From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/4] jump_label: Move cpu hotplug locking
Date: Tue, 1 Aug 2017 09:02:54 +0100 [thread overview]
Message-ID: <20170801080257.5056-2-marc.zyngier@arm.com> (raw)
In-Reply-To: <20170801080257.5056-1-marc.zyngier@arm.com>
As we're about to rework the locking, let's move the taking and
release of the CPU hotplug lock to locations that will make its
reworking completely obvious.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
kernel/jump_label.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index d11c506a6ac3..f11b10091100 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -105,6 +105,7 @@ void static_key_slow_inc(struct static_key *key)
{
int v, v1;
+ cpus_read_lock();
STATIC_KEY_CHECK_USE();
/*
@@ -121,11 +122,12 @@ void static_key_slow_inc(struct static_key *key)
*/
for (v = atomic_read(&key->enabled); v > 0; v = v1) {
v1 = atomic_cmpxchg(&key->enabled, v, v + 1);
- if (likely(v1 == v))
+ if (likely(v1 == v)) {
+ cpus_read_unlock();
return;
+ }
}
- cpus_read_lock();
jump_label_lock();
if (atomic_read(&key->enabled) == 0) {
atomic_set(&key->enabled, -1);
--
2.11.0
next prev parent reply other threads:[~2017-08-01 8:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-01 8:02 [PATCH v2 0/4] Working around CPU hotplug and static keys locking Marc Zyngier
2017-08-01 8:02 ` Marc Zyngier [this message]
2017-08-01 8:02 ` [PATCH v2 2/4] jump_label: Split out code under the hotplug lock Marc Zyngier
2017-08-01 8:02 ` [PATCH v2 3/4] jump_label: Provide hotplug context variants Marc Zyngier
2017-08-02 14:37 ` Peter Zijlstra
2017-08-02 15:02 ` Marc Zyngier
2017-08-01 8:02 ` [PATCH v2 4/4] clocksource/arm_arch_timer: Use static_branch_enable_cpuslocked() Marc Zyngier
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=20170801080257.5056-2-marc.zyngier@arm.com \
--to=marc.zyngier@arm.com \
--cc=linux-arm-kernel@lists.infradead.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).