From: zijun_hu <zijun_hu@zoho.com>
Date: Sat, 10 Sep 2016 10:34:03 +0000 (+1000)
Subject: mm-vmalloc-fix-align-value-calculation-error-v2
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=dba5fd1bf247600841a953a70f067ee114c8ae3f;p=deliverable%2Flinux.git

mm-vmalloc-fix-align-value-calculation-error-v2

i provide another patch called v2 based on your suggestion as shown below
it have following correction against original patch v1
1) use name get_count_order_long() instead of get_order_long()
2) return -1 if @l == 0 to consist with get_order_long()
3) cast type to int before returning from get_count_order_long()
4) move up function parameter checking for __get_vm_area_node()
5) more commit message is offered to make issue and approach clear
any comments about new patch is welcome

Link: http://lkml.kernel.org/r/57AABC8B.1040409@zoho.com
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 711d12dcda2f..93a07d1827c6 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -75,23 +75,6 @@ static inline int get_count_order(unsigned int count)
 	return order;
 }
 
-/**
- * get_count_order_long - get order after rounding @l up to power of 2
- * @l: parameter
- *
- * The same as get_count_order() but accepts a long type parameter
- * or 0 is returned if @l == 0UL
- */
-static inline int get_count_order_long(unsigned long l)
-{
-	if (l == 0UL)
-		return 0;
-	else if (l & (l - 1UL))
-		return fls_long(l);
-	else
-		return fls_long(l) - 1;
-}
-
 static __always_inline unsigned long hweight_long(unsigned long w)
 {
 	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
@@ -208,6 +191,22 @@ static inline unsigned fls_long(unsigned long l)
 	return fls64(l);
 }
 
+/**
+ * get_count_order_long - get order after rounding @l up to power of 2
+ * @l: parameter
+ *
+ * it is same as get_count_order() but with long type parameter
+ */
+static inline int get_count_order_long(unsigned long l)
+{
+	if (l == 0UL)
+		return -1;
+	else if (l & (l - 1UL))
+		return (int)fls_long(l);
+	else
+		return (int)fls_long(l) - 1;
+}
+
 /**
  * __ffs64 - find first set bit in a 64 bit word
  * @word: The 64 bit word
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 08032de13ebe..80660a0f989b 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1359,14 +1359,14 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
 	struct vm_struct *area;
 
 	BUG_ON(in_interrupt());
-	if (flags & VM_IOREMAP)
-		align = 1ul << clamp_t(int, get_count_order_long(size),
-				       PAGE_SHIFT, IOREMAP_MAX_ORDER);
-
 	size = PAGE_ALIGN(size);
 	if (unlikely(!size))
 		return NULL;
 
+	if (flags & VM_IOREMAP)
+		align = 1ul << clamp_t(int, get_count_order_long(size),
+				       PAGE_SHIFT, IOREMAP_MAX_ORDER);
+
 	area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
 	if (unlikely(!area))
 		return NULL;