Re: linux-next: Tree for March 1 (bluetooth/hci_sysfs)

David Miller
2010-03-02T02:14:15Z

From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Tue, 2 Mar 2010 12:15:26 +1100

> Hi Randy,
>
> On Mon, 01 Mar 2010 13:08:21 -0800 Randy Dunlap <randy.dunlap@oracle.com> wrote:
>>
>> static ssize_t inquiry_cache_read(struct file *file, char __user *userbuf,
>> size_t count, loff_t *ppos)
>> {
>> struct hci_dev *hdev = file->private_data;
>> struct inquiry_cache *cache = &hdev->inq_cache;
>> struct inquiry_entry *e;
>> char buf[4096]; // <<<<<<<<<<<<<<<<<<<<<<<<<<< huh? don't do that on stack.
>> int n = 0;
>
> Dave Miller is following up on that.

This looks like a job for.... SEQ FILE! :-)

I'm testing the following fix.

diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 1a79a6c..f02c2ff 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>
@@ -405,44 +406,85 @@ static struct device_type bt_host = {
.release = bt_host_release,
};

-static int inquiry_cache_open(struct inode *inode, struct file *file)
+static int inquiry_cache_show(struct seq_file *m, void *v)
{
- file->private_data = inode->i_private;
+ struct inquiry_entry *e = v;
+ struct inquiry_data *data;
+ bdaddr_t bdaddr;
+
+ data = &e->data;
+ baswap(&bdaddr, &data->bdaddr);
+
+ seq_printf(m, "%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);
+
return 0;
}

-static ssize_t inquiry_cache_read(struct file *file, char __user *userbuf,
- size_t count, loff_t *ppos)
+static void *inquiry_cache_get_idx(struct hci_dev *hdev, loff_t pos)
{
- struct hci_dev *hdev = file->private_data;
struct inquiry_cache *cache = &hdev->inq_cache;
- struct inquiry_entry *e;
- char buf[4096];
- int n = 0;
+ struct inquiry_entry *e = cache->list;
+
+ while (e && pos) {
+ e = e->next;
+ pos--;
+ }
+ return e;
+}
+
+static void *inquiry_cache_start(struct seq_file *m, loff_t *pos)
+{
+ struct hci_dev *hdev = m->private;

hci_dev_lock_bh(hdev);

- for (e = cache->list; e; e = e->next) {
- 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);
- }
+ return inquiry_cache_get_idx(hdev, *pos);
+}
+
+static void *inquiry_cache_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ struct inquiry_entry *e = v;
+
+ ++*pos;
+ return e->next;
+}
+
+static void inquiry_cache_stop(struct seq_file *m, void *v)
+{
+ struct hci_dev *hdev = m->private;

hci_dev_unlock_bh(hdev);
+}

- return simple_read_from_buffer(userbuf, count, ppos, buf, n);
+static const struct seq_operations inquiry_cache_ops = {
+ .start = inquiry_cache_start,
+ .next = inquiry_cache_next,
+ .stop = inquiry_cache_stop,
+ .show = inquiry_cache_show,
+};
+
+static int inquiry_cache_open(struct inode *inode, struct file *file)
+{
+ int rc = seq_open(file, &inquiry_cache_ops);
+
+ if (rc >= 0) {
+ struct seq_file *m = file->private_data;
+ m->private = inode->i_private;
+ }
+ return rc;
}

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 = seq_release,
};

int hci_register_sysfs(struct hci_dev *hdev)