linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
	linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Carsten Emde <C.Emde@osadl.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	John Kacur <jkacur@redhat.com>, Daniel Wagner <wagi@monom.org>,
	Tom Zanussi <zanussi@kernel.org>,
	"Srivatsa S. Bhat" <srivatsa@csail.mit.edu>
Subject: [PATCH RT 5/6] rwsem: Provide down_read_non_owner() and up_read_non_owner() for -RT
Date: Wed, 12 Aug 2020 21:45:39 -0400	[thread overview]
Message-ID: <20200813014555.980104906@goodmis.org> (raw)
In-Reply-To: 20200813014534.833107526@goodmis.org

5.4.54-rt33-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

The rwsem implementation on -RT allows multiple reader and there is no
owner tracking anymore.
We can provide down_read_non_owner() and up_read_non_owner() by skipping
the owner check bits which are only available in the !RT implementation.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/locking/rwsem.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 0d11ba11a32a..0325c721f9b3 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -1616,15 +1616,15 @@ void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
 }
 EXPORT_SYMBOL(_down_write_nest_lock);
 
-#ifndef CONFIG_PREEMPT_RT
 void down_read_non_owner(struct rw_semaphore *sem)
 {
 	might_sleep();
 	__down_read(sem);
+#ifndef CONFIG_PREEMPT_RT
 	__rwsem_set_reader_owned(sem, NULL);
+#endif
 }
 EXPORT_SYMBOL(down_read_non_owner);
-#endif
 
 void down_write_nested(struct rw_semaphore *sem, int subclass)
 {
@@ -1649,13 +1649,13 @@ int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass)
 }
 EXPORT_SYMBOL(down_write_killable_nested);
 
-#ifndef CONFIG_PREEMPT_RT
 void up_read_non_owner(struct rw_semaphore *sem)
 {
+#ifndef CONFIG_PREEMPT_RT
 	DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+#endif
 	__up_read(sem);
 }
 EXPORT_SYMBOL(up_read_non_owner);
-#endif
 
 #endif
-- 
2.28.0



  parent reply	other threads:[~2020-08-13  1:46 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-13  1:45 [PATCH RT 0/6] Linux 5.4.54-rt33-rc1 Steven Rostedt
2020-08-13  1:45 ` [PATCH RT 1/6] signal: Prevent double-free of user struct Steven Rostedt
2020-08-13  8:25   ` Rasmus Villemoes
2020-08-13 19:28     ` Steven Rostedt
2020-08-13  1:45 ` [PATCH RT 2/6] workqueue: Sync with upstream Steven Rostedt
2020-08-13  1:45 ` [PATCH RT 3/6] Bluetooth: Acquire sk_lock.slock without disabling interrupts Steven Rostedt
2020-08-13  1:45 ` [PATCH RT 4/6] net: phy: fixed_phy: Remove unused seqcount Steven Rostedt
2020-08-13  1:45 ` Steven Rostedt [this message]
2020-08-13  1:45 ` [PATCH RT 6/6] Linux 5.4.54-rt33-rc1 Steven Rostedt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200813014555.980104906@goodmis.org \
    --to=rostedt@goodmis.org \
    --cc=C.Emde@osadl.org \
    --cc=bigeasy@linutronix.de \
    --cc=jkacur@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rt-users@vger.kernel.org \
    --cc=srivatsa@csail.mit.edu \
    --cc=tglx@linutronix.de \
    --cc=wagi@monom.org \
    --cc=zanussi@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).