[PATCH mm-unstable 15/17] mm: powerpc: Introduce arch_mmap_hint()

[Kalesh Singh <kaleshsingh@google.com>]

Introduce powerpc 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>
---
 arch/powerpc/include/asm/book3s/64/slice.h |  1 +
 arch/powerpc/mm/book3s64/slice.c           | 31 ++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/slice.h b/arch/powerpc/include/asm/book3s/64/slice.h
index 5fbe18544cbd..89f629080e90 100644
--- a/arch/powerpc/include/asm/book3s/64/slice.h
+++ b/arch/powerpc/include/asm/book3s/64/slice.h
@@ -10,6 +10,7 @@
 #endif
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#define HAVE_ARCH_MMAP_HINT
 #endif
 
 #define SLICE_LOW_SHIFT		28
diff --git a/arch/powerpc/mm/book3s64/slice.c b/arch/powerpc/mm/book3s64/slice.c
index bc9a39821d1c..70b95968301a 100644
--- a/arch/powerpc/mm/book3s64/slice.c
+++ b/arch/powerpc/mm/book3s64/slice.c
@@ -647,6 +647,37 @@ static int file_to_psize(struct file *file)
 }
 #endif
 
+static unsigned long slice_mmap_hint(unsigned long addr, unsigned long len,
+				     unsigned long flags, unsigned int psize)
+{
+	unsigned long hint_addr = slice_get_unmapped_area(addr, len, flags, psize, 0);
+
+	if (IS_ERR_VALUE(hint_addr) || hint_addr != PAGE_ALIGN(addr))
+		return 0;
+
+	return hint_addr;
+}
+
+unsigned long arch_mmap_hint(struct file *filp, unsigned long addr,
+			     unsigned long len, unsigned long pgoff,
+			     unsigned long flags)
+{
+	unsigned int psize;
+
+	if (!addr)
+		return 0;
+
+	if (radix_enabled())
+		return generic_mmap_hint(filp, addr, len, pgoff, flags);
+
+	if (filp && is_file_hugepages(filp))
+		psize = file_to_psize(filp);
+	else
+		psize = mm_ctx_user_psize(&current->mm->context);
+
+	return slice_mmap_hint(addr, len, flags, psize);
+}
+
 unsigned long arch_get_unmapped_area(struct file *filp,
 				     unsigned long addr,
 				     unsigned long len,
-- 
2.47.0.338.g60cca15819-goog