Bluetooth: Use single_open() for inquiry cache within debugfs

The inquiry cache information in debugfs should be using seq_file support
and not allocating memory on the stack for the string. Since the usage of
these information is really seldom, using single_open() for it is good
enough.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 21 deletions

diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 1a79a6c7e30e..cafb55b0cea5 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -3,6 +3,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/debugfs.h>
+#include <linux/seq_file.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -405,20 +406,11 @@ static struct device_type bt_host = {
         .release = bt_host_release,
 };
 
-static int inquiry_cache_open(struct inode *inode, struct file *file)
-{
-        file->private_data = inode->i_private;
-        return 0;
-}
-
-static ssize_t inquiry_cache_read(struct file *file, char __user *userbuf,
-                                                size_t count, loff_t *ppos)
+static int inquiry_cache_show(struct seq_file *f, void *p)
 {
-        struct hci_dev *hdev = file->private_data;
+        struct hci_dev *hdev = f->private;
         struct inquiry_cache *cache = &hdev->inq_cache;
         struct inquiry_entry *e;
-        char buf[4096];
-        int n = 0;
 
         hci_dev_lock_bh(hdev);
 
@@ -426,23 +418,30 @@ static ssize_t inquiry_cache_read(struct file *file, char __user *userbuf,
                 struct inquiry_data *data = &e->data;
                 bdaddr_t bdaddr;
                 baswap(&bdaddr, &data->bdaddr);
-                n += sprintf(buf + n, "%s %d %d %d 0x%.2x%.2x%.2x 0x%.4x %d %d %u\n",
-                                batostr(&bdaddr),
-                                data->pscan_rep_mode, data->pscan_period_mode,
-                                data->pscan_mode, data->dev_class[2],
-                                data->dev_class[1], data->dev_class[0],
-                                __le16_to_cpu(data->clock_offset),
-                                data->rssi, data->ssp_mode, e->timestamp);
+                seq_printf(f, "%s %d %d %d 0x%.2x%.2x%.2x 0x%.4x %d %d %u\n",
+                           batostr(&bdaddr),
+                           data->pscan_rep_mode, data->pscan_period_mode,
+                           data->pscan_mode, data->dev_class[2],
+                           data->dev_class[1], data->dev_class[0],
+                           __le16_to_cpu(data->clock_offset),
+                           data->rssi, data->ssp_mode, e->timestamp);
         }
 
         hci_dev_unlock_bh(hdev);
 
-        return simple_read_from_buffer(userbuf, count, ppos, buf, n);
+        return 0;
+}
+
+static int inquiry_cache_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, inquiry_cache_show, inode->i_private);
 }
 
 static const struct file_operations inquiry_cache_fops = {
-        .open = inquiry_cache_open,
-        .read = inquiry_cache_read,
+        .open           = inquiry_cache_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
 };
 
 int hci_register_sysfs(struct hci_dev *hdev)