Commit c5141e6d authored by Eric Dumazet's avatar Eric Dumazet Committed by Linus Torvalds
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procfs: reorder struct pid_dentry to save space on 64bit archs, and constify 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: default avatarEric Dumazet <dada1@cosmosbay.com>
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d9a2f4a4

fs/proc/base.c

+27 −26
Original line number Diff line number Diff line
@@ -91,8 +91,8 @@ 
#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;
@@ -100,8 +100,8 @@ struct pid_entry { 
};



#define NOD(NAME, MODE, IOP, FOP, OP) {			\

	.len  = sizeof(NAME) - 1,			\

	.name = (NAME),					\

	.len  = sizeof(NAME) - 1,			\

	.mode = MODE,					\

	.iop  = IOP,					\

	.fop  = FOP,					\
@@ -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.
@@ -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;
@@ -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;
@@ -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);
@@ -1509,13 +1510,13 @@ out: 


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;
@@ -1544,8 +1545,8 @@ out_no_task: 
	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);
@@ -1553,14 +1554,14 @@ static int proc_pident_fill_cache(struct file *filp, void *dirent, filldir_t fil 


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;
@@ -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),
@@ -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, {}),

};
@@ -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);
@@ -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);
@@ -1846,8 +1847,8 @@ out_no_task: 
	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);
@@ -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),
@@ -2027,7 +2028,7 @@ out: 


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;
@@ -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;

	}
@@ -2168,7 +2169,7 @@ out_no_task: 
/*

 * 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),
@@ -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;

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