On 12.04.24 04:02, Wen Gu wrote:
On 2024/4/11 19:12, Alexandra Winter wrote:
On 09.04.24 03:44, Wen Gu wrote:
On 2024/4/4 23:15, Niklas Schnelle wrote:
On Thu, 2024-04-04 at 21:12 +0800, Wen Gu wrote:
On 2024/4/4 19:42, Niklas Schnelle wrote:
On Thu, 2024-04-04 at 17:32 +0800, Wen Gu wrote:
On 2024/4/4 00:25, Gerd Bayer wrote:
On Sun, 2024-03-24 at 21:55 +0800, Wen Gu wrote:
This implements some operations that loopback-ism does not support
currently:
- vlan operations, since there is no strong use-case for it.
- signal_event operations, since there is no event to be
processed
by the loopback-ism device.
Hi Wen,
I wonder if the these operations that are not supported by
loopback-ism
should rather be marked "optional" in the struct smcd_ops, and the
calling code should call these only when they are implemented.
Of course this would mean more changes to net/smc/smc_core.c - but
loopback-ism could omit these "boiler-plate" functions.
Hi Gerd.
Thank you for the thoughts! I agree that checks like
'if(smcd->ops->xxx)'
can avoid the device driver from implementing unsupported
operations. But I
am afraid that which operations need to be defined as 'optional'
may differ
from different device perspectives (e.g. for loopback-ism they
are vlan-related
opts and signal_event). So I perfer to simply let the smc
protocol assume
that all operations have been implemented, and let drivers to
decide which
ones are unsupported in implementation. What do you think?
Thanks!
I agree with Gerd, in my opinion it is better to document ops as
optional and then allow their function pointers to be NULL and check
for that. Acting like they are supported and then they turn out to be
nops to me seems to contradict the principle of least surprises. I
also
think we can find a subset of mandatory ops without which SMC-D is
impossible and then everything else should be optional.
I see. If we all agree to classify smcd_ops into mandatory and
optional ones,
I'll add a patch to mark the optional ops and check if they are
implemented.
Keep in mind I don't speak for the SMC maintainers but that does sound
reasonable to me.
Hi Wenjia and Jan, do you have any comments on this and [1]? Thanks!
[1]
https://lore.kernel.org/netdev/60b4aec0b4bf4474d651b653c86c280dafc4518a.camel@xxxxxxxxxxxxx/
As a first guess I think the following options may be mandatory:
* query_remote_gid()
* register_dmb()/unregister_dmb()
* move_data()
For this one could argue that either move_data() or
attach_dmb()/detach_dmb() is required though personally I would
prefer to always have move_data() as a fallback and simple API
* supports_v2()
* get_local_gid()
* get_chid()
* get_dev()
I agree with this classification. Just one point, maybe we can take
supports_v2() as an optional ops, like support_dmb_nocopy()? e.g. if
it is not implemented, we treat it as an ISMv1.
Thanks!
Interpreting a NULL supports_v2() as not supporting v2 sounds
reasonable to me.
Let me add my thoughts to the discussion:
For the vlan operations and signal_event operations that loopback-ism
does
not support:
I like the idea to set the ops to NULL and make sure the caller checks
that
and can live with it. That is readable and efficient.
I don't think there is a need to discuss a strategy now, which ops
could be
optional in the future. This is all inside the kernel. loopback-ism is
even
inside the smc module. Such comments in the code get outdated very
easily.
I would propose to mark those as optional struct smcd_ops, where all
callers can
handle a NULL pointer and still be productive.
Future support of other devices for SMC-D can update that.
Hi Sandy, just to confirm if I understand you correctly.
You are proposing that don't draw a conclusion about the classification
now,
but supplementally mark which one become a optional operation in struct
smcd_ops
during the introduction of new devices for SMC-D.
@Sandy, could you please elaborate your proposal, or comfirm what Wen
interpreted is what you mean?
If it is like what he said. IMO, I don't think it's necessary to dicuss
further on which ops could be mandatory or optional. It's actually clear
to me which are mandatory. And the classification should be much cleaner
for our code. However, I agree that the classification is not really in
the scope of this patches series. Especially if it is too expensive to
rebuild it, we do need a seperate set of cleanup patches to do it. Thus,
I'd like to let Wen take the decisions by ihmself. Any objections?
@All, if anyone has any strong opinion, I appreciate it if you could
bring up your options as soon as possible. That would help us to
accelerate the whole process.
Thanks,
Wenjia
