lockd: convert nsm_mutex to a spinlock (d8421202) · Commits · 戴 / test

fs/lockd/host.c

+19 −15

Original line number	Diff line number	Diff line
		@@ -457,7 +457,7 @@ nlm_gc_hosts(void)
		* Manage NSM handles
		*/
		static LIST_HEAD(nsm_handles);
		static DEFINE_MUTEX(nsm_mutex);
		static DEFINE_SPINLOCK(nsm_lock);

		static struct nsm_handle *
		__nsm_find(const struct sockaddr_in *sin,
		@@ -479,7 +479,8 @@ __nsm_find(const struct sockaddr_in *sin,
		return NULL;
		}

		mutex_lock(&nsm_mutex);
		retry:
		spin_lock(&nsm_lock);
		list_for_each_entry(pos, &nsm_handles, sm_link) {

		if (hostname && nsm_use_hostnames) {
		@@ -489,28 +490,32 @@ __nsm_find(const struct sockaddr_in *sin,
		} else if (!nlm_cmp_addr(&pos->sm_addr, sin))
		continue;
		atomic_inc(&pos->sm_count);
		kfree(nsm);
		nsm = pos;
		goto out;
		goto found;
		}

		if (!create) {
		nsm = NULL;
		goto out;
		if (nsm) {
		list_add(&nsm->sm_link, &nsm_handles);
		goto found;
		}
		spin_unlock(&nsm_lock);

		if (!create)
		return NULL;

		nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
		if (nsm == NULL)
		goto out;
		return NULL;

		nsm->sm_addr = *sin;
		nsm->sm_name = (char *) (nsm + 1);
		memcpy(nsm->sm_name, hostname, hostname_len);
		nsm->sm_name[hostname_len] = '\0';
		atomic_set(&nsm->sm_count, 1);
		goto retry;

		list_add(&nsm->sm_link, &nsm_handles);

		out:
		mutex_unlock(&nsm_mutex);
		found:
		spin_unlock(&nsm_lock);
		return nsm;
		}

		@@ -529,10 +534,9 @@ nsm_release(struct nsm_handle *nsm)
		{
		if (!nsm)
		return;
		mutex_lock(&nsm_mutex);
		if (atomic_dec_and_test(&nsm->sm_count)) {
		if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
		list_del(&nsm->sm_link);
		spin_unlock(&nsm_lock);
		kfree(nsm);
		}
		mutex_unlock(&nsm_mutex);
		}