Re: [PATCH v2] Bluetooth: Move force_bredr_smp debugfs into hci_debugfs_create_bredr

From: Alain Michaud
Date: Tue Oct 27 2020 - 12:16:32 EST


Friendly ping and adding my review-by tag.


On Wed, Oct 7, 2020 at 12:38 AM Claire Chang <tientzu@xxxxxxxxxxxx> wrote:
>
> Hi,
>
> This patch is to fix the kernel error
> [ 46.271811] debugfs: File 'force_bredr_smp' in directory 'hci0'
> already present!
>
> When powering off and on the bluetooth, the smp_register will try to create the
> force_bredr_smp entry again.
> Move the creation to hci_debugfs_create_bredr so the force_bredr_smp entry will
> only be created when HCI_SETUP and HCI_CONFIG are not set.
>
> Thanks,
> Claire
>
> On Tue, Sep 29, 2020 at 4:03 PM Claire Chang <tientzu@xxxxxxxxxxxx> wrote:
> >
> > Avoid multiple attempts to create the debugfs entry, force_bredr_smp,
> > by moving it from the SMP registration to the BR/EDR controller init
> > section. hci_debugfs_create_bredr is only called when HCI_SETUP and
> > HCI_CONFIG is not set.
> >
> > Signed-off-by: Claire Chang <tientzu@xxxxxxxxxxxx>
Reviewed-by: Alain Michaud <alainm@xxxxxxxxxxxx>
> > ---
> > v2: correct a typo in commit message
> >
> > net/bluetooth/hci_debugfs.c | 50 +++++++++++++++++++++++++++++++++++++
> > net/bluetooth/smp.c | 44 ++------------------------------
> > net/bluetooth/smp.h | 2 ++
> > 3 files changed, 54 insertions(+), 42 deletions(-)
> >
> > diff --git a/net/bluetooth/hci_debugfs.c b/net/bluetooth/hci_debugfs.c
> > index 5e8af2658e44..4626e0289a97 100644
> > --- a/net/bluetooth/hci_debugfs.c
> > +++ b/net/bluetooth/hci_debugfs.c
> > @@ -494,6 +494,45 @@ static int auto_accept_delay_get(void *data, u64 *val)
> > DEFINE_SIMPLE_ATTRIBUTE(auto_accept_delay_fops, auto_accept_delay_get,
> > auto_accept_delay_set, "%llu\n");
> >
> > +static ssize_t force_bredr_smp_read(struct file *file,
> > + char __user *user_buf,
> > + size_t count, loff_t *ppos)
> > +{
> > + struct hci_dev *hdev = file->private_data;
> > + char buf[3];
> > +
> > + buf[0] = hci_dev_test_flag(hdev, HCI_FORCE_BREDR_SMP) ? 'Y' : 'N';
> > + buf[1] = '\n';
> > + buf[2] = '\0';
> > + return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
> > +}
> > +
> > +static ssize_t force_bredr_smp_write(struct file *file,
> > + const char __user *user_buf,
> > + size_t count, loff_t *ppos)
> > +{
> > + struct hci_dev *hdev = file->private_data;
> > + bool enable;
> > + int err;
> > +
> > + err = kstrtobool_from_user(user_buf, count, &enable);
> > + if (err)
> > + return err;
> > +
> > + err = smp_force_bredr(hdev, enable);
> > + if (err)
> > + return err;
> > +
> > + return count;
> > +}
> > +
> > +static const struct file_operations force_bredr_smp_fops = {
> > + .open = simple_open,
> > + .read = force_bredr_smp_read,
> > + .write = force_bredr_smp_write,
> > + .llseek = default_llseek,
> > +};
> > +
> > static int idle_timeout_set(void *data, u64 val)
> > {
> > struct hci_dev *hdev = data;
> > @@ -589,6 +628,17 @@ void hci_debugfs_create_bredr(struct hci_dev *hdev)
> > debugfs_create_file("voice_setting", 0444, hdev->debugfs, hdev,
> > &voice_setting_fops);
> >
> > + /* If the controller does not support BR/EDR Secure Connections
> > + * feature, then the BR/EDR SMP channel shall not be present.
> > + *
> > + * To test this with Bluetooth 4.0 controllers, create a debugfs
