[PATCH 2/2] x86/paging: tidy paging_mfn_is_dirty()

[Jan Beulich <jbeulich@xxxxxxxx>]

The function returning a boolean indicator, make it return bool. Also
constify its struct domain parameter, albeit requiring to also adjust
mm_locked_by_me(). Furthermore the function is used by shadow code only.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/mm/mm-locks.h
+++ b/xen/arch/x86/mm/mm-locks.h
@@ -40,7 +40,7 @@ static inline void mm_lock_init(mm_lock_
     l->unlock_level = 0;
 }
 
-static inline int mm_locked_by_me(mm_lock_t *l)
+static inline int mm_locked_by_me(const mm_lock_t *l)
 {
     return (l->lock.recurse_cpu == current->processor);
 }
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -351,14 +351,14 @@ void paging_mark_dirty(struct domain *d,
     paging_mark_pfn_dirty(d, pfn);
 }
 
-
+#ifdef CONFIG_SHADOW_PAGING
 /* Is this guest page dirty? */
-int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn)
+bool paging_mfn_is_dirty(const struct domain *d, mfn_t gmfn)
 {
     pfn_t pfn;
     mfn_t mfn, *l4, *l3, *l2;
     unsigned long *l1;
-    int rv;
+    bool dirty;
 
     ASSERT(paging_locked_by_me(d));
     ASSERT(paging_mode_log_dirty(d));
@@ -367,36 +367,37 @@ int paging_mfn_is_dirty(struct domain *d
     pfn = _pfn(get_gpfn_from_mfn(mfn_x(gmfn)));
     /* Invalid pages can't be dirty. */
     if ( unlikely(!VALID_M2P(pfn_x(pfn))) )
-        return 0;
+        return false;
 
     mfn = d->arch.paging.log_dirty.top;
     if ( !mfn_valid(mfn) )
-        return 0;
+        return false;
 
     l4 = map_domain_page(mfn);
     mfn = l4[L4_LOGDIRTY_IDX(pfn)];
     unmap_domain_page(l4);
     if ( !mfn_valid(mfn) )
-        return 0;
+        return false;
 
     l3 = map_domain_page(mfn);
     mfn = l3[L3_LOGDIRTY_IDX(pfn)];
     unmap_domain_page(l3);
     if ( !mfn_valid(mfn) )
-        return 0;
+        return false;
 
     l2 = map_domain_page(mfn);
     mfn = l2[L2_LOGDIRTY_IDX(pfn)];
     unmap_domain_page(l2);
     if ( !mfn_valid(mfn) )
-        return 0;
+        return false;
 
     l1 = map_domain_page(mfn);
-    rv = test_bit(L1_LOGDIRTY_IDX(pfn), l1);
+    dirty = test_bit(L1_LOGDIRTY_IDX(pfn), l1);
     unmap_domain_page(l1);
-    return rv;
-}
 
+    return dirty;
+}
+#endif
 
 /* Read a domain's log-dirty bitmap and stats.  If the operation is a CLEAN,
  * clear the bitmap and stats as well. */
--- a/xen/include/asm-x86/paging.h
+++ b/xen/include/asm-x86/paging.h
@@ -173,7 +173,7 @@ void paging_mark_pfn_dirty(struct domain
 
 /* is this guest page dirty? 
  * This is called from inside paging code, with the paging lock held. */
-int paging_mfn_is_dirty(struct domain *d, mfn_t gmfn);
+bool paging_mfn_is_dirty(const struct domain *d, mfn_t gmfn);
 
 /*
  * Log-dirty radix tree indexing: