Re: Intermittent storage (dm-crypt?) freeze - regression 6.4->6.5

[Mikulas Patocka <mpatocka@redhat.com>]

On Fri, 3 Nov 2023, Keith Busch wrote:

> On Fri, Nov 03, 2023 at 09:30:07PM +0100, Marek Marczykowski-G'orecki wrote:
> > On Fri, Nov 03, 2023 at 10:54:00AM -0600, Keith Busch wrote:
> > > On Fri, Nov 03, 2023 at 05:15:49PM +0100, Marek Marczykowski-G'orecki wrote:
> > > > On Thu, Nov 02, 2023 at 06:06:33PM +0100, Mikulas Patocka wrote:
> > > > > Then, try this patch (without "iommu=panic"), reproduce the deadlock and 
> > > > > tell us which one of the "printk" statements is triggered during the 
> > > > > deadlock.
> > > > 
> > > > The "821" one - see below.
> > > 
> > > Thanks for confirming!
> > > 
> > > Could you try this patch?
> > 
> > Besides min3() being unhappy about types, it works.
> 
> Oops, should have changed the constant to "ul" instead of just "u".
> 
> Anyway, the overall idea makes sense to me, but I don't know the swiotlb
> stuff well.
> 
> Christoph, does that patch make sense? For reference:
> 
>    https://lore.kernel.org/linux-mm/ZUOr-vp0yRkLyvyi@kbusch-mbp.dhcp.thefacebook.com/T/#m8d34245e0eef43f8e9fe6cba6038d77ed2a93ad6

dma_opt_mapping_size returns "min(dma_max_mapping_size(dev), size)". So 
you don't have to call dma_max_mapping_size explicitly, you can leave the 
file drivers/nvme/host/pci.c as it is.

What about the other block device drivers (AHCI, SCSI...)? Should there be 
some generic framework that restricts max_hw_sectors according to 
dma_opt_mapping_size?

Mikulas