xen/mmu: Cleanup xen_pagetable_p2m_copy a bit.

Stefano noticed that the code runs only under 64-bit so
the comments about 32-bit are pointless.

Also we change the condition for xen_revector_p2m_tree
returning the same value (because it could not allocate
a swath of space to put the new P2M in) or it had been
called once already. In such we return early from the
function.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

1 files changed, 20 insertions, 20 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index c140efffe37e..9d74249542c5 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1209,29 +1209,29 @@ static void __init xen_pagetable_p2m_copy(void)
 
         size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
 
-        /* On 32-bit, we get zero so this never gets executed. */
         new_mfn_list = xen_revector_p2m_tree();
-        if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
-                /* using __ka address and sticking INVALID_P2M_ENTRY! */
-                memset((void *)xen_start_info->mfn_list, 0xff, size);
-
-                /* We should be in __ka space. */
-                BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
-                addr = xen_start_info->mfn_list;
-                /* We roundup to the PMD, which means that if anybody at this stage is
-                 * using the __ka address of xen_start_info or xen_start_info->shared_info
-                 * they are in going to crash. Fortunatly we have already revectored
-                 * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
-                size = roundup(size, PMD_SIZE);
-                xen_cleanhighmap(addr, addr + size);
-
-                size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
-                memblock_free(__pa(xen_start_info->mfn_list), size);
-                /* And revector! Bye bye old array */
-                xen_start_info->mfn_list = new_mfn_list;
-        } else
+        /* No memory or already called. */
+        if (!new_mfn_list || new_mfn_list == xen_start_info->mfn_list)
                 return;
 
+        /* using __ka address and sticking INVALID_P2M_ENTRY! */
+        memset((void *)xen_start_info->mfn_list, 0xff, size);
+
+        /* We should be in __ka space. */
+        BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
+        addr = xen_start_info->mfn_list;
+        /* We roundup to the PMD, which means that if anybody at this stage is
+         * using the __ka address of xen_start_info or xen_start_info->shared_info
+         * they are in going to crash. Fortunatly we have already revectored
+         * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
+        size = roundup(size, PMD_SIZE);
+        xen_cleanhighmap(addr, addr + size);
+
+        size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+        memblock_free(__pa(xen_start_info->mfn_list), size);
+        /* And revector! Bye bye old array */
+        xen_start_info->mfn_list = new_mfn_list;
+
         /* At this stage, cleanup_highmap has already cleaned __ka space
          * from _brk_limit way up to the max_pfn_mapped (which is the end of
          * the ramdisk). We continue on, erasing PMD entries that point to page