Skip to content
Commit 197267d0 authored by Frederic Barrat's avatar Frederic Barrat Committed by Michael Ellerman
Browse files

cxl: Fix driver use count



cxl keeps a driver use count, which is used with the hash memory model
on p8 to know when to upgrade local TLBIs to global and to trigger
callbacks to manage the MMU for PSL8.

If a process opens a context and closes without attaching or fails the
attachment, the driver use count is never decremented. As a
consequence, TLB invalidations remain global, even if there are no
active cxl contexts.

We should increment the driver use count when the process is attaching
to the cxl adapter, and not on open. It's not needed before the
adapter starts using the context and the use count is decremented on
the detach path, so it makes more sense.

It affects only the user api. The kernel api is already doing The
Right Thing.

Signed-off-by: default avatarFrederic Barrat <fbarrat@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v4.2+
Fixes: 7bb5d91a ("cxl: Rework context lifetimes")
Acked-by: default avatarAndrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent a3c01050
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment