This series simplifies epoll registration by moving it to flow creation time rather than deferring it to the first event update. By registering sockets with epoll immediately (using events=0), the epoll control functions can always use EPOLL_CTL_MOD, eliminating the need to track whether a flow is already registered. Patch 1 registers both splice sockets with epoll in tcp_splice_connect() before initiating the connection, allowing tcp_splice_epoll_ctl() to always use EPOLL_CTL_MOD. Patch 2 does the same for regular TCP connections in tcp_conn_from_tap(), tcp_tap_conn_from_sock(), and tcp_flow_migrate_target(), simplifying tcp_epoll_ctl() by removing the ADD/MOD conditional logic. Patch 3 removes EPOLLFD_ID_INVALID and related infrastructure now that all flows are registered at creation: flow_in_epoll(), flow_epollid_clear(), and the defensive checks in flow_epollfd(). Thanks, Laurent Changes in v2: - Explained error handling and rollback behavior in commit message (patch 1) - Added error handling for flow_epoll_set() in tcp_conn_from_tap() and tcp_tap_conn_from_sock() (patch 2) - Added ASSERT for epollid bounds check in flow_epollid_register() (patch 3) Laurent Vivier (3): tcp_splice: Register fds with epoll at flow creation tcp: Register fds with epoll at flow creation flow: Remove EPOLLFD_ID_INVALID flow.c | 34 +++------------------------------- flow.h | 6 +----- icmp.c | 1 - tcp.c | 47 ++++++++++++++++++++++++----------------------- tcp_splice.c | 20 ++++++++++---------- udp_flow.c | 1 - 6 files changed, 38 insertions(+), 71 deletions(-) -- 2.52.0