From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amol Grover Date: Fri, 10 Jan 2020 12:56:05 +0000 Subject: [PATCH 2/3] drivers: target: target_core_tpg: Pass lockdep expression to RCU lists Message-Id: <20200110124403.27882-2-frextrite@gmail.com> List-Id: References: <20200110124403.27882-1-frextrite@gmail.com> In-Reply-To: <20200110124403.27882-1-frextrite@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Martin K. Petersen" Cc: "Paul E . McKenney" , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, target-devel@vger.kernel.org, Joel Fernandes , linux-kernel-mentees@lists.linuxfoundation.org tpg->tpg_lun_hlist is traversed with hlist_for_each_entry_rcu outside an RCU read-side critical section but under the protection of tpg->tpg_lun_mutex. Hence, add the corresponding lockdep expression to the list traversal primitive to silence false-positive lockdep warnings, and harden RCU lists. Add macro for the corresponding lockdep expression to make the code clean and concise. Signed-off-by: Amol Grover --- drivers/target/target_core_tpg.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c index d24e0a3ba3ff..bc1c5dda81bf 100644 --- a/drivers/target/target_core_tpg.c +++ b/drivers/target/target_core_tpg.c @@ -30,6 +30,9 @@ #include "target_core_pr.h" #include "target_core_ua.h" +#define tpg_lun_mutex_held() \ + lockdep_is_held(&tpg->tpg_lun_mutex) + extern struct se_device *g_lun0_dev; /* __core_tpg_get_initiator_node_acl(): @@ -110,12 +113,12 @@ void core_tpg_add_node_to_devs( struct se_device *dev; mutex_lock(&tpg->tpg_lun_mutex); - hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) { + hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link, + tpg_lun_mutex_held()) { if (lun_orig && lun != lun_orig) continue; - dev = rcu_dereference_check(lun->lun_se_dev, - lockdep_is_held(&tpg->tpg_lun_mutex)); + dev = rcu_dereference_check(lun->lun_se_dev, tpg_lun_mutex_held()); /* * By default in LIO-Target $FABRIC_MOD, * demo_mode_write_protect is ON, or READ_ONLY; -- 2.24.1