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From: Rusty Russell <rusty@rustcorp.com.au>
To: torvalds@transmeta.com
Subject: [PATCH] Hotplug CPU prep II: CLONE_IDLETASK
Date: Thu, 09 May 2002 18:34:21 +1000
Cc: linux-kernel@vger.kernel.org
Linus, please apply.
This changes CLONE_PID ("if my pid is 0, copy it") to CLONE_IDLETASK
("if I have CAP_SYS_MODULE, set child's pid to zero").
This is requires for creating new idle processes without being an idle
process.
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
Name: CLONE_PID removal, CLONE_INITTASK added.
Author: Rusty Russell
Depends: Hotcpu/do-fork.patch.gz
D: This patch cleans up the idle thread creation code by redefining
D: CLONE_PID to CLONE_IDLETASK: "create a 0-pid process".
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/include/linux/sched.h working-2.5.14-dofork+clonepid/include/linux/sched.h
--- working-2.5.14-dofork/include/linux/sched.h Thu May 9 18:30:41 2002
+++ working-2.5.14-dofork+clonepid/include/linux/sched.h Thu May 9 18:25:21 2002
@@ -39,7 +39,7 @@
#define CLONE_FS 0x00000200 /* set if fs info shared between processes */
#define CLONE_FILES 0x00000400 /* set if open files shared between processes */
#define CLONE_SIGHAND 0x00000800 /* set if signal handlers and blocked signals shared */
-#define CLONE_PID 0x00001000 /* set if pid shared */
+#define CLONE_IDLETASK 0x00001000 /* set if new pid should be 0 */
#define CLONE_PTRACE 0x00002000 /* set if we want to let tracing continue on the child too */
#define CLONE_VFORK 0x00004000 /* set if the parent wants the child to wake it up on mm_release */
#define CLONE_PARENT 0x00008000 /* set if we want to have the same parent as the cloner */
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/alpha/kernel/smp.c working-2.5.14-dofork+clonepid/arch/alpha/kernel/smp.c
--- working-2.5.14-dofork/arch/alpha/kernel/smp.c Thu Mar 21 14:14:37 2002
+++ working-2.5.14-dofork+clonepid/arch/alpha/kernel/smp.c Thu May 9 18:25:22 2002
@@ -439,7 +439,7 @@
/* Don't care about the contents of regs since we'll never
reschedule the forked task. */
struct pt_regs regs;
- return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0);
+ return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0);
}
/*
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/i386/kernel/smpboot.c working-2.5.14-dofork+clonepid/arch/i386/kernel/smpboot.c
--- working-2.5.14-dofork/arch/i386/kernel/smpboot.c Thu May 9 18:30:41 2002
+++ working-2.5.14-dofork+clonepid/arch/i386/kernel/smpboot.c Thu May 9 18:25:22 2002
@@ -536,7 +536,7 @@
* don't care about the eip and regs settings since
* we'll never reschedule the forked task.
*/
- return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0);
+ return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0);
}
/* which physical APIC ID maps to which logical CPU number */
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/ia64/kernel/smpboot.c working-2.5.14-dofork+clonepid/arch/ia64/kernel/smpboot.c
--- working-2.5.14-dofork/arch/ia64/kernel/smpboot.c Tue Apr 23 11:39:33 2002
+++ working-2.5.14-dofork+clonepid/arch/ia64/kernel/smpboot.c Thu May 9 18:25:22 2002
@@ -398,7 +398,7 @@
* don't care about the eip and regs settings since
* we'll never reschedule the forked task.
*/
- return do_fork(CLONE_VM|CLONE_PID, 0, 0, 0);
+ return do_fork(CLONE_VM|CLONE_IDLETASK, 0, 0, 0);
}
static void __init
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/mips/kernel/smp.c working-2.5.14-dofork+clonepid/arch/mips/kernel/smp.c
--- working-2.5.14-dofork/arch/mips/kernel/smp.c Mon Apr 15 11:47:11 2002
+++ working-2.5.14-dofork+clonepid/arch/mips/kernel/smp.c Thu May 9 18:25:22 2002
@@ -122,7 +122,7 @@
/* Spawn a new process normally. Grab a pointer to
its task struct so we can mess with it */
- do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0);
+ do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0);
p = prev_task(&init_task);
/* Schedule the first task manually */
@@ -151,7 +151,7 @@
* The following code is purely to make sure
* Linux can schedule processes on this slave.
