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authorDan Williams <dan.j.williams@intel.com>2016-10-27 17:04:05 -0700
committerDan Williams <dan.j.williams@intel.com>2016-10-27 17:04:05 -0700
commit52e73eb2872c9af6f382b2b22954ca8214397a4e (patch)
tree535f1b0672bf4b1ad826a67e26437441ead156c7 /drivers/dax
parent867dfe342118b1ea0256a85f7c0d9ceb0ead032a (diff)
downloadlinux-52e73eb2872c9af6f382b2b22954ca8214397a4e.tar.bz2
device-dax: fix percpu_ref_exit ordering
We need to wait until the percpu_ref is released before exit. Otherwise, we sometimes lose the race and trigger this new warning that was added in v4.9 (commit a67823c1ed10 "percpu-refcount: init ->confirm_switch member properly"): WARNING: CPU: 0 PID: 3629 at lib/percpu-refcount.c:107 percpu_ref_exit+0x51/0x60 [..] Call Trace: [<ffffffff814bf093>] dump_stack+0x85/0xc2 [<ffffffff810b15db>] __warn+0xcb/0xf0 [<ffffffff810b170d>] warn_slowpath_null+0x1d/0x20 [<ffffffff814d70c1>] percpu_ref_exit+0x51/0x60 [<ffffffffa005706a>] dax_pmem_percpu_exit+0x1a/0x50 [dax_pmem] [<ffffffff81615f1f>] devm_action_release+0xf/0x20 Cc: <stable@vger.kernel.org> Fixes: ab68f2622136 ("/dev/dax, pmem: direct access to persistent memory") Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dax')
-rw-r--r--drivers/dax/pmem.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index 9630d8837ba9..4a15fa5df98b 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -44,7 +44,6 @@ static void dax_pmem_percpu_exit(void *data)
dev_dbg(dax_pmem->dev, "%s\n", __func__);
percpu_ref_exit(ref);
- wait_for_completion(&dax_pmem->cmp);
}
static void dax_pmem_percpu_kill(void *data)
@@ -54,6 +53,7 @@ static void dax_pmem_percpu_kill(void *data)
dev_dbg(dax_pmem->dev, "%s\n", __func__);
percpu_ref_kill(ref);
+ wait_for_completion(&dax_pmem->cmp);
}
static int dax_pmem_probe(struct device *dev)