patch-2.4.22 linux-2.4.22/arch/ia64/sn/io/alenlist.c

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diff -urN linux-2.4.21/arch/ia64/sn/io/alenlist.c linux-2.4.22/arch/ia64/sn/io/alenlist.c
@@ -1,899 +0,0 @@
-/* $Id$
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1992 - 1997, 2000-2002 Silicon Graphics, Inc.  All rights reserved.
- */
-
-/* Implementation of Address/Length Lists. */
-
-
-#include <linux/types.h>
-#include <linux/slab.h>
-#include <linux/mmzone.h>
-#include <asm/sn/sgi.h>
-#include <asm/sn/alenlist.h>
-
-/*
- * Logically, an Address/Length List is a list of Pairs, where each pair
- * holds an Address and a Length, all in some Address Space.  In this
- * context, "Address Space" is a particular Crosstalk Widget address
- * space, a PCI device address space, a VME bus address space, a
- * physical memory address space, etc.
- *
- * The main use for these Lists is to provide a single mechanism that
- * describes where in an address space a DMA occurs.  This allows the
- * various I/O Bus support layers to provide a single interface for
- * DMA mapping and DMA translation without regard to how the DMA target
- * was specified by upper layers.  The upper layers commonly specify a 
- * DMA target via a buf structure page list, a kernel virtual address,
- * a user virtual address, a vector of addresses (a la uio and iov), 
- * or possibly a pfn list.
- *
- * Address/Length Lists also enable drivers to take advantage of their
- * inate scatter/gather capabilities in systems where some address
- * translation may be required between bus adapters.  The driver forms
- * a List that represents physical memory targets.  This list is passed
- * to the various adapters, which apply various translations.  The final
- * list that's returned to the driver is in terms of its local address
- * address space -- addresses which can be passed off to a scatter/gather
- * capable DMA controller.
- *
- * The current implementation is intended to be useful both in kernels
- * that support interrupt threads (INTR_KTHREAD) and in systems that do
- * not support interrupt threads.  Of course, in the latter case, some
- * interfaces can be called only within a suspendable context.
- *
- * Basic operations on Address/Length Lists include:
- *	alenlist_create		Create a list
- *	alenlist_clear		Clear a list
- *	alenlist_destroy	Destroy a list
- *	alenlist_append		Append a Pair to the end of a list
- *	alenlist_replace	Replace a Pair in the middle of a list
- *	alenlist_get		Get an Address/Length Pair from a list
- *	alenlist_size		Return the number of Pairs in a list
- *	alenlist_concat		Append one list to the end of another
- *	alenlist_clone		Create a new copy of a list
- *
- * Operations that convert from upper-level specifications to Address/
- * Length Lists currently include:
- *	kvaddr_to_alenlist	Convert from a kernel virtual address
- *	uvaddr_to_alenlist	Convert from a user virtual address
- *	buf_to_alenlist		Convert from a buf structure
- *	alenlist_done		Tell system that we're done with an alenlist
- *				obtained from a conversion.
- * Additional convenience operations:
- *	alenpair_init		Create a list and initialize it with a Pair
- *	alenpair_get		Peek at the first pair on a List
- *
- * A supporting type for Address/Length Lists is an alenlist_cursor_t.  A
- * cursor marks a position in a List, and determines which Pair is fetched
- * by alenlist_get.
- *	alenlist_cursor_create	Allocate and initialize a cursor
- *	alenlist_cursor_destroy	Free space consumed by a cursor
- *	alenlist_cursor_init	(Re-)Initialize a cursor to point 
- *				to the start of a list
- *	alenlist_cursor_clone	Clone a cursor (at the current offset)
- *	alenlist_cursor_offset	Return the number of bytes into
- *				a list that this cursor marks
- * Multiple cursors can point at various points into a List.  Also, each
- * list maintains one "internal cursor" which may be updated by alenlist_clear
- * and alenlist_get.  If calling code simply wishes to scan sequentially
- * through a list starting at the beginning, and if it is the only user of
- * a list, it can rely on this internal cursor rather than managing a 
- * separate explicit cursor.