*/
- kernel_thread(0, NULL, CLONE_PID);
+ kernel_thread(0, NULL, CLONE_IDLETASK);
p = prev_task(&init_task);
sprintf(p->comm, "%s%d", "Idle", i);
init_tasks[i] = p;
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/mips64/sgi-ip27/ip27-init.c working-2.5.14-dofork+clonepid/arch/mips64/sgi-ip27/ip27-init.c
--- working-2.5.14-dofork/arch/mips64/sgi-ip27/ip27-init.c Thu Mar 21 14:14:41 2002
+++ working-2.5.14-dofork+clonepid/arch/mips64/sgi-ip27/ip27-init.c Thu May 9 18:25:22 2002
@@ -490,7 +490,7 @@
* The following code is purely to make sure
* Linux can schedule processes on this slave.
*/
- kernel_thread(0, NULL, CLONE_PID);
+ kernel_thread(0, NULL, CLONE_IDLETASK);
p = prev_task(&init_task);
sprintf(p->comm, "%s%d", "Idle", num_cpus);
init_tasks[num_cpus] = p;
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/ppc/kernel/smp.c working-2.5.14-dofork+clonepid/arch/ppc/kernel/smp.c
--- working-2.5.14-dofork/arch/ppc/kernel/smp.c Thu May 9 18:30:41 2002
+++ working-2.5.14-dofork+clonepid/arch/ppc/kernel/smp.c Thu May 9 18:26:00 2002
@@ -343,7 +343,7 @@
/* create a process for the processor */
/* only regs.msr is actually used, and 0 is OK for it */
memset(®s, 0, sizeof(struct pt_regs));
- p = do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0);
+ p = do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0);
if (IS_ERR(p))
panic("failed fork for CPU %d", i);
init_idle(p, i);
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/ppc64/kernel/smp.c working-2.5.14-dofork+clonepid/arch/ppc64/kernel/smp.c
--- working-2.5.14-dofork/arch/ppc64/kernel/smp.c Mon May 6 11:11:52 2002
+++ working-2.5.14-dofork+clonepid/arch/ppc64/kernel/smp.c Thu May 9 18:25:22 2002
@@ -640,7 +640,7 @@
memset(®s, 0, sizeof(struct pt_regs));
- if (do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0) < 0)
+ if (do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0) < 0)
panic("failed fork for CPU %d", i);
p = prev_task(&init_task);
if (!p)
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/s390/kernel/smp.c working-2.5.14-dofork+clonepid/arch/s390/kernel/smp.c
--- working-2.5.14-dofork/arch/s390/kernel/smp.c Thu Mar 21 14:14:41 2002
+++ working-2.5.14-dofork+clonepid/arch/s390/kernel/smp.c Thu May 9 18:25:22 2002
@@ -511,7 +511,7 @@
/* don't care about the psw and regs settings since we'll never
reschedule the forked task. */
memset(®s,0,sizeof(struct pt_regs));
- return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0);
+ return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0);
}
static void __init do_boot_cpu(int cpu)
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/s390x/kernel/smp.c working-2.5.14-dofork+clonepid/arch/s390x/kernel/smp.c
--- working-2.5.14-dofork/arch/s390x/kernel/smp.c Thu Mar 21 14:14:41 2002
+++ working-2.5.14-dofork+clonepid/arch/s390x/kernel/smp.c Thu May 9 18:25:22 2002
@@ -490,7 +490,7 @@
/* don't care about the psw and regs settings since we'll never
reschedule the forked task. */
memset(®s,0,sizeof(struct pt_regs));
- return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0);
