diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt
index 417e309..0d783c5 100644
--- a/Documentation/filesystems/tmpfs.txt
+++ b/Documentation/filesystems/tmpfs.txt
@@ -71,8 +71,8 @@
 to limit this tmpfs instance to that percentage of your physical RAM:
 the default, when neither size nor nr_blocks is specified, is size=50%
 
-If both nr_blocks (or size) and nr_inodes are set to 0, neither blocks
-nor inodes will be limited in that instance.  It is generally unwise to
+If nr_blocks=0 (or size=0), blocks will not be limited in that instance;
+if nr_inodes=0, inodes will not be limited.  It is generally unwise to
 mount with such options, since it allows any user with write access to
 use up all the memory on the machine; but enhances the scalability of
 that instance in a system with many cpus making intensive use of it.
@@ -97,4 +97,4 @@
 Author:
    Christoph Rohland <cr@sap.com>, 1.12.01
 Updated:
-   Hugh Dickins <hugh@veritas.com>, 01 September 2004
+   Hugh Dickins <hugh@veritas.com>, 13 March 2005
diff --git a/mm/shmem.c b/mm/shmem.c
index 61574b8..e64fa72 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -6,8 +6,8 @@
  *		 2000-2001 Christoph Rohland
  *		 2000-2001 SAP AG
  *		 2002 Red Hat Inc.
- * Copyright (C) 2002-2004 Hugh Dickins.
- * Copyright (C) 2002-2004 VERITAS Software Corporation.
+ * Copyright (C) 2002-2005 Hugh Dickins.
+ * Copyright (C) 2002-2005 VERITAS Software Corporation.
  * Copyright (C) 2004 Andi Kleen, SuSE Labs
  *
  * Extended attribute support for tmpfs:
@@ -194,7 +194,7 @@
 static void shmem_free_blocks(struct inode *inode, long pages)
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
-	if (sbinfo) {
+	if (sbinfo->max_blocks) {
 		spin_lock(&sbinfo->stat_lock);
 		sbinfo->free_blocks += pages;
 		inode->i_blocks -= pages*BLOCKS_PER_PAGE;
@@ -357,7 +357,7 @@
 		 * page (and perhaps indirect index pages) yet to allocate:
 		 * a waste to allocate index if we cannot allocate data.
 		 */
-		if (sbinfo) {
+		if (sbinfo->max_blocks) {
 			spin_lock(&sbinfo->stat_lock);
 			if (sbinfo->free_blocks <= 1) {
 				spin_unlock(&sbinfo->stat_lock);
@@ -677,8 +677,8 @@
 			spin_unlock(&shmem_swaplist_lock);
 		}
 	}
-	if (sbinfo) {
-		BUG_ON(inode->i_blocks);
+	BUG_ON(inode->i_blocks);
+	if (sbinfo->max_inodes) {
 		spin_lock(&sbinfo->stat_lock);
 		sbinfo->free_inodes++;
 		spin_unlock(&sbinfo->stat_lock);
@@ -1080,7 +1080,7 @@
 	} else {
 		shmem_swp_unmap(entry);
 		sbinfo = SHMEM_SB(inode->i_sb);
-		if (sbinfo) {
+		if (sbinfo->max_blocks) {
 			spin_lock(&sbinfo->stat_lock);
 			if (sbinfo->free_blocks == 0 ||
 			    shmem_acct_block(info->flags)) {
@@ -1269,7 +1269,7 @@
 	struct shmem_inode_info *info;
 	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
 
-	if (sbinfo) {
+	if (sbinfo->max_inodes) {
 		spin_lock(&sbinfo->stat_lock);
 		if (!sbinfo->free_inodes) {
 			spin_unlock(&sbinfo->stat_lock);
@@ -1319,7 +1319,7 @@
 			mpol_shared_policy_init(&info->policy);
 			break;
 		}
-	} else if (sbinfo) {
+	} else if (sbinfo->max_inodes) {
 		spin_lock(&sbinfo->stat_lock);
 		sbinfo->free_inodes++;
 		spin_unlock(&sbinfo->stat_lock);
@@ -1328,31 +1328,6 @@
 }
 
 #ifdef CONFIG_TMPFS
-
-static int shmem_set_size(struct shmem_sb_info *sbinfo,
-			  unsigned long max_blocks, unsigned long max_inodes)
-{
-	int error;
-	unsigned long blocks, inodes;
-
-	spin_lock(&sbinfo->stat_lock);
-	blocks = sbinfo->max_blocks - sbinfo->free_blocks;
-	inodes = sbinfo->max_inodes - sbinfo->free_inodes;
-	error = -EINVAL;
-	if (max_blocks < blocks)
-		goto out;
-	if (max_inodes < inodes)
-		goto out;
-	error = 0;
-	sbinfo->max_blocks  = max_blocks;
-	sbinfo->free_blocks = max_blocks - blocks;
-	sbinfo->max_inodes  = max_inodes;
-	sbinfo->free_inodes = max_inodes - inodes;
-out:
-	spin_unlock(&sbinfo->stat_lock);
-	return error;
-}
-
 static struct inode_operations shmem_symlink_inode_operations;
 static struct inode_operations shmem_symlink_inline_operations;
 
@@ -1607,15 +1582,17 @@
 	buf->f_type = TMPFS_MAGIC;
 	buf->f_bsize = PAGE_CACHE_SIZE;
 	buf->f_namelen = NAME_MAX;
-	if (sbinfo) {
-		spin_lock(&sbinfo->stat_lock);
+	spin_lock(&sbinfo->stat_lock);
+	if (sbinfo->max_blocks) {
 		buf->f_blocks = sbinfo->max_blocks;
 		buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
+	}
+	if (sbinfo->max_inodes) {
 		buf->f_files = sbinfo->max_inodes;
 		buf->f_ffree = sbinfo->free_inodes;
-		spin_unlock(&sbinfo->stat_lock);
 	}
 	/* else leave those fields 0 like simple_statfs */
+	spin_unlock(&sbinfo->stat_lock);
 	return 0;
 }
 
