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procfs: reorder struct pid_dentry to save space on 64bit archs, and c…
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…onstify them

Change the order of fields of struct pid_entry (file fs/proc/base.c) in order
to avoid a hole on 64bit archs.  (8 bytes saved per object)

Also change all pid_entry arrays to be const qualified, to make clear they
must not be modified.

Before (on x86_64) :

# size fs/proc/base.o
   text    data     bss     dec     hex filename
  15549    2192       0   17741    454d fs/proc/base.o

After :

# size fs/proc/base.o
   text    data     bss     dec     hex filename
  17229     176       0   17405    43fd fs/proc/base.o

Thats 336 bytes saved on kernel size on x86_64

Signed-off-by: Eric Dumazet <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Eric Dumazet authored and Linus Torvalds committed May 8, 2007
1 parent d9a2f4a commit c5141e6
Showing 1 changed file with 27 additions and 26 deletions.
53 changes: 27 additions & 26 deletions fs/proc/base.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -91,17 +91,17 @@
#define PROC_NUMBUF 13

struct pid_entry {
int len;
char *name;
int len;
mode_t mode;
const struct inode_operations *iop;
const struct file_operations *fop;
union proc_op op;
};

#define NOD(NAME, MODE, IOP, FOP, OP) { \
.len = sizeof(NAME) - 1, \
.name = (NAME), \
.len = sizeof(NAME) - 1, \
.mode = MODE, \
.iop = IOP, \
.fop = FOP, \
Expand Down Expand Up @@ -1159,7 +1159,8 @@ static struct dentry_operations pid_dentry_operations =

/* Lookups */

typedef struct dentry *instantiate_t(struct inode *, struct dentry *, struct task_struct *, void *);
typedef struct dentry *instantiate_t(struct inode *, struct dentry *,
struct task_struct *, const void *);

/*
* Fill a directory entry.
Expand All @@ -1175,7 +1176,7 @@ typedef struct dentry *instantiate_t(struct inode *, struct dentry *, struct tas
*/
static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
char *name, int len,
instantiate_t instantiate, struct task_struct *task, void *ptr)
instantiate_t instantiate, struct task_struct *task, const void *ptr)
{
struct dentry *child, *dir = filp->f_path.dentry;
struct inode *inode;
Expand Down Expand Up @@ -1310,9 +1311,9 @@ static struct dentry_operations tid_fd_dentry_operations =
};

static struct dentry *proc_fd_instantiate(struct inode *dir,
struct dentry *dentry, struct task_struct *task, void *ptr)
struct dentry *dentry, struct task_struct *task, const void *ptr)
{
unsigned fd = *(unsigned *)ptr;
unsigned fd = *(const unsigned *)ptr;
struct file *file;
struct files_struct *files;
struct inode *inode;
Expand Down Expand Up @@ -1478,9 +1479,9 @@ static const struct inode_operations proc_fd_inode_operations = {
};

static struct dentry *proc_pident_instantiate(struct inode *dir,
struct dentry *dentry, struct task_struct *task, void *ptr)
struct dentry *dentry, struct task_struct *task, const void *ptr)
{
struct pid_entry *p = ptr;
const struct pid_entry *p = ptr;
struct inode *inode;
struct proc_inode *ei;
struct dentry *error = ERR_PTR(-EINVAL);
Expand Down Expand Up @@ -1509,13 +1510,13 @@ static struct dentry *proc_pident_instantiate(struct inode *dir,

static struct dentry *proc_pident_lookup(struct inode *dir,
struct dentry *dentry,
struct pid_entry *ents,
const struct pid_entry *ents,
unsigned int nents)
{
struct inode *inode;
struct dentry *error;
struct task_struct *task = get_proc_task(dir);
struct pid_entry *p, *last;
const struct pid_entry *p, *last;

error = ERR_PTR(-ENOENT);
inode = NULL;
Expand Down Expand Up @@ -1544,23 +1545,23 @@ static struct dentry *proc_pident_lookup(struct inode *dir,
return error;
}

static int proc_pident_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
struct task_struct *task, struct pid_entry *p)
static int proc_pident_fill_cache(struct file *filp, void *dirent,
filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
{
return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
proc_pident_instantiate, task, p);
}

static int proc_pident_readdir(struct file *filp,
void *dirent, filldir_t filldir,
struct pid_entry *ents, unsigned int nents)
const struct pid_entry *ents, unsigned int nents)
{
int i;
int pid;
struct dentry *dentry = filp->f_path.dentry;
struct inode *inode = dentry->d_inode;
struct task_struct *task = get_proc_task(inode);
struct pid_entry *p, *last;
const struct pid_entry *p, *last;
ino_t ino;
int ret;

