[PATCH RFC 01/11] atm: let procfs copy out reads of the device files

[Christian Brauner]

Implement ->proc_read_buf() so procfs copies what is read from
/proc/net/atm/<dev> to userspace after it unpinned the entry. The
drivers' ->proc_read() keep filling their page.

Signed-off-by: Christian Brauner (Amutable) <brauner at kernel.org>
---
 net/atm/proc.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/net/atm/proc.c b/net/atm/proc.c
index ca0fc6b90998..cea930b4b840 100644
--- a/net/atm/proc.c
+++ b/net/atm/proc.c
@@ -30,11 +30,11 @@
 #include "resources.h"
 #include "common.h" /* atm_proc_init prototype */
 
-static ssize_t proc_dev_atm_read(struct file *file, char __user *buf,
+static ssize_t proc_dev_atm_read(struct file *file, char *buf,
 				 size_t count, loff_t *pos);
 
 static const struct proc_ops atm_dev_proc_ops = {
-	.proc_read	= proc_dev_atm_read,
+	.proc_read_buf	= proc_dev_atm_read,
 	.proc_lseek	= noop_llseek,
 };
 
@@ -246,7 +246,7 @@ static const struct seq_operations vcc_seq_ops = {
 	.show	= vcc_seq_show,
 };
 
-static ssize_t proc_dev_atm_read(struct file *file, char __user *buf,
+static ssize_t proc_dev_atm_read(struct file *file, char *buf,
 				 size_t count, loff_t *pos)
 {
 	struct atm_dev *dev;
@@ -267,8 +267,7 @@ static ssize_t proc_dev_atm_read(struct file *file, char __user *buf,
 			length = -EINVAL;
 	}
 	if (length >= 0) {
-		if (copy_to_user(buf, (char *)page, length))
-			length = -EFAULT;
+		memcpy(buf, (char *)page, length);
 		(*pos)++;
 	}
 	free_page(page);

-- 
2.53.0