> > + * switch that allows forcing BR/EDR SMP support and accepting
> > + * cross-transport pairing on non-AES encrypted connections.
> > + */
> > + if (!lmp_sc_capable(hdev))
> > + debugfs_create_file("force_bredr_smp", 0644, hdev->debugfs,
> > + hdev, &force_bredr_smp_fops);
> > +
> > if (lmp_ssp_capable(hdev)) {
> > debugfs_create_file("ssp_debug_mode", 0444, hdev->debugfs,
> > hdev, &ssp_debug_mode_fops);
> > diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
> > index 433227f96c73..8b817e4358fd 100644
> > --- a/net/bluetooth/smp.c
> > +++ b/net/bluetooth/smp.c
> > @@ -3353,31 +3353,8 @@ static void smp_del_chan(struct l2cap_chan *chan)
> > l2cap_chan_put(chan);
> > }
> >
> > -static ssize_t force_bredr_smp_read(struct file *file,
> > - char __user *user_buf,
> > - size_t count, loff_t *ppos)
> > +int smp_force_bredr(struct hci_dev *hdev, bool enable)
> > {
> > - struct hci_dev *hdev = file->private_data;
> > - char buf[3];
> > -
> > - buf[0] = hci_dev_test_flag(hdev, HCI_FORCE_BREDR_SMP) ? 'Y': 'N';
> > - buf[1] = '\n';
> > - buf[2] = '\0';
> > - return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
> > -}
> > -
> > -static ssize_t force_bredr_smp_write(struct file *file,
> > - const char __user *user_buf,
> > - size_t count, loff_t *ppos)
> > -{
> > - struct hci_dev *hdev = file->private_data;
> > - bool enable;
> > - int err;
> > -
> > - err = kstrtobool_from_user(user_buf, count, &enable);
> > - if (err)
> > - return err;
> > -
> > if (enable == hci_dev_test_flag(hdev, HCI_FORCE_BREDR_SMP))
> > return -EALREADY;
> >
> > @@ -3399,16 +3376,9 @@ static ssize_t force_bredr_smp_write(struct file *file,
> >
> > hci_dev_change_flag(hdev, HCI_FORCE_BREDR_SMP);
> >
> > - return count;
> > + return 0;
> > }
> >
> > -static const struct file_operations force_bredr_smp_fops = {
> > - .open = simple_open,
> > - .read = force_bredr_smp_read,
> > - .write = force_bredr_smp_write,
> > - .llseek = default_llseek,
> > -};
> > -
> > int smp_register(struct hci_dev *hdev)
> > {
> > struct l2cap_chan *chan;
> > @@ -3433,17 +3403,7 @@ int smp_register(struct hci_dev *hdev)
> >
> > hdev->smp_data = chan;
> >
> > - /* If the controller does not support BR/EDR Secure Connections
> > - * feature, then the BR/EDR SMP channel shall not be present.
> > - *
> > - * To test this with Bluetooth 4.0 controllers, create a debugfs
> > - * switch that allows forcing BR/EDR SMP support and accepting
> > - * cross-transport pairing on non-AES encrypted connections.
> > - */
> > if (!lmp_sc_capable(hdev)) {
> > - debugfs_create_file("force_bredr_smp", 0644, hdev->debugfs,
> > - hdev, &force_bredr_smp_fops);
> > -
> > /* Flag can be already set here (due to power toggle) */
> > if (!hci_dev_test_flag(hdev, HCI_FORCE_BREDR_SMP))
> > return 0;
> > diff --git a/net/bluetooth/smp.h b/net/bluetooth/smp.h
> > index 121edadd5f8d..fc35a8bf358e 100644
> > --- a/net/bluetooth/smp.h
> > +++ b/net/bluetooth/smp.h
> > @@ -193,6 +193,8 @@ bool smp_irk_matches(struct hci_dev *hdev, const u8 irk[16],
> > int smp_generate_rpa(struct hci_dev *hdev, const u8 irk[16], bdaddr_t *rpa);
> > int smp_generate_oob(struct hci_dev *hdev, u8 hash[16], u8 rand[16]);
> >
> > +int smp_force_bredr(struct hci_dev *hdev, bool enable);
> > +
> > int smp_register(struct hci_dev *hdev);
> > void smp_unregister(struct hci_dev *hdev);
> >
> > --
> > 2.28.0.618.gf4bc123cb7-goog
> >