mm: allow remote_vm access to non-io pfnmap memory

[pandora-kernel.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 628cadc..b9a95f1 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1403,6 +1403,7 @@ unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
        tlb_finish_mmu(&tlb, address, end);
        return end;
 }
+EXPORT_SYMBOL_GPL(zap_page_range);
 
 /**
  * zap_vma_ptes - remove ptes mapping the vma
@@ -1767,7 +1768,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                                else
                                                        return -EFAULT;
                                        }
-                                       if (ret & VM_FAULT_SIGBUS)
+                                       if (ret & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV))
                                                return i ? i : -EFAULT;
                                        BUG();
                                }
@@ -1871,7 +1872,7 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
                        return -ENOMEM;
                if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
                        return -EHWPOISON;
-               if (ret & VM_FAULT_SIGBUS)
+               if (ret & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV))
                        return -EFAULT;
                BUG();
        }
@@ -2661,17 +2662,24 @@ reuse:
                if (!dirty_page)
                        return ret;
 
-               /*
-                * Yes, Virginia, this is actually required to prevent a race
-                * with clear_page_dirty_for_io() from clearing the page dirty
-                * bit after it clear all dirty ptes, but before a racing
-                * do_wp_page installs a dirty pte.
-                *
-                * __do_fault is protected similarly.
-                */
                if (!page_mkwrite) {
-                       wait_on_page_locked(dirty_page);
-                       set_page_dirty_balance(dirty_page, page_mkwrite);
+                       struct address_space *mapping;
+                       int dirtied;
+
+                       lock_page(dirty_page);
+                       dirtied = set_page_dirty(dirty_page);
+                       VM_BUG_ON(PageAnon(dirty_page));
+                       mapping = dirty_page->mapping;
+                       unlock_page(dirty_page);
+
+                       if (dirtied && mapping) {
+                               /*
+                                * Some device drivers do not set page.mapping
+                                * but still dirty their pages
+                                */
+                               balance_dirty_pages_ratelimited(mapping);
+                       }
+
                }
                put_page(dirty_page);
                if (page_mkwrite) {
@@ -3117,7 +3125,7 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo
                if (prev && prev->vm_end == address)
                        return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
 
-               expand_downwards(vma, address - PAGE_SIZE);
+               return expand_downwards(vma, address - PAGE_SIZE);
        }
        if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
                struct vm_area_struct *next = vma->vm_next;
@@ -3126,7 +3134,7 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo
                if (next && next->vm_start == address + PAGE_SIZE)
                        return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
 
-               expand_upwards(vma, address + PAGE_SIZE);
+               return expand_upwards(vma, address + PAGE_SIZE);
        }
        return 0;
 }
@@ -3148,7 +3156,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
        /* Check if we need to add a guard page to the stack */
        if (check_stack_guard_page(vma, address) < 0)
-               return VM_FAULT_SIGBUS;
+               return VM_FAULT_SIGSEGV;
 
        /* Use the zero-page for reads */
        if (!(flags & FAULT_FLAG_WRITE)) {
@@ -3546,8 +3554,9 @@ retry:
 
                barrier();
                if (pmd_trans_huge(orig_pmd)) {
-                       if (flags & FAULT_FLAG_WRITE &&
-                           !pmd_write(orig_pmd) &&
+                       unsigned int dirty = flags & FAULT_FLAG_WRITE;
+
+                       if (dirty && !pmd_write(orig_pmd) &&
                            !pmd_trans_splitting(orig_pmd)) {
                                ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
                                                          orig_pmd);
@@ -3559,6 +3568,9 @@ retry:
                                if (unlikely(ret & VM_FAULT_OOM))
                                        goto retry;
                                return ret;
+                       } else {
+                               huge_pmd_set_accessed(mm, vma, address, pmd,
+                                                     orig_pmd, dirty);
                        }
                        return 0;
                }
@@ -3863,7 +3875,11 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
                        vma = find_vma(mm, addr);
                        if (!vma || vma->vm_start > addr)
                                break;
-                       if (vma->vm_ops && vma->vm_ops->access)
+                       if ((vma->vm_flags & VM_PFNMAP) &&
+                           !(vma->vm_flags & VM_IO))
+                               ret = generic_access_phys(vma, addr, buf,
+                                                         len, write);
+                       if (ret <= 0 && vma->vm_ops && vma->vm_ops->access)
                                ret = vma->vm_ops->access(vma, addr, buf,
                                                          len, write);
                        if (ret <= 0)