From: Stefano Garzarella <[email protected]> This reverts commit 4157501b9a8f ("vsock/virtio: fix skb overhead overflow on 32-bit builds"). The fix was semantically correct (although it would have been better to use mul_u32_u32(), as David pointed out), but in practice we are estimating the memory used to allocate the SKBs, and this will never cause a 32-bit variable to overflow on a 32-bit system, since the memory would have run out long before that. On 64-bit, SKB_TRUESIZE() already evaluates to size_t, so the multiplication is already in 64-bit arithmetic without the cast.
Let's revert this to avoid unnecessary 64-bit multiplies on the per-packet receive path on 32-bit systems. Reported-by: David Laight <[email protected]> Closes: https://lore.kernel.org/netdev/20260523173557.5cc4f4f6@pumpkin Suggested-by: "Michael S. Tsirkin" <[email protected]> Signed-off-by: Stefano Garzarella <[email protected]> --- net/vmw_vsock/virtio_transport_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index b143290a311d..d4d26fba9e37 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -417,7 +417,7 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk, static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs, u32 len) { - u64 skb_overhead = ((u64)skb_queue_len(&vvs->rx_queue) + 1) * SKB_TRUESIZE(0); + u64 skb_overhead = (skb_queue_len(&vvs->rx_queue) + 1) * SKB_TRUESIZE(0); /* Allow at most buf_alloc * 2 total budget (payload + overhead), * similar to how SO_RCVBUF is doubled to reserve space for sk_buff -- 2.54.0
