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| author | H. Peter Anvin <hpa@linux.intel.com> | 2014-05-22 00:23:19 +0200 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2014-05-22 00:23:19 +0200 |
| commit | e6ab9a20e73e790d47e6aa231fcf66f27b6ce3d4 (patch) | |
| tree | 6a41361e1de2a6693ccae96b99307e79a467236f /block | |
| parent | x86, espfix: Make it possible to disable 16-bit support (diff) | |
| parent | Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime option" (diff) | |
| download | linux-e6ab9a20e73e790d47e6aa231fcf66f27b6ce3d4.tar.xz linux-e6ab9a20e73e790d47e6aa231fcf66f27b6ce3d4.zip | |
Merge commit '7ed6fb9b5a5510e4ef78ab27419184741169978a' into x86/espfix
Merge in Linus' tree with:
fa81511bb0bb x86-64, modify_ldt: Make support for 16-bit segments a runtime option
... reverted, to avoid a conflict. This commit is no longer necessary
with the proper fix in place.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-cgroup.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index e4a4145926f6..1039fb9ff5f5 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -451,7 +451,20 @@ static int blkcg_reset_stats(struct cgroup_subsys_state *css, struct blkcg_gq *blkg; int i; - mutex_lock(&blkcg_pol_mutex); + /* + * XXX: We invoke cgroup_add/rm_cftypes() under blkcg_pol_mutex + * which ends up putting cgroup's internal cgroup_tree_mutex under + * it; however, cgroup_tree_mutex is nested above cgroup file + * active protection and grabbing blkcg_pol_mutex from a cgroup + * file operation creates a possible circular dependency. cgroup + * internal locking is planned to go through further simplification + * and this issue should go away soon. For now, let's trylock + * blkcg_pol_mutex and restart the write on failure. + * + * http://lkml.kernel.org/g/5363C04B.4010400@oracle.com + */ + if (!mutex_trylock(&blkcg_pol_mutex)) + return restart_syscall(); spin_lock_irq(&blkcg->lock); /* |