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| author | Tejun Heo | 2014-05-13 18:11:00 +0200 |
|---|---|---|
| committer | Tejun Heo | 2014-05-13 18:11:00 +0200 |
| commit | 7d331fa985d3a39d5b8cb60caf016d3e53e57c91 (patch) | |
| tree | 91521a5c39556347262c2b41c05428236e6ced46 | |
| parent | cgroup: update and fix parsing of "cgroup.subtree_control" (diff) | |
| download | kernel-qcow2-linux-7d331fa985d3a39d5b8cb60caf016d3e53e57c91.tar.gz kernel-qcow2-linux-7d331fa985d3a39d5b8cb60caf016d3e53e57c91.tar.xz kernel-qcow2-linux-7d331fa985d3a39d5b8cb60caf016d3e53e57c91.zip | |
cgroup: use restart_syscall() for retries after offline waits in cgroup_subtree_control_write()
After waiting for a child to finish offline,
cgroup_subtree_control_write() jumps up to retry from after the input
parsing and active protection breaking. This retry makes the
scheduled locking update - removal of cgroup_tree_mutex - more
difficult. Let's simplify it by returning with restart_syscall() for
retries.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
| -rw-r--r-- | kernel/cgroup.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 250def0694b4..3251cc9070fa 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2535,7 +2535,7 @@ out_finish: static int cgroup_subtree_control_write(struct cgroup_subsys_state *dummy_css, struct cftype *cft, char *buffer) { - unsigned int enable_req = 0, disable_req = 0, enable, disable; + unsigned int enable = 0, disable = 0; struct cgroup *cgrp = dummy_css->cgroup, *child; struct cgroup_subsys *ss; char *tok, *p; @@ -2554,11 +2554,11 @@ static int cgroup_subtree_control_write(struct cgroup_subsys_state *dummy_css, continue; if (*tok == '+') { - enable_req |= 1 << ssid; - disable_req &= ~(1 << ssid); + enable |= 1 << ssid; + disable &= ~(1 << ssid); } else if (*tok == '-') { - disable_req |= 1 << ssid; - enable_req &= ~(1 << ssid); + disable |= 1 << ssid; + enable &= ~(1 << ssid); } else { return -EINVAL; } @@ -2576,9 +2576,6 @@ static int cgroup_subtree_control_write(struct cgroup_subsys_state *dummy_css, */ cgroup_get(cgrp); kernfs_break_active_protection(cgrp->control_kn); -retry: - enable = enable_req; - disable = disable_req; mutex_lock(&cgroup_tree_mutex); @@ -2608,7 +2605,9 @@ retry: schedule(); finish_wait(&child->offline_waitq, &wait); cgroup_put(child); - goto retry; + + ret = restart_syscall(); + goto out_unbreak; } /* unavailable or not enabled on the parent? */ @@ -2692,6 +2691,7 @@ out_unlock: mutex_unlock(&cgroup_mutex); out_unlock_tree: mutex_unlock(&cgroup_tree_mutex); +out_unbreak: kernfs_unbreak_active_protection(cgrp->control_kn); cgroup_put(cgrp); return ret; |