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When receiving a packet from a guest, vhost_vsock_handle_tx_kick() calls vhost_vsock_alloc_linear_skb() to allocate and fill an SKB with the receive data. Unfortunately, these are always linear allocations and can therefore result in significant pressure on kmalloc() considering that the maximum packet size (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM) is a little over 64KiB, resulting in a 128KiB allocation for each packet. Rework the vsock SKB allocation so that, for sizes with page order greater than PAGE_ALLOC_COSTLY_ORDER, a nonlinear SKB is allocated instead with the packet header in the SKB and the receive data in the fragments. Finally, add a debug warning if virtio_vsock_skb_rx_put() is ever called on an SKB with a non-zero length, as this would be destructive for the nonlinear case. Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20250717090116.11987-8-will@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>