Patch "ceph: make iterate_sessions a global symbol" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ceph: make iterate_sessions a global symbol

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ceph-make-iterate_sessions-a-global-symbol.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 2a971077b3e5a10cb4f7fb2fb75c09f43dd68951
Author: Xiubo Li <xiubli@xxxxxxxxxx>
Date:   Mon Jul 5 09:22:55 2021 +0800

    ceph: make iterate_sessions a global symbol
    
    [ Upstream commit 59b312f36230ea91ebb6ce1b11f2781604495d30 ]
    
    Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
    Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
    Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
    Stable-dep-of: 5bd76b8de5b7 ("ceph: fix NULL pointer dereference for req->r_session")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 76e43a487bc6..7ae27a18cf18 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -4310,33 +4310,9 @@ static void flush_dirty_session_caps(struct ceph_mds_session *s)
 	dout("flush_dirty_caps done\n");
 }
 
-static void iterate_sessions(struct ceph_mds_client *mdsc,
-			     void (*cb)(struct ceph_mds_session *))
-{
-	int mds;
-
-	mutex_lock(&mdsc->mutex);
-	for (mds = 0; mds < mdsc->max_sessions; ++mds) {
-		struct ceph_mds_session *s;
-
-		if (!mdsc->sessions[mds])
-			continue;
-
-		s = ceph_get_mds_session(mdsc->sessions[mds]);
-		if (!s)
-			continue;
-
-		mutex_unlock(&mdsc->mutex);
-		cb(s);
-		ceph_put_mds_session(s);
-		mutex_lock(&mdsc->mutex);
-	}
-	mutex_unlock(&mdsc->mutex);
-}
-
 void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
 {
-	iterate_sessions(mdsc, flush_dirty_session_caps);
+	ceph_mdsc_iterate_sessions(mdsc, flush_dirty_session_caps, true);
 }
 
 void __ceph_touch_fmode(struct ceph_inode_info *ci,
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 36cf3638f501..45587b3025e4 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -809,6 +809,33 @@ static void put_request_session(struct ceph_mds_request *req)
 	}
 }
 
+void ceph_mdsc_iterate_sessions(struct ceph_mds_client *mdsc,
+				void (*cb)(struct ceph_mds_session *),
+				bool check_state)
+{
+	int mds;
+
+	mutex_lock(&mdsc->mutex);
+	for (mds = 0; mds < mdsc->max_sessions; ++mds) {
+		struct ceph_mds_session *s;
+
+		s = __ceph_lookup_mds_session(mdsc, mds);
+		if (!s)
+			continue;
+
+		if (check_state && !check_session_state(s)) {
+			ceph_put_mds_session(s);
+			continue;
+		}
+
+		mutex_unlock(&mdsc->mutex);
+		cb(s);
+		ceph_put_mds_session(s);
+		mutex_lock(&mdsc->mutex);
+	}
+	mutex_unlock(&mdsc->mutex);
+}
+
 void ceph_mdsc_release_request(struct kref *kref)
 {
 	struct ceph_mds_request *req = container_of(kref,
@@ -4377,24 +4404,12 @@ void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
 }
 
 /*
- * lock unlock sessions, to wait ongoing session activities
+ * lock unlock the session, to wait ongoing session activities
  */
-static void lock_unlock_sessions(struct ceph_mds_client *mdsc)
+static void lock_unlock_session(struct ceph_mds_session *s)
 {
-	int i;
-
-	mutex_lock(&mdsc->mutex);
-	for (i = 0; i < mdsc->max_sessions; i++) {
-		struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
-		if (!s)
-			continue;
-		mutex_unlock(&mdsc->mutex);
-		mutex_lock(&s->s_mutex);
-		mutex_unlock(&s->s_mutex);
-		ceph_put_mds_session(s);
-		mutex_lock(&mdsc->mutex);
-	}
-	mutex_unlock(&mdsc->mutex);
+	mutex_lock(&s->s_mutex);
+	mutex_unlock(&s->s_mutex);
 }
 
 static void maybe_recover_session(struct ceph_mds_client *mdsc)
@@ -4658,7 +4673,7 @@ void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
 	dout("pre_umount\n");
 	mdsc->stopping = 1;
 
-	lock_unlock_sessions(mdsc);
+	ceph_mdsc_iterate_sessions(mdsc, lock_unlock_session, false);
 	ceph_flush_dirty_caps(mdsc);
 	wait_requests(mdsc);
 
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index c0cff765cbf5..88fc80832016 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -518,6 +518,9 @@ 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_iterate_sessions(struct ceph_mds_client *mdsc,
+				       void (*cb)(struct ceph_mds_session *),
+				       bool check_state);
 extern struct ceph_msg *ceph_create_session_msg(u32 op, u64 seq);
 extern void __ceph_queue_cap_release(struct ceph_mds_session *session,
 				    struct ceph_cap *cap);