x86/paravirt: add spin_lock_flags lock op

It is useful for a pv_lock_ops backend to know whether interrupts are
enabled or not in the context a spin_lock is being called.  This
allows it to enable interrupts while spinning, which could be
particularly helpful when spinning becomes blocking.

The default implementation just calls the normal spin_lock op,
ignoring the flags.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 38d7f7f1dbc9..206359a8e43f 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -7,12 +7,18 @@
 
 #include <asm/paravirt.h>
 
+static void default_spin_lock_flags(struct raw_spinlock *lock, unsigned long flags)
+{
+        __raw_spin_lock(lock);
+}
+
 struct pv_lock_ops pv_lock_ops = {
 #ifdef CONFIG_SMP
         .spin_is_locked = __ticket_spin_is_locked,
         .spin_is_contended = __ticket_spin_is_contended,
 
         .spin_lock = __ticket_spin_lock,
+        .spin_lock_flags = default_spin_lock_flags,
         .spin_trylock = __ticket_spin_trylock,
         .spin_unlock = __ticket_spin_unlock,
 #endif