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>

4 files changed, 19 insertions, 19 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 8deae4eb9696..53afa8c76ada 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -116,7 +116,7 @@ static struct page *dequeue_huge_page_vma(struct vm_area_struct *vma,
                         break;
                 }
         }
-        mpol_free(mpol);        /* unref if mpol !NULL */
+        mpol_put(mpol); /* unref if mpol !NULL */
         return page;
 }
 
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);
 
diff --git a/mm/mmap.c b/mm/mmap.c
index 6aaf657adb87..36c85e04fa93 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -232,7 +232,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
                 vma->vm_ops->close(vma);
         if (vma->vm_file)
                 fput(vma->vm_file);
-        mpol_free(vma_policy(vma));
+        mpol_put(vma_policy(vma));
         kmem_cache_free(vm_area_cachep, vma);
         return next;
 }
@@ -626,7 +626,7 @@ again:			remove_next = 1 + (end > next->vm_end);
                 if (file)
                         fput(file);
                 mm->map_count--;
-                mpol_free(vma_policy(next));
+                mpol_put(vma_policy(next));
                 kmem_cache_free(vm_area_cachep, next);
                 /*
                  * In mprotect's case 6 (see comments on vma_merge),
@@ -1182,7 +1182,7 @@ munmap_back:
 
         if (file && vma_merge(mm, prev, addr, vma->vm_end,
                         vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
-                mpol_free(vma_policy(vma));
+                mpol_put(vma_policy(vma));
                 kmem_cache_free(vm_area_cachep, vma);
                 fput(file);
         } else {
diff --git a/mm/shmem.c b/mm/shmem.c
index 177c7a7d2bb3..5326876d814d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1196,7 +1196,7 @@ static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
         pvma.vm_ops = NULL;
         pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
         page = swapin_readahead(entry, gfp, &pvma, 0);
-        mpol_free(pvma.vm_policy);
+        mpol_put(pvma.vm_policy);
         return page;
 }
 
@@ -1212,7 +1212,7 @@ static struct page *shmem_alloc_page(gfp_t gfp,
         pvma.vm_ops = NULL;
         pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
         page = alloc_page_vma(gfp, &pvma, 0);
-        mpol_free(pvma.vm_policy);
+        mpol_put(pvma.vm_policy);
         return page;
 }
 #else /* !CONFIG_NUMA */