mm: use vm_unmapped_area() on sparc64 architecture

Update the sparc64 arch_get_unmapped_area[_topdown] functions to make use
of vm_unmapped_area() instead of implementing a brute force search.

[akpm@linux-foundation.org: remove now-unused COLOUR_ALIGN_DOWN()]
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 114 deletions

diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 878ef3d5fec5..59b66b739bf0 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -84,24 +84,13 @@ static inline unsigned long COLOUR_ALIGN(unsigned long addr,
         return base + off;
 }
 
-static inline unsigned long COLOUR_ALIGN_DOWN(unsigned long addr,
-                                              unsigned long pgoff)
-{
-        unsigned long base = addr & ~(SHMLBA-1);
-        unsigned long off = (pgoff<<PAGE_SHIFT) & (SHMLBA-1);
-
-        if (base + off <= addr)
-                return base + off;
-        return base - off;
-}
-
 unsigned long arch_get_unmapped_area(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;
-        unsigned long start_addr;
         int do_color_align;
+        struct vm_unmapped_area_info info;
 
         if (flags & MAP_FIXED) {
                 /* We do not accept a shared mapping if it would violate
@@ -134,50 +123,22 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
                         return addr;
         }
 
-        if (len > mm->cached_hole_size) {
-                start_addr = addr = mm->free_area_cache;
-        } else {
-                start_addr = addr = TASK_UNMAPPED_BASE;
-                mm->cached_hole_size = 0;
+        info.flags = 0;
+        info.length = len;
+        info.low_limit = TASK_UNMAPPED_BASE;
+        info.high_limit = min(task_size, VA_EXCLUDE_START);
+        info.align_mask = do_color_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+        info.align_offset = pgoff << PAGE_SHIFT;
+        addr = vm_unmapped_area(&info);
+
+        if ((addr & ~PAGE_MASK) && task_size > VA_EXCLUDE_END) {
+                VM_BUG_ON(addr != -ENOMEM);
+                info.low_limit = VA_EXCLUDE_END;
+                info.high_limit = task_size;
+                addr = vm_unmapped_area(&info);
         }
 
-        task_size -= len;
-
-full_search:
-        if (do_color_align)
-                addr = COLOUR_ALIGN(addr, pgoff);
-        else
-                addr = PAGE_ALIGN(addr);
-
-        for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
-                /* At this point:  (!vma || addr < vma->vm_end). */
-                if (addr < VA_EXCLUDE_START &&
-                    (addr + len) >= VA_EXCLUDE_START) {
-                        addr = VA_EXCLUDE_END;
-                        vma = find_vma(mm, VA_EXCLUDE_END);
-                }
-                if (unlikely(task_size < addr)) {
-                        if (start_addr != TASK_UNMAPPED_BASE) {
-                                start_addr = addr = TASK_UNMAPPED_BASE;
-                                mm->cached_hole_size = 0;
-                                goto full_search;
-                        }
-                        return -ENOMEM;
-                }
-                if (likely(!vma || addr + len <= vma->vm_start)) {
-                        /*
-                         * Remember the place where we stopped the search:
-                         */
-                        mm->free_area_cache = addr + len;
-                        return addr;
-                }
-                if (addr + mm->cached_hole_size < vma->vm_start)
-                        mm->cached_hole_size = vma->vm_start - addr;
-
-                addr = vma->vm_end;
-                if (do_color_align)
-                        addr = COLOUR_ALIGN(addr, pgoff);
-        }
+        return addr;
 }
 
 unsigned long
@@ -190,6 +151,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
         unsigned long task_size = STACK_TOP32;
         unsigned long addr = addr0;
         int do_color_align;
+        struct vm_unmapped_area_info info;
 
         /* This should only ever run for 32-bit processes.  */
         BUG_ON(!test_thread_flag(TIF_32BIT));
@@ -224,73 +186,27 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
                         return addr;
         }
 
-        /* check if free_area_cache is useful for us */
-        if (len <= mm->cached_hole_size) {
-                mm->cached_hole_size = 0;
-                mm->free_area_cache = mm->mmap_base;
-        }
+        info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+        info.length = len;
+        info.low_limit = PAGE_SIZE;
+        info.high_limit = mm->mmap_base;
+        info.align_mask = do_color_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+        info.align_offset = pgoff << PAGE_SHIFT;
+        addr = vm_unmapped_area(&info);
 
-        /* either no address requested or can't fit in requested address hole */
-        addr = mm->free_area_cache;
-        if (do_color_align) {
-                unsigned long base = COLOUR_ALIGN_DOWN(addr-len, pgoff);
-
-                addr = base + len;
-        }
-
-        /* make sure it can fit in the remaining address space */
-        if (likely(addr > len)) {
-                vma = find_vma(mm, addr-len);
-                if (!vma || addr <= vma->vm_start) {
-                        /* remember the address as a hint for next time */
-                        return (mm->free_area_cache = addr-len);
-                }
-        }
-
-        if (unlikely(mm->mmap_base < len))
-                goto bottomup;
-
-        addr = mm->mmap_base-len;
-        if (do_color_align)
-                addr = COLOUR_ALIGN_DOWN(addr, pgoff);
-
-        do {
-                /*
-                 * Lookup failure means no vma is above this address,
-                 * else if new region fits below vma->vm_start,
-                 * return with success:
-                 */
-                vma = find_vma(mm, addr);
-                if (likely(!vma || addr+len <= vma->vm_start)) {
-                        /* remember the address as a hint for next time */
-                        return (mm->free_area_cache = addr);
-                }
-
-                /* remember the largest hole we saw so far */
-                if (addr + mm->cached_hole_size < vma->vm_start)
-                        mm->cached_hole_size = vma->vm_start - addr;
-
-                /* try just below the current vma->vm_start */
-                addr = vma->vm_start-len;
-                if (do_color_align)
-                        addr = COLOUR_ALIGN_DOWN(addr, pgoff);
-        } while (likely(len < vma->vm_start));
-
-bottomup:
         /*
          * A failed mmap() very likely causes application failure,
          * so fall back to the bottom-up function here. This scenario
          * can happen with large stack limits and large mmap()
          * allocations.
          */
-        mm->cached_hole_size = ~0UL;
-        mm->free_area_cache = TASK_UNMAPPED_BASE;
-        addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
-        /*
-         * Restore the topdown base:
-         */
-        mm->free_area_cache = mm->mmap_base;
-        mm->cached_hole_size = ~0UL;
+        if (addr & ~PAGE_MASK) {
+                VM_BUG_ON(addr != -ENOMEM);
+                info.flags = 0;
+                info.low_limit = TASK_UNMAPPED_BASE;
+                info.high_limit = STACK_TOP32;
+                addr = vm_unmapped_area(&info);
+        }
 
         return addr;
 }