- *
- * The current implementation allows callers to allocate both cursors and
- * the lists as local stack (structure) variables.  This allows for some
- * extra efficiency at the expense of forward binary compatibility.  It 
- * is recommended that customer drivers refrain from local allocation.
- * In fact, we likely will choose to move the structures out of the public 
- * header file into a private place in order to discourage this usage.
- *
- * Currently, no locking is provided by the alenlist implementation.
- *
- * Implementation notes:
- * For efficiency, Pairs are grouped into "chunks" of, say, 32 Pairs
- * and a List consists of some number of these chunks.  Chunks are completely
- * invisible to calling code.  Chunks should be large enough to hold most
- * standard-sized DMA's, but not so large that they consume excessive space.
- *
- * It is generally expected that Lists will be constructed at one time and
- * scanned at a later time.  It is NOT expected that drivers will scan
- * a List while the List is simultaneously extended, although this is
- * theoretically possible with sufficient upper-level locking.
- *
- * In order to support demands of Real-Time drivers and in order to support
- * swapping under low-memory conditions, we support the concept of a
- * "pre-allocated fixed-sized List".  After creating a List with 
- * alenlist_create, a driver may explicitly grow the list (via "alenlist_grow")
- * to a specific number of Address/Length pairs.  It is guaranteed that future 
- * operations involving this list will never automatically grow the list 
- * (i.e. if growth is ever required, the operation will fail).  Additionally, 
- * operations that use alenlist's (e.g. DMA operations) accept a flag which 
- * causes processing to take place "in-situ"; that is, the input alenlist 
- * entries are replaced with output alenlist entries.  The combination of 
- * pre-allocated Lists and in-situ processing allows us to avoid the 
- * potential deadlock scenario where we sleep (waiting for memory) in the 
- * swap out path.
- *
- * For debugging, we track the number of allocated Lists in alenlist_count
- * the number of allocated chunks in alenlist_chunk_count, and the number
- * of allocate cursors in alenlist_cursor_count.  We also provide a debug 
- * routine, alenlist_show, which dumps the contents of an Address/Length List.
- *
- * Currently, Lists are formed by drivers on-demand.  Eventually, we may
- * associate an alenlist with a buf structure and keep it up to date as
- * we go along.  In that case, buf_to_alenlist simply returns a pointer
- * to the existing List, and increments the Lists's reference count.
- * alenlist_done would decrement the reference count and destroys the List
- * if it was the last reference.
- *
- * Eventually alenlist's may allow better support for user-level scatter/
- * gather operations (e.g. via readv/writev):  With proper support, we
- * could potentially handle a vector of reads with a single scatter/gather
- * DMA operation.  This could be especially useful on NUMA systems where
- * there's more of a reason for users to use vector I/O operations.
- *
- * Eventually, alenlist's may replace kaio lists, vhand page lists,
- * buffer cache pfdat lists, DMA page lists, etc.
- */
-
-/* Opaque data types */
-
-/* An Address/Length pair.  */
-typedef struct alen_s {
-	alenaddr_t	al_addr;
-	size_t		al_length;
-} alen_t;
-
-/* 
- * Number of elements in one chunk of an Address/Length List.
- *
- * This size should be sufficient to hold at least an "average" size
- * DMA request.  Must be at least 1, and should be a power of 2,
- * for efficiency.
- */
-#define ALEN_CHUNK_SZ ((512*1024)/NBPP)
-
-/*
- * A fixed-size set of Address/Length Pairs.  Chunks of Pairs are strung together 
- * to form a complete Address/Length List.  Chunking is entirely hidden within the 
- * alenlist implementation, and it simply makes allocation and growth of lists more 
- * efficient.
- */
-typedef struct alenlist_chunk_s {
-	alen_t			alc_pair[ALEN_CHUNK_SZ];/* list of addr/len pairs */
-	struct alenlist_chunk_s *alc_next;		/* point to next chunk of pairs */
-} *alenlist_chunk_t;
-
-/* 
- * An Address/Length List.  An Address/Length List is allocated with alenlist_create.  
- * Alternatively, a list can be allocated on the stack (local variable of type 
- * alenlist_t) and initialized with alenpair_init or with a combination of 
- * alenlist_clear and alenlist_append, etc.  Code which statically allocates these
- * structures loses forward binary compatibility!
