[PATCH -mm] fs.h: ifdef security fields

From: Alexey Dobriyan
Date: Sat Aug 05 2006 - 22:35:53 EST


[BSD security levels are deleted in -mm, assuming this below]

The only user of i_security, f_security, s_security fields is SELinux,
so ifdef them with CONFIG_SECURITY_SELINUX. Following Stephen Smalley's
suggestion, i_security initialization is moved to security_inode_alloc()
to not clutter core code with ifdefs and make alloc_inode() codepath
tiny little bit smaller and faster.

The user of (highly greppable) struct fown_struct::security field is
still to be found. I've checked every "fown_struct" and every "f_owner"
occurence. Additionally, it's removal doesn't break i386 allmodconfig
build.

struct inode, struct file, struct super_block, struct fown_struct
become smaller.

P.S. Combined with two reiserfs inode shrinking patches sent to
linux-fsdevel, I can finally suck 12 reiserfs inodes into one page.

/proc/slabinfo

-ext2_inode_cache 388 10
+ext2_inode_cache 384 10
-inode_cache 280 14
+inode_cache 276 14
-proc_inode_cache 296 13
+proc_inode_cache 292 13
-reiser_inode_cache 336 11
+reiser_inode_cache 332 12 <=
-shmem_inode_cache 372 10
+shmem_inode_cache 368 10

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---

fs/inode.c | 1 -
include/linux/fs.h | 8 ++++++--
include/linux/security.h | 1 +
3 files changed, 7 insertions(+), 3 deletions(-)

--- a/fs/inode.c
+++ b/fs/inode.c
@@ -133,7 +133,6 @@ #endif
inode->i_bdev = NULL;
inode->i_cdev = NULL;
inode->i_rdev = 0;
- inode->i_security = NULL;
inode->dirtied_when = 0;
if (security_inode_alloc(inode)) {
if (inode->i_sb->s_op->destroy_inode)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -552,7 +552,9 @@ struct inode {
unsigned int i_flags;

atomic_t i_writecount;
+#ifdef CONFIG_SECURITY_SELINUX
void *i_security;
+#endif
union {
void *generic_ip;
} u;
@@ -645,7 +647,6 @@ struct fown_struct {
rwlock_t lock; /* protects pid, uid, euid fields */
int pid; /* pid or -pgrp where SIGIO should be sent */
uid_t uid, euid; /* uid/euid of process setting the owner */
- void *security;
int signum; /* posix.1b rt signal to be delivered on IO */
};

@@ -688,8 +689,9 @@ struct file {
struct file_ra_state f_ra;

unsigned long f_version;
+#ifdef CONFIG_SECURITY_SELINUX
void *f_security;
-
+#endif
/* needed for tty driver, and maybe others */
void *private_data;

@@ -877,7 +879,9 @@ struct super_block {
int s_syncing;
int s_need_sync_fs;
atomic_t s_active;
+#ifdef CONFIG_SECURITY_SELINUX
void *s_security;
+#endif
struct xattr_handler **s_xattr;

struct list_head s_inodes; /* all inodes */
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1549,6 +1549,7 @@ static inline void security_sb_post_pivo

static inline int security_inode_alloc (struct inode *inode)
{
+ inode->i_security = NULL;
return security_ops->inode_alloc_security (inode);
}


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