From: Prabu Thayalan The old ionic_rx_service() and ionic_tx_service() used array indexing to access completion descriptors: comp = &((struct ionic_rxq_comp *)cq->base)[cq->tail_idx]; This assumes the stride is sizeof(struct ionic_rxq_comp) = 16 bytes. However, when the IONIC_Q_F_2X_CQ_DESC flag is set, the actual completion descriptor size is 32 bytes (2 * sizeof(comp)), and the completion itself is located at the end of that 32-byte slot. Array indexing with a 16-byte stride would access the wrong offset. Use pointer arithmetic that accounts for the actual descriptor size from cq->desc_size: comp = cq->base + cq->desc_size * cq->tail_idx + cq->desc_size - sizeof(*comp); This correctly calculates the completion location regardless of descriptor size. For the common case where desc_size equals sizeof(*comp), use array indexing in a likely() fast path to avoid performance regression. Fixes: 0ec9f6669a7d ("ionic: add handling of larger descriptors") Signed-off-by: Prabu Thayalan Signed-off-by: Eric Joyner --- .../net/ethernet/pensando/ionic/ionic_txrx.c | 27 ++++++++++--------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c index 301ebee2fdc5..27a113d63d28 100644 --- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c +++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c @@ -701,11 +701,7 @@ static void ionic_rx_clean(struct ionic_queue *q, __le64 *cq_desc_hwstamp; u64 hwstamp; - cq_desc_hwstamp = - (void *)comp + - qcq->cq.desc_size - - sizeof(struct ionic_rxq_comp) - - IONIC_HWSTAMP_CQ_NEGOFFSET; + cq_desc_hwstamp = (void *)comp - IONIC_HWSTAMP_CQ_NEGOFFSET; hwstamp = le64_to_cpu(*cq_desc_hwstamp); @@ -729,7 +725,12 @@ static bool __ionic_rx_service(struct ionic_cq *cq, struct bpf_prog *xdp_prog) struct ionic_queue *q = cq->bound_q; struct ionic_rxq_comp *comp; - comp = &((struct ionic_rxq_comp *)cq->base)[cq->tail_idx]; + if (likely(cq->desc_size == sizeof(*comp))) + comp = &((struct ionic_rxq_comp *)cq->base)[cq->tail_idx]; + else + comp = cq->base + + cq->desc_size * cq->tail_idx + + cq->desc_size - sizeof(*comp); if (!color_match(comp->pkt_type_color, cq->done_color)) return false; @@ -1180,7 +1181,6 @@ static void ionic_tx_clean(struct ionic_queue *q, bool in_napi) { struct ionic_tx_stats *stats = q_to_tx_stats(q); - struct ionic_qcq *qcq = q_to_qcq(q); struct sk_buff *skb; if (desc_info->xdpf) { @@ -1205,11 +1205,7 @@ static void ionic_tx_clean(struct ionic_queue *q, __le64 *cq_desc_hwstamp; u64 hwstamp; - cq_desc_hwstamp = - (void *)comp + - qcq->cq.desc_size - - sizeof(struct ionic_txq_comp) - - IONIC_HWSTAMP_CQ_NEGOFFSET; + cq_desc_hwstamp = (void *)comp - IONIC_HWSTAMP_CQ_NEGOFFSET; hwstamp = le64_to_cpu(*cq_desc_hwstamp); @@ -1244,7 +1240,12 @@ static bool ionic_tx_service(struct ionic_cq *cq, unsigned int pkts = 0; u16 index; - comp = &((struct ionic_txq_comp *)cq->base)[cq->tail_idx]; + if (likely(cq->desc_size == sizeof(*comp))) + comp = &((struct ionic_txq_comp *)cq->base)[cq->tail_idx]; + else + comp = cq->base + + cq->desc_size * cq->tail_idx + + cq->desc_size - sizeof(*comp); if (!color_match(comp->color, cq->done_color)) return false; -- 2.17.1