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SubjectRe: Memory corruption with CONFIG_SWIOTLB_DYNAMIC=y
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@tesarici.cz> 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

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