[PATCH mm-unstable v2 13/16] mm: sparc64: Introduce arch_mmap_hint()

[Kalesh Singh <kaleshsingh@google.com>]

Introduce sparc64 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>
---

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/sparc/include/asm/pgtable_64.h |  1 +
 arch/sparc/kernel/sys_sparc_64.c    | 96 +++++++++++------------------
 2 files changed, 37 insertions(+), 60 deletions(-)

diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 2b7f358762c1..f24a4eb2777b 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -1148,6 +1148,7 @@ static inline bool pte_access_permitted(pte_t pte, bool write)
  */
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#define HAVE_ARCH_MMAP_HINT
 
 /* We provide a special get_unmapped_area for framebuffer mmaps to try and use
  * the largest alignment possible such that larget PTEs can be used.
diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index c5a284df7b41..e44d55b30a84 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -98,17 +98,19 @@ static unsigned long get_align_mask(struct file *filp, unsigned long flags)
 	return 0;
 }
 
-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)
+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;
-	unsigned long task_size = TASK_SIZE;
-	int do_color_align;
-	struct vm_unmapped_area_info info = {};
-	bool file_hugepage = false;
+	unsigned long task_size;
+	bool do_color_align;
+	bool file_hugepage;
 
-	if (filp && is_file_hugepages(filp))
-		file_hugepage = true;
+	task_size = test_thread_flag(TIF_32BIT) ? STACK_TOP32 : TASK_SIZE;
+	if (unlikely(len > task_size || len >= VA_EXCLUDE_START))
+		return -ENOMEM;
+
+	file_hugepage = filp && is_file_hugepages(filp);
 
 	if (flags & MAP_FIXED) {
 		/* We do not accept a shared mapping if it would violate
@@ -120,26 +122,29 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
 		return addr;
 	}
 
-	if (test_thread_flag(TIF_32BIT))
-		task_size = STACK_TOP32;
-	if (unlikely(len > task_size || len >= VA_EXCLUDE_START))
-		return -ENOMEM;
+	do_color_align = (filp || (flags & MAP_SHARED)) && !file_hugepage;
 
-	do_color_align = 0;
-	if ((filp || (flags & MAP_SHARED)) && !file_hugepage)
-		do_color_align = 1;
+	if (do_color_align)
+		addr = COLOR_ALIGN(addr, pgoff);
+	else
+		addr = PAGE_ALIGN(addr);
 
-	if (addr) {
-		if (do_color_align)
-			addr = COLOR_ALIGN(addr, pgoff);
-		else
-			addr = PAGE_ALIGN(addr);
+	return generic_mmap_hint(filp, addr, len, pgoff, flags);
+}
 
-		vma = find_vma(mm, addr);
-		if (task_size - len >= addr &&
-		    (!vma || addr + len <= vm_start_gap(vma)))
-			return addr;
-	}
+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 vm_unmapped_area_info info = {};
+	unsigned long task_size;
+	bool file_hugepage;
+
+	addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+	if (addr)
+		return addr;
+
+	task_size = test_thread_flag(TIF_32BIT) ? STACK_TOP32 : TASK_SIZE;
+	file_hugepage = filp && is_file_hugepages(filp);
 
 	info.length = len;
 	info.low_limit = TASK_UNMAPPED_BASE;
@@ -164,49 +169,20 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 			  const unsigned long len, const unsigned long pgoff,
 			  const unsigned long flags, vm_flags_t vm_flags)
 {
-	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;
-	unsigned long task_size = STACK_TOP32;
 	unsigned long addr = addr0;
-	int do_color_align;
 	struct vm_unmapped_area_info info = {};
-	bool file_hugepage = false;
+	bool file_hugepage;
 
 	/* This should only ever run for 32-bit processes.  */
 	BUG_ON(!test_thread_flag(TIF_32BIT));
 
-	if (filp && is_file_hugepages(filp))
-		file_hugepage = true;
-
-	if (flags & MAP_FIXED) {
-		/* We do not accept a shared mapping if it would violate
-		 * cache aliasing constraints.
-		 */
-		if (!file_hugepage && (flags & MAP_SHARED) &&
-		    ((addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)))
-			return -EINVAL;
-		return addr;
-	}
-
-	if (unlikely(len > task_size))
-		return -ENOMEM;
-
-	do_color_align = 0;
-	if ((filp || (flags & MAP_SHARED)) && !file_hugepage)
-		do_color_align = 1;
-
 	/* requesting a specific address */
-	if (addr) {
-		if (do_color_align)
-			addr = COLOR_ALIGN(addr, pgoff);
-		else
-			addr = PAGE_ALIGN(addr);
+	addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+	if (addr)
+		return addr;
 
-		vma = find_vma(mm, addr);
-		if (task_size - len >= addr &&
-		    (!vma || addr + len <= vm_start_gap(vma)))
-			return addr;
-	}
+	file_hugepage = filp && is_file_hugepages(filp);
 
 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 	info.length = len;
-- 
2.47.0.338.g60cca15819-goog