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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2008-04-30 13:38:36 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-04-30 13:38:44 +0200 |
| commit | 0b18d318b80a7f350648ca8f7cc00a2f688104cb (patch) | |
| tree | 7a5346faefb67b24f05c00691ca170a6805b0921 /arch/s390 | |
| parent | f291e17227cf30432ca7c402220f62e6924dd97d (diff) | |
| download | linux-0b18d318b80a7f350648ca8f7cc00a2f688104cb.tar.gz linux-0b18d318b80a7f350648ca8f7cc00a2f688104cb.tar.bz2 linux-0b18d318b80a7f350648ca8f7cc00a2f688104cb.zip | |
[S390] smp: Fix locking order.
On some smp sysfs store attributes get_online_cpus() may block on
cpu_hotplug.lock, but we hold already smp_cpu_state_mutex. Since the
locking order on cpu hotplug via arch_update_cpu_topology is inverse
this might lead to deadlocks.
So make sure locking order is always the same.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kernel/smp.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 0dfa988c1b26..6bb5c050640f 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -890,8 +890,8 @@ static ssize_t cpu_configure_store(struct sys_device *dev, const char *buf, if (val != 0 && val != 1) return -EINVAL; - mutex_lock(&smp_cpu_state_mutex); get_online_cpus(); + mutex_lock(&smp_cpu_state_mutex); rc = -EBUSY; if (cpu_online(cpu)) goto out; @@ -919,8 +919,8 @@ static ssize_t cpu_configure_store(struct sys_device *dev, const char *buf, break; } out: - put_online_cpus(); mutex_unlock(&smp_cpu_state_mutex); + put_online_cpus(); return rc ? rc : count; } static SYSDEV_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store); @@ -1095,8 +1095,8 @@ static ssize_t __ref rescan_store(struct sys_device *dev, int cpu; int rc; - mutex_lock(&smp_cpu_state_mutex); get_online_cpus(); + mutex_lock(&smp_cpu_state_mutex); newcpus = cpu_present_map; rc = smp_rescan_cpus(); if (rc) @@ -1109,8 +1109,8 @@ static ssize_t __ref rescan_store(struct sys_device *dev, } rc = 0; out: - put_online_cpus(); mutex_unlock(&smp_cpu_state_mutex); + put_online_cpus(); if (!cpus_empty(newcpus)) topology_schedule_update(); return rc ? rc : count; @@ -1139,16 +1139,16 @@ static ssize_t dispatching_store(struct sys_device *dev, const char *buf, if (val != 0 && val != 1) return -EINVAL; rc = 0; - mutex_lock(&smp_cpu_state_mutex); get_online_cpus(); + mutex_lock(&smp_cpu_state_mutex); if (cpu_management == val) goto out; rc = topology_set_cpu_management(val); if (!rc) cpu_management = val; out: - put_online_cpus(); mutex_unlock(&smp_cpu_state_mutex); + put_online_cpus(); return rc ? rc : count; } static SYSDEV_ATTR(dispatching, 0644, dispatching_show, dispatching_store); |