linux/net/xdp
Magnus Karlsson d7012f05e3 xsk: Consolidate to one single cached producer pointer
Currently, the xsk ring code has two cached producer pointers:
prod_head and prod_tail. This patch consolidates these two into a
single one called cached_prod to make the code simpler and easier to
maintain. This will be in line with the user space part of the the
code found in libbpf, that only uses a single cached pointer.

The Rx path only uses the two top level functions
xskq_produce_batch_desc and xskq_produce_flush_desc and they both use
prod_head and never prod_tail. So just move them over to
cached_prod.

The Tx XDP_DRV path uses xskq_produce_addr_lazy and
xskq_produce_flush_addr_n and unnecessarily operates on both prod_tail
and prod_head, so move them over to just use cached_prod by skipping
the intermediate step of updating prod_tail.

The Tx path in XDP_SKB mode uses xskq_reserve_addr and
xskq_produce_addr. They currently use both cached pointers, but we can
operate on the global producer pointer in xskq_produce_addr since it
has to be updated anyway, thus eliminating the use of both cached
pointers. We can also remove the xskq_nb_free in xskq_produce_addr
since it is already called in xskq_reserve_addr. No need to do it
twice.

When there is only one cached producer pointer, we can also simplify
xskq_nb_free by removing one argument.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/1576759171-28550-4-git-send-email-magnus.karlsson@intel.com
2019-12-20 16:00:09 -08:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
xdp_umem.c xsk: Fix registration of Rx-only sockets 2019-10-23 20:22:11 -07:00
xdp_umem.h xdp: fix hang while unregistering device bound to xdp socket 2019-07-03 15:10:55 +02:00
xsk_diag.c xsk: lock the control mutex in sock_diag interface 2019-09-05 14:11:52 +02:00
xsk_queue.c net: xsk: add a simple buffer reuse queue 2018-09-25 13:13:15 -07:00
xsk_queue.h xsk: Consolidate to one single cached producer pointer 2019-12-20 16:00:09 -08:00
xsk.c xsk: Make xskmap flush_list common for all map instances 2019-12-19 21:09:43 -08:00
xsk.h xsk: add support for need_wakeup flag in AF_XDP rings 2019-08-17 23:07:32 +02:00