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8de8b71b78
While checking AF_XDP copy mode combined with busy poll, strange
results were observed. rxdrop and txonly scenarios worked fine, but
l2fwd broke immediately.
After a deeper look, it turned out that for l2fwd, Tx side was exiting
early due to xsk_no_wakeup() returning true and in the end
xsk_generic_xmit() was never called. Note that AF_XDP Tx in copy mode
is syscall steered, so the current behavior is broken.
Txonly scenario only worked due to the fact that
sk_mark_napi_id_once_xdp() was never called - since Rx side is not in
the picture for this case and mentioned function is called in
xsk_rcv_check(), sk::sk_napi_id was never set, which in turn meant that
xsk_no_wakeup() was returning false (see the sk->sk_napi_id >=
MIN_NAPI_ID check in there).
To fix this, prefer busy poll in xsk_sendmsg() only when zero copy is
enabled on a given AF_XDP socket. By doing so, busy poll in copy mode
would not exit early on Tx side and eventually xsk_generic_xmit() will
be called.
Fixes:
|
||
|---|---|---|
| .. | ||
| Kconfig | ||
| Makefile | ||
| xdp_umem.c | ||
| xdp_umem.h | ||
| xsk_buff_pool.c | ||
| xsk_diag.c | ||
| xsk_queue.c | ||
| xsk_queue.h | ||
| xsk.c | ||
| xsk.h | ||
| xskmap.c | ||