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authorTakashi Iwai <tiwai@suse.de>2017-07-03 19:51:42 +0200
committerTakashi Iwai <tiwai@suse.de>2017-07-03 19:51:42 +0200
commit818a23e3882b1bf65d1719e407be04716e69a4d5 (patch)
tree6e4267b570541f779e7d85c11eb14312fa86fbb1 /include/linux/cgroup.h
parenta178232ddab55048e347b43b697bfa5013ef819e (diff)
parentb821d298f8864dc3c3d42643812df43289159507 (diff)
Merge tag 'asoc-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Updates for v4.13 The big news with this release is the of-graph card, this provides a replacement for simple-card that is much more flexibile and scalable, allowing many more systems to use a generic sound card than was possible before: - The of-graph card, finally merged after a long and dedicated effort by Morimoto-san. - New widget types intended mainly for use with DSPs. - New drivers for Allwinner V3s SoCs, Ensonic ES8316, several classes of x86 machine, Rockchip PDM controllers, STM32 I2S and S/PDIF controllers and ZTE AUD96P22 CODECs.
Diffstat (limited to 'include/linux/cgroup.h')
-rw-r--r--include/linux/cgroup.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index ed2573e149fa..710a005c6b7a 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -344,6 +344,26 @@ static inline bool css_tryget_online(struct cgroup_subsys_state *css)
}
/**
+ * css_is_dying - test whether the specified css is dying
+ * @css: target css
+ *
+ * Test whether @css is in the process of offlining or already offline. In
+ * most cases, ->css_online() and ->css_offline() callbacks should be
+ * enough; however, the actual offline operations are RCU delayed and this
+ * test returns %true also when @css is scheduled to be offlined.
+ *
+ * This is useful, for example, when the use case requires synchronous
+ * behavior with respect to cgroup removal. cgroup removal schedules css
+ * offlining but the css can seem alive while the operation is being
+ * delayed. If the delay affects user visible semantics, this test can be
+ * used to resolve the situation.
+ */
+static inline bool css_is_dying(struct cgroup_subsys_state *css)
+{
+ return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);
+}
+
+/**
* css_put - put a css reference
* @css: target css
*