drm/i915/gem: consolidate 2big error checking for object sizes

Throw it into a simple helper, and throw a warning if we encounter an
object which has been initialised with an object size that exceeds our
limit of INT_MAX pages.

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20210122181514.541436-2-matthew.auld@intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index dc11497f830b6443a3e6f4e51dc8bd8aa0d933e5..5cc8a0b2387f52ed6962b085c4f2bc063ba0b5c2 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -244,14 +244,7 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
                }
        }
 
-       /*
-        * XXX: There is a prevalence of the assumption that we fit the
-        * object's page count inside a 32bit _signed_ variable. Let's document
-        * this and catch if we ever need to fix it. In the meantime, if you do
-        * spot such a local variable, please consider fixing!
-        */
-
-       if (dma_buf->size >> PAGE_SHIFT > INT_MAX)
+       if (i915_gem_object_size_2big(dma_buf->size))
                return ERR_PTR(-E2BIG);
 
        /* need to attach */

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index d0ae834d787afdcb5a9ff657517a512379922f91..3411ad197fa6c33c1c0125d2182fa9f5fce10e3b 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -16,6 +16,32 @@
 #include "i915_gem_gtt.h"
 #include "i915_vma_types.h"
 
+/*
+ * XXX: There is a prevalence of the assumption that we fit the
+ * object's page count inside a 32bit _signed_ variable. Let's document
+ * this and catch if we ever need to fix it. In the meantime, if you do
+ * spot such a local variable, please consider fixing!
+ *
+ * Aside from our own locals (for which we have no excuse!):
+ * - sg_table embeds unsigned int for num_pages
+ * - get_user_pages*() mixed ints with longs
+ */
+#define GEM_CHECK_SIZE_OVERFLOW(sz) \
+       GEM_WARN_ON((sz) >> PAGE_SHIFT > INT_MAX)
+
+static inline bool i915_gem_object_size_2big(u64 size)
+{
+       struct drm_i915_gem_object *obj;
+
+       if (GEM_CHECK_SIZE_OVERFLOW(size))
+               return true;
+
+       if (overflows_type(size, obj->base.size))
+               return true;
+
+       return false;
+}
+
 void i915_gem_init__objects(struct drm_i915_private *i915);
 
 struct drm_i915_gem_object *i915_gem_object_alloc(void);

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c
index 3e3dad22a683146984c2102714c7571d1b34d79c..77dfa908f1565d292824ef45846ad84fe8b102aa 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
@@ -161,17 +161,7 @@ i915_gem_object_create_region(struct intel_memory_region *mem,
        GEM_BUG_ON(!size);
        GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_MIN_ALIGNMENT));
 
-       /*
-        * XXX: There is a prevalence of the assumption that we fit the
-        * object's page count inside a 32bit _signed_ variable. Let's document
-        * this and catch if we ever need to fix it. In the meantime, if you do
-        * spot such a local variable, please consider fixing!
-        */
-
-       if (size >> PAGE_SHIFT > INT_MAX)
-               return ERR_PTR(-E2BIG);
-
-       if (overflows_type(size, obj->base.size))
+       if (i915_gem_object_size_2big(size))
                return ERR_PTR(-E2BIG);
 
        obj = i915_gem_object_alloc();

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index f2eaed6aca3d9265aa2d0562c80e1fc5c16e4503..3e4785c2dfa25629a5e737bb07fa53b510c35c11 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -770,21 +770,7 @@ i915_gem_userptr_ioctl(struct drm_device *dev,
                            I915_USERPTR_UNSYNCHRONIZED))
                return -EINVAL;
 
-       /*
-        * XXX: There is a prevalence of the assumption that we fit the
-        * object's page count inside a 32bit _signed_ variable. Let's document
-        * this and catch if we ever need to fix it. In the meantime, if you do
-        * spot such a local variable, please consider fixing!
-        *
-        * Aside from our own locals (for which we have no excuse!):
-        * - sg_table embeds unsigned int for num_pages
-        * - get_user_pages*() mixed ints with longs
-        */
-
-       if (args->user_size >> PAGE_SHIFT > INT_MAX)
-               return -E2BIG;
-
-       if (overflows_type(args->user_size, obj->base.size))
+       if (i915_gem_object_size_2big(args->user_size))
                return -E2BIG;
 
        if (!args->user_size)