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cifs: Fix locking usage for tcon fields

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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>
This commit is contained in:
Shyam Prasad N 2026-02-01 00:21:13 +05:30 committed by Steve French
parent 037ddbcc10
commit 96c4af4185
5 changed files with 11 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/smb/client/cached_dir.c
View File

@ -792,11 +792,11 @@ static void cfids_laundromat_worker(struct work_struct *work)
cfid->dentry = NULL; cfid->dentry = NULL;
if (cfid->is_open) { if (cfid->is_open) {
spin_lock(&cifs_tcp_ses_lock); spin_lock(&cfid->tcon->tc_lock);
++cfid->tcon->tc_count; ++cfid->tcon->tc_count;
trace_smb3_tcon_ref(cfid->tcon->debug_id, cfid->tcon->tc_count, trace_smb3_tcon_ref(cfid->tcon->debug_id, cfid->tcon->tc_count,
netfs_trace_tcon_ref_get_cached_laundromat); 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); queue_work(serverclose_wq, &cfid->close_work);
} else } else
/* /*

6
fs/smb/client/smb2misc.c
View File

@ -820,14 +820,14 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid,
int rc; int rc;
cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count); 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) { if (tcon->tc_count <= 0) {
struct TCP_Server_Info *server = NULL; struct TCP_Server_Info *server = NULL;
trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
netfs_trace_tcon_ref_see_cancelled_close); netfs_trace_tcon_ref_see_cancelled_close);
WARN_ONCE(tcon->tc_count < 0, "tcon refcount is negative"); WARN_ONCE(tcon->tc_count < 0, "tcon refcount is negative");
spin_unlock(&cifs_tcp_ses_lock); spin_unlock(&tcon->tc_lock);
if (tcon->ses) { if (tcon->ses) {
server = tcon->ses->server; server = tcon->ses->server;
@ -841,7 +841,7 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid,
tcon->tc_count++; tcon->tc_count++;
trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
netfs_trace_tcon_ref_get_cancelled_close); 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, rc = __smb2_handle_cancelled_cmd(tcon, SMB2_CLOSE_HE, 0,
persistent_fid, volatile_fid); persistent_fid, volatile_fid);

8
fs/smb/client/smb2ops.c
View File

@ -3107,7 +3107,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
struct cifs_tcon, struct cifs_tcon,
tcon_list); tcon_list);
if (tcon) { if (tcon) {
spin_lock(&tcon->tc_lock);
tcon->tc_count++; tcon->tc_count++;
spin_unlock(&tcon->tc_lock);
trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
netfs_trace_tcon_ref_get_dfs_refer); netfs_trace_tcon_ref_get_dfs_refer);
} }
@ -3176,13 +3178,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
out: out:
if (tcon && !tcon->ipc) { if (tcon && !tcon->ipc) {
/* ipc tcons are not refcounted */ /* ipc tcons are not refcounted */
spin_lock(&cifs_tcp_ses_lock); cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_dfs_refer);
tcon->tc_count--;
trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
netfs_trace_tcon_ref_dec_dfs_refer); 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(utf16_path);
kfree(dfs_req); kfree(dfs_req);

2
fs/smb/client/smb2pdu.c
View File

@ -4263,7 +4263,9 @@ void smb2_reconnect_server(struct work_struct *work)
list_for_each_entry(tcon, &ses->tcon_list, tcon_list) { list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
if (tcon->need_reconnect || tcon->need_reopen_files) { if (tcon->need_reconnect || tcon->need_reopen_files) {
spin_lock(&tcon->tc_lock);
tcon->tc_count++; tcon->tc_count++;
spin_unlock(&tcon->tc_lock);
trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
netfs_trace_tcon_ref_get_reconnect_server); netfs_trace_tcon_ref_get_reconnect_server);
list_add_tail(&tcon->rlist, &tmp_list); list_add_tail(&tcon->rlist, &tmp_list);

1
fs/smb/client/trace.h
View File

@ -189,6 +189,7 @@
EM(netfs_trace_tcon_ref_put_cancelled_close_fid, "PUT Cn-Fid") \ 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_cancelled_mid, "PUT Cn-Mid") \
EM(netfs_trace_tcon_ref_put_mnt_ctx, "PUT MntCtx") \ 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_reconnect_server, "PUT Reconn") \
EM(netfs_trace_tcon_ref_put_tlink, "PUT Tlink ") \ EM(netfs_trace_tcon_ref_put_tlink, "PUT Tlink ") \
EM(netfs_trace_tcon_ref_see_cancelled_close, "SEE Cn-Cls") \ EM(netfs_trace_tcon_ref_see_cancelled_close, "SEE Cn-Cls") \