Struct devices::virtio::queue::packed_descriptor_chain::PackedDescriptorChain

pub struct PackedDescriptorChain<'m> {
    avail_wrap_counter: bool,
    index: Option<u16>,
    count: u16,
    id: Option<u16>,
    queue_size: u16,
    mem: &'m GuestMemory,
    desc_table: GuestAddress,
}

Fields

avail_wrap_counter: bool

index: Option<u16>

Current descriptor index within desc_table, or None if the iterator is exhausted.

count: u16

Number of descriptors returned by the iterator already. If count reaches queue_size, the chain has a loop and is therefore invalid.

id: Option<u16>

Buffer Id, which locates at the last descriptor in the chain

queue_size: u16

mem: &'m GuestMemory

desc_table: GuestAddress

Implementations

impl<'m> PackedDescriptorChain<'m>

pub fn new( mem: &'m GuestMemory, desc_table: GuestAddress, queue_size: u16, avail_wrap_counter: bool, index: u16 ) -> PackedDescriptorChain<'m>

Construct a new iterator over a split virtqueue descriptor chain.

Arguments

• mem - The GuestMemory containing the descriptor chain.
• desc_table - Guest physical address of the descriptor table.
• queue_size - Total number of entries in the descriptor table.
• index - The index of the first descriptor in the chain.

Trait Implementations

impl DescriptorChainIter for PackedDescriptorChain<'_>

fn next(&mut self) -> Result<Option<Descriptor>>

Return the next descriptor in the chain, or None if there are no more descriptors.

fn count(&self) -> u16

Return the number of descriptor has been iterated in the chain

fn id(&self) -> Option<u16>

Return Packed descriptor chain buffer id if iterator reaches end, otherwise return None SplitDescriptorChainIter should return None.