[Xen-devel] [RFC PATCH for-next 11/18] x86/mem_sharing: Convert MEM_SHARING_DESTROY_GFN to a bool

[Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>]

MEM_SHARING_DESTROY_GFN is used on the 'flags' bitfield during unsharing.
However, the bitfield is not used for anything else, so just convert it to a
bool instead.

Signed-off-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxx>
---
 xen/arch/x86/mm/mem_sharing.c     | 7 +++----
 xen/arch/x86/mm/p2m.c             | 1 +
 xen/common/memory.c               | 2 +-
 xen/include/asm-x86/mem_sharing.h | 5 ++---
 4 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index bb6a44413b..157a3a1303 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -1175,7 +1175,7 @@ err_out:
  */
 int __mem_sharing_unshare_page(struct domain *d,
                                unsigned long gfn,
-                               uint16_t flags)
+                               bool destroy)
 {
     p2m_type_t p2mt;
     mfn_t mfn;
@@ -1231,7 +1231,7 @@ int __mem_sharing_unshare_page(struct domain *d,
      * If the GFN is getting destroyed drop the references to MFN
      * (possibly freeing the page), and exit early.
      */
-    if ( flags & MEM_SHARING_DESTROY_GFN )
+    if ( destroy )
     {
         if ( !last_gfn )
             mem_sharing_gfn_destroy(page, d, gfn_info);
@@ -1321,8 +1321,7 @@ int relinquish_shared_pages(struct domain *d)
         if ( mfn_valid(mfn) && p2m_is_shared(t) )
         {
             /* Does not fail with ENOMEM given the DESTROY flag */
-            BUG_ON(__mem_sharing_unshare_page(d, gfn,
-                   MEM_SHARING_DESTROY_GFN));
+            BUG_ON(__mem_sharing_unshare_page(d, gfn, true));
             /*
              * Clear out the p2m entry so no one else may try to
              * unshare.  Must succeed: we just read the old entry and
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 3d27c6c91a..aee0347785 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -512,6 +512,7 @@ mfn_t __get_gfn_type_access(struct p2m_domain *p2m, 
unsigned long gfn_l,
          */
         if ( mem_sharing_unshare_page(p2m->domain, gfn_l) < 0 )
             mem_sharing_notify_enomem(p2m->domain, gfn_l, false);
+
         mfn = p2m->get_entry(p2m, gfn, t, a, q, page_order, NULL);
     }
 
diff --git a/xen/common/memory.c b/xen/common/memory.c
index d5aff83f2d..04bcd84a15 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -352,7 +352,7 @@ int guest_remove_page(struct domain *d, unsigned long gmfn)
          * might be the only one using this shared page, and we need to
          * trigger proper cleanup. Once done, this is like any other page.
          */
-        rc = mem_sharing_unshare_page(d, gmfn, 0);
+        rc = mem_sharing_unshare_page(d, gmfn);
         if ( rc )
         {
             mem_sharing_notify_enomem(d, gmfn, false);
diff --git a/xen/include/asm-x86/mem_sharing.h 
b/xen/include/asm-x86/mem_sharing.h
index 57db72376b..18302adbfa 100644
--- a/xen/include/asm-x86/mem_sharing.h
+++ b/xen/include/asm-x86/mem_sharing.h
@@ -76,17 +76,16 @@ struct page_sharing_info
 unsigned int mem_sharing_get_nr_saved_mfns(void);
 unsigned int mem_sharing_get_nr_shared_mfns(void);
 
-#define MEM_SHARING_DESTROY_GFN       (1<<1)
 /* Only fails with -ENOMEM. Enforce it with a BUG_ON wrapper. */
 int __mem_sharing_unshare_page(struct domain *d,
                                unsigned long gfn,
-                               uint16_t flags);
+                               bool destroy);
 
 static inline
 int mem_sharing_unshare_page(struct domain *d,
                              unsigned long gfn)
 {
-    int rc = __mem_sharing_unshare_page(d, gfn, 0);
+    int rc = __mem_sharing_unshare_page(d, gfn, false);
     BUG_ON( rc && (rc != -ENOMEM) );
     return rc;
 }
-- 
2.20.1


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