@@ -1672,7 +1649,7 @@
 	 * but each new link needs a new dentry, pinning lowmem, and
 	 * tmpfs dentries cannot be pruned until they are unlinked.
 	 */
-	if (sbinfo) {
+	if (sbinfo->max_inodes) {
 		spin_lock(&sbinfo->stat_lock);
 		if (!sbinfo->free_inodes) {
 			spin_unlock(&sbinfo->stat_lock);
@@ -1697,7 +1674,7 @@
 
 	if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) {
 		struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
-		if (sbinfo) {
+		if (sbinfo->max_inodes) {
 			spin_lock(&sbinfo->stat_lock);
 			sbinfo->free_inodes++;
 			spin_unlock(&sbinfo->stat_lock);
@@ -1921,22 +1898,42 @@
 static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
-	unsigned long max_blocks = 0;
-	unsigned long max_inodes = 0;
+	unsigned long max_blocks = sbinfo->max_blocks;
+	unsigned long max_inodes = sbinfo->max_inodes;
+	unsigned long blocks;
+	unsigned long inodes;
+	int error = -EINVAL;
 
-	if (sbinfo) {
-		max_blocks = sbinfo->max_blocks;
-		max_inodes = sbinfo->max_inodes;
-	}
-	if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, &max_inodes))
-		return -EINVAL;
-	/* Keep it simple: disallow limited <-> unlimited remount */
-	if ((max_blocks || max_inodes) == !sbinfo)
-		return -EINVAL;
-	/* But allow the pointless unlimited -> unlimited remount */
-	if (!sbinfo)
-		return 0;
-	return shmem_set_size(sbinfo, max_blocks, max_inodes);
+	if (shmem_parse_options(data, NULL, NULL, NULL,
+				&max_blocks, &max_inodes))
+		return error;
+
+	spin_lock(&sbinfo->stat_lock);
+	blocks = sbinfo->max_blocks - sbinfo->free_blocks;
+	inodes = sbinfo->max_inodes - sbinfo->free_inodes;
+	if (max_blocks < blocks)
+		goto out;
+	if (max_inodes < inodes)
+		goto out;
+	/*
+	 * Those tests also disallow limited->unlimited while any are in
+	 * use, so i_blocks will always be zero when max_blocks is zero;
+	 * but we must separately disallow unlimited->limited, because
+	 * in that case we have no record of how much is already in use.
+	 */
+	if (max_blocks && !sbinfo->max_blocks)
+		goto out;
+	if (max_inodes && !sbinfo->max_inodes)
+		goto out;
+
+	error = 0;
+	sbinfo->max_blocks  = max_blocks;
+	sbinfo->free_blocks = max_blocks - blocks;
+	sbinfo->max_inodes  = max_inodes;
+	sbinfo->free_inodes = max_inodes - inodes;
+out:
+	spin_unlock(&sbinfo->stat_lock);
+	return error;
 }
 #endif
 
@@ -1961,11 +1958,11 @@
 	uid_t uid = current->fsuid;
 	gid_t gid = current->fsgid;
 	int err = -ENOMEM;
-
-#ifdef CONFIG_TMPFS
+	struct shmem_sb_info *sbinfo;
 	unsigned long blocks = 0;
 	unsigned long inodes = 0;
 
+#ifdef CONFIG_TMPFS
 	/*
 	 * Per default we only allow half of the physical ram per
 	 * tmpfs instance, limiting inodes to one per page of lowmem;
@@ -1976,34 +1973,34 @@
 		inodes = totalram_pages - totalhigh_pages;
 		if (inodes > blocks)
 			inodes = blocks;
-
-		if (shmem_parse_options(data, &mode,
-					&uid, &gid, &blocks, &inodes))
+		if (shmem_parse_options(data, &mode, &uid, &gid,
+					&blocks, &inodes))
 			return -EINVAL;
 	}
-
-	if (blocks || inodes) {
-		struct shmem_sb_info *sbinfo;
-		sbinfo = kmalloc(sizeof(struct shmem_sb_info), GFP_KERNEL);
-		if (!sbinfo)
-			return -ENOMEM;
-		sb->s_fs_info = sbinfo;
-		spin_lock_init(&sbinfo->stat_lock);
-		sbinfo->max_blocks = blocks;
-		sbinfo->free_blocks = blocks;
-		sbinfo->max_inodes = inodes;
-		sbinfo->free_inodes = inodes;
-	}
-	sb->s_xattr = shmem_xattr_handlers;
 #else
 	sb->s_flags |= MS_NOUSER;
 #endif
 
+	/* Round up to L1_CACHE_BYTES to resist false sharing */
+	sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info),
+				L1_CACHE_BYTES), GFP_KERNEL);
+	if (!sbinfo)
+		return -ENOMEM;
+
+	spin_lock_init(&sbinfo->stat_lock);
+	sbinfo->max_blocks = blocks;
+	sbinfo->free_blocks = blocks;
+	sbinfo->max_inodes = inodes;
+	sbinfo->free_inodes = inodes;
+
+	sb->s_fs_info = sbinfo;
 	sb->s_maxbytes = SHMEM_MAX_BYTES;
 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = TMPFS_MAGIC;
 	sb->s_op = &shmem_ops;
+	sb->s_xattr = shmem_xattr_handlers;
+
 	inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
 	if (!inode)
 		goto failed;