From: Christoph Hellwig <[email protected]> [ Upstream commit 2dd4122854f697afc777582d18548dded03ce5dd ]
For kref_get_unless_zero to protect against lookup vs free races we need to use it in all places where we aren't guaranteed to already hold a reference. There is no such guarantee in nvme_find_get_ns, so switch to kref_get_unless_zero in this function. Signed-off-by: Christoph Hellwig <[email protected]> Reviewed-by: Sagi Grimberg <[email protected]> Reviewed-by: Hannes Reinecke <[email protected]> Reviewed-by: Johannes Thumshirn <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- drivers/nvme/host/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 37f9039bb9ca..0655f45643d9 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -2299,7 +2299,8 @@ static struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid) mutex_lock(&ctrl->namespaces_mutex); list_for_each_entry(ns, &ctrl->namespaces, list) { if (ns->ns_id == nsid) { - kref_get(&ns->kref); + if (!kref_get_unless_zero(&ns->kref)) + continue; ret = ns; break; } -- 2.11.0