+ return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0);
}
static void __init do_boot_cpu(int cpu)
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/sparc/kernel/sun4d_smp.c working-2.5.14-dofork+clonepid/arch/sparc/kernel/sun4d_smp.c
--- working-2.5.14-dofork/arch/sparc/kernel/sun4d_smp.c Mon May 6 16:00:09 2002
+++ working-2.5.14-dofork+clonepid/arch/sparc/kernel/sun4d_smp.c Thu May 9 18:25:22 2002
@@ -214,7 +214,7 @@
int no;
/* Cook up an idler for this guy. */
- kernel_thread(start_secondary, NULL, CLONE_PID);
+ kernel_thread(start_secondary, NULL, CLONE_IDLETASK);
cpucount++;
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/sparc/kernel/sun4m_smp.c working-2.5.14-dofork+clonepid/arch/sparc/kernel/sun4m_smp.c
--- working-2.5.14-dofork/arch/sparc/kernel/sun4m_smp.c Mon May 6 16:00:09 2002
+++ working-2.5.14-dofork+clonepid/arch/sparc/kernel/sun4m_smp.c Thu May 9 18:25:22 2002
@@ -187,7 +187,7 @@
int timeout;
/* Cook up an idler for this guy. */
- kernel_thread(start_secondary, NULL, CLONE_PID);
+ kernel_thread(start_secondary, NULL, CLONE_IDLETASK);
cpucount++;
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/sparc64/kernel/smp.c working-2.5.14-dofork+clonepid/arch/sparc64/kernel/smp.c
--- working-2.5.14-dofork/arch/sparc64/kernel/smp.c Mon May 6 11:11:52 2002
+++ working-2.5.14-dofork+clonepid/arch/sparc64/kernel/smp.c Thu May 9 18:25:22 2002
@@ -268,7 +268,7 @@
int no;
prom_printf("Starting CPU %d... ", i);
- kernel_thread(NULL, NULL, CLONE_PID);
+ kernel_thread(NULL, NULL, CLONE_IDLETASK);
cpucount++;
p = prev_task(&init_task);
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/arch/x86_64/kernel/smpboot.c working-2.5.14-dofork+clonepid/arch/x86_64/kernel/smpboot.c
--- working-2.5.14-dofork/arch/x86_64/kernel/smpboot.c Tue Apr 23 11:39:33 2002
+++ working-2.5.14-dofork+clonepid/arch/x86_64/kernel/smpboot.c Thu May 9 18:25:22 2002
@@ -483,7 +483,7 @@
* don't care about the rip and regs settings since
* we'll never reschedule the forked task.
*/
- return do_fork(CLONE_VM|CLONE_PID, 0, ®s, 0);
+ return do_fork(CLONE_VM|CLONE_IDLETASK, 0, ®s, 0);
}
#if APIC_DEBUG
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.5.14-dofork/kernel/fork.c working-2.5.14-dofork+clonepid/kernel/fork.c
--- working-2.5.14-dofork/kernel/fork.c Thu May 9 18:30:41 2002
+++ working-2.5.14-dofork+clonepid/kernel/fork.c Thu May 9 18:25:22 2002
@@ -136,8 +136,8 @@
struct task_struct *p;
int pid;
- if (flags & CLONE_PID)
- return current->pid;
+ if (flags & CLONE_IDLETASK)
+ return 0;
spin_lock(&lastpid_lock);
if((++last_pid) & 0xffff8000) {
@@ -624,13 +624,10 @@
retval = -EPERM;
/*
- * CLONE_PID is only allowed for the initial SMP swapper
- * calls
+ * CLONE_IDLETASK is used to create idle threads.
*/
- if (clone_flags & CLONE_PID) {
- if (current->pid)
- goto fork_out;
- }
+ if ((clone_flags & CLONE_IDLETASK) && !capable(CAP_SYS_MODULE))
+ goto fork_out;
retval = -ENOMEM;
p = dup_task_struct(current);
-
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