From 3affbe6d7e23f26ef9b4e70043b9fb93bfe9ea32 Mon Sep 17 00:00:00 2001
From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Thu, 29 Apr 2010 11:59:41 -0700
Subject: [PATCH] Update nvpair's to include nv_alloc_fixed support

---
 module/nvpair/nvpair_alloc_fixed.c | 120 +++++++++++++++++++++++++++++
 scripts/zfs-update.sh              |   1 +
 2 files changed, 121 insertions(+)
 create mode 100644 module/nvpair/nvpair_alloc_fixed.c

diff --git a/module/nvpair/nvpair_alloc_fixed.c b/module/nvpair/nvpair_alloc_fixed.c
new file mode 100644
index 000000000..b1128eeb9
--- /dev/null
+++ b/module/nvpair/nvpair_alloc_fixed.c
@@ -0,0 +1,120 @@
+/*
+ * 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/stropts.h>
+#include <sys/isa_defs.h>
+#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;
diff --git a/scripts/zfs-update.sh b/scripts/zfs-update.sh
index 83525fe03..1b74b7e7e 100755
--- a/scripts/zfs-update.sh
+++ b/scripts/zfs-update.sh
@@ -83,6 +83,7 @@ cp ${SRC_UCM}/sys/avl_impl.h			${DST_MOD}/avl/include/sys/
 echo "* module/nvpair"
 mkdir -p ${DST_MOD}/nvpair/include/sys/
 cp ${SRC_CM}/nvpair/nvpair.c			${DST_MOD}/nvpair/
+cp ${SRC_CM}/nvpair/nvpair_alloc_fixed.c	${DST_MOD}/nvpair/
 cp ${SRC_UCM}/sys/nvpair.h			${DST_MOD}/nvpair/include/sys/
 cp ${SRC_UCM}/sys/nvpair_impl.h			${DST_MOD}/nvpair/include/sys/