We're not taking the read_lock() anymore now that all lookup is
lockless. Just use a simple spinlock.
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
fs/namespace.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 71509309652315e5aa9c6b16d13de678bf1c98b3..966dcd27c81cc877837eca747babe0bc31aaf922 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -78,8 +78,7 @@ static struct kmem_cache *mnt_cache __ro_after_init;
static DECLARE_RWSEM(namespace_sem);
static HLIST_HEAD(unmounted); /* protected by namespace_sem */
static LIST_HEAD(ex_mountpoints); /* protected by namespace_sem */
-static DEFINE_RWLOCK(mnt_ns_tree_lock);
-static seqcount_rwlock_t mnt_ns_tree_seqcount = SEQCNT_RWLOCK_ZERO(mnt_ns_tree_seqcount, &mnt_ns_tree_lock);
+static DEFINE_SEQLOCK(mnt_ns_tree_lock);
static struct rb_root mnt_ns_tree = RB_ROOT; /* protected by mnt_ns_tree_lock */
static LIST_HEAD(mnt_ns_list); /* protected by mnt_ns_tree_lock */
@@ -131,14 +130,12 @@ static int mnt_ns_cmp(struct rb_node *a, const struct rb_node *b)
static inline void mnt_ns_tree_write_lock(void)
{
- write_lock(&mnt_ns_tree_lock);
- write_seqcount_begin(&mnt_ns_tree_seqcount);
+ write_seqlock(&mnt_ns_tree_lock);
}
static inline void mnt_ns_tree_write_unlock(void)
{
- write_seqcount_end(&mnt_ns_tree_seqcount);
- write_unlock(&mnt_ns_tree_lock);
+ write_sequnlock(&mnt_ns_tree_lock);
}
static void mnt_ns_tree_add(struct mnt_namespace *ns)
@@ -163,7 +160,7 @@ static void mnt_ns_tree_add(struct mnt_namespace *ns)
static void mnt_ns_release(struct mnt_namespace *ns)
{
- lockdep_assert_not_held(&mnt_ns_tree_lock);
+ lockdep_assert_not_held(&mnt_ns_tree_lock.lock);
/* keep alive for {list,stat}mount() */
if (refcount_dec_and_test(&ns->passive)) {
@@ -228,11 +225,11 @@ static struct mnt_namespace *lookup_mnt_ns(u64 mnt_ns_id)
guard(rcu)();
do {
- seq = read_seqcount_begin(&mnt_ns_tree_seqcount);
+ seq = read_seqbegin(&mnt_ns_tree_lock);
node = rb_find_rcu(&mnt_ns_id, &mnt_ns_tree, mnt_ns_find);
if (node)
break;
- } while (read_seqcount_retry(&mnt_ns_tree_seqcount, seq));
+ } while (read_seqretry(&mnt_ns_tree_lock, seq));
if (!node)
return NULL;
--
2.45.2
