[PATCH mm-unstable v2 14/16] 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 <kaleshsi...@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/xtensa/kernel/syscall.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index dc54f854c2f5..6bbe10c2a633 100644
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -54,12 +54,12 @@ asmlinkage long xtensa_fadvise64_64(int fd, int advice,
 }
 
 #ifdef CONFIG_MMU
-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 vm_area_struct *vmm;
-       struct vma_iterator vmi;
+       if (len > TASK_SIZE)
+               return -ENOMEM;
 
        if (flags & MAP_FIXED) {
                /* We do not accept a shared mapping if it would violate
@@ -71,16 +71,27 @@ unsigned long arch_get_unmapped_area(struct file *filp, 
unsigned long addr,
                return addr;
        }
 
-       if (len > TASK_SIZE)
-               return -ENOMEM;
-       if (!addr)
-               addr = TASK_UNMAPPED_BASE;
-
        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)
+{
+       struct vm_area_struct *vmm;
+       struct vma_iterator vmi;
+
+       addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+       if (addr)
+               return addr;
+
+       addr = TASK_UNMAPPED_BASE;
+
        vma_iter_init(&vmi, current->mm, addr);
        for_each_vma(vmi, vmm) {
                /* At this point:  (addr < vmm->vm_end). */
-- 
2.47.0.338.g60cca15819-goog