From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Haggai Eran <haggaie@mellanox.com>
Cc: Doug Ledford <dledford@redhat.com>,
linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
Liran Liss <liranl@mellanox.com>,
Guy Shapiro <guysh@mellanox.com>,
Shachar Raindel <raindel@mellanox.com>,
Yotam Kenneth <yotamke@mellanox.com>,
Matan Barak <matanb@mellanox.com>
Subject: Re: [PATCH v3 for-next 01/13] IB/core: Use SRCU when reading client_list or device_list
Date: Tue, 12 May 2015 12:23:32 -0600 [thread overview]
Message-ID: <20150512182332.GD15891@obsidianresearch.com> (raw)
In-Reply-To: <555198B7.40302@mellanox.com>
On Tue, May 12, 2015 at 09:07:51AM +0300, Haggai Eran wrote:
> > I'm not sure RCU is the right way to approach this. The driver core
> > has the same basic task to perform, maybe review it's locking
> > arrangment between the device list and driver list.
> >
> > [Actually we probably should be using the driver core here, with IB
> > clients as device drivers, but that is way beyond scope of this..]
>
> So, I'm not very familiar with that code, but it seems that the main
> difference is that in the core a single driver can be attached to a
> device.
Roughly, a bus (IB would be a bus) has devices attached to it, and
devices have drivers attached to them. Bus:Device is 1:N,
Device:Drvier is 1:1.
There a a couple of reasons to be interested in re-using the driver
core, perhaps the best is that it has all the infrastructure to let us
auto-load client modules...
> I guess a similar thing we can do is to rely on the context we associate
> with a pair of a client and a device. If such a context exist, we don't
> need to call client->add again. What do you think?
I didn't look closely, isn't this enough?
device_register:
mutex_lock(client_mutex);
down_write(devices_rwsem);
list_add(device_list,dev,..);
up_write(devices_rwsem);
/* Caller must prevent device_register/unregister concurrancy on the
same dev */
foreach(client_list)
.. client->add(dev,...) ..
mutex_unlock(client_mutex)
client_register:
mutex_lock(client_mutex)
list_add(client_list,new_client..)
down_read(devices_rwsem);
foreach(device_list)
.. client->add(dev,new_client,..) ..
up_read(devices_rwsem);
mutex_unlock(client_mutex)
[Note, I didn't check this carefully, just intuitively seems like a
sane starting point]
Jason
next prev parent reply other threads:[~2015-05-12 18:23 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-10 10:26 [PATCH v3 for-next 00/13] Add network namespace support in the RDMA-CM Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 01/13] IB/core: Use SRCU when reading client_list or device_list Haggai Eran
2015-05-11 18:18 ` Jason Gunthorpe
2015-05-12 6:07 ` Haggai Eran
2015-05-12 18:23 ` Jason Gunthorpe [this message]
2015-05-13 8:10 ` Haggai Eran
[not found] ` <555306E7.9020000-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-05-13 15:57 ` Jason Gunthorpe
2015-05-14 10:35 ` Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 02/13] IB/addr: Pass network namespace as a parameter Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 05/13] IB/cm: Reference count ib_cm_ids Haggai Eran
[not found] ` <1431253604-9214-6-git-send-email-haggaie-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-05-11 18:34 ` Jason Gunthorpe
2015-05-12 6:50 ` Haggai Eran
[not found] ` <5551A2CB.1010407-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-05-12 18:54 ` Jason Gunthorpe
[not found] ` <20150512185447.GA3503-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-05-13 10:20 ` Haggai Eran
2015-05-13 16:58 ` Jason Gunthorpe
[not found] ` <20150513165823.GA20343-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-05-14 6:48 ` Haggai Eran
2015-05-15 19:11 ` Hefty, Sean
[not found] ` <1828884A29C6694DAF28B7E6B8A82373A8FDC0C3-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2015-05-17 6:27 ` Haggai Eran
2015-05-19 19:23 ` Jason Gunthorpe
[not found] ` <20150519192353.GA23612-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-05-19 22:52 ` Hefty, Sean
[not found] ` <1828884A29C6694DAF28B7E6B8A82373A8FDD412-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2015-05-19 23:46 ` Jason Gunthorpe
[not found] ` <20150519234654.GA26634-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-05-20 0:49 ` Hefty, Sean
2015-05-21 6:51 ` Haggai Eran
[not found] ` <555D806B.1090002-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-05-21 12:56 ` Hefty, Sean
[not found] ` <1431253604-9214-1-git-send-email-haggaie-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-05-10 10:26 ` [PATCH v3 for-next 03/13] IB/core: Find the network namespace matching connection parameters Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 04/13] IB/ipoib: Return IPoIB devices " Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 06/13] IB/cm: API to retrieve existing listening CM IDs Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 07/13] IB/cm: Expose service ID in request events Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 08/13] IB/cma: Refactor RDMA IP CM private-data parsing code Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 09/13] IB/cma: Add compare_data checks to the RDMA CM module Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 10/13] IB/cma: Separate port allocation to network namespaces Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 11/13] IB/cma: Share CM IDs between namespaces Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 12/13] IB/cma: Add support for network namespaces Haggai Eran
2015-05-10 10:26 ` [PATCH v3 for-next 13/13] IB/ucma: Take the network namespace from the process Haggai Eran
2015-05-12 17:52 ` [PATCH v3 for-next 00/13] Add network namespace support in the RDMA-CM Hefty, Sean
[not found] ` <1828884A29C6694DAF28B7E6B8A82373A8FD7B85-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2015-05-13 8:50 ` Haggai Eran
[not found] ` <55531073.1000305-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
2015-05-13 16:45 ` Hefty, Sean
[not found] ` <1828884A29C6694DAF28B7E6B8A82373A8FDA13B-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2015-05-13 17:18 ` Jason Gunthorpe
[not found] ` <20150513171823.GB20343-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2015-05-13 17:30 ` Hefty, Sean
[not found] ` <1828884A29C6694DAF28B7E6B8A82373A8FDA1AB-P5GAC/sN6hkd3b2yrw5b5LfspsVTdybXVpNB7YpNyf8@public.gmane.org>
2015-05-14 5:35 ` Haggai Eran
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