On Thu, Jan 24, 2019 at 09:41:07AM +0100, Christoph Hellwig wrote: > On Thu, Jan 24, 2019 at 09:29:23AM +0100, Joerg Roedel wrote: > > > As I've just introduced and fixed a bug in this area in the current > > > cycle - I don't think no_iotlb_memory is what your want (and maybe > > > not useful at all): if the arch valls swiotlb_exit after previously > > > initializing a buffer it won't be set. You probably want to check > > > for non-zero io_tlb_start and/or io_tlb_end. > > > > Okay, but that requires that I also set io_tlb_start and friends back to > > zero in the failure path of swiotlb_init(). Otherwise it could be left > > non-zero in case swiotlb_init_with_tbl() returns an error. > > Indeed, and we'll need to do that anyway as otherwise the dma mapping > path might cause problems similar to the one when swiotlb_exit is > called that I fixed. Turns out the the error path in swiotlb_init() is redundant because it will never be executed. If the function returns it will always return 0 because in case of failure it will just panic (through memblock_alloc). I'll clean that up in a separate patch-set. There are more users of that function and all of them panic when the function fails. Joerg
