Differential D4249 Diff 10457 sys/cddl/contrib/opensolaris/common/nvpair/opensolaris_nvpair_alloc_fixed.c

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sys/cddl/contrib/opensolaris/common/nvpair/opensolaris_nvpair_alloc_fixed.c

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				/*
				* CDDL HEADER START
				*
				* The contents of this file are subject to the terms of the
				* Common Development and Distribution License (the "License").
				* You may not use this file except in compliance with the License.
				*
				* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
				* or http://www.opensolaris.org/os/licensing.
				* See the License for the specific language governing permissions
				* and limitations under the License.
				*
				* When distributing Covered Code, include this CDDL HEADER in each
				* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
				* If applicable, add the following below this CDDL HEADER, with the
				* fields enclosed by brackets "[]" replaced with your own identifying
				* information: Portions Copyright [yyyy] [name of copyright owner]
				*
				* CDDL HEADER END
				*/

				/*
				* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
				* Use is subject to license terms.
				*/

				#pragma ident "%Z%%M% %I% %E% SMI"

				#include <sys/nvpair.h>
				#include <sys/sysmacros.h>
				#if defined(_KERNEL) && !defined(_BOOT)
				#include <sys/varargs.h>
				#else
				#include <stdarg.h>
				#include <strings.h>
				#endif

				/*
				* This allocator is very simple.
				* - it uses a pre-allocated buffer for memory allocations.
				* - it does _not_ free memory in the pre-allocated buffer.
				*
				* The reason for the selected implemention is simplicity.
				* This allocator is designed for the usage in interrupt context when
				* the caller may not wait for free memory.
				*/

				/* pre-allocated buffer for memory allocations */
				typedef struct nvbuf {
				uintptr_t nvb_buf; /* address of pre-allocated buffer */
				uintptr_t nvb_lim; /* limit address in the buffer */
				uintptr_t nvb_cur; /* current address in the buffer */
				} nvbuf_t;

				/*
				* Initialize the pre-allocated buffer allocator. The caller needs to supply
				*
				* buf address of pre-allocated buffer
				* bufsz size of pre-allocated buffer
				*
				* nv_fixed_init() calculates the remaining members of nvbuf_t.
				*/
				static int
				nv_fixed_init(nv_alloc_t *nva, va_list valist)
				{
				uintptr_t base = va_arg(valist, uintptr_t);
				uintptr_t lim = base + va_arg(valist, size_t);
				nvbuf_t nvb = (nvbuf_t )P2ROUNDUP(base, sizeof (uintptr_t));

				if (base == 0 \|\| (uintptr_t)&nvb[1] > lim)
				return (EINVAL);

				nvb->nvb_buf = (uintptr_t)&nvb[0];
				nvb->nvb_cur = (uintptr_t)&nvb[1];
				nvb->nvb_lim = lim;
				nva->nva_arg = nvb;

				return (0);
				}

				static void *
				nv_fixed_alloc(nv_alloc_t *nva, size_t size)
				{
				nvbuf_t *nvb = nva->nva_arg;
				uintptr_t new = nvb->nvb_cur;

				if (size == 0 \|\| new + size > nvb->nvb_lim)
				return (NULL);

				nvb->nvb_cur = P2ROUNDUP(new + size, sizeof (uintptr_t));

				return ((void *)new);
				}

				/ARGSUSED/
				static void
				nv_fixed_free(nv_alloc_t nva, void buf, size_t size)
				{
				/* don't free memory in the pre-allocated buffer */
				}

				static void
				nv_fixed_reset(nv_alloc_t *nva)
				{
				nvbuf_t *nvb = nva->nva_arg;

				nvb->nvb_cur = (uintptr_t)&nvb[1];
				}

				const nv_alloc_ops_t nv_fixed_ops_def = {
				nv_fixed_init, /* nv_ao_init() */
				NULL, /* nv_ao_fini() */
				nv_fixed_alloc, /* nv_ao_alloc() */
				nv_fixed_free, /* nv_ao_free() */
				nv_fixed_reset /* nv_ao_reset() */
				};

				const nv_alloc_ops_t *nv_fixed_ops = &nv_fixed_ops_def;