[xen staging] domain_page: handle NULL within unmap_domain_page() itself

[patchbot@xxxxxxx]

commit 84c2b2a81ab8aa0a14f50660ed7a214beae5a20f
Author:     Hongyan Xia <hongyxia@xxxxxxxxxx>
AuthorDate: Wed May 13 16:43:33 2020 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Fri May 15 19:35:09 2020 +0100

    domain_page: handle NULL within unmap_domain_page() itself
    
    The macro version UNMAP_DOMAIN_PAGE() does both NULL checking and
    variable clearing. Move NULL checking into the function itself so that
    the semantics is consistent with other similar constructs like XFREE().
    This also eases the use unmap_domain_page() in error handling paths,
    where we only care about NULL checking but not about variable clearing.
    
    Signed-off-by: Hongyan Xia <hongyxia@xxxxxxxxxx>
    Reviewed-by: Wei Liu <wl@xxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Julien Grall <jgrall@xxxxxxxxxx>
---
 xen/arch/arm/mm.c             | 3 +++
 xen/arch/x86/domain_page.c    | 2 +-
 xen/include/xen/domain_page.h | 7 ++-----
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 727107eefa..1b14f49345 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -498,6 +498,9 @@ void unmap_domain_page(const void *va)
     lpae_t *map = this_cpu(xen_dommap);
     int slot = ((unsigned long) va - DOMHEAP_VIRT_START) >> SECOND_SHIFT;
 
+    if ( !va )
+        return;
+
     local_irq_save(flags);
 
     ASSERT(slot >= 0 && slot < DOMHEAP_ENTRIES);
diff --git a/xen/arch/x86/domain_page.c b/xen/arch/x86/domain_page.c
index dd32712d2f..b03728e18e 100644
--- a/xen/arch/x86/domain_page.c
+++ b/xen/arch/x86/domain_page.c
@@ -181,7 +181,7 @@ void unmap_domain_page(const void *ptr)
     unsigned long va = (unsigned long)ptr, mfn, flags;
     struct vcpu_maphash_entry *hashent;
 
-    if ( va >= DIRECTMAP_VIRT_START )
+    if ( !va || va >= DIRECTMAP_VIRT_START )
         return;
 
     ASSERT(va >= MAPCACHE_VIRT_START && va < MAPCACHE_VIRT_END);
diff --git a/xen/include/xen/domain_page.h b/xen/include/xen/domain_page.h
index ab2be7b719..a182d33b67 100644
--- a/xen/include/xen/domain_page.h
+++ b/xen/include/xen/domain_page.h
@@ -73,11 +73,8 @@ static inline void unmap_domain_page_global(const void *va) 
{};
 #endif /* !CONFIG_DOMAIN_PAGE */
 
 #define UNMAP_DOMAIN_PAGE(p) do {   \
-    if ( p )                        \
-    {                               \
-        unmap_domain_page(p);       \
-        (p) = NULL;                 \
-    }                               \
+    unmap_domain_page(p);           \
+    (p) = NULL;                     \
 } while ( false )
 
 #endif /* __XEN_DOMAIN_PAGE_H__ */
--
generated by git-patchbot for /home/xen/git/xen.git#staging