x86/idt: Simplify alloc_intr_gate()

The only users of alloc_intr_gate() are hypervisors, which both check the
used_vectors bitmap whether they have allocated the gate already. Move that
check into alloc_intr_gate() and simplify the users.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Reviewed-by: K. Y. Srinivasan <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: Steven Rostedt <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 70e717fccdd6cabaf8eb778b6f407c43b6e0c412..9fc32651c911ef1f3f7824cfbe243ccf7b50336b 100644 (file)
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -59,13 +59,8 @@ void hyperv_vector_handler(struct pt_regs *regs)
 void hv_setup_vmbus_irq(void (*handler)(void))
 {
        vmbus_handler = handler;
-       /*
-        * Setup the IDT for hypervisor callback. Prevent reallocation
-        * at module reload.
-        */
-       if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
-               alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
-                               hyperv_callback_vector);
+       /* Setup the IDT for hypervisor callback */
+       alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
 }
 
 void hv_remove_vmbus_irq(void)

diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 8e9318d2b56df82f6dc4020b2919910a32e6a7d4..b609eac3d73cb63e79053503870f9764c2ebd097 100644 (file)
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -354,7 +354,7 @@ void set_intr_gate(unsigned int n, const void *addr)
 
 void alloc_intr_gate(unsigned int n, const void *addr)
 {
-       BUG_ON(test_bit(n, used_vectors) || n < FIRST_SYSTEM_VECTOR);
-       set_bit(n, used_vectors);
-       set_intr_gate(n, addr);
+       BUG_ON(n < FIRST_SYSTEM_VECTOR);
+       if (!test_and_set_bit(n, used_vectors))
+               set_intr_gate(n, addr);
 }

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 2d43118077e4eecc12f68bee605fb068def11c95..1ab4bd11f5f3f01f34b1a0055f836c9a0ce755ba 100644 (file)
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -1653,10 +1653,8 @@ void xen_callback_vector(void)
                        return;
                }
                pr_info("Xen HVM callback vector for event delivery is enabled\n");
-               /* in the restore case the vector has already been allocated */
-               if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
-                       alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
-                                       xen_hvm_callback_vector);
+               alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
+                               xen_hvm_callback_vector);
        }
 }
 #else