[PATCH] proc: make struct proc_dir_entry::namelen unsigned int

[Alexey Dobriyan]

Space is not really conserved, because of natural alignment for the next field.
sizeof(struct proc_dir_entry) remains the same.

Signed-off-by: Alexey Dobriyan <adob...@gmail.com>
---

fs/proc/generic.c | 8 ++++----
include/linux/proc_fs.h | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)

--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -28,7 +28,7 @@

DEFINE_SPINLOCK(proc_subdir_lock);

-static int proc_match(int len, const char *name, struct proc_dir_entry *de)
+static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
{
if (de->namelen != len)
return 0;
@@ -303,7 +303,7 @@ static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
{
const char *cp = name, *next;
struct proc_dir_entry *de;
- int len;
+ unsigned int len;

de = *ret;
if (!de)
@@ -602,7 +602,7 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
{
struct proc_dir_entry *ent = NULL;
const char *fn = name;
- int len;
+ unsigned int len;

/* make sure name is valid */
if (!name || !strlen(name)) goto out;
@@ -786,7 +786,7 @@ void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
struct proc_dir_entry **p;
struct proc_dir_entry *de = NULL;
const char *fn = name;
- int len;
+ unsigned int len;

spin_lock(&proc_subdir_lock);
if (__xlate_proc_name(name, &parent, &fn) != 0) {
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -50,7 +50,7 @@ typedef int (write_proc_t)(struct file *file, const char __user *buffer,

struct proc_dir_entry {
unsigned int low_ino;
- unsigned short namelen;
+ unsigned int namelen;
const char *name;
mode_t mode;
nlink_t nlink;
--
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[Andrew Morton]

On Tue, 8 Mar 2011 12:54:28 +0200
Alexey Dobriyan <adob...@gmail.com> wrote:

> Space is not really conserved, because of natural alignment for the next field.
> sizeof(struct proc_dir_entry) remains the same.
>

What is the reason for this patch??

[Alexey Dobriyan]

On Wed, Mar 09, 2011 at 03:03:06PM -0800, Andrew Morton wrote:
> On Tue, 8 Mar 2011 12:54:28 +0200
> Alexey Dobriyan <adob...@gmail.com> wrote:
>
> > Space is not really conserved, because of natural alignment for the next field.
> > sizeof(struct proc_dir_entry) remains the same.
> >
>
> What is the reason for this patch??

1. namelen is declared "unsigned short" which hints for "maybe space savings".
Indeed in 2.4 struct proc_dir_entry looked like:

struct proc_dir_entry {
unsigned short low_ino;
unsigned short namelen;

Now, low_ino is "unsigned int", all savings were gone for a long time.
"struct proc_dir_entry" is not that countless to worry about it's size,
anyway.

2. converting from unsigned short to int/unsigned int can only create
problems, we better play it safe.