[Cluster-devel] [PATCH 2/2] dlm: Add down/up_write_non_owner to keep lockdep happy

[Steven Whitehouse <swhiteho@redhat.com>]

I looked at possibly changing this to use completions, but
it seems that the usage here is not easily adapted to that.
This patch adds suitable annotation to the write side of
the ls_in_recovery semaphore so that we don't get nasty
messages from lockdep when mounting a gfs2 filesystem.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
---
 fs/dlm/lockspace.c    |    2 +-
 fs/dlm/member.c       |    2 +-
 fs/dlm/recoverd.c     |    2 +-
 include/linux/rwsem.h |    4 ++++
 kernel/rwsem.c        |   16 ++++++++++++++++
 5 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index 8dde538..fa0cc22 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -551,7 +551,7 @@ static int new_lockspace(const char *name, int namelen, void **lockspace,
 	INIT_LIST_HEAD(&ls->ls_root_list);
 	init_rwsem(&ls->ls_root_sem);
 
-	down_write(&ls->ls_in_recovery);
+	down_write_non_owner(&ls->ls_in_recovery);
 
 	spin_lock(&lslist_lock);
 	ls->ls_create_count = 1;
diff --git a/fs/dlm/member.c b/fs/dlm/member.c
index b128775..99bd086 100644
--- a/fs/dlm/member.c
+++ b/fs/dlm/member.c
@@ -318,7 +318,7 @@ int dlm_ls_stop(struct dlm_ls *ls)
 	 */
 
 	if (new)
-		down_write(&ls->ls_in_recovery);
+		down_write_non_owner(&ls->ls_in_recovery);
 
 	/*
 	 * The recoverd suspend/resume makes sure that dlm_recoverd (if
diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
index fd677c8..376479a 100644
--- a/fs/dlm/recoverd.c
+++ b/fs/dlm/recoverd.c
@@ -40,7 +40,7 @@ static int enable_locking(struct dlm_ls *ls, uint64_t seq)
 	if (ls->ls_recover_seq == seq) {
 		set_bit(LSFL_RUNNING, &ls->ls_flags);
 		/* unblocks processes waiting to enter the dlm */
-		up_write(&ls->ls_in_recovery);
+		up_write_non_owner(&ls->ls_in_recovery);
 		error = 0;
 	}
 	spin_unlock(&ls->ls_recover_lock);
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index efd348f..34643df 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -80,12 +80,16 @@ extern void down_write_nested(struct rw_semaphore *sem, int subclass);
  *   proper abstraction for this case is completions. ]
  */
 extern void down_read_non_owner(struct rw_semaphore *sem);
+extern void down_write_non_owner(struct rw_semaphore *sem);
 extern void up_read_non_owner(struct rw_semaphore *sem);
+extern void up_write_non_owner(struct rw_semaphore *sem);
 #else
 # define down_read_nested(sem, subclass)		down_read(sem)
 # define down_write_nested(sem, subclass)	down_write(sem)
 # define down_read_non_owner(sem)		down_read(sem)
+# define down_write_non_owner(sem)		down_write(sem)
 # define up_read_non_owner(sem)			up_read(sem)
+# define up_write_non_owner(sem)		up_write(sem)
 #endif
 
 #endif /* _LINUX_RWSEM_H */
diff --git a/kernel/rwsem.c b/kernel/rwsem.c
index cae050b..2c57eef 100644
--- a/kernel/rwsem.c
+++ b/kernel/rwsem.c
@@ -126,6 +126,15 @@ void down_read_non_owner(struct rw_semaphore *sem)
 
 EXPORT_SYMBOL(down_read_non_owner);
 
+void down_write_non_owner(struct rw_semaphore *sem)
+{
+	might_sleep();
+
+	 __down_write(sem);
+}
+
+EXPORT_SYMBOL(down_write_non_owner);
+
 void down_write_nested(struct rw_semaphore *sem, int subclass)
 {
 	might_sleep();
@@ -143,6 +152,13 @@ void up_read_non_owner(struct rw_semaphore *sem)
 
 EXPORT_SYMBOL(up_read_non_owner);
 
+void up_write_non_owner(struct rw_semaphore *sem)
+{
+	__up_write(sem);
+}
+
+EXPORT_SYMBOL(up_write_non_owner);
+
 #endif
 
 
-- 
1.6.2.5