[v3,6/9] x86/mm: add an end_of_loop label in map_pages_to_xen

Commit Message

Xia, Hongyan Oct. 2, 2019, 5:16 p.m. UTC

From: Wei Liu <[e-mail]>

We will soon need to clean up mappings whenever the out most loop is
ended. Add a new label and turn relevant continue's into goto's.

No functional change.

Signed-off-by: Wei Liu <[e-mail]>
---
 xen/arch/x86/mm.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Comments

Jan Beulich Nov. 22, 2019, 1:55 p.m. UTC | #1

On 02.10.2019 19:16, Hongyan Xia wrote:
> We will soon need to clean up mappings whenever the out most loop is
> ended. Add a new label and turn relevant continue's into goto's.

I think already when this still was RFC I did indicate that I'm not
happy about the introduction of these labels (including also patch 8).
I realize it's quite a lot to ask, but both functions would benefit
from splitting up into per-level helper functions, which - afaict -
would avoid the need for such labels, and which would at the same
time likely make it quite a bit easier to extend these to the
5-level page tables case down the road.

Thoughts?

Jan

Patch

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 26fcb2709b..5a5f0685cc 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5102,7 +5102,7 @@  int map_pages_to_xen(
             if ( !mfn_eq(mfn, INVALID_MFN) )
                 mfn  = mfn_add(mfn, 1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT));
             nr_mfns -= 1UL << (L3_PAGETABLE_SHIFT - PAGE_SHIFT);
-            continue;
+            goto end_of_loop;
         }
 
         if ( (l3e_get_flags(ol3e) & _PAGE_PRESENT) &&
@@ -5129,7 +5129,7 @@  int map_pages_to_xen(
                 if ( !mfn_eq(mfn, INVALID_MFN) )
                     mfn = mfn_add(mfn, i);
                 nr_mfns -= i;
-                continue;
+                goto end_of_loop;
             }
 
             l2t = alloc_xen_pagetable();
@@ -5310,7 +5310,7 @@  int map_pages_to_xen(
                 {
                     if ( locking )
                         spin_unlock(&map_pgdir_lock);
-                    continue;
+                    goto end_of_loop;
                 }
 
                 if ( l2e_get_flags(ol2e) & _PAGE_PSE )
@@ -5365,7 +5365,7 @@  int map_pages_to_xen(
             {
                 if ( locking )
                     spin_unlock(&map_pgdir_lock);
-                continue;
+                goto end_of_loop;
             }
 
             l2t = l3e_to_l2e(ol3e);
@@ -5390,6 +5390,7 @@  int map_pages_to_xen(
             else if ( locking )
                 spin_unlock(&map_pgdir_lock);
         }
+    end_of_loop:;
     }
 
 #undef flush_flags