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authorAleksa Sarai <cyphar@cyphar.com>2015-06-09 21:32:09 +1000
committerTejun Heo <tj@kernel.org>2015-07-14 17:29:23 -0400
commit7e47682ea555e7c1edef1d8fd96e2aa4c12abe59 (patch)
tree6012cbc180ae7d633be4ed2ff1f1f6f7f188c1a0 /include/linux/cgroup_subsys.h
parentd770e558e21961ad6cfdf0ff7df0eb5d7d4f0754 (diff)
cgroup: allow a cgroup subsystem to reject a fork
Add a new cgroup subsystem callback can_fork that conditionally states whether or not the fork is accepted or rejected by a cgroup policy. In addition, add a cancel_fork callback so that if an error occurs later in the forking process, any state modified by can_fork can be reverted. Allow for a private opaque pointer to be passed from cgroup_can_fork to cgroup_post_fork, allowing for the fork state to be stored by each subsystem separately. Also add a tagging system for cgroup_subsys.h to allow for CGROUP_<TAG> enumerations to be be defined and used. In addition, explicitly add a CGROUP_CANFORK_COUNT macro to make arrays easier to define. This is in preparation for implementing the pids cgroup subsystem. Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include/linux/cgroup_subsys.h')
-rw-r--r--include/linux/cgroup_subsys.h23
1 files changed, 23 insertions, 0 deletions
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index e4a96fb14403..ec43bce7e1ea 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -3,6 +3,17 @@
*
* DO NOT ADD ANY SUBSYSTEM WITHOUT EXPLICIT ACKS FROM CGROUP MAINTAINERS.
*/
+
+/*
+ * This file *must* be included with SUBSYS() defined.
+ * SUBSYS_TAG() is a noop if undefined.
+ */
+
+#ifndef SUBSYS_TAG
+#define __TMP_SUBSYS_TAG
+#define SUBSYS_TAG(_x)
+#endif
+
#if IS_ENABLED(CONFIG_CPUSETS)
SUBSYS(cpuset)
#endif
@@ -48,11 +59,23 @@ SUBSYS(hugetlb)
#endif
/*
+ * Subsystems that implement the can_fork() family of callbacks.
+ */
+SUBSYS_TAG(CANFORK_START)
+SUBSYS_TAG(CANFORK_END)
+
+/*
* The following subsystems are not supported on the default hierarchy.
*/
#if IS_ENABLED(CONFIG_CGROUP_DEBUG)
SUBSYS(debug)
#endif
+
+#ifdef __TMP_SUBSYS_TAG
+#undef __TMP_SUBSYS_TAG
+#undef SUBSYS_TAG
+#endif
+
/*
* DO NOT ADD ANY SUBSYSTEM WITHOUT EXPLICIT ACKS FROM CGROUP MAINTAINERS.
*/