dlm: add __CHECKER__ for false positives

This patch will adds #ifndef __CHECKER__ for false positives warnings
about an imbalance lock/unlock srcu handling. Which are shown by running
sparse checks:

fs/dlm/midcomms.c:1065:20: warning: context imbalance in 'dlm_midcomms_get_mhandle' - wrong count at exit

Using __CHECKER__ will tell sparse to ignore these sections.

Those imbalances are false positive because from upper layer it is
always required to call a function in sequence, e.g. if
dlm_midcomms_get_mhandle() is successful there must be a
dlm_midcomms_commit_mhandle() call afterwards.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 6ed935ad82471b4c71cf6eafc92101698eb47981..19e82f08c0e0ca6694b9ffb4a85a73abac5d8587 100644 (file)
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -1303,6 +1303,10 @@ static struct dlm_msg *dlm_lowcomms_new_msg_con(struct connection *con, int len,
        return msg;
 }
 
+/* avoid false positive for nodes_srcu, unlock happens in
+ * dlm_lowcomms_commit_msg which is a must call if success
+ */
+#ifndef __CHECKER__
 struct dlm_msg *dlm_lowcomms_new_msg(int nodeid, int len, gfp_t allocation,
                                     char **ppc, void (*cb)(void *data),
                                     void *data)
@@ -1336,6 +1340,7 @@ struct dlm_msg *dlm_lowcomms_new_msg(int nodeid, int len, gfp_t allocation,
        msg->idx = idx;
        return msg;
 }
+#endif
 
 static void _dlm_lowcomms_commit_msg(struct dlm_msg *msg)
 {
@@ -1362,11 +1367,16 @@ out:
        return;
 }
 
+/* avoid false positive for nodes_srcu, lock was happen in
+ * dlm_lowcomms_new_msg
+ */
+#ifndef __CHECKER__
 void dlm_lowcomms_commit_msg(struct dlm_msg *msg)
 {
        _dlm_lowcomms_commit_msg(msg);
        srcu_read_unlock(&connections_srcu, msg->idx);
 }
+#endif
 
 void dlm_lowcomms_put_msg(struct dlm_msg *msg)
 {

diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
index 3635e42b066962c14219baae56828b7479f4e0a7..f95f6f40c404cbcedd5777cb356e9f7ca2aeceaa 100644 (file)
--- a/fs/dlm/midcomms.c
+++ b/fs/dlm/midcomms.c
@@ -1062,6 +1062,10 @@ static struct dlm_msg *dlm_midcomms_get_msg_3_2(struct dlm_mhandle *mh, int node
        return msg;
 }
 
+/* avoid false positive for nodes_srcu, unlock happens in
+ * dlm_midcomms_commit_mhandle which is a must call if success
+ */
+#ifndef __CHECKER__
 struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len,
                                             gfp_t allocation, char **ppc)
 {
@@ -1127,6 +1131,7 @@ err:
        srcu_read_unlock(&nodes_srcu, idx);
        return NULL;
 }
+#endif
 
 static void dlm_midcomms_commit_msg_3_2(struct dlm_mhandle *mh)
 {
@@ -1136,6 +1141,10 @@ static void dlm_midcomms_commit_msg_3_2(struct dlm_mhandle *mh)
        dlm_lowcomms_commit_msg(mh->msg);
 }
 
+/* avoid false positive for nodes_srcu, lock was happen in
+ * dlm_midcomms_get_mhandle
+ */
+#ifndef __CHECKER__
 void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh)
 {
        switch (mh->node->version) {
@@ -1157,6 +1166,7 @@ void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh)
                break;
        }
 }
+#endif
 
 int dlm_midcomms_start(void)
 {