Subject: [RFC PATCH v3 00/12] Generic zcopy_* functions

From: Jonathan Lemon <[email-masked]>
Date: Wed, 30 Dec 2020 11:12:32 -0800

From: Jonathan Lemon <[email-masked]>

This is set of cleanup patches for zerocopy which are intended
to allow a introduction of a different zerocopy implementation.

The top level API will use the skb_zcopy_*() functions, while
the current TCP specific zerocopy ends up using msg_zerocopy_*()
calls.

There should be no functional changes from these patches.

v2->v3:
 Rename zc_flags to 'flags'.  Use SKBFL_xxx naming, similar
 to the SKBTX_xx naming.  Leave zerocopy_success naming alone.
 Reorder patches.

v1->v2:
 Break changes to skb_zcopy_put into 3 patches, in order to
 make it easier to follow the changes.  Add Willem's suggestion
 about renaming sock_zerocopy_

Patch 1: remove dead function
Patch 2: simplify sock_zerocopy_put
Patch 3: push status/refcounts into sock_zerocopy_callback
Patch 4: replace sock_zerocopy_put with skb_zcopy_put
Patch 5: rename sock_zerocopy_get
Patch 6:
  Add an optional skb parameter to callback, allowing access to
  the attached skb from the callback.
Patch 7:
  Add skb_zcopy_put_abort, and move zerocopy logic into the
  callback function.  There unfortunately is still a check
  against the callback type here.
Patch 8: Relocate skb_zcopy_clear() in skb_release_data()
Patch 9: rename sock_zerocopy_ to msg_zerocopy_
Patch 10:
  Move zerocopy bits from tx_flags into flags for clarity.
  These bits will be used in the RX path in the future.
Patch 11:
  Set the skb flags from the ubuf being attached, instead
  of a fixed value, allowing different initialization types.
Patch 12: Replace open-coded assignments with skb_zcopy_init()

Jonathan Lemon (12):
  skbuff: remove unused skb_zcopy_abort function
  skbuff: simplify sock_zerocopy_put
  skbuff: Push status and refcounts into sock_zerocopy_callback
  skbuff: replace sock_zerocopy_put() with skb_zcopy_put()
  skbuff: replace sock_zerocopy_get with skb_zcopy_get
  skbuff: Add skb parameter to the ubuf zerocopy callback
  skbuff: Call sock_zerocopy_put_abort from skb_zcopy_put_abort
  skbuff: Call skb_zcopy_clear() before unref'ing fragments
  skbuff: rename sock_zerocopy_* to msg_zerocopy_*
  net: group skb_shinfo zerocopy related bits together.
  skbuff: add flags to ubuf_info for ubuf setup
  tap/tun: add skb_zcopy_init() helper for initialization.

 drivers/net/tap.c                   |   6 +-
 drivers/net/tun.c                   |   6 +-
 drivers/net/xen-netback/common.h    |   3 +-
 drivers/net/xen-netback/interface.c |   4 +-
 drivers/net/xen-netback/netback.c   |   5 +-
 drivers/vhost/net.c                 |   4 +-
 include/linux/skbuff.h              | 106 +++++++++++++++-------------
 net/core/skbuff.c                   |  65 ++++++++---------
 net/ipv4/ip_output.c                |   5 +-
 net/ipv4/tcp.c                      |   8 +--
 net/ipv6/ip6_output.c               |   5 +-
 net/kcm/kcmsock.c                   |   4 +-
 12 files changed, 113 insertions(+), 108 deletions(-)

-- 
2.24.1