On Thu, Jan 24, 2019 at 04:00:00PM +0100, Joerg Roedel wrote:

On Thu, Jan 24, 2019 at 09:41:07AM +0100, Christoph Hellwig wrote:

quoted

On Thu, Jan 24, 2019 at 09:29:23AM +0100, Joerg Roedel wrote:

quoted

quoted

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

OK so are you going to post a new version then? Time's running out for 5.0.
This isn't a regression so maybe we should just defer it all to 5.1.

-- 
MST