Hi Ulisses,
On Tue, Apr 17, 2012 at 10:41:27AM -0300, Ulisses Furquim wrote:
> When adding HCI devices hci_register_dev assigns the same name
> hci1 for subsequently added AMP devices.
>
> ...
> [ 6958.381886] sysfs: cannot create duplicate filename
> '/devices/virtual/bluetooth/hci1
> ...
>
> We assume id starts with the number we'll try to add the new device
> and keep iterating until we find the proper place. The only difference
> is we start with 0 for BR/EDR device and 1 for AMP devices (thus AMP
> devices will never receive register as index 0). Then every hdev->id in
> the _ordered_ list <= to the id we want we increment id and move the
> variable head. In the end we'll have id as the first available one and
> head is where you need to add hdev after to keep the list ordered.
>
> Reported-by: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
> Signed-off-by: Ulisses Furquim <ulisses@xxxxxxxxxxxxxx>
> ---
>
> v2 - only increment id when we find it's already there in the list.
>
> ---
> net/bluetooth/hci_core.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
> index c4dc263..e2202a1 100644
> --- a/net/bluetooth/hci_core.c
> +++ b/net/bluetooth/hci_core.c
> @@ -1754,9 +1754,12 @@ int hci_register_dev(struct hci_dev *hdev)
>
> /* Find first available device id */
> list_for_each(p, &hci_dev_list) {
> - if (list_entry(p, struct hci_dev, list)->id != id)
> + int nid = list_entry(p, struct hci_dev, list)->id;
this looks bad IMO, better use hdev = list_entry
> + if (nid > id)
> break;
> - head = p; id++;
> + if (nid == id)
> + id++;
> + head = p;
> }
This does not work when creating 3rd AMP device:
[ 121.925367] Bluetooth: Chosen id 1
[ 121.958056] Created virtual AMP device hci1
[ 131.588553] Bluetooth: list: hdev->id 1 id 1
[ 131.661149] Bluetooth: Chosen id 2
[ 131.681159] Created virtual AMP device hci2
[ 139.904674] Bluetooth: list: hdev->id 2 id 1
[ 139.943904] Bluetooth: Chosen id 1
[ 139.944780] ------------[ cut here ]------------
[ 139.957882] WARNING: at fs/sysfs/dir.c:508 sysfs_add_one+0x9b/0xd0()
...
I suspect that you have to handle 2 cases when you add new device after or
before head otherwise list gets un-ordered.
I put debug prints like below:
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index aca8398..bbc42bc 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1801,6 +1801,7 @@ int hci_register_dev(struct hci_dev *hdev)
/* Find first available device id */
list_for_each(p, &hci_dev_list) {
int nid = list_entry(p, struct hci_dev, list)->id;
+ BT_ERR("\tlist: hdev->id %d id %d", nid, id);
if (nid > id)
break;
if (nid == id)
@@ -1808,6 +1809,8 @@ int hci_register_dev(struct hci_dev *hdev)
head = p;
}
+ BT_ERR("Chosen id %d", id);
+
sprintf(hdev->name, "hci%d", id);
hdev->id = id;
Best regards
Andrei Emeltchenko
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