diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2021-10-29 12:55:47 -0700 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2021-11-15 11:02:58 -0800 |
| commit | 08b9e0ab8af48895337192e683de44ab1e1b7427 (patch) | |
| tree | b668eb9786578faccd1bb7e8b1c9f817f29b3f74 /drivers/cxl | |
| parent | fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (diff) | |
cxl/pmem: Fix reference counting for delayed work
There is a potential race between queue_work() returning and the
queued-work running that could result in put_device() running before
get_device(). Introduce the cxl_nvdimm_bridge_state_work() helper that
takes the reference unconditionally, but drops it if no new work was
queued, to keep the references balanced.
Fixes: 8fdcb1704f61 ("cxl/pmem: Add initial infrastructure for pmem support")
Cc: <stable@vger.kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Link: https://lore.kernel.org/r/163553734757.2509761.3305231863616785470.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/cxl')
| -rw-r--r-- | drivers/cxl/pmem.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c index ceb2115981e5..38bcbb4e9409 100644 --- a/drivers/cxl/pmem.c +++ b/drivers/cxl/pmem.c @@ -266,14 +266,24 @@ static void cxl_nvb_update_state(struct work_struct *work) put_device(&cxl_nvb->dev); } +static void cxl_nvdimm_bridge_state_work(struct cxl_nvdimm_bridge *cxl_nvb) +{ + /* + * Take a reference that the workqueue will drop if new work + * gets queued. + */ + get_device(&cxl_nvb->dev); + if (!queue_work(cxl_pmem_wq, &cxl_nvb->state_work)) + put_device(&cxl_nvb->dev); +} + static void cxl_nvdimm_bridge_remove(struct device *dev) { struct cxl_nvdimm_bridge *cxl_nvb = to_cxl_nvdimm_bridge(dev); if (cxl_nvb->state == CXL_NVB_ONLINE) cxl_nvb->state = CXL_NVB_OFFLINE; - if (queue_work(cxl_pmem_wq, &cxl_nvb->state_work)) - get_device(&cxl_nvb->dev); + cxl_nvdimm_bridge_state_work(cxl_nvb); } static int cxl_nvdimm_bridge_probe(struct device *dev) @@ -294,8 +304,7 @@ static int cxl_nvdimm_bridge_probe(struct device *dev) } cxl_nvb->state = CXL_NVB_ONLINE; - if (queue_work(cxl_pmem_wq, &cxl_nvb->state_work)) - get_device(&cxl_nvb->dev); + cxl_nvdimm_bridge_state_work(cxl_nvb); return 0; } |