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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2008-11-14 18:18:07 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-11-20 14:54:49 -0800 |
| commit | 65347ce15fb47f3aa58107be55ec00fa6f1eda22 (patch) | |
| tree | 19360e971f482bc48f57ea95ec5d519a66ad3503 /arch | |
| parent | d12a87b8e4b2b1a830f248d2b76a2943effbea92 (diff) | |
| download | lwn-65347ce15fb47f3aa58107be55ec00fa6f1eda22.tar.gz lwn-65347ce15fb47f3aa58107be55ec00fa6f1eda22.zip | |
S390: cpu topology: fix locking
commit 74af283102b358b0da545460d0d176f473e110f6 upstream.
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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/topology.c | 11 |
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) |