From aeedd3a82678d89627bdd020a28e0af35ff45552 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Tue, 18 Jul 2023 14:44:20 -0700 Subject: [PATCH] drm/i915: Avoid -Wconstant-logical-operand in nsecs_to_jiffies_timeout() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Acked-by: Tvrtko Ursulin Signed-off-by: Maíra Canal Link: https://patchwork.freedesktop.org/patch/msgid/20230718-nsecs_to_jiffies_timeout-constant-logical-operand-v1-2-36ed8fc8faea@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 4a33ad2d..d4b918f 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; -- 2.7.4