From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: [PATCH v3 2/3] sched: Provide copy_user_cpus_mask() to copy out user mask Date: Fri, 12 Aug 2022 16:39:28 -0400 Message-ID: <20220812203929.364341-3-longman@redhat.com> References: <20220812203929.364341-1-longman@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1660336803; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PTybH4D4WwOeqo3rN415vbeLaTvaxhsUDN/KB9esUqw=; b=hWG9LNFswjTO52SCpmolgUQs+b48IeYYVw581gLvISdnyqabZ7sFnkx4WxCvX/qnSgpnpf /ceTCUt6akz16tTTUSMchduBbg+B8E6mq1X1nJ/1MEKieuMY20esb2uA+hB/4zAA4ZQnWH jo6eFwSMrrD77Y2rFa26Ra5q8HutRCw= In-Reply-To: <20220812203929.364341-1-longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-ID: Content-Type: text/plain; charset="us-ascii" To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , Tejun Heo , Zefan Li , Johannes Weiner , Will Deacon Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linus Torvalds , Waiman Long Since accessing the content of the user_cpus_ptr requires lock protection to ensure its validity, provide a helper function copy_user_cpus_mask() to facilitate its reading. Signed-off-by: Waiman Long --- include/linux/sched.h | 1 + kernel/sched/core.c | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/include/linux/sched.h b/include/linux/sched.h index cf7206a9b29a..e06bc1cbccca 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1831,6 +1831,7 @@ extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_effec extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask); extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask); extern int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node); +extern struct cpumask *copy_user_cpus_mask(struct task_struct *p, struct cpumask *user_mask); extern void release_user_cpus_ptr(struct task_struct *p); extern int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask); extern void force_compatible_cpus_allowed_ptr(struct task_struct *p); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7e2576068331..4d3b10e91e1a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2619,6 +2619,24 @@ void release_user_cpus_ptr(struct task_struct *p) kfree(clear_user_cpus_ptr(p)); } +/* + * Return the copied mask pointer or NULL if user mask not available. + */ +struct cpumask *copy_user_cpus_mask(struct task_struct *p, + struct cpumask *user_mask) +{ + struct rq_flags rf; + struct rq *rq = task_rq_lock(p, &rf); + struct cpumask *mask = NULL; + + if (p->user_cpus_ptr) { + cpumask_copy(user_mask, p->user_cpus_ptr); + mask = user_mask; + } + task_rq_unlock(rq, p, &rf); + return mask; +} + /* * This function is wildly self concurrent; here be dragons. * -- 2.31.1