Re: [PATCH 5.19 319/365] swiotlb: panic if nslabs is too small

On Tue, Aug 23, 2022 at 10:25:27AM -0700, Dongli Zhang wrote:

Adding Robin, Yu and swiotlb list.

Hi Greg,

There is an on-going discussion whether to revert this patch, because it breaks a corner case in MIPS when many kernel CONFIGs are not enabled (related to PCI and device). As a result, MIPS pre-allocates only PAGE_SIZE buffer as swiotlb.

https://lore.kernel.org/all/20220820012031.1285979-1-yuzhao@google.com/

However, the core idea of the patch is to panic on purpose if the swiotlb is configured with <1MB memory, in order to sync with the remap failure handler in swiotlb_init_remap().

Ok, I've dropped it from the 5.19 queue now. If you want it added to a future kernel release, just resend it.

thanks,

greg k-h