libceph: reference counting pagelist

this allow pagelist to present data that may be sent multiple times.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Sage Weil <sage@redhat.com>

2 files changed, 6 insertions, 5 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index e7d94113f2d6..9764c771cfb1 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -3071,10 +3071,8 @@ static void ceph_msg_data_destroy(struct ceph_msg_data *data)
                 return;
 
         WARN_ON(!list_empty(&data->links));
-        if (data->type == CEPH_MSG_DATA_PAGELIST) {
+        if (data->type == CEPH_MSG_DATA_PAGELIST)
                 ceph_pagelist_release(data->pagelist);
-                kfree(data->pagelist);
-        }
         kmem_cache_free(ceph_msg_data_cache, data);
 }
 
diff --git a/net/ceph/pagelist.c b/net/ceph/pagelist.c
index 92866bebb65f..c7c220a736e5 100644
--- a/net/ceph/pagelist.c
+++ b/net/ceph/pagelist.c
@@ -1,5 +1,6 @@
 #include <linux/module.h>
 #include <linux/gfp.h>
+#include <linux/slab.h>
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
 #include <linux/ceph/pagelist.h>
@@ -13,8 +14,10 @@ static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
         }
 }
 
-int ceph_pagelist_release(struct ceph_pagelist *pl)
+void ceph_pagelist_release(struct ceph_pagelist *pl)
 {
+        if (!atomic_dec_and_test(&pl->refcnt))
+                return;
         ceph_pagelist_unmap_tail(pl);
         while (!list_empty(&pl->head)) {
                 struct page *page = list_first_entry(&pl->head, struct page,
@@ -23,7 +26,7 @@ int ceph_pagelist_release(struct ceph_pagelist *pl)
                 __free_page(page);
         }
         ceph_pagelist_free_reserve(pl);
-        return 0;
+        kfree(pl);
 }
 EXPORT_SYMBOL(ceph_pagelist_release);