drm/i915: Unref context on failed eb_create

I opted to do this instead of grabbing the context reference after
eb_create since eb_create can potentially call the shrinker, and that
makes things very complicated. This simple patch balances the ref count
without requiring a great deal of review to make sure the shrinker path
is safe.

Theoretically (by design) the shrinker can end up destroying a context,
which enforces the reasoning for doing the fix this way instead of
moving the reference to later in the function.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ben Widawsky 2014-04-04 22:41:07 -07:00 committed by Daniel Vetter
parent cfa7698bd4
commit 935f38d694

View File

@ -1132,7 +1132,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
mutex_unlock(&dev->struct_mutex); mutex_unlock(&dev->struct_mutex);
ret = PTR_ERR(ctx); ret = PTR_ERR(ctx);
goto pre_mutex_err; goto pre_mutex_err;
} }
i915_gem_context_reference(ctx); i915_gem_context_reference(ctx);
@ -1142,6 +1142,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
eb = eb_create(args); eb = eb_create(args);
if (eb == NULL) { if (eb == NULL) {
i915_gem_context_unreference(ctx);
mutex_unlock(&dev->struct_mutex); mutex_unlock(&dev->struct_mutex);
ret = -ENOMEM; ret = -ENOMEM;
goto pre_mutex_err; goto pre_mutex_err;