Hello Liming Sun,
The patch bc05ea63b394: "platform/mellanox: Add BlueField-3 support
in the tmfifo driver" from Oct 18, 2022 (linux-next), leads to the
following Smatch static checker warning:
drivers/platform/mellanox/mlxbf-tmfifo.c:634 mlxbf_tmfifo_rxtx_word()
error: uninitialized symbol 'data'.
drivers/platform/mellanox/mlxbf-tmfifo.c
592 static void mlxbf_tmfifo_rxtx_word(struct mlxbf_tmfifo_vring *vring,
593 struct vring_desc *desc,
594 bool is_rx, int len)
595 {
596 struct virtio_device *vdev = vring->vq->vdev;
597 struct mlxbf_tmfifo *fifo = vring->fifo;
598 void *addr;
599 u64 data;
600
601 /* Get the buffer address of this desc. */
602 addr = phys_to_virt(virtio64_to_cpu(vdev, desc->addr));
603
604 /* Read a word from FIFO for Rx. */
605 if (is_rx)
606 data = readq(fifo->rx.data);
607
608 if (vring->cur_len + sizeof(u64) <= len) {
609 /* The whole word. */
610 if (!IS_VRING_DROP(vring)) {
611 if (is_rx)
612 memcpy(addr + vring->cur_len, &data,
613 sizeof(u64));
614 else
615 memcpy(&data, addr + vring->cur_len,
616 sizeof(u64));
617 }
if IS_VRING_DROP() is true then data isn't intialized.
618 vring->cur_len += sizeof(u64);
619 } else {
620 /* Leftover bytes. */
621 if (!IS_VRING_DROP(vring)) {
622 if (is_rx)
623 memcpy(addr + vring->cur_len, &data,
624 len - vring->cur_len);
625 else
626 memcpy(&data, addr + vring->cur_len,
627 len - vring->cur_len);
628 }
Same here.
629 vring->cur_len = len;
630 }
631
632 /* Write the word into FIFO for Tx. */
633 if (!is_rx)
--> 634 writeq(data, fifo->tx.data);
^^^^
Unitialized if IS_VRING_DROP() is true.
635 }
regards,
dan carpenter
