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authorAlexey Dobriyan <adobriyan@gmail.com>2016-12-12 16:45:32 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-12 18:55:09 -0800
commit1270dd8d994039b677d0504ba7260873d608bf75 (patch)
treeced0d62305e9cfa38afb22f6eed06e59e499763d
parentfs/proc/base.c: save decrement during lookup/readdir in /proc/$PID (diff)
downloadlinux-dev-1270dd8d994039b677d0504ba7260873d608bf75.tar.xz
linux-dev-1270dd8d994039b677d0504ba7260873d608bf75.zip
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: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--fs/proc/base.c19
-rw-r--r--fs/proc/internal.h1
-rw-r--r--fs/proc/root.c1
3 files changed, 15 insertions, 6 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 04a5fcad4c34..9b99df4893a4 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -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));
+}
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 153db5f85b47..bbba5d22aada 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -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 *);
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 8d3e484055a6..4bd0373576b5 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -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;