[PATCH] Cleanup patch for process freezing
1. Establish a simple API for process freezing defined in linux/include/sched.h:
frozen(process) Check for frozen process
freezing(process) Check if a process is being frozen
freeze(process) Tell a process to freeze (go to refrigerator)
thaw_process(process) Restart process
frozen_process(process) Process is frozen now
2. Remove all references to PF_FREEZE and PF_FROZEN from all
kernel sources except sched.h
3. Fix numerous locations where try_to_freeze is manually done by a driver
4. Remove the argument that is no longer necessary from two function calls.
5. Some whitespace cleanup
6. Clear potential race in refrigerator (provides an open window of PF_FREEZE
cleared before setting PF_FROZEN, recalc_sigpending does not check
PF_FROZEN).
This patch does not address the problem of freeze_processes() violating the rule
that a task may only modify its own flags by setting PF_FREEZE. This is not clean
in an SMP environment. freeze(process) is therefore not SMP safe!
Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/frv/kernel/signal.c b/arch/frv/kernel/signal.c
index d8d8f3d..36a2dff 100644
--- a/arch/frv/kernel/signal.c
+++ b/arch/frv/kernel/signal.c
@@ -536,10 +536,8 @@
if (!user_mode(regs))
return 1;
- if (current->flags & PF_FREEZE) {
- refrigerator(0);
+ if (try_to_freeze())
goto no_signal;
- }
if (!oldset)
oldset = ¤t->blocked;
diff --git a/arch/h8300/kernel/signal.c b/arch/h8300/kernel/signal.c
index a4799d6..5aab87e 100644
--- a/arch/h8300/kernel/signal.c
+++ b/arch/h8300/kernel/signal.c
@@ -517,10 +517,8 @@
if ((regs->ccr & 0x10))
return 1;
- if (current->flags & PF_FREEZE) {
- refrigerator(0);
+ if (try_to_freeze())
goto no_signal;
- }
current->thread.esp0 = (unsigned long) regs;
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index 08540bc..2451a3a 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -573,7 +573,7 @@
for ( ; ; ) {
set_current_state(TASK_INTERRUPTIBLE);
time_remaining = schedule_timeout(time_remaining);
- try_to_freeze(PF_FREEZE);
+ try_to_freeze();
if (time_after(jiffies,
prev_balance_time+balanced_irq_interval)) {
do_irq_balance();
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c
index b9b8f4e..ac5b1e9 100644
--- a/arch/i386/kernel/signal.c
+++ b/arch/i386/kernel/signal.c
@@ -608,10 +608,8 @@
if (!user_mode(regs))
return 1;
- if (current->flags & PF_FREEZE) {
- refrigerator(0);
+ if (try_to_freeze)
goto no_signal;
- }
if (!oldset)
oldset = ¤t->blocked;
diff --git a/arch/m32r/kernel/signal.c b/arch/m32r/kernel/signal.c
index 50311eb..5aef7e4 100644
--- a/arch/m32r/kernel/signal.c
+++ b/arch/m32r/kernel/signal.c
@@ -371,10 +371,8 @@
if (!user_mode(regs))
return 1;
- if (current->flags & PF_FREEZE) {
- refrigerator(0);
+ if (try_to_freeze())
goto no_signal;
- }
if (!oldset)
oldset = ¤t->blocked;
diff --git a/arch/ppc/kernel/signal.c b/arch/ppc/kernel/signal.c
index 7c8437da..8aaeb6f 100644
--- a/arch/ppc/kernel/signal.c
+++ b/arch/ppc/kernel/signal.c
@@ -705,8 +705,7 @@
unsigned long frame, newsp;
int signr, ret;
- if (current->flags & PF_FREEZE) {
- refrigerator(PF_FREEZE);
+ if (try_to_freeze()) {
signr = 0;
if (!signal_pending(current))
goto no_signal;
diff --git a/arch/x86_64/kernel/signal.c b/arch/x86_64/kernel/signal.c
index 98b7ba9..98590a9 100644
--- a/arch/x86_64/kernel/signal.c
+++ b/arch/x86_64/kernel/signal.c
@@ -425,7 +425,7 @@
if (!user_mode(regs))
return 1;
- if (try_to_freeze(0))
+ if (try_to_freeze())
goto no_signal;
if (!oldset)