From: Paulo Alcantara <pc@cjr.nz>
Date: Wed, 14 Sep 2022 04:34:51 +0000 (-0700)
Subject: cifs: add missing spinlock around tcon refcount
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=621a41ae0834cec9cab312d600d2b9de41dc6eac;p=linux.git

cifs: add missing spinlock around tcon refcount

Add missing spinlock to protect updates on tcon refcount in
cifs_put_tcon().

Fixes: d7d7a66aacd6 ("cifs: avoid use of global locks for high contention data")
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 0225f4c8adf0c..7ae6f2c08153e 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2345,7 +2345,9 @@ cifs_put_tcon(struct cifs_tcon *tcon)
 	ses = tcon->ses;
 	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) {
+		spin_unlock(&tcon->tc_lock);
 		spin_unlock(&cifs_tcp_ses_lock);
 		return;
 	}
@@ -2354,6 +2356,7 @@ cifs_put_tcon(struct cifs_tcon *tcon)
 	WARN_ON(tcon->tc_count < 0);
 
 	list_del_init(&tcon->tcon_list);
+	spin_unlock(&tcon->tc_lock);
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	/* cancel polling of interfaces */