cifs: Fix locking usage for tcon fields

[ Upstream commit 96c4af418586ee9a6aab61738644366426e05316 ]

We used to use the cifs_tcp_ses_lock to protect a lot of objects
that are not just the server, ses or tcon lists. We later introduced
srv_lock, ses_lock and tc_lock to protect fields within the
corresponding structs. This was done to provide a more granular
protection and avoid unnecessary serialization.

There were still a couple of uses of cifs_tcp_ses_lock to provide
tcon fields. In this patch, I've replaced them with tc_lock.

Cc: stable@vger.kernel.org
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index e3ea6fe7edb474ea18763311b9520cd1df755351..09939fe9666eabfe847b5ee5d6bf270ef7807818 100644 (file)
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -788,11 +788,11 @@ static void cfids_laundromat_worker(struct work_struct *work)
                cfid->dentry = NULL;
 
                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
                        /*

diff --git a/fs/smb/client/smb2misc.c b/fs/smb/client/smb2misc.c
index 96bfe4c63ccf9091aff49c5c345a3a4ba6c5a55b..a6fc8ff398ebfa3a03c6da9508fadd1602233fa3 100644 (file)
--- a/fs/smb/client/smb2misc.c
+++ b/fs/smb/client/smb2misc.c
@@ -819,14 +819,14 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid,
        int rc;
 
        cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
-       spin_lock(&cifs_tcp_ses_lock);
+       spin_lock(&tcon->tc_lock);
        if (tcon->tc_count <= 0) {
                struct TCP_Server_Info *server = NULL;
 
                trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                                    netfs_trace_tcon_ref_see_cancelled_close);
                WARN_ONCE(tcon->tc_count < 0, "tcon refcount is negative");
-               spin_unlock(&cifs_tcp_ses_lock);
+               spin_unlock(&tcon->tc_lock);
 
                if (tcon->ses) {
                        server = tcon->ses->server;
@@ -840,7 +840,7 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid,
        tcon->tc_count++;
        trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                            netfs_trace_tcon_ref_get_cancelled_close);
-       spin_unlock(&cifs_tcp_ses_lock);
+       spin_unlock(&tcon->tc_lock);
 
        rc = __smb2_handle_cancelled_cmd(tcon, SMB2_CLOSE_HE, 0,
                                         persistent_fid, volatile_fid);

diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index c3c5fddb2caab8fc632c10144b25e17c4a7a8aa6..1b404def355e92e7e11bcd935118c569a9c65c9d 100644 (file)
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -3074,7 +3074,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
                                                struct cifs_tcon,
                                                tcon_list);
                if (tcon) {
+                       spin_lock(&tcon->tc_lock);
                        tcon->tc_count++;
+                       spin_unlock(&tcon->tc_lock);
                        trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                                            netfs_trace_tcon_ref_get_dfs_refer);
                }
@@ -3143,13 +3145,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
  out:
        if (tcon && !tcon->ipc) {
                /* ipc tcons are not refcounted */
-               spin_lock(&cifs_tcp_ses_lock);
-               tcon->tc_count--;
+               cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_dfs_refer);
                trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                                    netfs_trace_tcon_ref_dec_dfs_refer);
-               /* tc_count can never go negative */
-               WARN_ON(tcon->tc_count < 0);
-               spin_unlock(&cifs_tcp_ses_lock);
        }
        kfree(utf16_path);
        kfree(dfs_req);

diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index e661d40213eabc830009b22a7d175a208cbc1090..8082507586e8113db6e43fe871ae562c3f856c21 100644 (file)
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -4174,7 +4174,9 @@ void smb2_reconnect_server(struct work_struct *work)
 
                list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
                        if (tcon->need_reconnect || tcon->need_reopen_files) {
+                               spin_lock(&tcon->tc_lock);
                                tcon->tc_count++;
+                               spin_unlock(&tcon->tc_lock);
                                trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
                                                    netfs_trace_tcon_ref_get_reconnect_server);
                                list_add_tail(&tcon->rlist, &tmp_list);

diff --git a/fs/smb/client/trace.h b/fs/smb/client/trace.h
index 28e00c34df1cbb062b3d28676130f04bff7ac300..e592b2627119f04a9f37194e2831ef8b9821eada 100644 (file)
--- a/fs/smb/client/trace.h
+++ b/fs/smb/client/trace.h
@@ -59,6 +59,7 @@
        EM(netfs_trace_tcon_ref_put_cancelled_close_fid, "PUT Cn-Fid") \
        EM(netfs_trace_tcon_ref_put_cancelled_mid,      "PUT Cn-Mid") \
        EM(netfs_trace_tcon_ref_put_mnt_ctx,            "PUT MntCtx") \
+       EM(netfs_trace_tcon_ref_put_dfs_refer,          "PUT DfsRfr") \
        EM(netfs_trace_tcon_ref_put_reconnect_server,   "PUT Reconn") \
        EM(netfs_trace_tcon_ref_put_tlink,              "PUT Tlink ") \
        EM(netfs_trace_tcon_ref_see_cancelled_close,    "SEE Cn-Cls") \