Re: Memory corruption with CONFIG_SWIOTLB_DYNAMIC=y

[Petr Tesařík]

Hello everybody,

I don't think I have ever seen an answer to my question regarding
alignment constraints on swiotlb bounce buffers:

On Wed, 8 Nov 2023 10:13:47 +0100
Petr Tesařík <petr@xxxxxxxxxxx> wrote:

>[...]
> To sum it up, there are two types of alignment:
> 
> 1. specified by a device's min_align_mask; this says how many low
>    bits of a buffer's physical address must be preserved,
> 
> 2. specified by allocation size and/or the alignment parameter;
>    this says how many low bits in the first IO TLB slot's physical
>    address must be zero.
> 
> I hope somebody can confirm or correct this summary before I go
> and break something. You know, it's not like cleanups in SWIOTLB
> have never broken anything.  ;-)

If no answer means that nobody knows, then based on my understanding the
existing code (both implementation and users), I can assume that this
is the correct interpretation.

I'm giving it a few more days. If there's still no reaction, expect a
beautiful documentation patch and a less beautiful cleanup patch in the
next week.

Petr T