[PATCH mm-unstable v2 06/16] mm: csky: Introduce arch_mmap_hint()

[Kalesh Singh]

Introduce csky 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 at 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/csky/abiv1/inc/abi/pgtable-bits.h |  1 +
 arch/csky/abiv1/mmap.c                 | 68 ++++++++++++++------------
 2 files changed, 38 insertions(+), 31 deletions(-)

diff --git a/arch/csky/abiv1/inc/abi/pgtable-bits.h b/arch/csky/abiv1/inc/abi/pgtable-bits.h
index ae7a2f76dd42..c346a9fcb522 100644
--- a/arch/csky/abiv1/inc/abi/pgtable-bits.h
+++ b/arch/csky/abiv1/inc/abi/pgtable-bits.h
@@ -51,5 +51,6 @@
 					((offset) << 10)})
 
 #define HAVE_ARCH_UNMAPPED_AREA
+#define HAVE_ARCH_MMAP_HINT
 
 #endif /* __ASM_CSKY_PGTABLE_BITS_H */
diff --git a/arch/csky/abiv1/mmap.c b/arch/csky/abiv1/mmap.c
index 1047865e82a9..0c5c51a081e4 100644
--- a/arch/csky/abiv1/mmap.c
+++ b/arch/csky/abiv1/mmap.c
@@ -13,6 +13,39 @@
 	((((addr)+SHMLBA-1)&~(SHMLBA-1)) +	\
 	 (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
 
+unsigned long arch_mmap_hint(struct file *filp, unsigned long addr,
+			     unsigned long len, unsigned long pgoff,
+			     unsigned long flags)
+{
+	bool do_align;
+
+	if (len > TASK_SIZE)
+		return -ENOMEM;
+
+	/*
+	 * We only need to do colour alignment if either the I or D
+	 * caches alias.
+	 */
+	do_align = filp || (flags & MAP_SHARED);
+
+	/*
+	 * We enforce the MAP_FIXED case.
+	 */
+	if (flags & MAP_FIXED) {
+		if (flags & MAP_SHARED &&
+		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
+			return -EINVAL;
+		return addr;
+	}
+
+	if (do_align)
+		addr = COLOUR_ALIGN(addr, pgoff);
+	else
+		addr = PAGE_ALIGN(addr);
+
+	return generic_mmap_hint(filp, addr, len, pgoff, flags);
+}
+
 /*
  * We need to ensure that shared mappings are correctly aligned to
  * avoid aliasing issues with VIPT caches.  We need to ensure that
@@ -27,8 +60,7 @@ 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;
-	int do_align = 0;
+	bool do_align;
 	struct vm_unmapped_area_info info = {
 		.length = len,
 		.low_limit = mm->mmap_base,
@@ -36,37 +68,11 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		.align_offset = pgoff << PAGE_SHIFT
 	};
 
-	/*
-	 * We only need to do colour alignment if either the I or D
-	 * caches alias.
-	 */
-	do_align = filp || (flags & MAP_SHARED);
-
-	/*
-	 * 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) {
-		if (do_align)
-			addr = COLOUR_ALIGN(addr, pgoff);
-		else
-			addr = PAGE_ALIGN(addr);
-
-		vma = find_vma(mm, addr);
-		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vm_start_gap(vma)))
-			return addr;
-	}
 
+	do_align = filp || (flags & MAP_SHARED);
 	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
 	return vm_unmapped_area(&info);
 }
-- 
2.47.0.338.g60cca15819-goog