xen/p2m: Move code around to allow for better re-usage.

We are going to be using the early_alloc_p2m (and
early_alloc_p2m_middle) code in follow up patches which
are not related to setting identity pages.

Hence lets move the code out in its own function and
rename them as appropiate.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 34 insertions, 28 deletions

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 1b267e75158d..3cc3afeb09a1 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -499,7 +499,7 @@ static bool alloc_p2m(unsigned long pfn)
         return true;
 }
 
-static bool __init __early_alloc_p2m(unsigned long pfn)
+static bool __init early_alloc_p2m_middle(unsigned long pfn)
 {
         unsigned topidx, mididx, idx;
 
@@ -541,6 +541,36 @@ static bool __init __early_alloc_p2m(unsigned long pfn)
         }
         return idx != 0;
 }
+
+static bool __init early_alloc_p2m(unsigned long pfn)
+{
+        unsigned topidx = p2m_top_index(pfn);
+        unsigned long *mid_mfn_p;
+        unsigned long **mid;
+
+        mid = p2m_top[topidx];
+        mid_mfn_p = p2m_top_mfn_p[topidx];
+        if (mid == p2m_mid_missing) {
+                mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
+
+                p2m_mid_init(mid);
+
+                p2m_top[topidx] = mid;
+
+                BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
+        }
+        /* And the save/restore P2M tables.. */
+        if (mid_mfn_p == p2m_mid_missing_mfn) {
+                mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
+                p2m_mid_mfn_init(mid_mfn_p);
+
+                p2m_top_mfn_p[topidx] = mid_mfn_p;
+                p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
+                /* Note: we don't set mid_mfn_p[midix] here,
+                 * look in early_alloc_p2m_middle */
+        }
+        return true;
+}
 unsigned long __init set_phys_range_identity(unsigned long pfn_s,
                                       unsigned long pfn_e)
 {
@@ -559,35 +589,11 @@ unsigned long __init set_phys_range_identity(unsigned long pfn_s,
                 pfn < ALIGN(pfn_e, (P2M_MID_PER_PAGE * P2M_PER_PAGE));
                 pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE)
         {
-                unsigned topidx = p2m_top_index(pfn);
-                unsigned long *mid_mfn_p;
-                unsigned long **mid;
-
-                mid = p2m_top[topidx];
-                mid_mfn_p = p2m_top_mfn_p[topidx];
-                if (mid == p2m_mid_missing) {
-                        mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
-
-                        p2m_mid_init(mid);
-
-                        p2m_top[topidx] = mid;
-
-                        BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
-                }
-                /* And the save/restore P2M tables.. */
-                if (mid_mfn_p == p2m_mid_missing_mfn) {
-                        mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
-                        p2m_mid_mfn_init(mid_mfn_p);
-
-                        p2m_top_mfn_p[topidx] = mid_mfn_p;
-                        p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
-                        /* Note: we don't set mid_mfn_p[midix] here,
-                         * look in __early_alloc_p2m */
-                }
+                WARN_ON(!early_alloc_p2m(pfn));
         }
 
-        __early_alloc_p2m(pfn_s);
-        __early_alloc_p2m(pfn_e);
+        early_alloc_p2m_middle(pfn_s);
+        early_alloc_p2m_middle(pfn_e);
 
         for (pfn = pfn_s; pfn < pfn_e; pfn++)
                 if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn)))