1 files changed, 50 insertions, 2 deletions

diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
index c837e8e463db..5e6f36f6d876 100644
--- a/arch/x86/xen/multicalls.c
+++ b/arch/x86/xen/multicalls.c
@@ -26,13 +26,22 @@
 
 #include "multicalls.h"
 
+#define MC_DEBUG        1
+
 #define MC_BATCH        32
 #define MC_ARGS         (MC_BATCH * 16 / sizeof(u64))
 
 struct mc_buffer {
         struct multicall_entry entries[MC_BATCH];
+#if MC_DEBUG
+        struct multicall_entry debug[MC_BATCH];
+#endif
         u64 args[MC_ARGS];
-        unsigned mcidx, argidx;
+        struct callback {
+                void (*fn)(void *);
+                void *data;
+        } callbacks[MC_BATCH];
+        unsigned mcidx, argidx, cbidx;
 };
 
 static DEFINE_PER_CPU(struct mc_buffer, mc_buffer);
@@ -43,6 +52,7 @@ void xen_mc_flush(void)
         struct mc_buffer *b = &__get_cpu_var(mc_buffer);
         int ret = 0;
         unsigned long flags;
+        int i;
 
         BUG_ON(preemptible());
 
@@ -51,13 +61,31 @@ void xen_mc_flush(void)
         local_irq_save(flags);
 
         if (b->mcidx) {
-                int i;
+#if MC_DEBUG
+                memcpy(b->debug, b->entries,
+                       b->mcidx * sizeof(struct multicall_entry));
+#endif
 
                 if (HYPERVISOR_multicall(b->entries, b->mcidx) != 0)
                         BUG();
                 for (i = 0; i < b->mcidx; i++)
                         if (b->entries[i].result < 0)
                                 ret++;
+
+#if MC_DEBUG
+                if (ret) {
+                        printk(KERN_ERR "%d multicall(s) failed: cpu %d\n",
+                               ret, smp_processor_id());
+                        for(i = 0; i < b->mcidx; i++) {
+                                printk("  call %2d/%d: op=%lu arg=[%lx] result=%ld\n",
+                                       i+1, b->mcidx,
+                                       b->debug[i].op,
+                                       b->debug[i].args[0],
+                                       b->entries[i].result);
+                        }
+                }
+#endif
+
                 b->mcidx = 0;
                 b->argidx = 0;
         } else
@@ -65,6 +93,13 @@ void xen_mc_flush(void)
 
         local_irq_restore(flags);
 
+        for(i = 0; i < b->cbidx; i++) {
+                struct callback *cb = &b->callbacks[i];
+
+                (*cb->fn)(cb->data);
+        }
+        b->cbidx = 0;
+
         BUG_ON(ret);
 }
 
@@ -88,3 +123,16 @@ struct multicall_space __xen_mc_entry(size_t args)
 
         return ret;
 }
+
+void xen_mc_callback(void (*fn)(void *), void *data)
+{
+        struct mc_buffer *b = &__get_cpu_var(mc_buffer);
+        struct callback *cb;
+
+        if (b->cbidx == MC_BATCH)
+                xen_mc_flush();
+
+        cb = &b->callbacks[b->cbidx++];
+        cb->fn = fn;
+        cb->data = data;
+}