Backport RXRPC for 6.1.y from 6.2

[Wentao Guan]

> Why is this needed?  If you want this, please provide a working set of
> patches properly submitted, along with the reasoning why you just don't
> move to a newer kernel version.  And do you really use the AFS
> filesystem in a 6.1.y kernel tree?  If so, why?

FYI, there are bugfixes such as ("rxrpc: Fix conn-level packet handling to unshare RESPONSE packets")
affect the 6.1.y kernel, and the final goal is clean apply fixes for CVE-2026-43500 such as
("rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present") in maillist.

> move to a newer kernel version.  And do you really use the AFS
> filesystem in a 6.1.y kernel tree?  If so, why?
NO, just affected by compiled kernel which enabled the config:(,
we are preparing fix such as disable AFS and AF_RXRPC or fix it...

BRs
Wentao Guan