We currently have the ability to call lockdep_assert_held to throw a
warning when a spinlock isn't held in a codepath. There are also times
when we'd like to throw a warning when a lock is held (i.e. when there
is the potential for deadlock with atomic_dec_and_lock or similar).
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 4 ++++
include/linux/lockdep.h | 4 ++++
2 files changed, 8 insertions(+)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 4f82e502f53a..1446cbfc42b4 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -263,6 +263,8 @@ static void nfsd4_free_file(struct nfs4_file *f)
static inline void
put_nfs4_file(struct nfs4_file *fi)
{
+ lockdep_assert_not_held(&state_lock);
+
if (atomic_dec_and_lock(&fi->fi_ref, &state_lock)) {
hlist_del(&fi->fi_hash);
spin_unlock(&state_lock);
@@ -420,6 +422,8 @@ static __be32 nfs4_file_check_deny(struct nfs4_file *fp, u32 deny)
static void __nfs4_file_put_access(struct nfs4_file *fp, int oflag)
{
+ lockdep_assert_not_held(&fp->fi_lock);
+
if (atomic_dec_and_lock(&fp->fi_access[oflag], &fp->fi_lock)) {
struct file *f1 = NULL;
struct file *f2 = NULL;
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 008388f920d7..1e5f1d544029 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -362,6 +362,8 @@ extern void lockdep_trace_alloc(gfp_t mask);
WARN_ON(debug_locks && !lockdep_is_held(l)); \
} while (0)
+#define lockdep_assert_not_held(l) WARN_ON(debug_locks && lockdep_is_held(l))
+
#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
#else /* !CONFIG_LOCKDEP */
@@ -413,6 +415,8 @@ struct lock_class_key { };
#define lockdep_assert_held(l) do { (void)(l); } while (0)
+#define lockdep_assert_not_held(l) (void)(l)
+
#define lockdep_recursing(tsk) (0)
#endif /* !LOCKDEP */
--
1.9.3
--
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