- *
- * A statically allocated List is sufficiently large to hold ALEN_CHUNK_SZ pairs.
- */
-struct alenlist_s {
-	unsigned short		al_flags;
-	unsigned short		al_logical_size;	/* logical size of list, in pairs */
-	unsigned short		al_actual_size;		/* actual size of list, in pairs */
-	struct alenlist_chunk_s	*al_last_chunk;		/* pointer to last logical chunk */
-	struct alenlist_cursor_s al_cursor;		/* internal cursor */
-	struct alenlist_chunk_s	al_chunk;		/* initial set of pairs */
-	alenaddr_t		al_compaction_address;	/* used to compact pairs */
-};
-
-/* al_flags field */
-#define AL_FIXED_SIZE	0x1	/* List is pre-allocated, and of fixed size */
-
-
-zone_t *alenlist_zone = NULL;
-zone_t *alenlist_chunk_zone = NULL;
-zone_t *alenlist_cursor_zone = NULL;
-
-#if DEBUG
-int alenlist_count=0;		/* Currently allocated Lists */
-int alenlist_chunk_count = 0;	/* Currently allocated chunks */
-int alenlist_cursor_count = 0;	/* Currently allocate cursors */
-#define INCR_COUNT(ptr) atomic_inc((ptr));
-#define DECR_COUNT(ptr) atomic_dec((ptr));
-#else
-#define INCR_COUNT(ptr)
-#define DECR_COUNT(ptr)
-#endif /* DEBUG */
-
-#if DEBUG
-static void alenlist_show(alenlist_t);
-#endif /* DEBUG */
-
-/*
- * Initialize Address/Length List management.  One time initialization.
- */
-void
-alenlist_init(void)
-{
-	alenlist_zone = snia_kmem_zone_init(sizeof(struct alenlist_s), "alenlist");
-	alenlist_chunk_zone = snia_kmem_zone_init(sizeof(struct alenlist_chunk_s), "alchunk");
-	alenlist_cursor_zone = snia_kmem_zone_init(sizeof(struct alenlist_cursor_s), "alcursor");
-#if DEBUG
-	idbg_addfunc("alenshow", alenlist_show);
-#endif /* DEBUG */
-}
-
-
-/*
- * Initialize an Address/Length List cursor.
- */
-static void
-do_cursor_init(alenlist_t alenlist, alenlist_cursor_t cursorp)
-{
-	cursorp->al_alenlist = alenlist;
-	cursorp->al_offset = 0;
-	cursorp->al_chunk = &alenlist->al_chunk;
-	cursorp->al_index = 0;
-	cursorp->al_bcount = 0;
-}
-
-
-/*
- * Create an Address/Length List, and clear it.
- * Set the cursor to the beginning.
- */
-alenlist_t 
-alenlist_create(unsigned flags)
-{
-	alenlist_t alenlist;
-
-	alenlist = snia_kmem_zone_alloc(alenlist_zone, flags & AL_NOSLEEP ? VM_NOSLEEP : 0);
-	if (alenlist) {
-		INCR_COUNT(&alenlist_count);
-
-		alenlist->al_flags = 0;
-		alenlist->al_logical_size = 0;
-		alenlist->al_actual_size = ALEN_CHUNK_SZ;
-		alenlist->al_last_chunk = &alenlist->al_chunk;
-		alenlist->al_chunk.alc_next = NULL;
-		do_cursor_init(alenlist, &alenlist->al_cursor);
-	}
-
-	return(alenlist);
-}
-
-
-/*
- * Grow an Address/Length List so that all resources needed to contain
- * the specified number of Pairs are pre-allocated.  An Address/Length
- * List that has been explicitly "grown" will never *automatically*
- * grow, shrink, or be destroyed.
- *
- * Pre-allocation is useful for Real-Time drivers and for drivers that
- * may be used along the swap-out path and therefore cannot afford to 
- * sleep until memory is freed.
- * 
- * The cursor is set to the beginning of the list.
