drm/i915: be more solid in checking the alignment

The alignment is u64, and yet is_power_of_2() assumes unsigned long,
which might give different results between 32b and 64b kernel.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
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/20200305203534.210466-1-matthew.auld@intel.com
Cc: stable@vger.kernel.org
(cherry picked from commit 2920516b2f719546f55079bc39a7fe409d9e80ab)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 60c984e..7643a30 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -423,7 +423,8 @@ eb_validate_vma(struct i915_execbuffer *eb,
        if (unlikely(entry->flags & eb->invalid_flags))
                return -EINVAL;
 
-       if (unlikely(entry->alignment && !is_power_of_2(entry->alignment)))
+       if (unlikely(entry->alignment &&
+                    !is_power_of_2_u64(entry->alignment)))
                return -EINVAL;
 
        /*

diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index b0ade76..d34141f 100644 (file)
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -234,6 +234,11 @@ static inline u64 ptr_to_u64(const void *ptr)
        __idx;                                                          \
 })
 
+static inline bool is_power_of_2_u64(u64 n)
+{
+       return (n != 0 && ((n & (n - 1)) == 0));
+}
+
 static inline void __list_del_many(struct list_head *head,
                                   struct list_head *first)
 {