	    daddr_t	bmu_avail;	/* space available under us	*/
+	    u_daddr_t	bmu_bitmap;	/* bitmap if we are a leaf	*/
+	} u;
+	daddr_t		bm_bighint;	/* biggest contiguous block hint*/
+} blmeta_t;
+
+typedef struct blist {
+	daddr_t		bl_blocks;	/* area of coverage		*/
+	daddr_t		bl_radix;	/* coverage radix		*/
+	daddr_t		bl_skip;	/* starting skip		*/
+	daddr_t		bl_free;	/* number of free blocks	*/
+	blmeta_t	*bl_root;	/* root of radix tree		*/
+	daddr_t		bl_rootblks;	/* daddr_t blks allocated for tree */
+} *blist_t;
+
+#define BLIST_META_RADIX	16
+#define BLIST_BMAP_RADIX	(sizeof(u_daddr_t)*8)
+
+#define BLIST_MAX_ALLOC		BLIST_BMAP_RADIX
+
+extern blist_t blist_create(daddr_t blocks, int flags);
+extern void blist_destroy(blist_t blist);
+extern daddr_t blist_alloc(blist_t blist, daddr_t count);
+extern void blist_free(blist_t blist, daddr_t blkno, daddr_t count);
+extern int blist_fill(blist_t bl, daddr_t blkno, daddr_t count);
+extern void blist_print(blist_t blist);
+extern void blist_resize(blist_t *pblist, daddr_t count, int freenew, int flags);
+
+#endif	/* _SYS_BLIST_H_ */
+