[RFC PATCH 0/1] nvme-pci: detect I/O queue depth changes after reset

[Keith Busch]

On Wed, May 27, 2026 at 03:19:51PM +0200, Christoph Hellwig wrote:
> On Wed, May 27, 2026 at 03:53:19PM +0800, guzebing wrote:
> > This RFC instead takes the smaller approach of detecting the reset-time
> > CAP.MQES change and making it visible.  If the live I/O queue depth
> > shrinks, reset recovery is failed before recreating I/O queues.  If it
> > grows, the driver warns and continues with the existing queue resources.
> 
> Unlike the other version this at least sounds doable without creating
> a complete mess.  So if we can live with this version that'd make me
> much happier.

Abandoning the device here sounds pretty harsh when blk-mq already
supports user space decreasing the q-depth on a live queue. Why can't
the driver do the same thing?