[PATCH 3/3] drm/ttm: remove ttm_bo_wait_unreserved

[Daniel Vetter]

On Wed, Aug 21, 2019 at 4:30 PM Thomas Hellström (VMware)
<thomas_os at shipmail.org> wrote:
>
> On 8/21/19 4:10 PM, Daniel Vetter wrote:
> > On Wed, Aug 21, 2019 at 3:16 PM Thomas Hellström (VMware)
> > <thomas_os at shipmail.org> wrote:
> >> On 8/20/19 4:53 PM, Daniel Vetter wrote:
> >>> With nouveau fixed all ttm-using drives have the correct nesting of
> >>> mmap_sem vs dma_resv, and we can just lock the buffer.
> >>>
> >>> Assuming I didn't screw up anything with my audit of course.
> >>>
> >>> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> >>> Cc: Christian Koenig <christian.koenig at amd.com>
> >>> Cc: Huang Rui <ray.huang at amd.com>
> >>> Cc: Gerd Hoffmann <kraxel at redhat.com>
> >>> Cc: "VMware Graphics" <linux-graphics-maintainer at vmware.com>
> >>> Cc: Thomas Hellstrom <thellstrom at vmware.com>
> >>> ---
> >>>    drivers/gpu/drm/ttm/ttm_bo.c    | 34 ---------------------------------
> >>>    drivers/gpu/drm/ttm/ttm_bo_vm.c | 26 +------------------------
> >>>    include/drm/ttm/ttm_bo_api.h    |  1 -
> >>>    3 files changed, 1 insertion(+), 60 deletions(-)
> >>>
> >>>
> >>> +     dma_resv_lock(bo->base.resv, NULL);
> >> interruptible, or at least killable. (IIRC think killable is the right
> >> choice in fault code, even if TTM initially implemented interruptible to
> >> get reasonable Xorg "silken mouse" latency).
> > I think interruptible is fine. I chickend out of that for v1 because I
> > always mix up the return code for _lock_interruptibl() :-)
>
> :). IIRC I think the in-kernel users of fault() were unhappy with
> interruptible.  (GUP?), but I guess it's better to use a bulk change at
> some point if necessary.

We've been using interruptible since forever, returning
VM_FAULT_NOPAGE to get the signal handled and re-run. Seems to not
have pissed off anyone thus far. I think if we do this I'll do it as a
follow-up.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch