From: Waiman Long <longman@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.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 2/3] rwsem: Implement down_read_interruptible
Date: Mon, 7 Dec 2020 10:33:52 -0500 [thread overview]
Message-ID: <7be81903-14e3-7485-83e7-02e65e80e8c3@redhat.com> (raw)
In-Reply-To: <20201207090243.GE3040@hirez.programming.kicks-ass.net>
On 12/7/20 4:02 AM, Peter Zijlstra wrote:
> On Thu, Dec 03, 2020 at 08:59:13PM -0500, Waiman Long wrote:
>> On 12/3/20 3:11 PM, Eric W. Biederman wrote:
>>> +static inline int __down_read_interruptible(struct rw_semaphore *sem)
>>> +{
>>> + if (!rwsem_read_trylock(sem)) {
>>> + if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_INTERRUPTIBLE)))
>>> + return -EINTR;
>>> + DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
>>> + } else {
>>> + rwsem_set_reader_owned(sem);
>>> + }
>>> + return 0;
>>> +}
>>> +
>>> static inline int __down_read_killable(struct rw_semaphore *sem)
>>> {
>>> if (!rwsem_read_trylock(sem)) {
>>> @@ -1495,6 +1507,20 @@ void __sched down_read(struct rw_semaphore *sem)
>>> }
>>> EXPORT_SYMBOL(down_read);
>>> +int __sched down_read_interruptible(struct rw_semaphore *sem)
>>> +{
>>> + might_sleep();
>>> + rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
>>> +
>>> + if (LOCK_CONTENDED_RETURN(sem, __down_read_trylock, __down_read_interruptible)) {
>>> + rwsem_release(&sem->dep_map, _RET_IP_);
>>> + return -EINTR;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL(down_read_interruptible);
>>> +
>>> int __sched down_read_killable(struct rw_semaphore *sem)
>>> {
>>> might_sleep();
>> Acked-by: Waiman Long <longman@redhat.com>
> Yeah, that seems correct.. There's an unfortunate amount of copy-paste
> there though.
>
> Do we want to follow that up with something like this?
I am actually thinking about similar streamlining once the patch lands.
Your suggested changes look fine to me.
Cheers,
Longman
next prev parent reply other threads:[~2020-12-07 15:35 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
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 [this message]
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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