We don't need the absolute speed of rcu for this. And
i915_address_space in general dont need rcu protection anywhere else,
after we've made gem contexts and engines a lot more immutable.
Note that this semantically reverts
commit aabbe344dc3ca5f7d8263a02608ba6179e8a4499
Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Fri Aug 30 19:03:25 2019 +0100
drm/i915: Use RCU for unlocked vm_idr lookup
except we have the conversion from idr to xarray in between.
v2: kref_get_unless_zero is no longer required (Maarten)
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Jon Bloomfield <jon.bloomfield@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: "Thomas Hellström" <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: Jason Ekstrand <jason@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index be2392bbcecc..d89ff55d8fc8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1874,11 +1874,11 @@ i915_gem_vm_lookup(struct drm_i915_file_private *file_priv, u32 id)
{
struct i915_address_space *vm;
- rcu_read_lock();
+ xa_lock(&file_priv->vm_xa);
vm = xa_load(&file_priv->vm_xa, id);
- if (vm && !kref_get_unless_zero(&vm->ref))
- vm = NULL;
- rcu_read_unlock();
+ if (vm)
+ kref_get(&vm->ref);
+ xa_unlock(&file_priv->vm_xa);
return vm;
}
--
2.33.0
