Re: [PATCH net-next v4.1] rds: Expose feature parameters via sysfs (and ELF)

[Andrew Lunn <andrew@lunn.ch>]

On Fri, Jun 27, 2025 at 08:44:49PM -0400, Konrad Rzeszutek Wilk wrote:
> On Wed, Jun 25, 2025 at 04:30:09PM -0700, Jakub Kicinski wrote:
> > On Mon, 23 Jun 2025 11:51:36 -0400 Konrad Rzeszutek Wilk wrote:
> > > With the value of 'supported' in them. In the future this value
> > > could change to say 'deprecated' or have other values (for example
> > > different versions) or can be runtime changed.
> > 
> > I'm curious how this theoretical 'deprecated' value would work
> > in context of uAPI which can never regress..
> 
> Kind of sad considering there are some APIs that should really
> be fixed. Perhaps more of 'it-is-busted-use-this-other-API'?

I expect any attempt to actually use 'deprecated' is going to draw a
lot of close review and push back. ABI is ABI, even if it is broken.

> > $ git log --oneline --since='6 months ago' -- net/rds/ 
> > 433dce0692a0 rds: Correct spelling
> > 6e307a873d30 rds: Correct endian annotation of port and addr assignments
> > 5bccdc51f90c replace strncpy with strscpy_pad
> > c50d295c37f2 rds: Use nested-BH locking for rds_page_remainder
> > 0af5928f358c rds: Acquire per-CPU pointer within BH disabled section
> > aaaaa6639cf5 rds: Disable only bottom halves in rds_page_remainder_alloc()
> > 357660d7596b Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
> > 5c70eb5c593d net: better track kernel sockets lifetime
> > c451715d78e3 net/rds: Replace deprecated strncpy() with strscpy_pad()
> > 7f5611cbc487 rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy
> > $
> > 
> > IOW applying this patch is a bit of a leap of faith that RDS
> > upstreaming will restart. I don't have anything against the patch
> 
> It has to. We have to make the RDS TCP be bug-free as there are
> customers demanding that. 

Maybe we should hold off on this patch until there is a real need for
it? Make it part of a patch series which adds new functionality to the
ABI. It is only when the ABI changes does it make any sense to have
this API.

	Andrew