Expand Down Expand Up @@ -1675,7 +1676,7 @@ static const struct file_operations proc_pid_attr_operations = {
.write = proc_pid_attr_write,
};

static struct pid_entry attr_dir_stuff[] = {
static const struct pid_entry attr_dir_stuff[] = {
REG("current", S_IRUGO|S_IWUGO, pid_attr),
REG("prev", S_IRUGO, pid_attr),
REG("exec", S_IRUGO|S_IWUGO, pid_attr),
Expand Down Expand Up @@ -1741,7 +1742,7 @@ static const struct inode_operations proc_self_inode_operations = {
* that properly belong to the /proc filesystem, as they describe
* describe something that is process related.
*/
static struct pid_entry proc_base_stuff[] = {
static const struct pid_entry proc_base_stuff[] = {
NOD("self", S_IFLNK|S_IRWXUGO,
&proc_self_inode_operations, NULL, {}),
};
Expand Down Expand Up @@ -1770,9 +1771,9 @@ static struct dentry_operations proc_base_dentry_operations =
};

static struct dentry *proc_base_instantiate(struct inode *dir,
struct dentry *dentry, struct task_struct *task, void *ptr)
struct dentry *dentry, struct task_struct *task, const void *ptr)
{
struct pid_entry *p = ptr;
const struct pid_entry *p = ptr;
struct inode *inode;
struct proc_inode *ei;
struct dentry *error = ERR_PTR(-EINVAL);
Expand Down Expand Up @@ -1820,7 +1821,7 @@ static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
{
struct dentry *error;
struct task_struct *task = get_proc_task(dir);
struct pid_entry *p, *last;
const struct pid_entry *p, *last;

error = ERR_PTR(-ENOENT);

Expand All @@ -1846,8 +1847,8 @@ static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry)
return error;
}

static int proc_base_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
struct task_struct *task, struct pid_entry *p)
static int proc_base_fill_cache(struct file *filp, void *dirent,
filldir_t filldir, struct task_struct *task, const struct pid_entry *p)
{
return proc_fill_cache(filp, dirent, filldir, p->name, p->len,
proc_base_instantiate, task, p);
Expand Down Expand Up @@ -1884,7 +1885,7 @@ static int proc_pid_io_accounting(struct task_struct *task, char *buffer)
static const struct file_operations proc_task_operations;
static const struct inode_operations proc_task_inode_operations;

static struct pid_entry tgid_base_stuff[] = {
static const struct pid_entry tgid_base_stuff[] = {
DIR("task", S_IRUGO|S_IXUGO, task),
DIR("fd", S_IRUSR|S_IXUSR, fd),
INF("environ", S_IRUSR, pid_environ),
Expand Down Expand Up @@ -2027,7 +2028,7 @@ void proc_flush_task(struct task_struct *task)

static struct dentry *proc_pid_instantiate(struct inode *dir,
struct dentry * dentry,
struct task_struct *task, void *ptr)
struct task_struct *task, const void *ptr)
{
struct dentry *error = ERR_PTR(-ENOENT);
struct inode *inode;
Expand Down Expand Up @@ -2142,7 +2143,7 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
goto out_no_task;

for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) {
struct pid_entry *p = &proc_base_stuff[nr];
const struct pid_entry *p = &proc_base_stuff[nr];
if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0)
goto out;
}
Expand All @@ -2168,7 +2169,7 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
/*
* Tasks
*/
static struct pid_entry tid_base_stuff[] = {
static const struct pid_entry tid_base_stuff[] = {
DIR("fd", S_IRUSR|S_IXUSR, fd),
INF("environ", S_IRUSR, pid_environ),
INF("auxv", S_IRUSR, pid_auxv),
Expand Down Expand Up @@ -2238,7 +2239,7 @@ static const struct inode_operations proc_tid_base_inode_operations = {
};

static struct dentry *proc_task_instantiate(struct inode *dir,
struct dentry *dentry, struct task_struct *task, void *ptr)
struct dentry *dentry, struct task_struct *task, const void *ptr)
{
struct dentry *error = ERR_PTR(-ENOENT);
struct inode *inode;
Expand Down

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