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authorTejun Heo <tj@kernel.org>2014-09-24 13:00:21 -0400
committerTejun Heo <tj@kernel.org>2014-09-24 13:00:21 -0400
commitd06efebf0c37d438fcf07057be00dd40fcfce08d (patch)
tree31a0786d132aadf4cbb9725f3f444ef6e1052128 /lib/percpu-refcount.c
parentbb2e226b3bef596dd56be97df655d857b4603923 (diff)
parent0a30288da1aec914e158c2d7a3482a85f632750f (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block into for-3.18
This is to receive 0a30288da1ae ("blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe") which implements __percpu_ref_kill_expedited() to work around SCSI blk-mq stall. The commit reverted and patches to implement proper fix will be added. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'lib/percpu-refcount.c')
-rw-r--r--lib/percpu-refcount.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index 559ee0b20318..c6c31e2829b1 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -189,3 +189,19 @@ void percpu_ref_kill_and_confirm(struct percpu_ref *ref,
call_rcu_sched(&ref->rcu, percpu_ref_kill_rcu);
}
EXPORT_SYMBOL_GPL(percpu_ref_kill_and_confirm);
+
+/*
+ * XXX: Temporary kludge to work around SCSI blk-mq stall. Used only by
+ * block/blk-mq.c::blk_mq_freeze_queue(). Will be removed during v3.18
+ * devel cycle. Do not use anywhere else.
+ */
+void __percpu_ref_kill_expedited(struct percpu_ref *ref)
+{
+ WARN_ONCE(ref->pcpu_count_ptr & PCPU_REF_DEAD,
+ "percpu_ref_kill() called more than once on %pf!",
+ ref->release);
+
+ ref->pcpu_count_ptr |= PCPU_REF_DEAD;
+ synchronize_sched_expedited();
+ percpu_ref_kill_rcu(&ref->rcu);
+}