Skip to contentSkip to conversation

proc: make struct proc_dir_entry::namelen unsigned int

PATCH In review Alexey Dobriyan 2 participants 3 messages Mar 8, 2011 – Mar 9, 2011 Proc filesystem

lore
Share & tools
lore

Alexey Dobriyan

author
#0 lore raw

PATCH 1/1 proc: make struct proc_dir_entry::namelen unsigned int

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 <[email protected]>

---

 fs/proc/generic.c       |    8 ++++----
 include/linux/proc_fs.h |    2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)
fs/proc/generic.c +4 -4
@@ -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) {
include/linux/proc_fs.h +1 -1
@@ -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;
#1 lore raw
Quoted 3 lines · On Tue, 8 Mar 2011 12:54:28 +0200 Alexey Dobriyan <[email protected]> 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??

author
#2 lore raw
Quoted 8 lines · Andrew Morton
Quoted 3 lines · On Tue, 8 Mar 2011 12:54:28 +0200 Alexey Dobriyan <[email protected]> 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.