Return-Path: MIME-Version: 1.0 In-Reply-To: References: <1328588997-25029-1-git-send-email-aguedespe@gmail.com> <1328588997-25029-4-git-send-email-aguedespe@gmail.com> Date: Tue, 7 Feb 2012 14:41:47 -0300 Message-ID: Subject: Re: [PATCH 3/3] Bluetooth: Use advertising cache thread-safe functions From: Andre Guedes To: Ulisses Furquim Cc: Anderson Lizardo , Andre Guedes , linux-bluetooth@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hi Ulisses, On Tue, Feb 7, 2012 at 12:20 PM, Ulisses Furquim wrote: > Hi Andre, > > On Tue, Feb 7, 2012 at 12:46 PM, Andre Guedes > wrote: >> Hi Ulisses, >> >> On Tue, Feb 7, 2012 at 10:26 AM, Ulisses Furquim wrote: >>> Hi Andre, >>> >>> On Tue, Feb 7, 2012 at 10:20 AM, Andre Guedes >>> wrote: >>>> Hi Lizardo, >>>> >>>> On Tue, Feb 7, 2012 at 7:48 AM, Anderson Lizardo >>>> wrote: >>>>> Hi Andre, >>>>> >>>>> On Tue, Feb 7, 2012 at 12:29 AM, Andre Guedes wrote: >>>>>> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c >>>>>> index 6808069..3933ccd 100644 >>>>>> --- a/net/bluetooth/hci_event.c >>>>>> +++ b/net/bluetooth/hci_event.c >>>>>> @@ -3255,12 +3255,10 @@ static inline void hci_le_adv_report_evt(struct hci_dev *hdev, >>>>>> ? ? ? ?void *ptr = &skb->data[1]; >>>>>> ? ? ? ?s8 rssi; >>>>>> >>>>>> - ? ? ? hci_dev_lock(hdev); >>>>>> - >>>>> >>>>> So there is no need to lock hdev between the hci_add_adv_entry() and >>>>> mgmt_device_found() calls? This looks different from what is done for >>>>> BR/EDR for the inquiry cache. >>>> >>>> Yes, mgmt_device_found() does not require locking hdev->lock. >>> >>> We could then move the lock and unlock calls to inside the loop. But >>> as we might have more than one call to hci_add_adv_entry() it'd be >>> good to lock and unlock only once, no? Any problems I don't see? >> >> Yes, that's right. For this particular case, it may be better to lock >> hdev outside while() and call the thread-unsafe version here. >> >> This way, it may be better we just drop patches 02/03 and 03/03. >> >>>>>> ? ? ? ?while (num_reports--) { >>>>>> ? ? ? ? ? ? ? ?struct hci_ev_le_advertising_info *ev = ptr; >>>>>> >>>>>> - ? ? ? ? ? ? ? __hci_add_adv_entry(hdev, ev); >>>>>> + ? ? ? ? ? ? ? hci_add_adv_entry(hdev, ev); >>>>>> >>>>>> ? ? ? ? ? ? ? ?rssi = ev->data[ev->length]; >>>>>> ? ? ? ? ? ? ? ?mgmt_device_found(hdev, &ev->bdaddr, LE_LINK, ev->bdaddr_type, >>>>>> @@ -3268,8 +3266,6 @@ static inline void hci_le_adv_report_evt(struct hci_dev *hdev, >>>>>> >>>>>> ? ? ? ? ? ? ? ?ptr += sizeof(*ev) + ev->length + 1; >>>>>> ? ? ? ?} >>>>>> - >>>>>> - ? ? ? hci_dev_unlock(hdev); >>>>>> ?} >>>>>> >>>>>> ?static inline void hci_le_ltk_request_evt(struct hci_dev *hdev, >>>>>> -- >>>>>> 1.7.9 >>> >>> While I don't see anything wrong with your changes I don't think we >>> really need it. All the other functions that need to be called with >>> hdev->lock held don't have "__" prefix so it'll be different than the >>> others. And you added 3 new locked functions but your last patch only >>> uses 2 of them and only in 2 places. Unless I'm missing something here >>> we don't really need this refactoring at all. Do you have any other >>> reason to do that? Are you gonna use those functions in other >>> patchset? >> >> Yes, some other functions don't have the prefix "__" and that fact >> makes a bit painful and error-prone since we always have to dig in >> the "call chain" to know if we need to hold hdev->lock or not. >> Prefixing a function with "__" is just a standard way to indicate >> that. > > I understand that. I just don't know if Marcel will want to change > them all to have "__" prefixes, though. Having only one subset with > this prefix can make things even more confusing, don't you agree? Yes, this is pretty much an RFC series, I just realized I missed changing the --subject-prefix. > And have you been working with these functions or is this just a > cleanup you thought it'd be good to do? Just a cleanup. Andre