[PATCH RESUBMIT] fs/proc/task_mmu: use __seq_open_private()

[Rob Jones <rob.jones@codethink.co.uk>]

Reduce boilerplate code by using __seq_open_private() instead of seq_open().

This function has been around, undocumented, for years. It can simplify
the set up code for seq file operations.

Signed-off-by: Rob Jones <rob.jones@codethink.co.uk>
---

This patch was originally submitted on 12th September as part 2/2.

Part 1 was pipped at the post by someone else doing the same thing.

This part resubmitted as a stand-alone patch.

 fs/proc/task_mmu.c |   42 ++++++++++++++++--------------------------
 1 file changed, 16 insertions(+), 26 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 442177b..c8e9045 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -235,19 +235,14 @@ static int do_maps_open(struct inode *inode, struct file *file,
 			const struct seq_operations *ops)
 {
 	struct proc_maps_private *priv;
-	int ret = -ENOMEM;
-	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-	if (priv) {
-		priv->pid = proc_pid(inode);
-		ret = seq_open(file, ops);
-		if (!ret) {
-			struct seq_file *m = file->private_data;
-			m->private = priv;
-		} else {
-			kfree(priv);
-		}
-	}
-	return ret;
+
+	priv = __seq_open_private(file, ops, sizeof(*priv));
+	if (!priv)
+		return -ENOMEM;
+
+	priv->pid = proc_pid(inode);
+
+	return 0;
 }
 
 static void
@@ -1495,19 +1490,14 @@ static int numa_maps_open(struct inode *inode, struct file *file,
 			  const struct seq_operations *ops)
 {
 	struct numa_maps_private *priv;
-	int ret = -ENOMEM;
-	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-	if (priv) {
-		priv->proc_maps.pid = proc_pid(inode);
-		ret = seq_open(file, ops);
-		if (!ret) {
-			struct seq_file *m = file->private_data;
-			m->private = priv;
-		} else {
-			kfree(priv);
-		}
-	}
-	return ret;
+
+	priv = __seq_open_private(file, ops, sizeof(*priv));
+	if (!priv)
+		return -ENOMEM;
+
+	priv->proc_maps.pid = proc_pid(inode);
+
+	return 0;
 }
 
 static int pid_numa_maps_open(struct inode *inode, struct file *file)
-- 
1.7.10.4