[dpdk-dev,v4,2/2] i40evf: support to report pf reset event

  When Linux PF and DPDK VF are used for i40e PMD, In case of PF reset,
interrupt will go via adminq event, VF need be informed the event,
a callback mechanism is introduced by VF. This will allow VF to
invoke callback when reset happens.
Users can register a callback for this interrupt event like:
  rte_eth_dev_callback_register(portid,
		RTE_ETH_EVENT_INTR_RESET,
		reset_event_callback,
		arg);

Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>
Acked-by: Helin Zhang <helin.zhang@intel.com>
---
 doc/guides/rel_notes/release_16_04.rst |   2 +
 drivers/net/i40e/i40e_ethdev_vf.c      | 272 +++++++++++++++++++++++++++++----
 lib/librte_ether/rte_ethdev.h          |   1 +
 3 files changed, 246 insertions(+), 29 deletions(-)
  

2016-03-09 14:00, Jingjing Wu:
> When Linux PF and DPDK VF are used for i40e PMD, In case of PF reset,
> interrupt will go via adminq event, VF need be informed the event,
> a callback mechanism is introduced by VF. This will allow VF to
> invoke callback when reset happens.
> Users can register a callback for this interrupt event like:
>   rte_eth_dev_callback_register(portid,
> 		RTE_ETH_EVENT_INTR_RESET,
> 		reset_event_callback,
> 		arg);
[...]
> --- a/doc/guides/rel_notes/release_16_04.rst
> +++ b/doc/guides/rel_notes/release_16_04.rst
> @@ -105,6 +105,8 @@ This section should contain new features added in this release. Sample format:
>    be down.
>    We added the support of auto-neg by SW to avoid this link down issue.
>  
> +* **Added pf reset event reported in i40e vf PMD driver.

Bruce, is this comment clear enough for an user?

Beware of the wrong formating (missing **)
  

On Wed, Mar 09, 2016 at 10:59:56AM +0100, Thomas Monjalon wrote:
> 2016-03-09 14:00, Jingjing Wu:
> > When Linux PF and DPDK VF are used for i40e PMD, In case of PF reset,
> > interrupt will go via adminq event, VF need be informed the event,
> > a callback mechanism is introduced by VF. This will allow VF to
> > invoke callback when reset happens.
> > Users can register a callback for this interrupt event like:
> >   rte_eth_dev_callback_register(portid,
> > 		RTE_ETH_EVENT_INTR_RESET,
> > 		reset_event_callback,
> > 		arg);
> [...]
> > --- a/doc/guides/rel_notes/release_16_04.rst
> > +++ b/doc/guides/rel_notes/release_16_04.rst
> > @@ -105,6 +105,8 @@ This section should contain new features added in this release. Sample format:
> >    be down.
> >    We added the support of auto-neg by SW to avoid this link down issue.
> >  
> > +* **Added pf reset event reported in i40e vf PMD driver.
> 
> Bruce, is this comment clear enough for an user?
> 
> Beware of the wrong formating (missing **)

It's pretty ok, though I might word it a little differently myself. "reported"
should be "reporting".

Your question, though, does bring up the issue of scope and reviews again. I, as
committer, spend a lot of time tweaking commit messages, sanity checking
patches for compilation errors under various settings, and running checkpatch
etc. before applying them. However, IMHO it is up to the maintainers of the
various subsystems to enforce proper documentation in the patches submitted.
The maintainers are the primary gatekeepers here, and I, for one, don't want to
end up having to review all patches in detail before I apply them - otherwise
we'll be limited to a very small number of driver patches per release :)

In this case, if the submitter of the patch and the maintainer of the driver in
question are happy with the documentation, then who am I to go querying that. :-)

Having committers do full review on apply will only have two possible effects:
1. make the maintainers less conscientious about their job, since they know the
  committers will catch any real bugs or issues on apply
2. cause a lot of problems for submitters as they see a lot of issues being
  flagged at the last minute by committers, when they thought their patch was
  safely acked and ready for commit for some time.

We certainly see lots of the second issue occurring right now, I believe - [I'm
obvously not going to comment on the former :-)]

I'd be very much in favour of having a rule that once a patch is acked by a
maintainer, then it must be applied. We may suffer a bit from slightly lower
quality patches getting applied, but the speed of applying patches should
increase, and the patch contents can always be fixed by subsequent patches later.
[Unlike commit message which can't be fixed later without rewriting git history]
In this case, I feel that phrase "the perfect is the enemy of the good" applies.
https://en.wikipedia.org/wiki/Perfect_is_the_enemy_of_good

Just my 2c on this. I'm sure you have a different view, Thomas, so it's probably
a discussion worth having.

/Bruce
  

I've changed the title for this discussion.

