Driver supported smp linux kernel need use smp_wmb/smp_rmb, nor wmb/rmb?

David Yang david.yangshuai at
Thu Aug 26 03:43:29 EDT 2010

Hello all,

Start with linux 2.6.33,  the DMA coherent buffers are mapped as Normal
Non-cacheable, so our drivers using dma_alloc_coherent() add the
barriers (e.g. wmb/rmb) to ensure that read/wirte coherence with

Now our drivers are stable at the non-smp linux 2.6.33,  if our driver
need support the smp linux 2.6.33, we need replace wmb()/rmb() to

Thank for any help


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