mm: larger stack guard gap, between vmas

[pandora-kernel.git] / arch / parisc / kernel / sys_parisc.c

diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 7ea75d1..1d4ac8d 100644 (file)
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -35,17 +35,27 @@
 
 static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
 {
-       struct vm_area_struct *vma;
+       struct vm_area_struct *vma, *prev;
+       unsigned long prev_end;
 
        addr = PAGE_ALIGN(addr);
 
-       for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
+       for (vma = find_vma_prev(current->mm, addr, &prev); ; prev = vma,
+                                                       vma = vma->vm_next) {
+               if (prev) {
+                       prev_end = vm_end_gap(prev);
+                       if (addr < prev_end) {
+                               addr = prev_end;
+                               /* If vma already violates gap, forget it */
+                               if (vma && addr > vma->vm_start)
+                                       addr = vma->vm_start;
+                       }
+               }
                /* At this point:  (!vma || addr < vma->vm_end). */
                if (TASK_SIZE - len < addr)
                        return -ENOMEM;
-               if (!vma || addr + len <= vma->vm_start)
+               if (!vma || addr + len <= vm_start_gap(vma))
                        return addr;
-               addr = vma->vm_end;
        }
 }
 
@@ -70,22 +80,32 @@ static int get_offset(struct address_space *mapping)
 static unsigned long get_shared_area(struct address_space *mapping,
                unsigned long addr, unsigned long len, unsigned long pgoff)
 {
-       struct vm_area_struct *vma;
+       struct vm_area_struct *vma, *prev;
+       unsigned long prev_end;
        int offset = mapping ? get_offset(mapping) : 0;
 
        offset = (offset + (pgoff << PAGE_SHIFT)) & 0x3FF000;
 
        addr = DCACHE_ALIGN(addr - offset) + offset;
 
-       for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
+       for (vma = find_vma_prev(current->mm, addr, &prev); ; prev = vma,
+                                                       vma = vma->vm_next) {
+               if (prev) {
+                       prev_end = vm_end_gap(prev);
+                       if (addr < prev_end) {
+                               addr = DCACHE_ALIGN(prev_end - offset) + offset;
+                               if (addr < prev_end)    /* handle wraparound */
+                                       return -ENOMEM;
+                               /* If vma already violates gap, forget it */
+                               if (vma && addr > vma->vm_start)
+                                       addr = vma->vm_start;
+                       }
+               }
                /* At this point:  (!vma || addr < vma->vm_end). */
                if (TASK_SIZE - len < addr)
                        return -ENOMEM;
-               if (!vma || addr + len <= vma->vm_start)
+               if (!vma || addr + len <= vm_start_gap(vma))
                        return addr;
-               addr = DCACHE_ALIGN(vma->vm_end - offset) + offset;
-               if (addr < vma->vm_end) /* handle wraparound */
-                       return -ENOMEM;
        }
 }