[S390] smp_call_function/smp_call_function_on locking.

smp_call_function and smp_call_function_on share the same lock and
smp_call_function_on disables softirq's so it can be called from
softirq context as well. Hence smp_call_function muss disable
softirqs as well to avoid deadlocks.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 65b52320d145..83a4ea6e3d60 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -57,7 +57,7 @@ static void smp_ext_bitcall(int, ec_bit_sig);
 static void smp_ext_bitcall_others(ec_bit_sig);
 
 /*
-5B * Structure and data for smp_call_function(). This is designed to minimise
+ * Structure and data for smp_call_function(). This is designed to minimise
  * static memory requirements. It also looks cleaner.
  */
 static DEFINE_SPINLOCK(call_lock);
@@ -104,7 +104,7 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
  * remote CPUs are nearly ready to execute <<func>> or are or have executed.
  *
  * You must not call this function with disabled interrupts or from a
- * hardware interrupt handler or from a bottom half handler.
+ * hardware interrupt handler.
  */
 {
         struct call_data_struct data;
@@ -113,8 +113,8 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
         if (cpus <= 0)
                 return 0;
 
-        /* Can deadlock when called with interrupts disabled */
-        WARN_ON(irqs_disabled());
+        /* Can deadlock when interrupts are disabled or if in wrong context */
+        WARN_ON(irqs_disabled() || in_irq());
 
         data.func = func;
         data.info = info;
@@ -123,7 +123,7 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
         if (wait)
                 atomic_set(&data.finished, 0);
 
-        spin_lock(&call_lock);
+        spin_lock_bh(&call_lock);
         call_data = &data;
         /* Send a message to all other CPUs and wait for them to respond */
         smp_ext_bitcall_others(ec_call_function);
@@ -135,7 +135,7 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
         if (wait)
                 while (atomic_read(&data.finished) != cpus)
                         cpu_relax();
-        spin_unlock(&call_lock);
+        spin_unlock_bh(&call_lock);
 
         return 0;
 }
@@ -159,6 +159,9 @@ int smp_call_function_on(void (*func) (void *info), void *info,
         if (!cpu_online(cpu))
                 return -EINVAL;
 
+        /* Can deadlock when interrupts are disabled or if in wrong context */
+        WARN_ON(irqs_disabled() || in_irq());
+
         /* disable preemption for local function call */
         curr_cpu = get_cpu();