Re: [PATCH v3 0/2] Prevent non-NCQ command starvation

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

On 12/31/25 19:04, Niklas Cassel wrote:
> On Sat, Dec 20, 2025 at 09:21:38AM +0900, Damien Le Moal wrote:
>> This small patch series addresses potential command starvation issues
>> with non-NCQ passthrough commands issued to a device accessed through
> 
> Here and everywhere else:
> s/non-NCQ passthrough commands/non-NCQ commands/
> 
> The problem is really not related to passthrough commands,
> but rather the mix between NCQ and non-NCQ commands.
> 
> E.g. you can perform a ioctl with the REQ_OP_DISCARD command,
> for most ATA devices this is a SCSI WRITE SAME 16 CMD, which gets
> translated to either a NCQ or non-NCQ command depending on if the
> device supports NCQ encapsulated Data Set Management (DSM) commands,
> and specifically if the device has the QUEUED DATA SET MANAGEMENT
> SUPPORTS TRIM bit set or not, which is not a given.
> 
> TL;DR: the starvation problem is not directly tied to non-NCQ
> passthrough commands, but any command, even commands that goes via
> the block layer, that happens to be translated to a non-NCQ command.

Yep. I corrected that.


-- 
Damien Le Moal
Western Digital Research