2016-03-09 11:01, Bruce Richardson:
[snip comments about minor issue in release notes]

> Your question, though, does bring up the issue of scope and reviews again. I, as
> committer, spend a lot of time tweaking commit messages, sanity checking
> patches for compilation errors under various settings, and running checkpatch
> etc. before applying them. However, IMHO it is up to the maintainers of the
> various subsystems to enforce proper documentation in the patches submitted.
> The maintainers are the primary gatekeepers here, and I, for one, don't want to
> end up having to review all patches in detail before I apply them - otherwise
> we'll be limited to a very small number of driver patches per release :)

Yes that's a problem.

> In this case, if the submitter of the patch and the maintainer of the driver in
> question are happy with the documentation, then who am I to go querying that. :-)
> 
> Having committers do full review on apply will only have two possible effects:
> 1. make the maintainers less conscientious about their job, since they know the
>   committers will catch any real bugs or issues on apply

Yes we need maintainers to be conscientious on every parts of the patches.
One problem about the release notes and doc, is that not a lot of maintainers
have the "english skills".
Note that it would be easier if we would allow to write in Irish, Chinese or
French languages ;)
Unfortunately we took the constraints of writing in C and English.

> 2. cause a lot of problems for submitters as they see a lot of issues being
>   flagged at the last minute by committers, when they thought their patch was
>   safely acked and ready for commit for some time.
> 
> We certainly see lots of the second issue occurring right now, I believe - [I'm
> obvously not going to comment on the former :-)]
> 
> I'd be very much in favour of having a rule that once a patch is acked by a
> maintainer, then it must be applied. We may suffer a bit from slightly lower
> quality patches getting applied, but the speed of applying patches should
> increase, and the patch contents can always be fixed by subsequent patches later.
> [Unlike commit message which can't be fixed later without rewriting git history]
> In this case, I feel that phrase "the perfect is the enemy of the good" applies.
> https://en.wikipedia.org/wiki/Perfect_is_the_enemy_of_good

Yes but I don't think saying we are OK to decrease the quality is a good message.
The reality is that people never rework what was been committed.
That's why we must be very careful on API and documentation.
About the release notes, decreasing its quality mean we don't care wether it is
read and understood. So maybe we can shrink it to less details and have only a
title with a git/author reference.

> Just my 2c on this. I'm sure you have a different view, Thomas, so it's probably
> a discussion worth having.

Thanks for bringing the discussion.
  

On Wed, Mar 09, 2016 at 12:26:58PM +0100, Thomas Monjalon wrote:
> I've changed the title for this discussion.
> 
> 2016-03-09 11:01, Bruce Richardson:
> [snip comments about minor issue in release notes]
> 
> > Your question, though, does bring up the issue of scope and reviews again. I, as
> > committer, spend a lot of time tweaking commit messages, sanity checking
> > patches for compilation errors under various settings, and running checkpatch
> > etc. before applying them. However, IMHO it is up to the maintainers of the
> > various subsystems to enforce proper documentation in the patches submitted.
> > The maintainers are the primary gatekeepers here, and I, for one, don't want to
> > end up having to review all patches in detail before I apply them - otherwise
> > we'll be limited to a very small number of driver patches per release :)
> 
> Yes that's a problem.
> 
> > In this case, if the submitter of the patch and the maintainer of the driver in
> > question are happy with the documentation, then who am I to go querying that. :-)
> > 
> > Having committers do full review on apply will only have two possible effects:
> > 1. make the maintainers less conscientious about their job, since they know the
> >   committers will catch any real bugs or issues on apply
> 
> Yes we need maintainers to be conscientious on every parts of the patches.

Definite +1

> One problem about the release notes and doc, is that not a lot of maintainers
> have the "english skills".
> Note that it would be easier if we would allow to write in Irish, Chinese or
> French languages ;)
> Unfortunately we took the constraints of writing in C and English.
> 

Yes, language is a good point, and I'm ok with helping to clean up grammar and 
minor language issues e.g. the one word correction I suggested at the start of
this discussion. For the scope of the text, and whether it contains enough
information, I would tend to push that responsibility back on the maintainer
though.


> > 2. cause a lot of problems for submitters as they see a lot of issues being
> >   flagged at the last minute by committers, when they thought their patch was
> >   safely acked and ready for commit for some time.
> > 
> > We certainly see lots of the second issue occurring right now, I believe - [I'm
> > obvously not going to comment on the former :-)]
> > 
> > I'd be very much in favour of having a rule that once a patch is acked by a
> > maintainer, then it must be applied. We may suffer a bit from slightly lower
> > quality patches getting applied, but the speed of applying patches should
> > increase, and the patch contents can always be fixed by subsequent patches later.
> > [Unlike commit message which can't be fixed later without rewriting git history]
> > In this case, I feel that phrase "the perfect is the enemy of the good" applies.
> > https://en.wikipedia.org/wiki/Perfect_is_the_enemy_of_good
> 
> Yes but I don't think saying we are OK to decrease the quality is a good message.
> The reality is that people never rework what was been committed.

