Re: [Intel-gfx] [PATCH] drm/i915: remove struct_member macro

[Tvrtko Ursulin]

On 09/12/2022 12:14, Andrzej Hajda wrote:

Since it is used only to get type of member it can be replaced
with typeof_member.

Signed-off-by: Andrzej Hajda <andrzej.ha...@intel.com>
---
  drivers/gpu/drm/i915/i915_utils.h       | 4 +---
  drivers/gpu/drm/i915/intel_runtime_pm.h | 2 +-
  2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_utils.h 
b/drivers/gpu/drm/i915/i915_utils.h
index 6c14d13364bf78..b64192d9c7daa7 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -149,8 +149,6 @@ bool i915_error_injected(void);
  #define page_pack_bits(ptr, bits) ptr_pack_bits(ptr, bits, PAGE_SHIFT)
  #define page_unpack_bits(ptr, bits) ptr_unpack_bits(ptr, bits, PAGE_SHIFT)

-#define struct_member(T, member) (((T *)0)->member)

-
  #define fetch_and_zero(ptr) ({                                                
\
        typeof(*ptr) __T = *(ptr);                                      \
        *(ptr) = (typeof(*ptr))0;                                       \
@@ -170,7 +168,7 @@ static __always_inline ptrdiff_t ptrdiff(const void *a, 
const void *b)
   */
  #define container_of_user(ptr, type, member) ({                               
\
        void __user *__mptr = (void __user *)(ptr);                     \
-       BUILD_BUG_ON_MSG(!__same_type(*(ptr), struct_member(type, member)) && \
+       BUILD_BUG_ON_MSG(!__same_type(*(ptr), typeof_member(type, member)) && \

#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))

#define typeof_member(T, m)     typeof(((T*)0)->m)

So expands to:

__builtin_types_compatible_p(typeof(*(ptr)), typeof(typeof(((type*)0)->m)));

I guess that's okay since infinite number of typeofs is still a typeof.

Regards,

Tvrtko

                         !__same_type(*(ptr), void),                    \
                         "pointer type mismatch in container_of()");  \
        ((type __user *)(__mptr - offsetof(type, member))); })
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h 
b/drivers/gpu/drm/i915/intel_runtime_pm.h
index 98b8b28baaa15e..e592e8d6499a1f 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.h
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.h
@@ -96,7 +96,7 @@ struct intel_runtime_pm {
  };

#define BITS_PER_WAKEREF \

-       BITS_PER_TYPE(struct_member(struct intel_runtime_pm, wakeref_count))
+       BITS_PER_TYPE(typeof_member(struct intel_runtime_pm, wakeref_count))
  #define INTEL_RPM_WAKELOCK_SHIFT      (BITS_PER_WAKEREF / 2)
  #define INTEL_RPM_WAKELOCK_BIAS               (1 << INTEL_RPM_WAKELOCK_SHIFT)
  #define INTEL_RPM_RAW_WAKEREF_MASK    (INTEL_RPM_WAKELOCK_BIAS - 1)