[PATCH 6/7] cifs: tc_count updates should be done with tc_lock

[nspmangalore@gmail.com]

From: Shyam Prasad N <sprasad@microsoft.com>

We had problems with deadlocks using the cifs_tcp_ses_lock for
protecting a lot of structures. So we broke it down into smaller
spinlocks. cifs_tcon struct fields are protected by tc_lock now.
Hence we should stick to using that.

Fixes: 3fa640d035e5 ("smb: During unmount, ensure all cached dir instances drop their dentry")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
---
 fs/smb/client/cached_dir.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index 2746d693d80a..4abf5bbd8baf 100644
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -650,10 +650,12 @@ int cached_dir_lease_break(struct cifs_tcon *tcon, __u8 lease_key[16])
 			spin_unlock(&cfid->fid_lock);
 			cfids->num_entries--;
 
+			spin_lock(&cfid->tcon->tc_lock);
 			++tcon->tc_count;
 			trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
 					    netfs_trace_tcon_ref_get_cached_lease_break);
 			queue_work(cfid_put_wq, &cfid->put_work);
+			spin_unlock(&cfid->tcon->tc_lock);
 			spin_unlock(&cfids->cfid_list_lock);
 			return true;
 		}
@@ -767,11 +769,11 @@ static void cfids_laundromat_worker(struct work_struct *work)
 		dput(dentry);
 
 		if (cfid->is_open) {
-			spin_lock(&cifs_tcp_ses_lock);
+			spin_lock(&cfid->tcon->tc_lock);
 			++cfid->tcon->tc_count;
 			trace_smb3_tcon_ref(cfid->tcon->debug_id, cfid->tcon->tc_count,
 					    netfs_trace_tcon_ref_get_cached_laundromat);
-			spin_unlock(&cifs_tcp_ses_lock);
+			spin_unlock(&cfid->tcon->tc_lock);
 			queue_work(serverclose_wq, &cfid->close_work);
 		} else
 			/*
-- 
2.43.0