[PATCH 2/2] drm/i915: Avoid -Wconstant-logical-operand in nsecs_to_jiffies_timeout()

[Nathan Chancellor]

A proposed update to clang's -Wconstant-logical-operand to warn when the
left hand side is a constant shows the following instance in
nsecs_to_jiffies_timeout() when NSEC_PER_SEC is not a multiple of HZ,
such as CONFIG_HZ=300:

  drivers/gpu/drm/i915/gem/i915_gem_wait.c:189:24: warning: use of logical '&&' with constant operand [-Wconstant-logical-operand]
    189 |         if (NSEC_PER_SEC % HZ &&
        |             ~~~~~~~~~~~~~~~~~ ^
  drivers/gpu/drm/i915/gem/i915_gem_wait.c:189:24: note: use '&' for a bitwise operation
    189 |         if (NSEC_PER_SEC % HZ &&
        |                               ^~
        |                               &
  drivers/gpu/drm/i915/gem/i915_gem_wait.c:189:24: note: remove constant to silence this warning
  1 warning generated.

Turn this into an explicit comparison against zero to make the
expression a boolean to make it clear this should be a logical check,
not a bitwise one.

Link: https://reviews.llvm.org/D142609
Signed-off-by: Nathan Chancellor <nathan at kernel.org>
---
 drivers/gpu/drm/i915/gem/i915_gem_wait.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_wait.c b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
index 4a33ad2d122b..d4b918fb11ce 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_wait.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_wait.c
@@ -186,7 +186,7 @@ i915_gem_object_wait(struct drm_i915_gem_object *obj,
 static inline unsigned long nsecs_to_jiffies_timeout(const u64 n)
 {
 	/* nsecs_to_jiffies64() does not guard against overflow */
-	if (NSEC_PER_SEC % HZ &&
+	if ((NSEC_PER_SEC % HZ) != 0 &&
 	    div_u64(n, NSEC_PER_SEC) >= MAX_JIFFY_OFFSET / HZ)
 		return MAX_JIFFY_OFFSET;
 

-- 
2.41.0