RFC nmdesc cleanups and optimisations

This series uses newly introduced struct netmem_desc, which represents common fields b/w netmem types, for optimisations and to start addressing some of the netmem technical debt.

First, replace __netmem_clear_lsb with netmem_to_nmdesc(). The helper optimises pp fields accesses, but now we can do the same but cleaner.

The second problem is abundance of places where the user has struct page / net_iov but still needs to cast it to netmem back and forth just to be able to use generic helpers. It's not the prettiest pattern and often can't be optimised. Start introducing netmem_desc based helpers and using them instead.

There is more work we can do, but these are the patches I want to pull into zcrx. It's an RFC for now, I'll send it as a pull request without zcrx bits.

Byungchul Park (1):
net: replace __netmem_clear_lsb() with netmem_to_nmdesc()

Pavel Begunkov (5):
net: move pp_page_to_nmdesc()
net: page_pool: remove page_pool_set_dma_addr()
net: convert page pool dma helpers to netmem_desc
net: page_pool: convert refcounting helpers to nmdesc io_uring/zcrx: avoid netmem casts with nmdesc

 include/net/netmem.h            | 75 +++++++++++++++------------------
 include/net/page_pool/helpers.h | 41 ++++++++++++++----
 io_uring/zcrx.c                 | 12 +++---
 net/core/devmem.c               |  5 ---
 net/core/netmem_priv.h          | 20 +++------
 net/core/page_pool_priv.h       | 14 +++---
 6 files changed, 82 insertions(+), 85 deletions(-)

2.49.0