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authorHeiko Carstens <heiko.carstens@de.ibm.com>2008-11-14 18:18:07 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-11-14 18:18:54 +0100
commit74af283102b358b0da545460d0d176f473e110f6 (patch)
tree5f5fc2faea5c40f6b597d6237ffa3f4a2e0585f4
parent85acc407bf1c49fb40b8f461c2c7526af736d87e (diff)
downloadlinux-stericsson-74af283102b358b0da545460d0d176f473e110f6.tar.gz
[S390] cpu topology: fix locking
cpu_coregroup_map used to grab a mutex on s390 since it was only called from process context. Since c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832 "block: add support for IO CPU affinity" this is not true anymore. It now also gets called from softirq context. To prevent possible deadlocks change this in architecture code and use a spinlock instead of a mutex. Cc: stable@kernel.org Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/kernel/topology.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index 632b13e10053..a947899dcba1 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -65,18 +65,21 @@ static int machine_has_topology_irq;
static struct timer_list topology_timer;
static void set_topology_timer(void);
static DECLARE_WORK(topology_work, topology_work_fn);
+/* topology_lock protects the core linked list */
+static DEFINE_SPINLOCK(topology_lock);
cpumask_t cpu_core_map[NR_CPUS];
cpumask_t cpu_coregroup_map(unsigned int cpu)
{
struct core_info *core = &core_info;
+ unsigned long flags;
cpumask_t mask;
cpus_clear(mask);
if (!machine_has_topology)
return cpu_present_map;
- mutex_lock(&smp_cpu_state_mutex);
+ spin_lock_irqsave(&topology_lock, flags);
while (core) {
if (cpu_isset(cpu, core->mask)) {
mask = core->mask;
@@ -84,7 +87,7 @@ cpumask_t cpu_coregroup_map(unsigned int cpu)
}
core = core->next;
}
- mutex_unlock(&smp_cpu_state_mutex);
+ spin_unlock_irqrestore(&topology_lock, flags);
if (cpus_empty(mask))
mask = cpumask_of_cpu(cpu);
return mask;
@@ -133,7 +136,7 @@ static void tl_to_cores(struct tl_info *info)
union tl_entry *tle, *end;
struct core_info *core = &core_info;
- mutex_lock(&smp_cpu_state_mutex);
+ spin_lock_irq(&topology_lock);
clear_cores();
tle = info->tle;
end = (union tl_entry *)((unsigned long)info + info->length);
@@ -157,7 +160,7 @@ static void tl_to_cores(struct tl_info *info)
}
tle = next_tle(tle);
}
- mutex_unlock(&smp_cpu_state_mutex);
+ spin_unlock_irq(&topology_lock);
}
static void topology_update_polarization_simple(void)