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Peter Anvin" , Arnd Bergmann , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Boqun Feng , Waiman Long , Andrew Morton , Miguel Ojeda , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jinjie Ruan , Ada Couprie Diaz , Lyude Paul , Sohil Mehta , Pawan Gupta , "Xin Li (Intel)" , Sean Christopherson , Nikunj A Dadhania , Joel Fernandes , Andy Shevchenko , Randy Dunlap , Yury Norov , Sebastian Andrzej Siewior , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-s390@vger.kernel.org, linux-arch@vger.kernel.org, rust-for-linux@vger.kernel.org Subject: [PATCH 09/11] sched: Avoid signed comparison of preempt_count() in __cant_migrate() Date: Thu, 7 May 2026 21:21:09 -0700 Message-ID: <20260508042111.24358-10-boqun@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260508042111.24358-1-boqun@kernel.org> References: <20260508042111.24358-1-boqun@kernel.org> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Currently preempt_count() is always a non-negative int on all archs (PREEMPT_NEED_RESCHED archs will mask out the MSB when return preempt_count()), hence the checking in __cant_migrate() is in fact just checking whether preempt_count() is 0 or not. In a future change, we are going to use all the 32 bits of preempt_count(), which would make negative int values possible from preempt_count(). Therefore convert the "> 0" comparison into a zero checking to prepare for the future change. No functional changes are intended. Signed-off-by: Boqun Feng --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 75dba7cc09bd..636e6a15f104 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9207,7 +9207,7 @@ void __cant_migrate(const char *file, int line) if (!IS_ENABLED(CONFIG_PREEMPT_COUNT)) return; - if (preempt_count() > 0) + if (preempt_count()) return; if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) -- 2.50.1 (Apple Git-155)