On Wed, Aug 09, 2023 at 03:20:43PM -0600, Jonathan Corbet wrote: > > spin_unlock_irqrestore(&dev->dma_io_tlb_lock, flags); > > > > - /* Pairs with smp_rmb() in swiotlb_find_pool(). */ > > - smp_wmb(); > > found: > > + dev->dma_uses_io_tlb = true; > > + /* Pairs with smp_rmb() in is_swiotlb_buffer() */ > > + smp_wmb(); > > + > > ...and here you set it if swiotlb is used. > > But, as far as I can tell, you don't actually *use* this field anywhere. > What am I missing? It's very much unused. Petr, I guess you wanted to use this in is_swiotlb_buffer to avoid the lookup unless required. Can you send a follow up?
