[PATCH mm-unstable 10/17] mm: s390: Introduce arch_mmap_hint()

[Kalesh Singh]

Introduce s390 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>
---
 arch/s390/include/asm/pgtable.h |  1 +
 arch/s390/mm/mmap.c             | 32 ++++++++++++++++----------------
 2 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 48268095b0a3..eaecb558ab9b 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1997,6 +1997,7 @@ extern void s390_reset_cmma(struct mm_struct *mm);
 /* s390 has a private copy of get unmapped area to deal with cache synonyms */
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#define HAVE_ARCH_MMAP_HINT
 
 #define pmd_pgtable(pmd) \
 	((pgtable_t)__va(pmd_val(pmd) & -sizeof(pte_t)*PTRS_PER_PTE))
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 33f3504be90b..3f82401b77cd 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -83,12 +83,21 @@ static int get_align_mask(struct file *filp, unsigned long flags)
 	return 0;
 }
 
+unsigned long arch_mmap_hint(struct file *filp, unsigned long addr,
+			     unsigned long len, unsigned long pgoff,
+			     unsigned long flags)
+{
+	if (len > TASK_SIZE - mmap_min_addr)
+		return 0;
+
+	return generic_mmap_hint(filp, addr, len, pgoff, flags);
+}
+
 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 				     unsigned long len, unsigned long pgoff,
 				     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 = {};
 
 	if (len > TASK_SIZE - mmap_min_addr)
@@ -97,13 +106,9 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	if (flags & MAP_FIXED)
 		goto check_asce_limit;
 
-	if (addr) {
-		addr = PAGE_ALIGN(addr);
-		vma = find_vma(mm, addr);
-		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
-		    (!vma || addr + len <= vm_start_gap(vma)))
-			goto check_asce_limit;
-	}
+	addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+	if (addr)
+		goto check_asce_limit;
 
 	info.length = len;
 	info.low_limit = mm->mmap_base;
@@ -123,7 +128,6 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, unsigned long ad
 					     unsigned long len, unsigned long pgoff,
 					     unsigned long flags, vm_flags_t vm_flags)
 {
-	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;
 	struct vm_unmapped_area_info info = {};
 
@@ -135,13 +139,9 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, unsigned long ad
 		goto check_asce_limit;
 
 	/* requesting a specific address */
-	if (addr) {
-		addr = PAGE_ALIGN(addr);
-		vma = find_vma(mm, addr);
-		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
-				(!vma || addr + len <= vm_start_gap(vma)))
-			goto check_asce_limit;
-	}
+	addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+	if (addr)
+		goto check_asce_limit;
 
 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 	info.length = len;
-- 
2.47.0.338.g60cca15819-goog