Merge branch 'selftests-test-xdp_tx-for-single-buffer'

Dimitri Daskalakis says:

====================
selftests: Test XDP_TX for single-buffer

Ensure single buffer XDP functions correctly by covering the following cases:
1) Zero size payload
2) Full MTU
3) Single buffer packets through a multi-buffer XDP program

These changes were tested with netdevsim and fbnic.

 # ./ksft-net-drv/drivers/net/xdp.py
 TAP version 13
 1..10
 ok 1 xdp.test_xdp_native_pass_sb
 ok 2 xdp.test_xdp_native_pass_mb
 ok 3 xdp.test_xdp_native_drop_sb
 ok 4 xdp.test_xdp_native_drop_mb
 ok 5 xdp.test_xdp_native_tx_sb
 ok 6 xdp.test_xdp_native_tx_mb
 # Failed run: pkt_sz 2048, offset 1. Last successful run: pkt_sz 1024, offset 256. Reason: Adjustment failed
 ok 7 xdp.test_xdp_native_adjst_tail_grow_data
 ok 8 xdp.test_xdp_native_adjst_tail_shrnk_data
 # Failed run: pkt_sz 512, offset -256. Last successful run: pkt_sz 512, offset -128. Reason: Adjustment failed
 ok 9 xdp.test_xdp_native_adjst_head_grow_data
 # Failed run: pkt_sz (2048) > HDS threshold (1536) and offset 64 > 48
 ok 10 xdp.test_xdp_native_adjst_head_shrnk_data
 # Totals: pass:10 fail:0 xfail:0 xpass:0 skip:0 error:0
====================

Link: https://patch.msgid.link/20250821014023.1481662-1-dimitri.daskalakis1@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>