[PATCH RFC 22/22] PNP: isapnp: let procfs copy out reads

[Christian Brauner]

Implement ->proc_read_buf() so procfs copies what is read from
/proc/bus/isapnp/<card>/<dev> to userspace after it unpinned the entry.

Signed-off-by: Christian Brauner (Amutable) <brauner@xxxxxxxxxx>
---
 drivers/pnp/isapnp/proc.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/pnp/isapnp/proc.c b/drivers/pnp/isapnp/proc.c
index 8197c7f29743..152fd5bfbc06 100644
--- a/drivers/pnp/isapnp/proc.c
+++ b/drivers/pnp/isapnp/proc.c
@@ -19,37 +19,31 @@ static loff_t isapnp_proc_bus_lseek(struct file *file, loff_t off, int whence)
 	return fixed_size_llseek(file, off, whence, 256);
 }
 
-static ssize_t isapnp_proc_bus_read(struct file *file, char __user * buf,
+static ssize_t isapnp_proc_bus_read(struct file *file, char *buf,
 				    size_t nbytes, loff_t * ppos)
 {
 	struct pnp_dev *dev = pde_data(file_inode(file));
 	loff_t pos = *ppos;
-	int cnt, size = 256;
+	int size = 256;
+	size_t cnt;
 
 	if (pos >= size)
 		return 0;
 	if (nbytes > size - pos)
 		nbytes = size - pos;
-	cnt = nbytes;
-
-	if (!access_ok(buf, cnt))
-		return -EINVAL;
 
 	isapnp_cfg_begin(dev->card->number, dev->number);
-	for (; pos < 256 && cnt > 0; pos++, buf++, cnt--) {
-		unsigned char val;
-		val = isapnp_read_byte(pos);
-		put_user(val, buf);
-	}
+	for (cnt = 0; cnt < nbytes; cnt++)
+		buf[cnt] = isapnp_read_byte(pos + cnt);
 	isapnp_cfg_end();
 
-	*ppos = pos;
+	*ppos = pos + nbytes;
 	return nbytes;
 }
 
 static const struct proc_ops isapnp_proc_bus_proc_ops = {
 	.proc_lseek	= isapnp_proc_bus_lseek,
-	.proc_read	= isapnp_proc_bus_read,
+	.proc_read_buf	= isapnp_proc_bus_read,
 };
 
 static int isapnp_proc_attach_device(struct pnp_dev *dev)

-- 
2.53.0