drm/i915/gt: Onion unwind for scratch page allocation failure

In switching to using objects for our ppGTT scratch pages, care was not
taken to avoid trying to unref NULL objects on failure. And for gen6
ppGTT, it appears we forgot entirely to unwind after a partial allocation
failure.

Fixes: 89351925a477 ("drm/i915/gt: Switch to object allocations for page directories")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201019083444.1286-1-chris@chris-wilson.co.uk
(cherry picked from commit fa812ce96a46efc27cae4dcad866aaee9cb25d28)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
index fd0d24d28763f11ebadccd62318e2172f731274c..c30adc05fa987dbfb32d8a774792598540ee9c90 100644 (file)
--- a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
@@ -239,18 +239,24 @@ static int gen6_ppgtt_init_scratch(struct gen6_ppgtt *ppgtt)
                               I915_CACHE_NONE, PTE_READ_ONLY);
 
        vm->scratch[1] = vm->alloc_pt_dma(vm, I915_GTT_PAGE_SIZE_4K);
-       if (IS_ERR(vm->scratch[1]))
-               return PTR_ERR(vm->scratch[1]);
+       if (IS_ERR(vm->scratch[1])) {
+               ret = PTR_ERR(vm->scratch[1]);
+               goto err_scratch0;
+       }
 
        ret = pin_pt_dma(vm, vm->scratch[1]);
-       if (ret) {
-               i915_gem_object_put(vm->scratch[1]);
-               return ret;
-       }
+       if (ret)
+               goto err_scratch1;
 
        fill32_px(vm->scratch[1], vm->scratch[0]->encode);
 
        return 0;
+
+err_scratch1:
+       i915_gem_object_put(vm->scratch[1]);
+err_scratch0:
+       i915_gem_object_put(vm->scratch[0]);
+       return ret;
 }
 
 static void gen6_ppgtt_free_pd(struct gen6_ppgtt *ppgtt)

diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
index eb64f474a78c6ac529f74a3c505d73514287e4a1..38c7069b77494087478821c23f8a2995d30b8649 100644 (file)
--- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
+++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
@@ -604,7 +604,8 @@ static int gen8_init_scratch(struct i915_address_space *vm)
        return 0;
 
 free_scratch:
-       free_scratch(vm);
+       while (i--)
+               i915_gem_object_put(vm->scratch[i]);
        return -ENOMEM;
 }