- */
-int
-alenlist_grow(alenlist_t alenlist, size_t npairs)
-{
-	/* 
-	 * This interface should be used relatively rarely, so
-	 * the implementation is kept simple: We clear the List,
-	 * then append npairs bogus entries.  Finally, we mark
-	 * the list as FIXED_SIZE and re-initialize the internal
-	 * cursor.
-	 */
-
-	/* 
-	 * Temporarily mark as non-fixed size, since we're about
-	 * to shrink and expand it.
-	 */
-	alenlist->al_flags &= ~AL_FIXED_SIZE;
-
-	/* Free whatever was in the alenlist. */
-	alenlist_clear(alenlist);
-
-	/* Allocate everything that we need via automatic expansion. */
-	while (npairs--)
-		if (alenlist_append(alenlist, 0, 0, AL_NOCOMPACT) == ALENLIST_FAILURE)
-			return(ALENLIST_FAILURE);
-
-	/* Now, mark as FIXED_SIZE */
-	alenlist->al_flags |= AL_FIXED_SIZE;
-
-	/* Clear out bogus entries */
-	alenlist_clear(alenlist);
-
-	/* Initialize internal cursor to the beginning */
-	do_cursor_init(alenlist, &alenlist->al_cursor);
-
-	return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Clear an Address/Length List so that it holds no pairs.
- */
-void
-alenlist_clear(alenlist_t alenlist)
-{
-	alenlist_chunk_t chunk, freechunk;
-
-	/*
-	 * If this List is not FIXED_SIZE, free all the
-	 * extra chunks.
-	 */
-	if (!(alenlist->al_flags & AL_FIXED_SIZE)) {
-		/* First, free any extension alenlist chunks */
-		chunk = alenlist->al_chunk.alc_next;
-		while (chunk) {
-			freechunk = chunk;
-			chunk = chunk->alc_next;
-			snia_kmem_zone_free(alenlist_chunk_zone, freechunk);
-			DECR_COUNT(&alenlist_chunk_count);
-		}
-		alenlist->al_actual_size = ALEN_CHUNK_SZ;
-		alenlist->al_chunk.alc_next = NULL;
-	}
-
-	alenlist->al_logical_size = 0;
-	alenlist->al_last_chunk = &alenlist->al_chunk;
-	do_cursor_init(alenlist, &alenlist->al_cursor);
-}
-
-
-/*
- * Create and initialize an Address/Length Pair.
- * This is intended for degenerate lists, consisting of a single 
- * address/length pair.
- */
-alenlist_t
-alenpair_init(	alenaddr_t address, 
-		size_t length)
-{
-	alenlist_t alenlist;
-
-	alenlist = alenlist_create(0);
-
-	alenlist->al_logical_size = 1;
-	ASSERT(alenlist->al_last_chunk == &alenlist->al_chunk);
-	alenlist->al_chunk.alc_pair[0].al_length = length;
-	alenlist->al_chunk.alc_pair[0].al_addr = address;
-
-	return(alenlist);
-}
-
-/*
- * Return address/length from a degenerate (1-pair) List, or
- * first pair from a larger list.  Does NOT update the internal cursor,
- * so this is an easy way to peek at a start address.
- */
-int
-alenpair_get(	alenlist_t alenlist,
-		alenaddr_t *address,
-		size_t *length)
-{
-	if (alenlist->al_logical_size == 0)
-		return(ALENLIST_FAILURE);
-
-	*length = alenlist->al_chunk.alc_pair[0].al_length;
-	*address = alenlist->al_chunk.alc_pair[0].al_addr;
-	return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Destroy an Address/Length List.
- */
-void 
-alenlist_destroy(alenlist_t alenlist)
-{
-	if (alenlist == NULL)
-		return;
-
-	/* 
-	 * Turn off FIXED_SIZE so this List can be 
-	 * automatically shrunk.
-	 */
-	alenlist->al_flags &= ~AL_FIXED_SIZE;
-
-	/* Free extension chunks first */
-	if (alenlist->al_chunk.alc_next)
-		alenlist_clear(alenlist);
-
-	/* Now, free the alenlist itself */
-	snia_kmem_zone_free(alenlist_zone, alenlist);
-	DECR_COUNT(&alenlist_count);
-}
-
-/*
- * Release an Address/Length List.
