[XEN PATCH] xen: fix violations of MISRA C:2012 Rule 3.1

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

In the file 'xen/common/xmalloc_tlsf.c' is not clear how
the commented-out code should interact with the previous statement.
To resolve the MISRA violation generated by the nested comment
a #if .. #endif block with an explanatory comment substitutes
the earlier construct.

In the file 'xen/include/xen/atomic.h' the nested comment has been removed,
since the code sample is already explained by the preceding comment.

Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
---
Following the suggestion of this message
https://lore.kernel.org/xen-devel/536f3049-41f7-b127-ba94-81925e34ea0f@xxxxxxxx/
an explanatory comment has been added.
---
 xen/common/xmalloc_tlsf.c | 13 ++++++++++---
 xen/include/xen/atomic.h  |  2 +-
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/xen/common/xmalloc_tlsf.c b/xen/common/xmalloc_tlsf.c
index c21bf71e88..56c3849414 100644
--- a/xen/common/xmalloc_tlsf.c
+++ b/xen/common/xmalloc_tlsf.c
@@ -139,10 +139,17 @@ static inline void MAPPING_SEARCH(unsigned long *r, int 
*fl, int *sl)
         *r = *r + t;
         *fl = flsl(*r) - 1;
         *sl = (*r >> (*fl - MAX_LOG2_SLI)) - MAX_SLI;
-        *fl -= FLI_OFFSET;
-        /*if ((*fl -= FLI_OFFSET) < 0) // FL will be always >0!
-         *fl = *sl = 0;
+        /* 
+         * It's unclear what was the purpose of the commented-out code that now
+         * is in the #else branch. The current form is motivated by the 
correction
+         * of a violation MISRA:C 2012 Rule 3.1
          */
+#if 1
+        *fl -= FLI_OFFSET;
+#else
+        if ((*fl -= FLI_OFFSET) < 0) // FL will be always >0!
+          *fl = *sl = 0;
+#endif
         *r &= ~t;
     }
 }
diff --git a/xen/include/xen/atomic.h b/xen/include/xen/atomic.h
index 529213ebbb..fa750a18ae 100644
--- a/xen/include/xen/atomic.h
+++ b/xen/include/xen/atomic.h
@@ -78,7 +78,7 @@ static inline void _atomic_set(atomic_t *v, int i);
  *      int old = atomic_read(&v);
  *      int new = old + 1;
  *      if ( likely(old == atomic_cmpxchg(&v, old, new)) )
- *          break; // success!
+ *          break;
  *  }
  */
 static inline int atomic_cmpxchg(atomic_t *v, int old, int new);
-- 
2.34.1