[PATCH mm-unstable 14/17] mm: xtensa: Introduce arch_mmap_hint()

[Kalesh Singh]

Introduce xtensa arch_mmap_hint() and define HAVE_ARCH_MMAP_HINT.

If a sufficiently sized hole doesn't exist at the hint address,
fallback to searching the entire valid VA space instead of only
the VA space above the hint address.

Signed-off-by: Kalesh Singh <kaleshsingh at google.com>
---
 arch/xtensa/include/asm/pgtable.h |  1 +
 arch/xtensa/kernel/syscall.c      | 26 ++++++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 1647a7cc3fbf..31b7da0805ec 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -425,5 +425,6 @@ void update_mmu_tlb_range(struct vm_area_struct *vma,
  * SHM area cache aliasing for userland.
  */
 #define HAVE_ARCH_UNMAPPED_AREA
+#define HAVE_ARCH_MMAP_HINT
 
 #endif /* _XTENSA_PGTABLE_H */
diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index dc54f854c2f5..353cce1ac9f1 100644
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -54,6 +54,24 @@ asmlinkage long xtensa_fadvise64_64(int fd, int advice,
 }
 
 #ifdef CONFIG_MMU
+unsigned long arch_mmap_hint(struct file *filp, unsigned long addr,
+			     unsigned long len, unsigned long pgoff,
+			     unsigned long flags)
+{
+	if (!addr)
+		return 0;
+
+	if (len > TASK_SIZE)
+		return 0;
+
+	if (flags & MAP_SHARED)
+		addr = COLOUR_ALIGN(addr, pgoff);
+	else
+		addr = PAGE_ALIGN(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)
@@ -73,8 +91,12 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 
 	if (len > TASK_SIZE)
 		return -ENOMEM;
-	if (!addr)
-		addr = TASK_UNMAPPED_BASE;
+
+	addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+	if (addr)
+		return addr;
+
+	addr = TASK_UNMAPPED_BASE;
 
 	if (flags & MAP_SHARED)
 		addr = COLOUR_ALIGN(addr, pgoff);
-- 
2.47.0.338.g60cca15819-goog