Re: Zoned storage and BLK_STS_RESOURCE

[Damien Le Moal <dlemoal@kernel.org>]

On 2024/12/16 13:22, Bart Van Assche wrote:
> On 12/16/24 12:54 PM, Damien Le Moal wrote:
>> Yes. But I am still confused. Where is the problem ?
> 
> Here: 
> https://lore.kernel.org/linux-block/95ab028e-6cf7-474e-aa33-37ab3bccd078@kernel.org/. 
> In that message another approach is
> suggested than what I described in my previous message.

OK. So you are talking about an issue that potentially can happen *if* you
modify zone write plugging to issue more than one write at a time per zone. This
issue of reordering cannot happen today as there is always at most one write per
zone in-flight.

> UFSHCI 3.0 controllers preserve the command order except if these are in
> a power-saving mode called auto-hibernation (AH8). When leaving that
> mode, commands are submitted in tag order (0..31). The approach
> described above provides an elegant solution for the unaligned write
> errors that can be caused by command reordering when leaving AH8 mode.
> I'm not aware of any other elegant approach to deal with the reordering
> that can be caused by leaving the UFSHCI AH8 mode.

As I said, I do not know enough about UFS to comment on potential solutions as I
do not fully grasp the problem.


-- 
Damien Le Moal
Western Digital Research