Struct DmaBufIdentity 

pub(crate) struct DmaBufIdentity {
    dev: u64,
    ino: u64,
    size: i64,
    modifier: u64,
    width: u32,
    height: u32,
}

The stable identity of a dmabuf, so a cache keyed by the raw fd number cannot hand back a stale import after that fd was closed and recycled onto a different buffer.

The fd integer alone is not an identity: the host’s slot renegotiation frees the backing buffer objects and the kernel reissues the same small fd numbers for the new ones. Since Linux 5.3 each dma-buf carries its own inode, so (st_dev, st_ino) distinguishes two buffers that reuse one fd number, and size reports the true allocation; the DRM format modifier and the geometry round out the identity for older kernels where the inode is shared. A cache hit requires every field to match, so a recycled fd whose buffer differs in any of them is re-imported instead of reused.

Fields

dev: u64

ino: u64

size: i64

modifier: u64

width: u32

height: u32

Implementations

impl DmaBufIdentity

pub(crate) fn probe(fd: i32, modifier: u64, width: u32, height: u32) -> Self

Read the identity of the buffer behind fd: fstat supplies the inode and allocation size, and the caller supplies the modifier and geometry from the dmabuf descriptor. A failed fstat leaves the inode/size zero, which still combines with the modifier and geometry.

Trait Implementations

impl Clone for DmaBufIdentity

fn clone(&self) -> DmaBufIdentity

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for DmaBufIdentity

impl Debug for DmaBufIdentity

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for DmaBufIdentity

impl PartialEq for DmaBufIdentity

fn eq(&self, other: &DmaBufIdentity) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for DmaBufIdentity