ceph: use kref for struct ceph_mds_request

Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/mds_client.c

@@ -400,11 +400,11 @@ static void put_request_session(struct ceph_mds_request *req)
 	}
 }
 
-void ceph_mdsc_put_request(struct ceph_mds_request *req)
+void ceph_mdsc_release_request(struct kref *kref)
 {
-	dout("mdsc put_request %p %d -> %d\n", req,
-	     atomic_read(&req->r_ref), atomic_read(&req->r_ref)-1);
-	if (atomic_dec_and_test(&req->r_ref)) {
+	struct ceph_mds_request *req = container_of(kref,
+						    struct ceph_mds_request,
+						    r_kref);
 	if (req->r_request)
 		ceph_msg_put(req->r_request);
 	if (req->r_reply) {
@@ -434,7 +434,6 @@ void ceph_mdsc_put_request(struct ceph_mds_request *req)
 	put_request_session(req);
 	ceph_unreserve_caps(&req->r_caps_reservation);
 	kfree(req);
-	}
 }
 
 /*
@@ -1097,7 +1096,7 @@ ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
 	req->r_resend_mds = -1;
 	INIT_LIST_HEAD(&req->r_unsafe_dir_item);
 	req->r_fmode = -1;
-	atomic_set(&req->r_ref, 1);  /* one for request_tree, one for caller */
+	kref_init(&req->r_kref);
 	INIT_LIST_HEAD(&req->r_wait);
 	init_completion(&req->r_completion);
 	init_completion(&req->r_safe_completion);

fs/ceph/mds_client.h

@@ -2,6 +2,7 @@
 #define _FS_CEPH_MDS_CLIENT_H
 
 #include <linux/completion.h>
+#include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/radix-tree.h>
@@ -203,7 +204,7 @@ struct ceph_mds_request {
 	int               r_num_stale;
 	int               r_resend_mds; /* mds to resend to next, if any*/
 
-	atomic_t          r_ref;
+	struct kref       r_kref;
 	struct list_head  r_wait;
 	struct completion r_completion;
 	struct completion r_safe_completion;
@@ -306,9 +307,13 @@ extern int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
 				struct ceph_mds_request *req);
 static inline void ceph_mdsc_get_request(struct ceph_mds_request *req)
 {
-	atomic_inc(&req->r_ref);
+	kref_get(&req->r_kref);
+}
+extern void ceph_mdsc_release_request(struct kref *kref);
+static inline void ceph_mdsc_put_request(struct ceph_mds_request *req)
+{
+	kref_put(&req->r_kref, ceph_mdsc_release_request);
 }
-extern void ceph_mdsc_put_request(struct ceph_mds_request *req);
 
 extern void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc);