nvme: introduce helper function to get ctrl state

[ Upstream commit 5c687c287c46fadb14644091823298875a5216aa ]

The controller state is typically written by another CPU, so reading it
should ensure no optimizations are taken. This is a repeated pattern in
the driver, so start with adding a convenience function that returns the
controller state with READ_ONCE().

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 74f74b4..13f7146 100644 (file)
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -391,6 +391,11 @@ struct nvme_ctrl {
        enum nvme_dctype dctype;
 };
 
+static inline enum nvme_ctrl_state nvme_ctrl_state(struct nvme_ctrl *ctrl)
+{
+       return READ_ONCE(ctrl->state);
+}
+
 enum nvme_iopolicy {
        NVME_IOPOLICY_NUMA,
        NVME_IOPOLICY_RR,