Introduce sh arch_mmap_hint() and define HAVE_ARCH_MMAP_HINT.
This is a preparatory patch, no functional change is introduced.
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/sh/include/asm/pgtable.h |  1 +
 arch/sh/mm/mmap.c             | 83 ++++++++++++++---------------------
 2 files changed, 33 insertions(+), 51 deletions(-)

diff --git a/arch/sh/include/asm/pgtable.h b/arch/sh/include/asm/pgtable.h
index 729f5c6225fb..072dbe038808 100644
--- a/arch/sh/include/asm/pgtable.h
+++ b/arch/sh/include/asm/pgtable.h
@@ -149,5 +149,6 @@ static inline bool pte_access_permitted(pte_t pte, bool 
write)
 /* arch/sh/mm/mmap.c */
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
+#define HAVE_ARCH_MMAP_HINT
 
 #endif /* __ASM_SH_PGTABLE_H */
diff --git a/arch/sh/mm/mmap.c b/arch/sh/mm/mmap.c
index c442734d9b0c..ebda962e8c4e 100644
--- a/arch/sh/mm/mmap.c
+++ b/arch/sh/mm/mmap.c
@@ -51,14 +51,14 @@ static inline unsigned long COLOUR_ALIGN(unsigned long addr,
        return base + off;
 }
 
-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;
-       int do_colour_align;
-       struct vm_unmapped_area_info info = {};
+       bool do_colour_align;
+
+       if (unlikely(len > TASK_SIZE))
+               return -ENOMEM;
 
        if (flags & MAP_FIXED) {
                /* We do not accept a shared mapping if it would violate
@@ -70,24 +70,29 @@ unsigned long arch_get_unmapped_area(struct file *filp, 
unsigned long addr,
                return addr;
        }
 
-       if (unlikely(len > TASK_SIZE))
-               return -ENOMEM;
+       do_colour_align = filp || (flags & MAP_SHARED);
 
-       do_colour_align = 0;
-       if (filp || (flags & MAP_SHARED))
-               do_colour_align = 1;
+       if (do_colour_align)
+               addr = COLOUR_ALIGN(addr, pgoff);
+       else
+               addr = PAGE_ALIGN(addr);
 
-       if (addr) {
-               if (do_colour_align)
-                       addr = COLOUR_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 = {};
+       bool do_colour_align;
+
+       addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+       if (addr)
+               return addr;
+
+       do_colour_align = filp || (flags & MAP_SHARED);
 
        info.length = len;
        info.low_limit = TASK_UNMAPPED_BASE;
@@ -102,41 +107,17 @@ 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 addr = addr0;
-       int do_colour_align;
        struct vm_unmapped_area_info info = {};
+       bool do_colour_align;
 
-       if (flags & MAP_FIXED) {
-               /* We do not accept a shared mapping if it would violate
-                * cache aliasing constraints.
-                */
-               if ((flags & MAP_SHARED) &&
-                   ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
-                       return -EINVAL;
+       /* requesting a specific address */
+       addr = arch_mmap_hint(filp, addr, len, pgoff, flags);
+       if (addr)
                return addr;
-       }
 
-       if (unlikely(len > TASK_SIZE))
-               return -ENOMEM;
-
-       do_colour_align = 0;
-       if (filp || (flags & MAP_SHARED))
-               do_colour_align = 1;
-
-       /* requesting a specific address */
-       if (addr) {
-               if (do_colour_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;
-       }
+       do_colour_align = filp || (flags & MAP_SHARED);
 
        info.flags = VM_UNMAPPED_AREA_TOPDOWN;
        info.length = len;
-- 
2.47.0.338.g60cca15819-goog


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