[PATCH mm-unstable v2 07/16] mm: loongarch: Introduce arch_mmap_hint()

[Kalesh Singh <kaleshsingh@xxxxxxxxxx>]

Introduce loongarch 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/loongarch/include/asm/pgtable.h |  1 +
 arch/loongarch/mm/mmap.c             | 49 +++++++++++++++-------------
 2 files changed, 28 insertions(+), 22 deletions(-)

diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index da346733a1da..326a6c4b7488 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -624,6 +624,7 @@ static inline long pmd_protnone(pmd_t pmd)
  */
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#define HAVE_ARCH_MMAP_HINT
 
 #endif /* !__ASSEMBLY__ */
 
diff --git a/arch/loongarch/mm/mmap.c b/arch/loongarch/mm/mmap.c
index 914e82ff3f65..9e57bb27642f 100644
--- a/arch/loongarch/mm/mmap.c
+++ b/arch/loongarch/mm/mmap.c
@@ -17,15 +17,11 @@
 
 enum mmap_allocation_direction {UP, DOWN};
 
-static unsigned long arch_get_unmapped_area_common(struct file *filp,
-	unsigned long addr0, 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;
-	unsigned long addr = addr0;
-	int do_color_align;
-	struct vm_unmapped_area_info info = {};
+	bool do_color_align;
 
 	if (unlikely(len > TASK_SIZE))
 		return -ENOMEM;
@@ -45,22 +41,31 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
 		return addr;
 	}
 
-	do_color_align = 0;
-	if (filp || (flags & MAP_SHARED))
-		do_color_align = 1;
+	do_color_align = filp || (flags & MAP_SHARED);
+
+	if (do_color_align)
+		addr = COLOUR_ALIGN(addr, 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 addr0, unsigned long len, unsigned long pgoff,
+	unsigned long flags, enum mmap_allocation_direction dir)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long addr = addr0;
+	bool do_color_align;
+	struct vm_unmapped_area_info info = {};
 
 	/* requesting a specific address */
-	if (addr) {
-		if (do_color_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;
-	}
+	addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+	if (addr)
+		return addr;
+
+	do_color_align = filp || (flags & MAP_SHARED);
 
 	info.length = len;
 	info.align_mask = do_color_align ? (PAGE_MASK & SHM_ALIGN_MASK) : 0;
-- 
2.47.0.338.g60cca15819-goog