[PATCH] arch: x86: kernel: fixed unused label issue

From: Piotr Gregor
Date: Wed Dec 14 2016 - 06:24:16 EST


The patch_default label is only used from within
case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock)
and
case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted)
i.e. when #if defined(CONFIG_PARAVIRT_SPINLOCKS) is true.
Therefore no code jumps to this label in case CONFIG_PARAVIRT_SPINLOCKS
is not defined and label should be removed in that case.
Moving #endif directive just after that label fixes the issue.

In addition,there are three errors reported by checkpatch script
on this file. This commit fixes two of them. The last one is
ERROR: Macros with multiple statements should be enclosed
in a do - while loop
which probably is a false alarm here as PATCH_SITE macro defines
a case in switch local to native_patch function not meant to be used
in other places.

Signed-off-by: Piotr Gregor <piotrgregor@xxxxxxxxxxx>
---
arch/x86/kernel/paravirt_patch_64.c | 67 +++++++++++++++++++------------------
1 file changed, 34 insertions(+), 33 deletions(-)

diff --git a/arch/x86/kernel/paravirt_patch_64.c b/arch/x86/kernel/paravirt_patch_64.c
index f4fcf26..7ce2848 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -44,43 +44,44 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
const unsigned char *start, *end;
unsigned ret;

-#define PATCH_SITE(ops, x) \
- case PARAVIRT_PATCH(ops.x): \
- start = start_##ops##_##x; \
- end = end_##ops##_##x; \
- goto patch_site
- switch(type) {
- PATCH_SITE(pv_irq_ops, restore_fl);
- PATCH_SITE(pv_irq_ops, save_fl);
- PATCH_SITE(pv_irq_ops, irq_enable);
- PATCH_SITE(pv_irq_ops, irq_disable);
- PATCH_SITE(pv_cpu_ops, usergs_sysret64);
- PATCH_SITE(pv_cpu_ops, swapgs);
- PATCH_SITE(pv_mmu_ops, read_cr2);
- PATCH_SITE(pv_mmu_ops, read_cr3);
- PATCH_SITE(pv_mmu_ops, write_cr3);
- PATCH_SITE(pv_mmu_ops, flush_tlb_single);
- PATCH_SITE(pv_cpu_ops, wbinvd);
+#define PATCH_SITE(ops, x) \
+ case PARAVIRT_PATCH(ops.x): \
+ start = start_##ops##_##x; \
+ end = end_##ops##_##x; \
+ goto patch_site
+
+ switch (type) {
+ PATCH_SITE(pv_irq_ops, restore_fl);
+ PATCH_SITE(pv_irq_ops, save_fl);
+ PATCH_SITE(pv_irq_ops, irq_enable);
+ PATCH_SITE(pv_irq_ops, irq_disable);
+ PATCH_SITE(pv_cpu_ops, usergs_sysret64);
+ PATCH_SITE(pv_cpu_ops, swapgs);
+ PATCH_SITE(pv_mmu_ops, read_cr2);
+ PATCH_SITE(pv_mmu_ops, read_cr3);
+ PATCH_SITE(pv_mmu_ops, write_cr3);
+ PATCH_SITE(pv_mmu_ops, flush_tlb_single);
+ PATCH_SITE(pv_cpu_ops, wbinvd);
#if defined(CONFIG_PARAVIRT_SPINLOCKS)
- case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):
- if (pv_is_native_spin_unlock()) {
- start = start_pv_lock_ops_queued_spin_unlock;
- end = end_pv_lock_ops_queued_spin_unlock;
- goto patch_site;
- }
- goto patch_default;
+ case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):
+ if (pv_is_native_spin_unlock()) {
+ start = start_pv_lock_ops_queued_spin_unlock;
+ end = end_pv_lock_ops_queued_spin_unlock;
+ goto patch_site;
+ }
+ goto patch_default;

- case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
- if (pv_is_native_vcpu_is_preempted()) {
- start = start_pv_lock_ops_vcpu_is_preempted;
- end = end_pv_lock_ops_vcpu_is_preempted;
- goto patch_site;
- }
- goto patch_default;
-#endif
+ case PARAVIRT_PATCH(pv_lock_ops.vcpu_is_preempted):
+ if (pv_is_native_vcpu_is_preempted()) {
+ start = start_pv_lock_ops_vcpu_is_preempted;
+ end = end_pv_lock_ops_vcpu_is_preempted;
+ goto patch_site;
+ }
+ goto patch_default;

- default:
patch_default:
+#endif
+ default:
ret = paravirt_patch_default(type, clobbers, ibuf, addr, len);
break;

--
2.1.4