import tmpfs code, originally from netbsd.

heavy lifting by Pedro Martelletto, timestamp fixes by me.

THIS IS NOT ENABLED YET, AND REQUIRES UVM CHANGES AND REVIEW.
Imported, so that working on it can be mostly done in tree with less painful
diff exchanges, and that we have history of further changes.

okay tedu@, deraadt@

1 files changed, 229 insertions, 0 deletions

diff --git a/sys/tmpfs/tmpfs_mem.c b/sys/tmpfs/tmpfs_mem.c
new file mode 100644
index 00000000000..d88adb0bcb7
--- /dev/null
+++ b/sys/tmpfs/tmpfs_mem.c
@@ -0,0 +1,229 @@
+/*	$NetBSD: tmpfs_mem.c,v 1.4 2011/05/24 01:09:47 rmind Exp $	*/
+
+/*
+ * Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Mindaugas Rasiukevicius.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``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 FOUNDATION OR CONTRIBUTORS
+ * 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.
+ */
+
+/*
+ * tmpfs memory allocation routines.
+ * Implements memory usage accounting and limiting.
+ */
+
+#if 0
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: tmpfs_mem.c,v 1.4 2011/05/24 01:09:47 rmind Exp $");
+#endif
+
+#include <sys/param.h>
+#include <sys/namei.h>
+#include <sys/pool.h>
+#include <sys/vnode.h>
+#include <sys/malloc.h>
+
+#include <tmpfs/tmpfs.h>
+
+extern struct pool	tmpfs_dirent_pool;
+extern struct pool	tmpfs_node_pool;
+
+void
+tmpfs_mntmem_init(struct tmpfs_mount *mp, uint64_t memlimit)
+{
+
+	rw_init(&mp->tm_acc_lock, "tacclk");
+	mp->tm_mem_limit = memlimit;
+	mp->tm_bytes_used = 0;
+}
+
+void
+tmpfs_mntmem_destroy(struct tmpfs_mount *mp)
+{
+
+	KASSERT(mp->tm_bytes_used == 0);
+	/* mutex_destroy(&mp->tm_acc_lock); */
+}
+
+/*
+ * tmpfs_mem_info: return the number of available memory pages.
+ *
+ * => If 'total' is true, then return _total_ amount of pages.
+ * => If false, then return the amount of _free_ memory pages.
+ *
+ * Remember to remove TMPFS_PAGES_RESERVED from the returned value to avoid
+ * excessive memory usage.
+ */
+size_t
+tmpfs_mem_info(int total)
+{
+	int size = 0;
+
+	/* XXX: unlocked */
+	size += uvmexp.swpages;
+	if (!total) {
+		size -= uvmexp.swpgonly;
+	}
+
+	size += uvmexp.free;
+	/* size += uvmexp.filepages; */
+	if (size > uvmexp.wired) {
+		size -= uvmexp.wired;
+	} else {
+		size = 0;
+	}
+
+	KASSERT(size >= 0);
+
+	return (size_t)size;
+}
+
+uint64_t
+tmpfs_bytes_max(struct tmpfs_mount *mp)
+{
+	size_t freepages = tmpfs_mem_info(0);
+	uint64_t avail_mem;
+
+	if (freepages < TMPFS_PAGES_RESERVED) {
+		freepages = 0;
+	} else {
+		freepages -= TMPFS_PAGES_RESERVED;
+	}
+	avail_mem = round_page(mp->tm_bytes_used) + (freepages << PAGE_SHIFT);
+	return MIN(mp->tm_mem_limit, avail_mem);
+}
+
+uint64_t
+tmpfs_pages_avail(struct tmpfs_mount *mp)
+{
+
+	return (tmpfs_bytes_max(mp) - mp->tm_bytes_used) >> PAGE_SHIFT;
+}
+
+int
+tmpfs_mem_incr(struct tmpfs_mount *mp, size_t sz)
+{
+	uint64_t lim;
+
+	rw_enter_write(&mp->tm_acc_lock);
+	lim = tmpfs_bytes_max(mp);
+	if (mp->tm_bytes_used + sz >= lim) {
+		rw_exit_write(&mp->tm_acc_lock);
+		return 0;
+	}
+	mp->tm_bytes_used += sz;
+	rw_exit_write(&mp->tm_acc_lock);
+	return 1;
+}
+
+void
+tmpfs_mem_decr(struct tmpfs_mount *mp, size_t sz)
+{
+
+	rw_enter_write(&mp->tm_acc_lock);
+	KASSERT(mp->tm_bytes_used >= sz);
+	mp->tm_bytes_used -= sz;
+	rw_exit_write(&mp->tm_acc_lock);
+}
+
+struct tmpfs_dirent *
+tmpfs_dirent_get(struct tmpfs_mount *mp)
+{
+
+	if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_dirent))) {
+		return NULL;
+	}
+	return pool_get(&tmpfs_dirent_pool, PR_WAITOK);
+}
+
+void
+tmpfs_dirent_put(struct tmpfs_mount *mp, struct tmpfs_dirent *de)
+{
+
+	tmpfs_mem_decr(mp, sizeof(struct tmpfs_dirent));
+	pool_put(&tmpfs_dirent_pool, de);
+}
+
+struct tmpfs_node *
+tmpfs_node_get(struct tmpfs_mount *mp)
+{
+
+	mp->tm_nodes_cnt++;
+	if (mp->tm_nodes_cnt > mp->tm_nodes_max) {
+		mp->tm_nodes_cnt--;
+		return NULL;
+	}
+	if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_node))) {
+		return NULL;
+	}
+	return pool_get(&tmpfs_node_pool, PR_WAITOK);
+}
+
+void
+tmpfs_node_put(struct tmpfs_mount *mp, struct tmpfs_node *tn)
+{
+
+	mp->tm_nodes_cnt--;
+	tmpfs_mem_decr(mp, sizeof(struct tmpfs_node));
+	pool_put(&tmpfs_node_pool, tn);
+}
+
+/*
+ * Quantum size to round-up the tmpfs names in order to reduce re-allocations.
+ */
+
+#define	TMPFS_NAME_QUANTUM	(32)
+#define	roundup2(x, y)	(((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
+
+char *
+tmpfs_strname_alloc(struct tmpfs_mount *mp, size_t len)
+{
+	const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM);
+
+	KASSERT(sz > 0 && sz <= 1024);
+	if (!tmpfs_mem_incr(mp, sz)) {
+		return NULL;
+	}
+	return malloc(sz, M_TEMP, M_WAITOK); /* XXX */
+}
+
+void
+tmpfs_strname_free(struct tmpfs_mount *mp, char *str, size_t len)
+{
+	const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM);
+
+	KASSERT(sz > 0 && sz <= 1024);
+	tmpfs_mem_decr(mp, sz);
+	free(str, M_TEMP);
+}
+
+int
+tmpfs_strname_neqlen(struct componentname *fcnp, struct componentname *tcnp)
+{
+	const size_t fln = roundup2(fcnp->cn_namelen, TMPFS_NAME_QUANTUM);
+	const size_t tln = roundup2(tcnp->cn_namelen, TMPFS_NAME_QUANTUM);
+
+	return (fln != tln) || memcmp(fcnp->cn_nameptr, tcnp->cn_nameptr, fln);
+}