- * This is in preparation for a day when alenlist's may be longer-lived, and
- * perhaps associated with a buf structure.  We'd add a reference count, and
- * this routine would decrement the count.  For now, we create alenlist's on
- * on demand and free them when done.  If the driver is not explicitly managing
- * a List for its own use, it should call alenlist_done rather than alenlist_destroy.
- */
-void
-alenlist_done(alenlist_t alenlist)
-{
-	alenlist_destroy(alenlist);
-}
-
-
-/*
- * Append another address/length to the end of an Address/Length List,
- * growing the list if permitted and necessary.
- *
- * Returns: SUCCESS/FAILURE
- */
-int 
-alenlist_append(	alenlist_t alenlist, 		/* append to this list */
-			alenaddr_t address, 		/* address to append */
-			size_t length,			/* length to append */
-			unsigned flags)
-{
-	alen_t *alenp;
-	int index, last_index;
-
-	index = alenlist->al_logical_size % ALEN_CHUNK_SZ;
-
-	if ((alenlist->al_logical_size > 0)) {
-		/*
-		 * See if we can compact this new pair in with the previous entry.
-		 * al_compaction_address holds that value that we'd need to see
-		 * in order to compact.
-		 */
-		if (!(flags & AL_NOCOMPACT) &&
-		    (alenlist->al_compaction_address == address)) {
-			last_index = (alenlist->al_logical_size-1) % ALEN_CHUNK_SZ;
-			alenp = &(alenlist->al_last_chunk->alc_pair[last_index]);
-			alenp->al_length += length;
-			alenlist->al_compaction_address += length;
-			return(ALENLIST_SUCCESS);
-		}
-
-		/*
-		 * If we're out of room in this chunk, move to a new chunk.
-	 	 */
-		if (index == 0) {
-			if (alenlist->al_flags & AL_FIXED_SIZE) {
-				alenlist->al_last_chunk = alenlist->al_last_chunk->alc_next;
-
-				/* If we're out of space in a FIXED_SIZE List, quit. */
-				if (alenlist->al_last_chunk == NULL) {
-					ASSERT(alenlist->al_logical_size == alenlist->al_actual_size);
-					return(ALENLIST_FAILURE);
-				}
-			} else {
-				alenlist_chunk_t new_chunk;
-
-				new_chunk = snia_kmem_zone_alloc(alenlist_chunk_zone, 
-							flags & AL_NOSLEEP ? VM_NOSLEEP : 0);
-
-				if (new_chunk == NULL)
-					return(ALENLIST_FAILURE);
-
-				alenlist->al_last_chunk->alc_next = new_chunk;
-				new_chunk->alc_next = NULL;
-				alenlist->al_last_chunk = new_chunk;
-				alenlist->al_actual_size += ALEN_CHUNK_SZ;
-				INCR_COUNT(&alenlist_chunk_count);
-			}
-		}
-	}
-
-	alenp = &(alenlist->al_last_chunk->alc_pair[index]);
-	alenp->al_addr = address;
-	alenp->al_length = length;
-	
-	alenlist->al_logical_size++;
-	alenlist->al_compaction_address = address + length;
-
-	return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Replace an item in an Address/Length List.  Cursor is updated so
- * that alenlist_get will get the next item in the list.  This interface 
- * is not very useful for drivers; but it is useful to bus providers 
- * that need to translate between address spaced in situ.  The old Address
- * and Length are returned.
- */
-/* ARGSUSED */
-int
-alenlist_replace(	alenlist_t alenlist, 		/* in: replace in this list */
-			alenlist_cursor_t cursorp, 	/* inout: which item to replace */
-			alenaddr_t *addrp, 		/* inout: address */
-			size_t *lengthp,		/* inout: length */
-			unsigned flags)
-{
-	alen_t *alenp;
-	alenlist_chunk_t chunk;
-	unsigned int index;
-	size_t length;
-	alenaddr_t addr;
-
-	if ((addrp == NULL) || (lengthp == NULL))
-		return(ALENLIST_FAILURE);
-
-	if (alenlist->al_logical_size == 0)
-		return(ALENLIST_FAILURE);
-
-	addr = *addrp;
-	length = *lengthp;
-
-	/* 
-	 * If no cursor explicitly specified, use the Address/Length List's 
-	 * internal cursor.
