proc: ->low_ino cleanup

- ->low_ino is write-once field -- reading it under locks is unnecessary.

- /proc/$PID stuff never reaches pde_put()/free_proc_entry() --
   PROC_DYNAMIC_FIRST check never triggers.

- in proc_get_inode(), inode number always matches proc dir entry, so
  save one parameter.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/generic.c

@@ -425,13 +425,10 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
 		if (de->namelen != dentry->d_name.len)
 			continue;
 		if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
-			unsigned int ino;
-
-			ino = de->low_ino;
 			pde_get(de);
 			spin_unlock(&proc_subdir_lock);
 			error = -EINVAL;
-			inode = proc_get_inode(dir->i_sb, ino, de);
+			inode = proc_get_inode(dir->i_sb, de);
 			goto out_unlock;
 		}
 	}
@@ -768,12 +765,7 @@ EXPORT_SYMBOL(proc_create_data);
 
 static void free_proc_entry(struct proc_dir_entry *de)
 {
-	unsigned int ino = de->low_ino;
-
-	if (ino < PROC_DYNAMIC_FIRST)
-		return;
-
-	release_inode_number(ino);
+	release_inode_number(de->low_ino);
 
 	if (S_ISLNK(de->mode))
 		kfree(de->data);

fs/proc/inode.c

@@ -416,12 +416,11 @@ static const struct file_operations proc_reg_file_ops_no_compat = {
 };
 #endif
 
-struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
-				struct proc_dir_entry *de)
+struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
 {
 	struct inode * inode;
 
-	inode = iget_locked(sb, ino);
+	inode = iget_locked(sb, de->low_ino);
 	if (!inode)
 		return NULL;
 	if (inode->i_state & I_NEW) {
@@ -471,7 +470,7 @@ int proc_fill_super(struct super_block *s)
 	s->s_time_gran = 1;
 
 	pde_get(&proc_root);
-	root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
+	root_inode = proc_get_inode(s, &proc_root);
 	if (!root_inode)
 		goto out_no_root;
 	root_inode->i_uid = 0;

fs/proc/internal.h

@@ -109,7 +109,7 @@ void pde_put(struct proc_dir_entry *pde);
 
 extern struct vfsmount *proc_mnt;
 int proc_fill_super(struct super_block *);
-struct inode *proc_get_inode(struct super_block *, unsigned int, struct proc_dir_entry *);
+struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
 
 /*
  * These are generic /proc routines that use the internal