A recent commit in clang added -Wtautological-compare to -Wall, which is
enabled for i915 after -Wtautological-compare is disabled for the rest
of the kernel so we see the following warning on x86_64:

 ../drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c:1433:22: warning:
 result of comparison of constant 576460752303423487 with expression of
 type 'unsigned int' is always false
         if (unlikely(remain > N_RELOC(ULONG_MAX)))
 ../include/linux/compiler.h:78:42: note: expanded from macro 'unlikely'
 # define unlikely(x)    __builtin_expect(!!(x), 0)
 1 warning generated.

It is not wrong in the case where ULONG_MAX > UINT_MAX but it does not
account for the case where this file is built for 32-bit x86, where
ULONG_MAX == UINT_MAX and this check is still relevant.

Cast remain to unsigned long, which keeps the generated code the same
(verified with clang-11 on x86_64 and GCC 9.2.0 on x86 and x86_64) and
the warning is silenced so we can catch more potential issues in the

Link: https://github.com/ClangBuiltLinux/linux/issues/778
Suggested-by: Michel Dänzer <mic...@daenzer.net>
Signed-off-by: Nathan Chancellor <natechancel...@gmail.com>

Round 3 :)

Previous threads/patches:


 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c 
index 60c984e10c4a..47f4d8ab281e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -1430,7 +1430,7 @@ static int eb_relocate_vma(struct i915_execbuffer *eb, 
struct i915_vma *vma)
        urelocs = u64_to_user_ptr(entry->relocs_ptr);
        remain = entry->relocation_count;
-       if (unlikely(remain > N_RELOC(ULONG_MAX)))
+       if (unlikely((unsigned long)remain > N_RELOC(ULONG_MAX)))
                return -EINVAL;

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