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

[Kalesh Singh <kaleshsingh@google.com>]

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 <kaleshsingh@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