On Mon, May 23, 2022 at 4:00 AM Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote: > > The memory barrier dma_mb() is introduced by commit a76a37777f2c > ("iommu/arm-smmu-v3: Ensure queue is read after updating prod pointer"), > which is used to ensure that prior (both reads and writes) accesses > to memory by a CPU are ordered w.r.t. a subsequent MMIO write, this > is only defined on arm64, but it is a generic memory barrier, let's > add dma_mb() into documentation and include/asm-generic/barrier.h. > > Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> > --- I assume you plan this to get merged through the arm64 tree. Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx> # for asm-generic