new helper: readlink_copy()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 5 insertions, 11 deletions

diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index 9ae46b8..8902609 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -146,7 +146,7 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int bufl
 	struct task_struct *task;
 	void *ns;
 	char name[50];
-	int len = -EACCES;
+	int res = -EACCES;
 
 	task = get_proc_task(inode);
 	if (!task)
@@ -155,24 +155,18 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int bufl
 	if (!ptrace_may_access(task, PTRACE_MODE_READ))
 		goto out_put_task;
 
-	len = -ENOENT;
+	res = -ENOENT;
 	ns = ns_ops->get(task);
 	if (!ns)
 		goto out_put_task;
 
 	snprintf(name, sizeof(name), "%s:[%u]", ns_ops->name, ns_ops->inum(ns));
-	len = strlen(name);
-
-	if (len > buflen)
-		len = buflen;
-	if (copy_to_user(buffer, name, len))
-		len = -EFAULT;
-
+	res = readlink_copy(buffer, buflen, name);
 	ns_ops->put(ns);
 out_put_task:
 	put_task_struct(task);
 out:
-	return len;
+	return res;
 }
 
 static const struct inode_operations proc_ns_link_inode_operations = {
diff --git a/fs/proc/self.c b/fs/proc/self.c
index ffeb202..4348bb8 100644
--- a/fs/proc/self.c
+++ b/fs/proc/self.c
@@ -16,7 +16,7 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
 	if (!tgid)
 		return -ENOENT;
 	sprintf(tmp, "%d", tgid);
-	return vfs_readlink(dentry,buffer,buflen,tmp);
+	return readlink_copy(buffer, buflen, tmp);
 }
 
 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)