-	 */
-	if (cursorp == NULL)
-		cursorp = &alenlist->al_cursor;
-
-	chunk = cursorp->al_chunk;
-	index = cursorp->al_index;
-
-	ASSERT(cursorp->al_alenlist == alenlist);
-	if (cursorp->al_alenlist != alenlist)
-		return(ALENLIST_FAILURE);
-
-	alenp = &chunk->alc_pair[index];
-
-	/* Return old values */
-	*addrp = alenp->al_length;
-	*lengthp = alenp->al_addr;
-
-	/* Set up new values */
-	alenp->al_length = length;
-	alenp->al_addr = addr;
-
-	/* Update cursor to point to next item */
-	cursorp->al_bcount = length;
-
-	return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Initialize a cursor in order to walk an alenlist.
- * An alenlist_cursor always points to the last thing that was obtained
- * from the list.  If al_chunk is NULL, then nothing has yet been obtained.
- *
- * Note: There is an "internal cursor" associated with every Address/Length List.
- * For users that scan sequentially through a List, it is more efficient to
- * simply use the internal cursor.  The caller must insure that no other users
- * will simultaneously scan the List.  The caller can reposition the internal
- * cursor by calling alenlist_cursor_init with a NULL cursorp.
- */
-int
-alenlist_cursor_init(alenlist_t alenlist, size_t offset, alenlist_cursor_t cursorp)
-{
-	size_t byte_count;
-
-	if (cursorp == NULL)
-		cursorp = &alenlist->al_cursor;
-
-	/* Get internal cursor's byte count for use as a hint.
-	 *
-	 * If the internal cursor points passed the point that we're interested in,
-	 * we need to seek forward from the beginning.  Otherwise, we can seek forward
-	 * from the internal cursor.
-	 */
-	if ((offset > 0) &&
-	   ((byte_count = alenlist_cursor_offset(alenlist, (alenlist_cursor_t)NULL)) <= offset)) {
-		offset -= byte_count;
-		alenlist_cursor_clone(alenlist, NULL, cursorp);
-	} else
-		do_cursor_init(alenlist, cursorp);
-
-	/* We could easily speed this up, but it shouldn't be used very often. */
-	while (offset != 0) {
-		alenaddr_t addr;
-		size_t length;
-
-		if (alenlist_get(alenlist, cursorp, offset, &addr, &length, 0) != ALENLIST_SUCCESS)
-			return(ALENLIST_FAILURE);
-		offset -= length;
-	}
-	return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Copy a cursor.  The source cursor is either an internal alenlist cursor
- * or an explicit cursor.
- */
-int
-alenlist_cursor_clone(	alenlist_t alenlist, 
-			alenlist_cursor_t cursorp_in, 
-			alenlist_cursor_t cursorp_out)
-{
-	ASSERT(cursorp_out);
-
-	if (alenlist && cursorp_in)
-		if (alenlist != cursorp_in->al_alenlist)
-			return(ALENLIST_FAILURE);
-
-	if (alenlist)
-		*cursorp_out = alenlist->al_cursor; /* small structure copy */
-	else if (cursorp_in)
-		*cursorp_out = *cursorp_in; /* small structure copy */
-	else
-		return(ALENLIST_FAILURE); /* no source */
-
-	return(ALENLIST_SUCCESS);
-}
-
-/*
- * Return the number of bytes passed so far according to the specified cursor.
- * If cursorp is NULL, use the alenlist's internal cursor.
- */
-size_t
-alenlist_cursor_offset(alenlist_t alenlist, alenlist_cursor_t cursorp)
-{
-	ASSERT(!alenlist || !cursorp || (alenlist == cursorp->al_alenlist));
-
-	if (cursorp == NULL) {
-		ASSERT(alenlist);
-		cursorp = &alenlist->al_cursor;
-	}
-
-	return(cursorp->al_offset);
-}
-
-/*
- * Allocate and initialize an Address/Length List cursor.
