[PATCH mm-unstable v2 09/16] mm: parisc: Introduce arch_align_mmap_hint()

[Kalesh Singh]

Introduce parisc 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/parisc/include/asm/pgtable.h |  1 +
 arch/parisc/kernel/sys_parisc.c   | 53 +++++++++++++++++--------------
 2 files changed, 31 insertions(+), 23 deletions(-)

diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index babf65751e81..73987357c78e 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -505,6 +505,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
 
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#define HAVE_ARCH_MMAP_HINT
 
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index f852fe274abe..c1702d481e33 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -96,24 +96,16 @@ unsigned long mmap_upper_limit(struct rlimit *rlim_stack)
 
 enum mmap_allocation_direction {UP, DOWN};
 
-static unsigned long arch_get_unmapped_area_common(struct file *filp,
-	unsigned long addr, unsigned long len, unsigned long pgoff,
-	unsigned long flags, enum mmap_allocation_direction dir)
+unsigned long arch_mmap_hint(struct file *filp, unsigned long addr,
+			     unsigned long len, unsigned long pgoff,
+			     unsigned long flags)
 {
-	struct mm_struct *mm = current->mm;
-	struct vm_area_struct *vma, *prev;
 	unsigned long filp_pgoff;
-	int do_color_align;
-	struct vm_unmapped_area_info info = {
-		.length = len
-	};
+	bool do_color_align;
 
 	if (unlikely(len > TASK_SIZE))
 		return -ENOMEM;
 
-	do_color_align = 0;
-	if (filp || (flags & MAP_SHARED))
-		do_color_align = 1;
 	filp_pgoff = GET_FILP_PGOFF(filp);
 
 	if (flags & MAP_FIXED) {
@@ -128,18 +120,33 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 		return addr;
 	}
 
-	if (addr) {
-		if (do_color_align)
-			addr = COLOR_ALIGN(addr, filp_pgoff, pgoff);
-		else
-			addr = PAGE_ALIGN(addr);
+	do_color_align = filp || (flags & MAP_SHARED);
 
-		vma = find_vma_prev(mm, addr, &prev);
-		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vm_start_gap(vma)) &&
-		    (!prev || addr >= vm_end_gap(prev)))
-			return addr;
-	}
+	if (do_color_align)
+		addr = COLOR_ALIGN(addr, filp_pgoff, pgoff);
+	else
+		addr = PAGE_ALIGN(addr);
+
+	return generic_mmap_hint(filp, addr, len, pgoff, flags);
+}
+
+static unsigned long arch_get_unmapped_area_common(struct file *filp,
+	unsigned long addr, unsigned long len, unsigned long pgoff,
+	unsigned long flags, enum mmap_allocation_direction dir)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long filp_pgoff;
+	bool do_color_align;
+	struct vm_unmapped_area_info info = {
+		.length = len
+	};
+
+	addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+	if (addr)
+		return addr;
+
+	filp_pgoff = GET_FILP_PGOFF(filp);
+	do_color_align = filp || (flags & MAP_SHARED);
 
 	info.align_mask = do_color_align ? (PAGE_MASK & (SHM_COLOUR - 1)) : 0;
 	info.align_offset = shared_align_offset(filp_pgoff, pgoff);
-- 
2.47.0.338.g60cca15819-goog