mm: mempolicy: turn vma_set_policy() into vma_dup_policy()

Simple cleanup.  Every user of vma_set_policy() does the same work, this
looks a bit annoying imho.  And the new trivial helper which does
mpol_dup() + vma_set_policy() to simplify the callers.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 0d7df39..b2f8977 100644 (file)
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -91,7 +91,6 @@ static inline struct mempolicy *mpol_dup(struct mempolicy *pol)
 }
 
 #define vma_policy(vma) ((vma)->vm_policy)
-#define vma_set_policy(vma, pol) ((vma)->vm_policy = (pol))
 
 static inline void mpol_get(struct mempolicy *pol)
 {
@@ -126,6 +125,7 @@ struct shared_policy {
        spinlock_t lock;
 };
 
+int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst);
 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol);
 int mpol_set_shared_policy(struct shared_policy *info,
                                struct vm_area_struct *vma,
@@ -240,7 +240,12 @@ mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
 }
 
 #define vma_policy(vma) NULL
-#define vma_set_policy(vma, pol) do {} while(0)
+
+static inline int
+vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
+{
+       return 0;
+}
 
 static inline void numa_policy_init(void)
 {

diff --git a/kernel/fork.c b/kernel/fork.c
index 84703db..81ccb4f 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -351,7 +351,6 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
        struct rb_node **rb_link, *rb_parent;
        int retval;
        unsigned long charge;
-       struct mempolicy *pol;
 
        uprobe_start_dup_mmap();
        down_write(&oldmm->mmap_sem);
@@ -400,11 +399,9 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
                        goto fail_nomem;
                *tmp = *mpnt;
                INIT_LIST_HEAD(&tmp->anon_vma_chain);
-               pol = mpol_dup(vma_policy(mpnt));
-               retval = PTR_ERR(pol);
-               if (IS_ERR(pol))
+               retval = vma_dup_policy(mpnt, tmp);
+               if (retval)
                        goto fail_nomem_policy;
-               vma_set_policy(tmp, pol);
                tmp->vm_mm = mm;
                if (anon_vma_fork(tmp, mpnt))
                        goto fail_nomem_anon_vma_fork;
@@ -472,7 +469,7 @@ out:
        uprobe_end_dup_mmap();
        return retval;
 fail_nomem_anon_vma_fork:
-       mpol_put(pol);
+       mpol_put(vma_policy(tmp));
 fail_nomem_policy:
        kmem_cache_free(vm_area_cachep, tmp);
 fail_nomem:

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4baf12e..6b1d426 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2065,6 +2065,16 @@ retry_cpuset:
 }
 EXPORT_SYMBOL(alloc_pages_current);
 
+int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
+{
+       struct mempolicy *pol = mpol_dup(vma_policy(src));
+
+       if (IS_ERR(pol))
+               return PTR_ERR(pol);
+       dst->vm_policy = pol;
+       return 0;
+}
+
 /*
  * If mpol_dup() sees current->cpuset == cpuset_being_rebound, then it
  * rebinds the mempolicy its copying by calling mpol_rebind_policy()

diff --git a/mm/mmap.c b/mm/mmap.c
index f9c97d1..14f6bb4 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2380,7 +2380,6 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
 static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
              unsigned long addr, int new_below)
 {
-       struct mempolicy *pol;
        struct vm_area_struct *new;
        int err = -ENOMEM;
 
@@ -2404,12 +2403,9 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
                new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
        }
 
-       pol = mpol_dup(vma_policy(vma));
-       if (IS_ERR(pol)) {
-               err = PTR_ERR(pol);
+       err = vma_dup_policy(vma, new);
+       if (err)
                goto out_free_vma;
-       }
-       vma_set_policy(new, pol);
 
        if (anon_vma_clone(new, vma))
                goto out_free_mpol;
@@ -2437,7 +2433,7 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
                fput(new->vm_file);
        unlink_anon_vmas(new);
  out_free_mpol:
-       mpol_put(pol);
+       mpol_put(vma_policy(new));
  out_free_vma:
        kmem_cache_free(vm_area_cachep, new);
  out_err:
@@ -2780,7 +2776,6 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
        struct mm_struct *mm = vma->vm_mm;
        struct vm_area_struct *new_vma, *prev;
        struct rb_node **rb_link, *rb_parent;
-       struct mempolicy *pol;
        bool faulted_in_anon_vma = true;
 
        /*
@@ -2825,10 +2820,8 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
                        new_vma->vm_start = addr;
                        new_vma->vm_end = addr + len;
                        new_vma->vm_pgoff = pgoff;
-                       pol = mpol_dup(vma_policy(vma));
-                       if (IS_ERR(pol))
+                       if (vma_dup_policy(vma, new_vma))
                                goto out_free_vma;
-                       vma_set_policy(new_vma, pol);
                        INIT_LIST_HEAD(&new_vma->anon_vma_chain);
                        if (anon_vma_clone(new_vma, vma))
                                goto out_free_mempol;
@@ -2843,7 +2836,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
        return new_vma;
 
  out_free_mempol:
-       mpol_put(pol);
+       mpol_put(vma_policy(new_vma));
  out_free_vma:
        kmem_cache_free(vm_area_cachep, new_vma);
        return NULL;