[PATCH] mm/mmap.c: remove incorrect MAP_FIXED flag comparison from mmap_region

From: Piotr Kwapulinski
Date: Tue Nov 17 2015 - 12:27:25 EST


The following flag comparison in mmap_region is not fully correct:

if (!(vm_flags & MAP_FIXED))

The vm_flags should not be compared with MAP_FIXED (0x10). It is a bit
confusing. This condition is almost always true since VM_MAYREAD (0x10)
flag is almost always set by default. This patch removes this condition.

Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@xxxxxxxxx>
---
mm/mmap.c | 7 -------
1 file changed, 7 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 2ce04a6..02422ea 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1547,13 +1547,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
if (!may_expand_vm(mm, len >> PAGE_SHIFT)) {
unsigned long nr_pages;

- /*
- * MAP_FIXED may remove pages of mappings that intersects with
- * requested mapping. Account for the pages it would unmap.
- */
- if (!(vm_flags & MAP_FIXED))
- return -ENOMEM;
-
nr_pages = count_vma_pages_range(mm, addr, addr + len);

if (!may_expand_vm(mm, (len >> PAGE_SHIFT) - nr_pages))
--
2.6.2

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