[PATCH 1/3] cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALL.

From: Rusty Russell
Date: Sat Feb 07 2009 - 02:39:44 EST


(Thanks to Al Viro for reminding me of this, via Ingo)

CPU_MASK_ALL is the (deprecated) "all bits set" cpumask, defined as so:

#define CPU_MASK_ALL (cpumask_t) { { ... } }

Taking the address of such a temporary is questionable at best,
unfortunately 321a8e9d (cpumask: add CPU_MASK_ALL_PTR macro) added
CPU_MASK_ALL_PTR:

#define CPU_MASK_ALL_PTR (&CPU_MASK_ALL)

Which formalizes this practice. One day gcc could bite us over this
usage (though we seem to have gotten away with it so far).

So replace everywhere which used &CPU_MASK_ALL or CPU_MASK_ALL_PTR
with the modern "cpu_all_mask" (a real struct cpumask *), and remove
CPU_MASK_ALL_PTR altogether.

Also remove the confusing and deprecated large-NR_CPUS-only
"cpu_mask_all".

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Mike Travis <travis@xxxxxxx>
---
arch/mips/alchemy/common/time.c | 2 +-
arch/sparc/include/asm/topology_64.h | 2 +-
arch/x86/include/asm/es7000/apic.h | 2 +-
arch/x86/include/asm/numaq/apic.h | 2 +-
include/linux/cpumask.h | 6 ------
init/main.c | 7 +------
kernel/kmod.c | 2 +-
kernel/kthread.c | 4 ++--
mm/pdflush.c | 2 +-
9 files changed, 9 insertions(+), 20 deletions(-)

diff --git a/arch/mips/alchemy/common/time.c b/arch/mips/alchemy/common/time.c
--- a/arch/mips/alchemy/common/time.c
+++ b/arch/mips/alchemy/common/time.c
@@ -89,7 +89,7 @@ static struct clock_event_device au1x_rt
.irq = AU1000_RTC_MATCH2_INT,
.set_next_event = au1x_rtcmatch2_set_next_event,
.set_mode = au1x_rtcmatch2_set_mode,
- .cpumask = CPU_MASK_ALL_PTR,
+ .cpumask = cpu_all_mask,
};

static struct irqaction au1x_rtcmatch2_irqaction = {
diff --git a/arch/sparc/include/asm/topology_64.h b/arch/sparc/include/asm/topology_64.h
--- a/arch/sparc/include/asm/topology_64.h
+++ b/arch/sparc/include/asm/topology_64.h
@@ -49,7 +49,7 @@ static inline int pcibus_to_node(struct
node_to_cpumask(pcibus_to_node(bus)))
#define cpumask_of_pcibus(bus) \
(pcibus_to_node(bus) == -1 ? \
- CPU_MASK_ALL_PTR : \
+ cpu_all_mask : \
cpumask_of_node(pcibus_to_node(bus)))

#define SD_NODE_INIT (struct sched_domain) { \
diff --git a/arch/x86/include/asm/es7000/apic.h b/arch/x86/include/asm/es7000/apic.h
--- a/arch/x86/include/asm/es7000/apic.h
+++ b/arch/x86/include/asm/es7000/apic.h
@@ -13,7 +13,7 @@ static inline int apic_id_registered(voi

static inline const cpumask_t *target_cpus_cluster(void)
{
- return &CPU_MASK_ALL;
+ return cpu_all_mask;
}

static inline const cpumask_t *target_cpus(void)
diff --git a/arch/x86/include/asm/numaq/apic.h b/arch/x86/include/asm/numaq/apic.h
--- a/arch/x86/include/asm/numaq/apic.h
+++ b/arch/x86/include/asm/numaq/apic.h
@@ -9,7 +9,7 @@

static inline const cpumask_t *target_cpus(void)
{
- return &CPU_MASK_ALL;
+ return cpu_all_mask;
}

#define NO_BALANCE_IRQ (1)
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -324,8 +324,6 @@ static inline const struct cpumask *get_
[BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
} }

-#define CPU_MASK_ALL_PTR (&CPU_MASK_ALL)
-
#else

#define CPU_MASK_ALL \
@@ -333,10 +331,6 @@ static inline const struct cpumask *get_
[0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL, \
[BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \
} }
-
-/* cpu_mask_all is in init/main.c */
-extern cpumask_t cpu_mask_all;
-#define CPU_MASK_ALL_PTR (&cpu_mask_all)

#endif

diff --git a/init/main.c b/init/main.c
--- a/init/main.c
+++ b/init/main.c
@@ -358,11 +358,6 @@ static inline void smp_prepare_cpus(unsi
static inline void smp_prepare_cpus(unsigned int maxcpus) { }

#else
-
-#if NR_CPUS > BITS_PER_LONG
-cpumask_t cpu_mask_all __read_mostly = CPU_MASK_ALL;
-EXPORT_SYMBOL(cpu_mask_all);
-#endif

/* Setup number of possible processor ids */
int nr_cpu_ids __read_mostly = NR_CPUS;
@@ -834,7 +829,7 @@ static int __init kernel_init(void * unu
/*
* init can run on any cpu.
*/
- set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR);
+ set_cpus_allowed_ptr(current, cpu_all_mask);
/*
* Tell the world that we're going to be the grim
* reaper of innocent orphaned children.
diff --git a/kernel/kmod.c b/kernel/kmod.c
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -167,7 +167,7 @@ static int ____call_usermodehelper(void
}

/* We can run anywhere, unlike our parent keventd(). */
- set_cpus_allowed_ptr(current, CPU_MASK_ALL_PTR);
+ set_cpus_allowed_ptr(current, cpu_all_mask);

/*
* Our parent is keventd, which runs with elevated scheduling priority.
diff --git a/kernel/kthread.c b/kernel/kthread.c
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -110,7 +110,7 @@ static void create_kthread(struct kthrea
*/
sched_setscheduler(create->result, SCHED_NORMAL, &param);
set_user_nice(create->result, KTHREAD_NICE_LEVEL);
- set_cpus_allowed_ptr(create->result, CPU_MASK_ALL_PTR);
+ set_cpus_allowed_ptr(create->result, cpu_all_mask);
}
complete(&create->done);
}
@@ -240,7 +240,7 @@ int kthreadd(void *unused)
set_task_comm(tsk, "kthreadd");
ignore_signals(tsk);
set_user_nice(tsk, KTHREAD_NICE_LEVEL);
- set_cpus_allowed_ptr(tsk, CPU_MASK_ALL_PTR);
+ set_cpus_allowed_ptr(tsk, cpu_all_mask);

current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG;

diff --git a/mm/pdflush.c b/mm/pdflush.c
--- a/mm/pdflush.c
+++ b/mm/pdflush.c
@@ -191,7 +191,7 @@ static int pdflush(void *dummy)

/*
* Some configs put our parent kthread in a limited cpuset,
- * which kthread() overrides, forcing cpus_allowed == CPU_MASK_ALL.
+ * which kthread() overrides, forcing cpus_allowed == cpu_all_mask.
* Our needs are more modest - cut back to our cpusets cpus_allowed.
* This is needed as pdflush's are dynamically created and destroyed.
* The boottime pdflush's are easily placed w/o these 2 lines.

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