- */
-alenlist_cursor_t
-alenlist_cursor_create(alenlist_t alenlist, unsigned flags)
-{
-	alenlist_cursor_t cursorp;
-
-	ASSERT(alenlist != NULL);
-	cursorp = snia_kmem_zone_alloc(alenlist_cursor_zone, flags & AL_NOSLEEP ? VM_NOSLEEP : 0);
-	if (cursorp) {
-		INCR_COUNT(&alenlist_cursor_count);
-		alenlist_cursor_init(alenlist, 0, cursorp);
-	}
-	return(cursorp);
-}
-
-/*
- * Free an Address/Length List cursor.
- */
-void
-alenlist_cursor_destroy(alenlist_cursor_t cursorp)
-{
-	DECR_COUNT(&alenlist_cursor_count);
-	snia_kmem_zone_free(alenlist_cursor_zone, cursorp);
-}
-
-
-/*
- * Fetch an address/length pair from an Address/Length List.  Update
- * the "cursor" so that next time this routine is called, we'll get
- * the next address range.  Never return a length that exceeds maxlength
- * (if non-zero).  If maxlength is a power of 2, never return a length 
- * that crosses a maxlength boundary.  [This may seem strange at first,
- * but it's what many drivers want.]
- *
- * Returns: SUCCESS/FAILURE
- */
-int
-alenlist_get(	alenlist_t alenlist, 		/* in: get from this list */
-		alenlist_cursor_t cursorp, 	/* inout: which item to get */
-		size_t	maxlength,		/* in: at most this length */
-		alenaddr_t *addrp, 		/* out: address */
-		size_t *lengthp,		/* out: length */
-		unsigned flags)
-{
-	alen_t *alenp;
-	alenlist_chunk_t chunk;
-	unsigned int index;
-	size_t bcount;
-	size_t length;
-
-	/* 
-	 * If no cursor explicitly specified, use the Address/Length List's 
-	 * internal cursor.
-	 */
-	if (cursorp == NULL) {
-		if (alenlist->al_logical_size == 0)
-			return(ALENLIST_FAILURE);
-		cursorp = &alenlist->al_cursor;
-	}
-
-	chunk = cursorp->al_chunk;
-	index = cursorp->al_index;
-	bcount = cursorp->al_bcount;
-
-	ASSERT(cursorp->al_alenlist == alenlist);
-	if (cursorp->al_alenlist != alenlist)
-		return(ALENLIST_FAILURE);
-
-	alenp = &chunk->alc_pair[index];
-	length = alenp->al_length - bcount;
-
-	/* Bump up to next pair, if we're done with this pair. */
-	if (length == 0) {
-		cursorp->al_bcount = bcount = 0;
-		cursorp->al_index = index = (index + 1) % ALEN_CHUNK_SZ;
-
-		/* Bump up to next chunk, if we're done with this chunk. */
-		if (index == 0) {
-			if (cursorp->al_chunk == alenlist->al_last_chunk)
-				return(ALENLIST_FAILURE);
-			chunk = chunk->alc_next;
-			ASSERT(chunk != NULL);
-		} else {
-			/* If in last chunk, don't go beyond end. */
-			if (cursorp->al_chunk == alenlist->al_last_chunk) {
-				int last_size = alenlist->al_logical_size % ALEN_CHUNK_SZ;
-				if (last_size && (index >= last_size))
-					return(ALENLIST_FAILURE);
-			}
-		}
-
-		alenp = &chunk->alc_pair[index];
-		length = alenp->al_length;
-	}
-
-	/* Constrain what we return according to maxlength */
-	if (maxlength) {
-		size_t maxlen1 = maxlength - 1;
-
-		if ((maxlength & maxlen1) == 0) /* power of 2 */
-			maxlength -= 
-			   ((alenp->al_addr + cursorp->al_bcount) & maxlen1);
-
-		length = min(maxlength, length);
-	}
-
-	/* Update the cursor, if desired. */
-	if (!(flags & AL_LEAVE_CURSOR)) {
-		cursorp->al_bcount += length;
-		cursorp->al_chunk = chunk;
-	}
-
-	*lengthp = length;
-	*addrp = alenp->al_addr + bcount;
-
-	return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Return the number of pairs in the specified Address/Length List.
- * (For FIXED_SIZE Lists, this returns the logical size of the List, 
- * not the actual capacity of the List.)
