[PATCH] proc: rearrange args

From: Alexey Dobriyan
Date: Thu Jan 04 2018 - 13:00:06 EST


Rearrange args for smaller code.

lookup revolves around memcmp() which gets len 3rd arg, so propagate
length as 3rd arg.

readdir and lookup add additional arg to VFS ->readdir and ->lookup,
so better add it to the end.

Space savings on x86_64:

add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-18 (-18)
Function old new delta
proc_readdir 22 13 -9
proc_lookup 18 9 -9

proc_match() is smaller if not inlined, I promise!

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---

fs/proc/generic.c | 18 +++++++++---------
fs/proc/internal.h | 5 ++---
fs/proc/proc_net.c | 4 ++--
3 files changed, 13 insertions(+), 14 deletions(-)

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

static DEFINE_RWLOCK(proc_subdir_lock);

-static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
+static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
{
if (len < de->namelen)
return -1;
@@ -60,7 +60,7 @@ static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
struct proc_dir_entry *de = rb_entry(node,
struct proc_dir_entry,
subdir_node);
- int result = proc_match(len, name, de);
+ int result = proc_match(name, de, len);

if (result < 0)
node = node->rb_left;
@@ -84,7 +84,7 @@ static bool pde_subdir_insert(struct proc_dir_entry *dir,
struct proc_dir_entry *this = rb_entry(*new,
struct proc_dir_entry,
subdir_node);
- int result = proc_match(de->namelen, de->name, this);
+ int result = proc_match(de->name, this, de->namelen);

parent = *new;
if (result < 0)
@@ -211,8 +211,8 @@ void proc_free_inum(unsigned int inum)
* Don't create negative dentries here, return -ENOENT by hand
* instead.
*/
-struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
- struct dentry *dentry)
+struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
+ struct proc_dir_entry *de)
{
struct inode *inode;

@@ -235,7 +235,7 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
- return proc_lookup_de(PDE(dir), dir, dentry);
+ return proc_lookup_de(dir, dentry, PDE(dir));
}

/*
@@ -247,8 +247,8 @@ struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
* value of the readdir() call, as long as it's non-negative
* for success..
*/
-int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
- struct dir_context *ctx)
+int proc_readdir_de(struct file *file, struct dir_context *ctx,
+ struct proc_dir_entry *de)
{
int i;

@@ -292,7 +292,7 @@ int proc_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);

- return proc_readdir_de(PDE(inode), file, ctx);
+ return proc_readdir_de(file, ctx, PDE(inode));
}

/*
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -153,10 +153,9 @@ extern bool proc_fill_cache(struct file *, struct dir_context *, const char *, i
* generic.c
*/
extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
-extern struct dentry *proc_lookup_de(struct proc_dir_entry *, struct inode *,
- struct dentry *);
+struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
extern int proc_readdir(struct file *, struct dir_context *);
-extern int proc_readdir_de(struct proc_dir_entry *, struct file *, struct dir_context *);
+int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *);

static inline struct proc_dir_entry *pde_get(struct proc_dir_entry *pde)
{
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -135,7 +135,7 @@ static struct dentry *proc_tgid_net_lookup(struct inode *dir,
de = ERR_PTR(-ENOENT);
net = get_proc_task_net(dir);
if (net != NULL) {
- de = proc_lookup_de(net->proc_net, dir, dentry);
+ de = proc_lookup_de(dir, dentry, net->proc_net);
put_net(net);
}
return de;
@@ -172,7 +172,7 @@ static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
ret = -EINVAL;
net = get_proc_task_net(file_inode(file));
if (net != NULL) {
- ret = proc_readdir_de(net->proc_net, file, ctx);
+ ret = proc_readdir_de(file, ctx, net->proc_net);
put_net(net);
}
return ret;