pstore: Add proper unregister lock checking (6248a066) · Commits · 戴 / test

fs/pstore/platform.c

+17 −4

Original line number	Diff line number	Diff line
		@@ -69,8 +69,9 @@ static void pstore_dowork(struct work_struct *);
		static DECLARE_WORK(pstore_work, pstore_dowork);

		/*
		* psinfo_lock just protects "psinfo" during
		* calls to pstore_register()
		* psinfo_lock protects "psinfo" during calls to
		* pstore_register(), pstore_unregister(), and
		* the filesystem mount/unmount routines.
		*/
		static DEFINE_MUTEX(psinfo_lock);
		struct pstore_info *psinfo;
		@@ -587,8 +588,6 @@ int pstore_register(struct pstore_info *psi)
		psinfo = psi;
		mutex_init(&psinfo->read_mutex);
		sema_init(&psinfo->buf_lock, 1);
		mutex_unlock(&psinfo_lock);


		if (psi->flags & PSTORE_FLAGS_DMESG)
		allocate_buf_for_compression();
		@@ -620,12 +619,25 @@ int pstore_register(struct pstore_info *psi)

		pr_info("Registered %s as persistent store backend\n", psi->name);

		mutex_unlock(&psinfo_lock);
		return 0;
		}
		EXPORT_SYMBOL_GPL(pstore_register);

		void pstore_unregister(struct pstore_info *psi)
		{
		/* It's okay to unregister nothing. */
		if (!psi)
		return;

		mutex_lock(&psinfo_lock);

		/* Only one backend can be registered at a time. */
		if (WARN_ON(psi != psinfo)) {
		mutex_unlock(&psinfo_lock);
		return;
		}

		/* Stop timer and make sure all work has finished. */
		pstore_update_ms = -1;
		del_timer_sync(&pstore_timer);
		@@ -644,6 +656,7 @@ void pstore_unregister(struct pstore_info *psi)

		psinfo = NULL;
		backend = NULL;
		mutex_unlock(&psinfo_lock);
		}
		EXPORT_SYMBOL_GPL(pstore_unregister);