Commit 1270dd8d authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds
Browse files

fs/proc: calculate /proc/* and /proc/*/task/* nlink at init time 

Runtime nlink calculation works but meh.  I don't know how to do it at
compile time, but I know how to do it at init time.

Shift "2+" part into init time as a bonus.

Link: http://lkml.kernel.org/r/20161122195549.GB29812@avx2


Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: default avatarVegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bac5f5d5

fs/proc/base.c

+13 −6
Original line number Diff line number Diff line
@@ -104,6 +104,9 @@ 
 *	in /proc for a task before it execs a suid executable.

 */



static u8 nlink_tid;

static u8 nlink_tgid;



struct pid_entry {

	const char *name;

	unsigned int len;
@@ -139,13 +142,13 @@ struct pid_entry { 
 * Count the number of hardlinks for the pid_entry table, excluding the .

 * and .. links.

 */

static unsigned int pid_entry_count_dirs(const struct pid_entry *entries,

static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,

	unsigned int n)

{

	unsigned int i;

	unsigned int count;



	count = 0;

	count = 2;

	for (i = 0; i < n; ++i) {

		if (S_ISDIR(entries[i].mode))

			++count;
@@ -3068,8 +3071,7 @@ static int proc_pid_instantiate(struct inode *dir, 
	inode->i_fop = &proc_tgid_base_operations;

	inode->i_flags|=S_IMMUTABLE;



	set_nlink(inode, 2 + pid_entry_count_dirs(tgid_base_stuff,

						  ARRAY_SIZE(tgid_base_stuff)));

	set_nlink(inode, nlink_tgid);



	d_set_d_op(dentry, &pid_dentry_operations);
@@ -3361,8 +3363,7 @@ static int proc_task_instantiate(struct inode *dir, 
	inode->i_fop = &proc_tid_base_operations;

	inode->i_flags|=S_IMMUTABLE;



	set_nlink(inode, 2 + pid_entry_count_dirs(tid_base_stuff,

						  ARRAY_SIZE(tid_base_stuff)));

	set_nlink(inode, nlink_tid);



	d_set_d_op(dentry, &pid_dentry_operations);
@@ -3552,3 +3553,9 @@ static const struct file_operations proc_task_operations = { 
	.iterate_shared	= proc_task_readdir,

	.llseek		= generic_file_llseek,

};



void __init set_proc_pid_nlink(void)

{

	nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));

	nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));

}

fs/proc/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -211,6 +211,7 @@ extern const struct inode_operations proc_link_inode_operations; 
extern const struct inode_operations proc_pid_link_inode_operations;



extern void proc_init_inodecache(void);

void set_proc_pid_nlink(void);

extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);

extern int proc_fill_super(struct super_block *, void *data, int flags);

extern void proc_entry_rundown(struct proc_dir_entry *);

fs/proc/root.c

+1 −0
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ void __init proc_root_init(void) 
	int err;



	proc_init_inodecache();

	set_proc_pid_nlink();

	err = register_filesystem(&proc_fs_type);

	if (err)

		return;

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