mempolicy: rename mpol_free to mpol_put

This is a change that was requested some time ago by Mel Gorman.  Makes sense
to me, so here it is.

Note: I retain the name "mpol_free_shared_policy()" because it actually does
free the shared_policy, which is NOT a reference counted object.  However, ...

The mempolicy object[s] referenced by the shared_policy are reference counted,
so mpol_put() is used to release the reference held by the shared_policy.  The
mempolicy might not be freed at this time, because some task attached to the
shared object associated with the shared policy may be in the process of
allocating a page based on the mempolicy.  In that case, the task performing
the allocation will hold a reference on the mempolicy, obtained via
mpol_shared_policy_lookup().  The mempolicy will be freed when all tasks
holding such a reference have called mpol_put() for the mempolicy.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 13 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index c1b907789d84..ce2c5b6bf9f8 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -529,7 +529,7 @@ static int policy_vma(struct vm_area_struct *vma, struct mempolicy *new)
         if (!err) {
                 mpol_get(new);
                 vma->vm_policy = new;
-                mpol_free(old);
+                mpol_put(old);
         }
         return err;
 }
@@ -595,7 +595,7 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags,
         new = mpol_new(mode, flags, nodes);
         if (IS_ERR(new))
                 return PTR_ERR(new);
-        mpol_free(current->mempolicy);
+        mpol_put(current->mempolicy);
         current->mempolicy = new;
         mpol_set_task_struct_flag();
         if (new && new->policy == MPOL_INTERLEAVE &&
@@ -948,7 +948,7 @@ static long do_mbind(unsigned long start, unsigned long len,
         }
 
         up_write(&mm->mmap_sem);
-        mpol_free(new);
+        mpol_put(new);
         return err;
 }
 
@@ -1446,14 +1446,14 @@ struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
                 nid = interleave_nid(pol, vma, addr, HPAGE_SHIFT);
                 if (unlikely(pol != &default_policy &&
                                 pol != current->mempolicy))
-                        __mpol_free(pol);       /* finished with pol */
+                        __mpol_put(pol);        /* finished with pol */
                 return node_zonelist(nid, gfp_flags);
         }
 
         zl = zonelist_policy(GFP_HIGHUSER, pol);
         if (unlikely(pol != &default_policy && pol != current->mempolicy)) {
                 if (pol->policy != MPOL_BIND)
-                        __mpol_free(pol);       /* finished with pol */
+                        __mpol_put(pol);        /* finished with pol */
                 else
                         *mpol = pol;    /* unref needed after allocation */
         }
@@ -1512,7 +1512,7 @@ alloc_page_vma(gfp_t gfp, struct vm_area_struct *vma, unsigned long addr)
                 nid = interleave_nid(pol, vma, addr, PAGE_SHIFT);
                 if (unlikely(pol != &default_policy &&
                                 pol != current->mempolicy))
-                        __mpol_free(pol);       /* finished with pol */
+                        __mpol_put(pol);        /* finished with pol */
                 return alloc_page_interleave(gfp, 0, nid);
         }
         zl = zonelist_policy(gfp, pol);
@@ -1522,7 +1522,7 @@ alloc_page_vma(gfp_t gfp, struct vm_area_struct *vma, unsigned long addr)
                  */
                 struct page *page =  __alloc_pages_nodemask(gfp, 0,
                                                 zl, nodemask_policy(gfp, pol));
-                __mpol_free(pol);
+                __mpol_put(pol);
                 return page;
         }
         /*
@@ -1624,7 +1624,7 @@ int __mpol_equal(struct mempolicy *a, struct mempolicy *b)
 }
 
 /* Slow path of a mpol destructor. */
-void __mpol_free(struct mempolicy *p)
+void __mpol_put(struct mempolicy *p)
 {
         if (!atomic_dec_and_test(&p->refcnt))
                 return;
@@ -1720,7 +1720,7 @@ static void sp_delete(struct shared_policy *sp, struct sp_node *n)
 {
         pr_debug("deleting %lx-l%lx\n", n->start, n->end);
         rb_erase(&n->nd, &sp->root);
-        mpol_free(n->policy);
+        mpol_put(n->policy);
         kmem_cache_free(sn_cache, n);
 }
 
@@ -1780,7 +1780,7 @@ restart:
                 sp_insert(sp, new);
         spin_unlock(&sp->lock);
         if (new2) {
-                mpol_free(new2->policy);
+                mpol_put(new2->policy);
                 kmem_cache_free(sn_cache, new2);
         }
         return 0;
@@ -1805,7 +1805,7 @@ void mpol_shared_policy_init(struct shared_policy *info, unsigned short policy,
                         /* Policy covers entire file */
                         pvma.vm_end = TASK_SIZE;
                         mpol_set_shared_policy(info, &pvma, newpol);
-                        mpol_free(newpol);
+                        mpol_put(newpol);
                 }
         }
 }
@@ -1848,7 +1848,7 @@ void mpol_free_shared_policy(struct shared_policy *p)
                 n = rb_entry(next, struct sp_node, nd);
                 next = rb_next(&n->nd);
                 rb_erase(&n->nd, &p->root);
-                mpol_free(n->policy);
+                mpol_put(n->policy);
                 kmem_cache_free(sn_cache, n);
         }
         spin_unlock(&p->lock);
@@ -2068,7 +2068,7 @@ int show_numa_map(struct seq_file *m, void *v)
          * unref shared or other task's mempolicy
          */
         if (pol != &default_policy && pol != current->mempolicy)
-                __mpol_free(pol);
+                __mpol_put(pol);
 
         seq_printf(m, "%08lx %s", vma->vm_start, buffer);