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| author | Dave Airlie <airlied@redhat.com> | 2014-06-05 12:28:59 +0200 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2014-06-05 12:28:59 +0200 |
| commit | 8d4ad9d4bb0a618c975a32d77087694ec6336f68 (patch) | |
| tree | d18d12688174a623e3503b11118e44ef8186c90b /block/blk-cgroup.c | |
| parent | drm: add drm_fb_helper_restore_fbdev_mode_unlocked() (diff) | |
| parent | Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux (diff) | |
| download | linux-8d4ad9d4bb0a618c975a32d77087694ec6336f68.tar.xz linux-8d4ad9d4bb0a618c975a32d77087694ec6336f68.zip | |
Merge commit '9e9a928eed8796a0a1aaed7e0b676db86ba84594' into drm-next
Merge drm-fixes into drm-next.
Both i915 and radeon need this done for later patches.
Conflicts:
drivers/gpu/drm/drm_crtc_helper.c
drivers/gpu/drm/i915/i915_drv.h
drivers/gpu/drm/i915/i915_gem.c
drivers/gpu/drm/i915/i915_gem_execbuffer.c
drivers/gpu/drm/i915/i915_gem_gtt.c
Diffstat (limited to 'block/blk-cgroup.c')
| -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); /* |