linux-kernel - [PATCH -mm 3/3] proc: drop several "PDE valid/invalid" checks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <20080329210257.GC16275@martell.zuzino.mipt.ru>
Date:	Sun, 30 Mar 2008 00:02:57 +0300
From:	Alexey Dobriyan <adobriyan@...il.com>
To:	akpm@...l.org
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH -mm 3/3] proc: drop several "PDE valid/invalid" checks

proc-misc code is noticeably full of "if (de)" checks when PDE passed
is always valid. Remove them.

Addition of such check in proc_lookup_de() is for failed lookup case.

Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
---

 fs/proc/generic.c |   33 ++++++++++---------------
 fs/proc/inode.c   |   69 +++++++++++++++++++++++++-----------------------------
 2 files changed, 46 insertions(+), 56 deletions(-)

--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -388,20 +388,18 @@ struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
 
 	lock_kernel();
 	spin_lock(&proc_subdir_lock);
-	if (de) {
-		for (de = de->subdir; de ; de = de->next) {
-			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;
-				de_get(de);
-				spin_unlock(&proc_subdir_lock);
-				error = -EINVAL;
-				inode = proc_get_inode(dir->i_sb, ino, de);
-				goto out_unlock;
-			}
+	for (de = de->subdir; de ; de = de->next) {
+		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;
+			de_get(de);
+			spin_unlock(&proc_subdir_lock);
+			error = -EINVAL;
+			inode = proc_get_inode(dir->i_sb, ino, de);
+			goto out_unlock;
 		}
 	}
 	spin_unlock(&proc_subdir_lock);
@@ -413,7 +411,8 @@ out_unlock:
 		d_add(dentry, inode);
 		return NULL;
 	}
-	de_put(de);
+	if (de)
+		de_put(de);
 	return ERR_PTR(error);
 }
 
@@ -443,10 +442,6 @@ int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent,
 	lock_kernel();
 
 	ino = inode->i_ino;
-	if (!de) {
-		ret = -EINVAL;
-		goto out;
-	}
 	i = filp->f_pos;
 	switch (i) {
 		case 0:
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -25,8 +25,7 @@
 
 struct proc_dir_entry *de_get(struct proc_dir_entry *de)
 {
-	if (de)
-		atomic_inc(&de->count);
+	atomic_inc(&de->count);
 	return de;
 }
 
@@ -35,18 +34,16 @@ struct proc_dir_entry *de_get(struct proc_dir_entry *de)
  */
 void de_put(struct proc_dir_entry *de)
 {
-	if (de) {	
-		lock_kernel();		
-		if (!atomic_read(&de->count)) {
-			printk("de_put: entry %s already free!\n", de->name);
-			unlock_kernel();
-			return;
-		}
-
-		if (atomic_dec_and_test(&de->count))
-			free_proc_entry(de);
+	lock_kernel();		
+	if (!atomic_read(&de->count)) {
+		printk("de_put: entry %s already free!\n", de->name);
 		unlock_kernel();
+		return;
 	}
+
+	if (atomic_dec_and_test(&de->count))
+		free_proc_entry(de);
+	unlock_kernel();
 }
 
 /*
@@ -392,7 +389,7 @@ struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
 {
 	struct inode * inode;
 
-	if (de != NULL && !try_module_get(de->owner))
+	if (!try_module_get(de->owner))
 		goto out_mod;
 
 	inode = iget_locked(sb, ino);
@@ -402,30 +399,29 @@ struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
 		inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
 		PROC_I(inode)->fd = 0;
 		PROC_I(inode)->pde = de;
-		if (de) {
-			if (de->mode) {
-				inode->i_mode = de->mode;
-				inode->i_uid = de->uid;
-				inode->i_gid = de->gid;
-			}
-			if (de->size)
-				inode->i_size = de->size;
-			if (de->nlink)
-				inode->i_nlink = de->nlink;
-			if (de->proc_iops)
-				inode->i_op = de->proc_iops;
-			if (de->proc_fops) {
-				if (S_ISREG(inode->i_mode)) {
+
+		if (de->mode) {
+			inode->i_mode = de->mode;
+			inode->i_uid = de->uid;
+			inode->i_gid = de->gid;
+		}
+		if (de->size)
+			inode->i_size = de->size;
+		if (de->nlink)
+			inode->i_nlink = de->nlink;
+		if (de->proc_iops)
+			inode->i_op = de->proc_iops;
+		if (de->proc_fops) {
+			if (S_ISREG(inode->i_mode)) {
 #ifdef CONFIG_COMPAT
-					if (!de->proc_fops->compat_ioctl)
-						inode->i_fop =
-							&proc_reg_file_ops_no_compat;
-					else
+				if (!de->proc_fops->compat_ioctl)
+					inode->i_fop =
+						&proc_reg_file_ops_no_compat;
+				else
 #endif
-						inode->i_fop = &proc_reg_file_ops;
-				} else {
-					inode->i_fop = de->proc_fops;
-				}
+					inode->i_fop = &proc_reg_file_ops;
+			} else {
+				inode->i_fop = de->proc_fops;
 			}
 		}
 		unlock_new_inode(inode);
@@ -433,8 +429,7 @@ struct inode *proc_get_inode(struct super_block *sb, unsigned int ino,
 	return inode;
 
 out_ino:
-	if (de != NULL)
-		module_put(de->owner);
+	module_put(de->owner);
 out_mod:
 	return NULL;
 }			

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/