Re: [PATCH v9 09/13] x86/smpboot: add exit path for clone_mapping()

[Jan Beulich]

On 06.04.2021 13:05, Hongyan Xia wrote:
> From: Wei Liu 
> 
> We will soon need to clean up page table mappings in the exit path.
> 
> No functional change.
> 
> Signed-off-by: Wei Liu 
> Signed-off-by: Hongyan Xia 

Acked-by: Jan Beulich 

[PATCH v9 09/13] x86/smpboot: add exit path for clone_mapping()

[Hongyan Xia]

From: Wei Liu 

We will soon need to clean up page table mappings in the exit path.

No functional change.

Signed-off-by: Wei Liu 
Signed-off-by: Hongyan Xia 

---
Changed in v7:
- edit commit message.
- begin with rc = 0 and set it to -ENOMEM ahead of if().
---
 xen/arch/x86/smpboot.c | 16 +++-
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 82c1012e892f..e90c4dfa8a88 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -696,6 +696,7 @@ static int clone_mapping(const void *ptr, root_pgentry_t 
*rpt)
 l3_pgentry_t *pl3e;
 l2_pgentry_t *pl2e;
 l1_pgentry_t *pl1e;
+int rc = 0;
 
 /*
  * Sanity check 'linear'.  We only allow cloning from the Xen virtual
@@ -736,7 +737,7 @@ static int clone_mapping(const void *ptr, root_pgentry_t 
*rpt)
 pl1e = l2e_to_l1e(*pl2e) + l1_table_offset(linear);
 flags = l1e_get_flags(*pl1e);
 if ( !(flags & _PAGE_PRESENT) )
-return 0;
+goto out;
 pfn = l1e_get_pfn(*pl1e);
 }
 }
@@ -744,8 +745,9 @@ static int clone_mapping(const void *ptr, root_pgentry_t 
*rpt)
 if ( !(root_get_flags(rpt[root_table_offset(linear)]) & _PAGE_PRESENT) )
 {
 pl3e = alloc_xen_pagetable();
+rc = -ENOMEM;
 if ( !pl3e )
-return -ENOMEM;
+goto out;
 clear_page(pl3e);
 l4e_write([root_table_offset(linear)],
   l4e_from_paddr(__pa(pl3e), __PAGE_HYPERVISOR));
@@ -758,8 +760,9 @@ static int clone_mapping(const void *ptr, root_pgentry_t 
*rpt)
 if ( !(l3e_get_flags(*pl3e) & _PAGE_PRESENT) )
 {
 pl2e = alloc_xen_pagetable();
+rc = -ENOMEM;
 if ( !pl2e )
-return -ENOMEM;
+goto out;
 clear_page(pl2e);
 l3e_write(pl3e, l3e_from_paddr(__pa(pl2e), __PAGE_HYPERVISOR));
 }
@@ -774,8 +777,9 @@ static int clone_mapping(const void *ptr, root_pgentry_t 
*rpt)
 if ( !(l2e_get_flags(*pl2e) & _PAGE_PRESENT) )
 {
 pl1e = alloc_xen_pagetable();
+rc = -ENOMEM;
 if ( !pl1e )
-return -ENOMEM;
+goto out;
 clear_page(pl1e);
 l2e_write(pl2e, l2e_from_paddr(__pa(pl1e), __PAGE_HYPERVISOR));
 }
@@ -796,7 +800,9 @@ static int clone_mapping(const void *ptr, root_pgentry_t 
*rpt)
 else
 l1e_write(pl1e, l1e_from_pfn(pfn, flags));
 
-return 0;
+rc = 0;
+ out:
+return rc;
 }
 
 DEFINE_PER_CPU(root_pgentry_t *, root_pgt);
-- 
2.23.3