- */
-int
-alenlist_size(alenlist_t alenlist)
-{
-	return(alenlist->al_logical_size);
-}
-
-
-/*
- * Concatenate two Address/Length Lists.
- */
-void
-alenlist_concat(alenlist_t from,
-		alenlist_t to)
-{
-	struct alenlist_cursor_s cursor;
-	alenaddr_t addr;
-	size_t length;
-
-	alenlist_cursor_init(from, 0, &cursor);
-
-	while(alenlist_get(from, &cursor, (size_t)0, &addr, &length, 0) == ALENLIST_SUCCESS)
-		alenlist_append(to, addr, length, 0);
-}
-
-/*
- * Create a copy of a list.
- * (Not all attributes of the old list are cloned.  For instance, if
- * a FIXED_SIZE list is cloned, the resulting list is NOT FIXED_SIZE.)
- */
-alenlist_t
-alenlist_clone(alenlist_t old_list, unsigned flags)
-{
-	alenlist_t new_list;
-
-	new_list = alenlist_create(flags);
-	if (new_list != NULL)
-		alenlist_concat(old_list, new_list);
-
-	return(new_list);
-}
-
-
-/* 
- * Convert a kernel virtual address to a Physical Address/Length List.
- */
-alenlist_t
-kvaddr_to_alenlist(alenlist_t alenlist, caddr_t kvaddr, size_t length, unsigned flags)
-{
-	alenaddr_t paddr;
-	long offset;
-	size_t piece_length;
-	int created_alenlist;
-
-	if (length <=0)
-		return(NULL);
-
-	/* If caller supplied a List, use it.  Otherwise, allocate one. */
-	if (alenlist == NULL) {
-		alenlist = alenlist_create(0);
-		created_alenlist = 1;
-	} else {
-		alenlist_clear(alenlist);
-		created_alenlist = 0;
-	}
-
-	paddr = kvtophys(kvaddr);
-	offset = poff(kvaddr);
-
-	/* Handle first page */
-	piece_length = min((size_t)(NBPP - offset), length);
-	if (alenlist_append(alenlist, paddr, piece_length, flags) == ALENLIST_FAILURE)
-		goto failure;
-	length -= piece_length;
-	kvaddr += piece_length;
-
-	/* Handle middle pages */
-	while (length >= NBPP) {
-		paddr = kvtophys(kvaddr);
-		if (alenlist_append(alenlist, paddr, NBPP, flags) == ALENLIST_FAILURE)
-			goto failure;
-		length -= NBPP;
-		kvaddr += NBPP;
-	}
-
-	/* Handle last page */
-	if (length) {
-		ASSERT(length < NBPP);
-		paddr = kvtophys(kvaddr);
-		if (alenlist_append(alenlist, paddr, length, flags) == ALENLIST_FAILURE)
-			goto failure;
-	}
-
-	alenlist_cursor_init(alenlist, 0, NULL);
-	return(alenlist);
-
-failure:
-	if (created_alenlist)
-		alenlist_destroy(alenlist);
-	return(NULL);
-}
-
-
-#if DEBUG
-static void
-alenlist_show(alenlist_t alenlist)
-{
-	struct alenlist_cursor_s cursor;
-	alenaddr_t addr;
-	size_t length;
-	int i = 0;
-
-	alenlist_cursor_init(alenlist, 0, &cursor);
-
-	qprintf("Address/Length List@0x%x:\n", alenlist);
-	qprintf("logical size=0x%x actual size=0x%x last_chunk at 0x%x\n", 
-		alenlist->al_logical_size, alenlist->al_actual_size, 
-		alenlist->al_last_chunk);
-	qprintf("cursor: chunk=0x%x index=%d offset=0x%x\n",
-		alenlist->al_cursor.al_chunk, 
-		alenlist->al_cursor.al_index,
-		alenlist->al_cursor.al_bcount);
-	while(alenlist_get(alenlist, &cursor, (size_t)0, &addr, &length, 0) == ALENLIST_SUCCESS)
-		qprintf("%d:\t0x%lx 0x%lx\n", ++i, addr, length);
-}
-#endif /* DEBUG */
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TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)