From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matan Barak Subject: Re: [PATCH v3 for-next 02/33] IB/core: Add kref to IB devices Date: Tue, 28 Apr 2015 17:03:11 +0300 Message-ID: <553F931F.6000302@mellanox.com> References: <1427318422-12004-1-git-send-email-somnath.kotur@emulex.com> <9f65de5e-ed5f-48d2-bff2-03ffbe4f4876@CMEXHTCAS2.ad.emulex.com> <553DF294.4070507@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Or Gerlitz Cc: Somnath Kotur , Roland Dreier , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On 4/28/2015 2:51 PM, Or Gerlitz wrote: > On Mon, Apr 27, 2015 at 11:25 AM, Matan Barak wrote: >> On 4/26/2015 11:10 PM, Or Gerlitz wrote: >>> On Thu, Mar 26, 2015 at 12:19 AM, Somnath Kotur >>> wrote: >>>> >>>> From: Matan Barak >>>> >>>> Previously. we used device_mutex lock in order to protect >>>> the device's list. That means that in order to guarantee a >>>> device isn't freed while we use it, we had to lock all >>>> devices. >>> >>> >>> Matan, looking on the cover letter, it says: "[...] Patch 0002 adds a >>> reference count mechanism to IB devices. This mechanism is similar to >>> dev_hold and dev_put available for net devices. This is mandatory for >>> later patches [...]" > >> Correct, I'll change that into: >> Currently we use device_mutex lock for protecting the device's list. In the >> current approach, in order to guarantee a device isn't freed we have to lock >> all devices. >> Adding a kref per IB device. Before an IB device is unregistered, we wait >> until it's not held anymore. > > Why is this change mandatory for the proposed design? > The cleanup of roce_gid_cache is done in a different context, so we need to make sure the device is still alive while doing so. In addition, we don't want that the unregistration process of ib_core will free our context data. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html