On Tue, Sep 29, 2026 at 08:56:01AM +0200, Karl Mehltretter wrote:

On Tue, Sep 29, 2026 at 06:00:27AM +0000, sashiko-bot@kernel.org wrote:

...

On architectures with a 256KB PAGE_SIZE (such as Hexagon or PowerPC), this new validation evaluates to 65536 < 262144, unconditionally returning -EINVAL and breaking all CPU mappings.

Right, the misc device has no dma_parms, so it gets the 64K default and sync fails with 256K pages

I would ignore this, it seems fictional to me, and if someone really needs to support this rediculous combination it should be done inside sg_alloc_table_from_pages_segment(:)

The misc device has no real segment limit, so for v3 I'll give it dma_parms with an unlimited max segment size and keep the -EINVAL for importers that report a limit below PAGE_SIZE.

The params have to come from the *importing* device, not the udmabuf misc device. You don't get to control what they are, and there is no reason to put a dma_parms on a misc deivce.

Jason