[PATCH mm-unstable v2 05/16] mm: arc: Use generic_mmap_hint()

[Kalesh Singh]

Introduce arc arch_mmap_hint() and define HAVE_ARCH_MMAP_HINT.
This is a preparatory patch, no functional change is introduced.

Signed-off-by: Kalesh Singh <kaleshsi...@google.com>
---

Changes in v2:
  - MAP_FIXED case is also handled in arch_mmap_hint() since this is just a
    special case of the hint addr being "enforced", per Yang Shi.
  - Consolidate error handling in arch_mmap_hint().

 arch/arc/include/asm/pgtable.h |  1 +
 arch/arc/mm/mmap.c             | 43 +++++++++++++++++-----------------
 2 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 4cf45a99fd79..af3210ea4888 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -28,6 +28,7 @@ extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE);
 
 /* to cope with aliasing VIPT cache */
 #define HAVE_ARCH_UNMAPPED_AREA
+#define HAVE_ARCH_MMAP_HINT
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/arc/mm/mmap.c b/arch/arc/mm/mmap.c
index 2185afe8d59f..df01d4d9964b 100644
--- a/arch/arc/mm/mmap.c
+++ b/arch/arc/mm/mmap.c
@@ -14,6 +14,26 @@
 
 #include <asm/cacheflush.h>
 
+unsigned long arch_mmap_hint(struct file *filp, unsigned long addr,
+                            unsigned long len, unsigned long pgoff,
+                            unsigned long flags)
+{
+       if (len > TASK_SIZE)
+               return -ENOMEM;
+
+       /*
+        * We enforce the MAP_FIXED case.
+        */
+       if (flags & MAP_FIXED) {
+               if (flags & MAP_SHARED &&
+                   (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
+                       return -EINVAL;
+               return addr;
+       }
+
+       return generic_mmap_hint(filp, addr, len, pgoff, flags);
+}
+
 /*
  * Ensure that shared mappings are correctly aligned to
  * avoid aliasing issues with VIPT caches.
@@ -27,30 +47,11 @@ arch_get_unmapped_area(struct file *filp, unsigned long 
addr,
                unsigned long flags, vm_flags_t vm_flags)
 {
        struct mm_struct *mm = current->mm;
-       struct vm_area_struct *vma;
        struct vm_unmapped_area_info info = {};
 
-       /*
-        * We enforce the MAP_FIXED case.
-        */
-       if (flags & MAP_FIXED) {
-               if (flags & MAP_SHARED &&
-                   (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
-                       return -EINVAL;
+       addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+       if (addr)
                return addr;
-       }
-
-       if (len > TASK_SIZE)
-               return -ENOMEM;
-
-       if (addr) {
-               addr = PAGE_ALIGN(addr);
-
-               vma = find_vma(mm, addr);
-               if (TASK_SIZE - len >= addr &&
-                   (!vma || addr + len <= vm_start_gap(vma)))
-                       return addr;
-       }
 
        info.length = len;
        info.low_limit = mm->mmap_base;
-- 
2.47.0.338.g60cca15819-goog