Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=91e0c5f3dad47838cb2ecc1865ce789a0b7182b1
Commit:     91e0c5f3dad47838cb2ecc1865ce789a0b7182b1
Parent:     f0d733942750c1ee6358c3a4a1a5d7ba73b7122f
Author:     Jeremy Fitzhardinge <[EMAIL PROTECTED]>
AuthorDate: Tue Oct 16 11:51:30 2007 -0700
Committer:  Jeremy Fitzhardinge <[EMAIL PROTECTED]>
CommitDate: Tue Oct 16 11:51:30 2007 -0700

    xen: add batch completion callbacks
    
    This adds a mechanism to register a callback function to be called once
    a batch of hypercalls has been issued.  This is typically used to unlock
    things which must remain locked until the hypercall has taken place.
    
    [ Stable folks: pre-req for 2.6.23 bugfix "xen: deal with stale cr3
      values when unpinning pagetables" ]
    
    Signed-off-by: Jeremy Fitzhardinge <[EMAIL PROTECTED]>
    Cc: Stable Kernel <[EMAIL PROTECTED]>
---
 arch/x86/xen/multicalls.c |   29 ++++++++++++++++++++++++++---
 arch/x86/xen/multicalls.h |    3 +++
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
index c837e8e..ce9c4b4 100644
--- a/arch/x86/xen/multicalls.c
+++ b/arch/x86/xen/multicalls.c
@@ -32,7 +32,11 @@
 struct mc_buffer {
        struct multicall_entry entries[MC_BATCH];
        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 +47,7 @@ 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());
 
@@ -51,8 +56,6 @@ void xen_mc_flush(void)
        local_irq_save(flags);
 
        if (b->mcidx) {
-               int i;
-
                if (HYPERVISOR_multicall(b->entries, b->mcidx) != 0)
                        BUG();
                for (i = 0; i < b->mcidx; i++)
@@ -65,6 +68,13 @@ 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 +98,16 @@ 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;
+}
diff --git a/arch/x86/xen/multicalls.h b/arch/x86/xen/multicalls.h
index 5d96a5f..8bae996 100644
--- a/arch/x86/xen/multicalls.h
+++ b/arch/x86/xen/multicalls.h
@@ -42,4 +42,7 @@ static inline void xen_mc_issue(unsigned mode)
        local_irq_restore(x86_read_percpu(xen_mc_irq_flags));
 }
 
+/* Set up a callback to be called when the current batch is flushed */
+void xen_mc_callback(void (*fn)(void *), void *data);
+
 #endif /* _XEN_MULTICALLS_H */
-
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