Yes, point taken.

> That's why we must be very careful on API and documentation.
> About the release notes, decreasing its quality mean we don't care wether it is
> read and understood. So maybe we can shrink it to less details and have only a
> title with a git/author reference.

I don't think I agree with that. I think the doc should be readable independently
of having the git repo.

> 
> > Just my 2c on this. I'm sure you have a different view, Thomas, so it's probably
> > a discussion worth having.
> 
> Thanks for bringing the discussion.

Indeed. So I would summarise this as:
* an ask to the maintainers to pay increased attention to documentation side of
patches when reviewing and acking.
* on my end, I will do some doc reviews as part of applying commits, but on a
best-effort basis. The primary responsibility is with the maintainers to ensure
documentation quantity before patch application stage.

Does that seem reasonable?

Regards,
/Bruce
  

2016-03-09 14:15, Bruce Richardson:
> On Wed, Mar 09, 2016 at 12:26:58PM +0100, Thomas Monjalon wrote:
> > I've changed the title for this discussion.
> > 
> > 2016-03-09 11:01, Bruce Richardson:
> > [snip comments about minor issue in release notes]
> > 
> > > Your question, though, does bring up the issue of scope and reviews again. I, as
> > > committer, spend a lot of time tweaking commit messages, sanity checking
> > > patches for compilation errors under various settings, and running checkpatch
> > > etc. before applying them. However, IMHO it is up to the maintainers of the
> > > various subsystems to enforce proper documentation in the patches submitted.
> > > The maintainers are the primary gatekeepers here, and I, for one, don't want to
> > > end up having to review all patches in detail before I apply them - otherwise
> > > we'll be limited to a very small number of driver patches per release :)
> > 
> > Yes that's a problem.
> > 
> > > In this case, if the submitter of the patch and the maintainer of the driver in
> > > question are happy with the documentation, then who am I to go querying that. :-)
> > > 
> > > Having committers do full review on apply will only have two possible effects:
> > > 1. make the maintainers less conscientious about their job, since they know the
> > >   committers will catch any real bugs or issues on apply
> > 
> > Yes we need maintainers to be conscientious on every parts of the patches.
> 
> Definite +1
> 
> > One problem about the release notes and doc, is that not a lot of maintainers
> > have the "english skills".
> > Note that it would be easier if we would allow to write in Irish, Chinese or
> > French languages ;)
> > Unfortunately we took the constraints of writing in C and English.
> > 
> 
> Yes, language is a good point, and I'm ok with helping to clean up grammar and 
> minor language issues e.g. the one word correction I suggested at the start of
> this discussion. For the scope of the text, and whether it contains enough
> information, I would tend to push that responsibility back on the maintainer
> though.
> 
> 
> > > 2. cause a lot of problems for submitters as they see a lot of issues being
> > >   flagged at the last minute by committers, when they thought their patch was
> > >   safely acked and ready for commit for some time.
> > > 
> > > We certainly see lots of the second issue occurring right now, I believe - [I'm
> > > obvously not going to comment on the former :-)]
> > > 
> > > I'd be very much in favour of having a rule that once a patch is acked by a
> > > maintainer, then it must be applied. We may suffer a bit from slightly lower
> > > quality patches getting applied, but the speed of applying patches should
> > > increase, and the patch contents can always be fixed by subsequent patches later.
> > > [Unlike commit message which can't be fixed later without rewriting git history]
> > > In this case, I feel that phrase "the perfect is the enemy of the good" applies.
> > > https://en.wikipedia.org/wiki/Perfect_is_the_enemy_of_good
> > 
> > Yes but I don't think saying we are OK to decrease the quality is a good message.
> > The reality is that people never rework what was been committed.
> 
> Yes, point taken.
> 
> > That's why we must be very careful on API and documentation.
> > About the release notes, decreasing its quality mean we don't care wether it is
> > read and understood. So maybe we can shrink it to less details and have only a
> > title with a git/author reference.
> 
> I don't think I agree with that. I think the doc should be readable independently
> of having the git repo.
> 
> > 
> > > Just my 2c on this. I'm sure you have a different view, Thomas, so it's probably
> > > a discussion worth having.
> > 
> > Thanks for bringing the discussion.
> 
> Indeed. So I would summarise this as:
> * an ask to the maintainers to pay increased attention to documentation side of
> patches when reviewing and acking.
> * on my end, I will do some doc reviews as part of applying commits, but on a
> best-effort basis. The primary responsibility is with the maintainers to ensure
> documentation quantity before patch application stage.
> 
> Does that seem reasonable?

Yes and I'd like to hear some maintainers to comment or commit this summary.