[PATCH mm-unstable v2 10/16] mm: s390: Use generic_mmap_hint()

[Kalesh Singh <kaleshsingh@xxxxxxxxxx>]

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@xxxxxxxxxx>
---

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/s390/include/asm/pgtable.h |  1 +
 arch/s390/mm/mmap.c             | 51 +++++++++++++++------------------
 2 files changed, 24 insertions(+), 28 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..8afb046605c9 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -83,28 +83,33 @@ 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)
+{
+	/* requested length too big for entire address space */
+	if (len > TASK_SIZE - mmap_min_addr)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED)
+		return addr;
+
+	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)
-		return -ENOMEM;
-
-	if (flags & MAP_FIXED)
+	addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+	if (IS_ERR_VALUE(addr))
+		return addr;
+	if (addr)
 		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;
-	}
-
 	info.length = len;
 	info.low_limit = mm->mmap_base;
 	info.high_limit = TASK_SIZE;
@@ -123,25 +128,15 @@ 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 = {};
 
-	/* requested length too big for entire address space */
-	if (len > TASK_SIZE - mmap_min_addr)
-		return -ENOMEM;
-
-	if (flags & MAP_FIXED)
-		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 (IS_ERR_VALUE(addr))
+		return addr;
+	if (addr)
+		goto check_asce_limit;
 
 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 	info.length = len;
-- 
2.47.0.338.g60cca15819-goog