From d3891851c52f30a3ca29f5f1b591da10ee357835 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sat, 23 Jul 2022 15:30:47 +0200 Subject: [PATCH] Revert "cgroup: Use separate src/dst nodes when preloading css_sets for migration" This reverts commit ad44e05f3e016bdcb1ad25af35ade5b5f41ccd68 which is commit 07fd5b6cdf3cc30bfde8fe0f644771688be04447 upstream. It breaks the kernel ABI and is not something that is an issue for Android devices, so revert it. Signed-off-by: Greg Kroah-Hartman Change-Id: I89125948bbf90805d25a446afeab69f6581442bc --- include/linux/cgroup-defs.h | 3 +-- kernel/cgroup/cgroup.c | 37 ++++++++++++++----------------------- 2 files changed, 15 insertions(+), 25 deletions(-) diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index f5ebec80986d..e77b6b0da731 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -255,8 +255,7 @@ struct css_set { * List of csets participating in the on-going migration either as * source or destination. Protected by cgroup_mutex. */ - struct list_head mg_src_preload_node; - struct list_head mg_dst_preload_node; + struct list_head mg_preload_node; struct list_head mg_node; /* diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 23f0db2900e4..177d57ce9016 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -743,8 +743,7 @@ struct css_set init_css_set = { .task_iters = LIST_HEAD_INIT(init_css_set.task_iters), .threaded_csets = LIST_HEAD_INIT(init_css_set.threaded_csets), .cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links), - .mg_src_preload_node = LIST_HEAD_INIT(init_css_set.mg_src_preload_node), - .mg_dst_preload_node = LIST_HEAD_INIT(init_css_set.mg_dst_preload_node), + .mg_preload_node = LIST_HEAD_INIT(init_css_set.mg_preload_node), .mg_node = LIST_HEAD_INIT(init_css_set.mg_node), /* @@ -1220,8 +1219,7 @@ static struct css_set *find_css_set(struct css_set *old_cset, INIT_LIST_HEAD(&cset->threaded_csets); INIT_HLIST_NODE(&cset->hlist); INIT_LIST_HEAD(&cset->cgrp_links); - INIT_LIST_HEAD(&cset->mg_src_preload_node); - INIT_LIST_HEAD(&cset->mg_dst_preload_node); + INIT_LIST_HEAD(&cset->mg_preload_node); INIT_LIST_HEAD(&cset->mg_node); /* Copy the set of subsystem state objects generated in @@ -2631,27 +2629,21 @@ int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp) */ void cgroup_migrate_finish(struct cgroup_mgctx *mgctx) { + LIST_HEAD(preloaded); struct css_set *cset, *tmp_cset; lockdep_assert_held(&cgroup_mutex); spin_lock_irq(&css_set_lock); - list_for_each_entry_safe(cset, tmp_cset, &mgctx->preloaded_src_csets, - mg_src_preload_node) { - cset->mg_src_cgrp = NULL; - cset->mg_dst_cgrp = NULL; - cset->mg_dst_cset = NULL; - list_del_init(&cset->mg_src_preload_node); - put_css_set_locked(cset); - } + list_splice_tail_init(&mgctx->preloaded_src_csets, &preloaded); + list_splice_tail_init(&mgctx->preloaded_dst_csets, &preloaded); - list_for_each_entry_safe(cset, tmp_cset, &mgctx->preloaded_dst_csets, - mg_dst_preload_node) { + list_for_each_entry_safe(cset, tmp_cset, &preloaded, mg_preload_node) { cset->mg_src_cgrp = NULL; cset->mg_dst_cgrp = NULL; cset->mg_dst_cset = NULL; - list_del_init(&cset->mg_dst_preload_node); + list_del_init(&cset->mg_preload_node); put_css_set_locked(cset); } @@ -2693,7 +2685,7 @@ void cgroup_migrate_add_src(struct css_set *src_cset, src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root); - if (!list_empty(&src_cset->mg_src_preload_node)) + if (!list_empty(&src_cset->mg_preload_node)) return; WARN_ON(src_cset->mg_src_cgrp); @@ -2704,7 +2696,7 @@ void cgroup_migrate_add_src(struct css_set *src_cset, src_cset->mg_src_cgrp = src_cgrp; src_cset->mg_dst_cgrp = dst_cgrp; get_css_set(src_cset); - list_add_tail(&src_cset->mg_src_preload_node, &mgctx->preloaded_src_csets); + list_add_tail(&src_cset->mg_preload_node, &mgctx->preloaded_src_csets); } /** @@ -2729,7 +2721,7 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) /* look up the dst cset for each src cset and link it to src */ list_for_each_entry_safe(src_cset, tmp_cset, &mgctx->preloaded_src_csets, - mg_src_preload_node) { + mg_preload_node) { struct css_set *dst_cset; struct cgroup_subsys *ss; int ssid; @@ -2748,7 +2740,7 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) if (src_cset == dst_cset) { src_cset->mg_src_cgrp = NULL; src_cset->mg_dst_cgrp = NULL; - list_del_init(&src_cset->mg_src_preload_node); + list_del_init(&src_cset->mg_preload_node); put_css_set(src_cset); put_css_set(dst_cset); continue; @@ -2756,8 +2748,8 @@ int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx) src_cset->mg_dst_cset = dst_cset; - if (list_empty(&dst_cset->mg_dst_preload_node)) - list_add_tail(&dst_cset->mg_dst_preload_node, + if (list_empty(&dst_cset->mg_preload_node)) + list_add_tail(&dst_cset->mg_preload_node, &mgctx->preloaded_dst_csets); else put_css_set(dst_cset); @@ -2988,8 +2980,7 @@ static int cgroup_update_dfl_csses(struct cgroup *cgrp) goto out_finish; spin_lock_irq(&css_set_lock); - list_for_each_entry(src_cset, &mgctx.preloaded_src_csets, - mg_src_preload_node) { + list_for_each_entry(src_cset, &mgctx.preloaded_src_csets, mg_preload_node) { struct task_struct *task, *ntask; /* all tasks in src_csets need to be migrated */