drm/amdgpu: Use READ_ONCE() when reading the values in 'sdma_v4_4_2_ring_get_rptr'

Use READ_ONCE() instead of declaring the pointer volatile. To prevent
the compiler from refetching or reordering the read, so that the read
value is always consistent.

Link: https://lwn.net/Articles/624126/
Cc: Felix Kuehling <[email protected]>
Cc: Guchun Chen <[email protected]>
Cc: Christian König <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: "Pan, Xinhui" <[email protected]>
Cc: Le Ma <[email protected]>
Cc: Hawking Zhang <[email protected]>
Signed-off-by: Srinivasan Shanmugam <[email protected]>
Reviewed-by: Le Ma <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

0 files changed, 0 insertions, 0 deletions