From 961ccddd59d627b89bd3dc284b6517833bbdf25d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 23 Jun 2008 13:55:38 +1000 Subject: sched: add new API sched_setscheduler_nocheck: add a flag to control access checks Hidehiro Kawai noticed that sched_setscheduler() can fail in stop_machine: it calls sched_setscheduler() from insmod, which can have CAP_SYS_MODULE without CAP_SYS_NICE. Two cases could have failed, so are changed to sched_setscheduler_nocheck: kernel/softirq.c:cpu_callback() - CPU hotplug callback kernel/stop_machine.c:__stop_machine_run() - Called from various places, including modprobe() Signed-off-by: Rusty Russell Cc: Jeremy Fitzhardinge Cc: Hidehiro Kawai Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: sugita Cc: Satoshi OSHIMA Signed-off-by: Ingo Molnar --- kernel/stop_machine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/stop_machine.c') diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index b7350bbfb076..ba9b2054ecbd 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -187,7 +187,7 @@ struct task_struct *__stop_machine_run(int (*fn)(void *), void *data, struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; /* One high-prio thread per cpu. We'll do this one. */ - sched_setscheduler(p, SCHED_FIFO, ¶m); + sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m); kthread_bind(p, cpu); wake_up_process(p); wait_for_completion(&smdata.done); -- cgit v1.2.3 From 65c011845316d3c1381f478ca0d8265c43b3b039 Mon Sep 17 00:00:00 2001 From: Mike Travis Date: Tue, 15 Jul 2008 14:14:30 -0700 Subject: cpumask: Replace cpumask_of_cpu with cpumask_of_cpu_ptr * This patch replaces the dangerous lvalue version of cpumask_of_cpu with new cpumask_of_cpu_ptr macros. These are patterned after the node_to_cpumask_ptr macros. In general terms, if there is a cpumask_of_cpu_map[] then a pointer to the cpumask_of_cpu_map[cpu] entry is used. The cpumask_of_cpu_map is provided when there is a large NR_CPUS count, reducing greatly the amount of code generated and stack space used for cpumask_of_cpu(). The pointer to the cpumask_t value is needed for calling set_cpus_allowed_ptr() to reduce the amount of stack space needed to pass the cpumask_t value. If there isn't a cpumask_of_cpu_map[], then a temporary variable is declared and filled in with value from cpumask_of_cpu(cpu) as well as a pointer variable pointing to this temporary variable. Afterwards, the pointer is used to reference the cpumask value. The compiler will optimize out the extra dereference through the pointer as well as the stack space used for the pointer, resulting in identical code. A good example of the orthogonal usages is in net/sunrpc/svc.c: case SVC_POOL_PERCPU: { unsigned int cpu = m->pool_to[pidx]; cpumask_of_cpu_ptr(cpumask, cpu); *oldmask = current->cpus_allowed; set_cpus_allowed_ptr(current, cpumask); return 1; } case SVC_POOL_PERNODE: { unsigned int node = m->pool_to[pidx]; node_to_cpumask_ptr(nodecpumask, node); *oldmask = current->cpus_allowed; set_cpus_allowed_ptr(current, nodecpumask); return 1; } Signed-off-by: Mike Travis Signed-off-by: Ingo Molnar --- kernel/stop_machine.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/stop_machine.c') diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index ba9b2054ecbd..738b411ff2d3 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -33,8 +33,9 @@ static int stopmachine(void *cpu) { int irqs_disabled = 0; int prepared = 0; + cpumask_of_cpu_ptr(cpumask, (int)(long)cpu); - set_cpus_allowed_ptr(current, &cpumask_of_cpu((int)(long)cpu)); + set_cpus_allowed_ptr(current, cpumask); /* Ack: we are alive */ smp_mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */ -- cgit v1.2.3