From: Waiman Long <longman@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>,
linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Jann Horn <jannh@google.com>,
Vasiliy Kulikov <segoon@openwall.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Bernd Edlinger <bernd.edlinger@hotmail.de>,
Oleg Nesterov <oleg@redhat.com>,
Christopher Yeoh <cyeoh@au1.ibm.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Sargun Dhillon <sargun@sargun.me>,
Christian Brauner <christian.brauner@ubuntu.com>,
Arnd Bergmann <arnd@arndb.de>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: Re: [PATCH 1/3] rwsem: Implement down_read_killable_nested
Date: Thu, 3 Dec 2020 20:58:33 -0500 [thread overview]
Message-ID: <c4e66f5a-a48c-5a72-a733-9e1bcd77274a@redhat.com> (raw)
In-Reply-To: <87o8jabqh3.fsf@x220.int.ebiederm.org>
On 12/3/20 3:10 PM, Eric W. Biederman wrote:
> In preparation for converting exec_update_mutex to a rwsem so that
> multiple readers can execute in parallel and not deadlock, add
> down_read_killable_nested. This is needed so that kcmp_lock
> can be converted from working on a mutexes to working on rw_semaphores.
>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Will Deacon <will@kernel.org>
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> ---
> include/linux/rwsem.h | 2 ++
> kernel/locking/rwsem.c | 14 ++++++++++++++
> 2 files changed, 16 insertions(+)
>
> diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
> index 25e3fde85617..13021b08b2ed 100644
> --- a/include/linux/rwsem.h
> +++ b/include/linux/rwsem.h
> @@ -171,6 +171,7 @@ extern void downgrade_write(struct rw_semaphore *sem);
> * See Documentation/locking/lockdep-design.rst for more details.)
> */
> extern void down_read_nested(struct rw_semaphore *sem, int subclass);
> +extern int __must_check down_read_killable_nested(struct rw_semaphore *sem, int subclass);
> extern void down_write_nested(struct rw_semaphore *sem, int subclass);
> extern int down_write_killable_nested(struct rw_semaphore *sem, int subclass);
> extern void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest_lock);
> @@ -191,6 +192,7 @@ extern void down_read_non_owner(struct rw_semaphore *sem);
> extern void up_read_non_owner(struct rw_semaphore *sem);
> #else
> # define down_read_nested(sem, subclass) down_read(sem)
> +# define down_read_killable_nested(sem, subclass) down_read_killable(sem)
> # define down_write_nest_lock(sem, nest_lock) down_write(sem)
> # define down_write_nested(sem, subclass) down_write(sem)
> # define down_write_killable_nested(sem, subclass) down_write_killable(sem)
> diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
> index f11b9bd3431d..54d11cb97551 100644
> --- a/kernel/locking/rwsem.c
> +++ b/kernel/locking/rwsem.c
> @@ -1605,6 +1605,20 @@ void down_read_nested(struct rw_semaphore *sem, int subclass)
> }
> EXPORT_SYMBOL(down_read_nested);
>
> +int down_read_killable_nested(struct rw_semaphore *sem, int subclass)
> +{
> + might_sleep();
> + rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
> +
> + if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_killable)) {
> + rwsem_release(&sem->dep_map, _RET_IP_);
> + return -EINTR;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(down_read_killable_nested);
> +
> void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
> {
> might_sleep();
Acked-by: Waiman Long <longman@redhat.com>
-Longman
next prev parent reply other threads:[~2020-12-04 2:00 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 20:09 [PATCH 0/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-03 20:10 ` [PATCH 1/3] rwsem: Implement down_read_killable_nested Eric W. Biederman
2020-12-04 1:58 ` Waiman Long [this message]
2020-12-09 18:38 ` [tip: locking/core] " tip-bot2 for Eric W. Biederman
2020-12-03 20:11 ` [PATCH 2/3] rwsem: Implement down_read_interruptible Eric W. Biederman
2020-12-04 1:59 ` Waiman Long
2020-12-07 9:02 ` Peter Zijlstra
2020-12-07 15:33 ` Waiman Long
2020-12-07 16:58 ` David Laight
2020-12-07 19:02 ` Waiman Long
2020-12-08 9:12 ` David Laight
2020-12-08 12:32 ` Peter Zijlstra
2020-12-08 13:13 ` David Laight
2020-12-08 15:34 ` Waiman Long
2020-12-08 16:23 ` David Laight
2020-12-07 15:56 ` Eric W. Biederman
2020-12-08 14:52 ` Peter Zijlstra
2020-12-08 18:27 ` Eric W. Biederman
2020-12-09 18:36 ` Peter Zijlstra
2020-12-10 19:33 ` Eric W. Biederman
2020-12-11 8:16 ` Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] locking/rwsem: Introduce rwsem_write_trylock() tip-bot2 for Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] locking/rwsem: Fold __down_{read,write}*() tip-bot2 for Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] locking/rwsem: Better collate rwsem_read_trylock() tip-bot2 for Peter Zijlstra
2020-12-09 18:38 ` [tip: locking/core] rwsem: Implement down_read_interruptible tip-bot2 for Eric W. Biederman
2020-12-03 20:12 ` [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-04 16:08 ` Bernd Edlinger
2020-12-04 17:21 ` Linus Torvalds
2020-12-04 19:34 ` Eric W. Biederman
2020-12-04 20:10 ` Linus Torvalds
2020-12-04 20:30 ` Bernd Edlinger
2020-12-04 20:48 ` Linus Torvalds
2020-12-04 21:48 ` Davidlohr Bueso
2020-12-05 18:05 ` Eric W. Biederman
2020-12-07 9:15 ` Peter Zijlstra
2020-12-07 9:09 ` Peter Zijlstra
2020-12-07 18:40 ` Linus Torvalds
2020-12-08 8:34 ` [PATCH] perf: Break deadlock involving exec_update_mutex Peter Zijlstra
2020-12-08 18:37 ` Linus Torvalds
2020-12-10 18:38 ` Davidlohr Bueso
2020-12-10 19:40 ` Eric W. Biederman
2020-12-05 17:43 ` [PATCH 3/3] exec: Transform exec_update_mutex into a rw_semaphore Eric W. Biederman
2020-12-04 17:39 ` Eric W. Biederman
2020-12-03 22:42 ` [PATCH 0/3] " Linus Torvalds
2020-12-04 1:56 ` Waiman Long
2020-12-04 4:54 ` Davidlohr Bueso
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