This series prepares the vhost-user path for multi-buffer support, where a single virtqueue element can use more than one iovec entry. Currently, iovec arrays are tightly coupled to virtqueue elements: callers must pre-initialize each element's in_sg/out_sg pointers before calling vu_queue_pop(), and each element is assumed to own exactly one iovec slot. This makes it impossible for a single element to span multiple iovec entries, which is needed for UDP multi-buffer reception. The series decouples iovec storage from elements in three patches: - Patch 1 passes iovec arrays as separate parameters to vu_queue_pop() and vu_queue_map_desc(), so the caller controls where descriptors are mapped rather than reading them from pre-initialized element fields. - Patch 2 passes the actual remaining out_sg capacity to vu_queue_pop() in vu_handle_tx() instead of a fixed per-element constant, enabling dynamic iovec allocation. - Patch 3 moves iovec pool management into vu_collect(), which now accepts the iovec array and tracks consumed entries across elements with a running counter. This removes vu_set_element() and vu_init_elem() entirely. Callers that still assume one iovec per element assert this invariant explicitly until they are updated for multi-buffer. The follow-up udp-iov_vu series builds on this to implement actual multi-buffer support in the UDP vhost-user path. Laurent Vivier (3): virtio: Pass iovec arrays as separate parameters to vu_queue_pop() vu_handle_tx: Pass actual remaining out_sg capacity to vu_queue_pop() vu_common: Move iovec management into vu_collect() tcp_vu.c | 23 ++++++++------- udp_vu.c | 21 ++++++++------ virtio.c | 29 ++++++++++++++----- virtio.h | 4 ++- vu_common.c | 83 ++++++++++++++++++++++++----------------------------- vu_common.h | 22 ++------------ 6 files changed, 91 insertions(+), 91 deletions(-) -- 2.53.0