[PATCH AUTOSEL 6.6 40/43] nvme: cancel pending I/O if nvme controller is in terminal state

Sasha Levin
2024-05-07T23:12:07Z

From: Nilay Shroff <nilay@linux.ibm.com>

[ Upstream commit 25bb3534ee21e39eb9301c4edd7182eb83cb0d07 ]

While I/O is running, if the pci bus error occurs then
in-flight I/O can not complete. Worst, if at this time,
user (logically) hot-unplug the nvme disk then the
nvme_remove() code path can't forward progress until
in-flight I/O is cancelled. So these sequence of events
may potentially hang hot-unplug code path indefinitely.
This patch helps cancel the pending/in-flight I/O from the
nvme request timeout handler in case the nvme controller
is in the terminal (DEAD/DELETING/DELETING_NOIO) state and
that helps nvme_remove() code path forward progress and
finish successfully.

Link: https://lore.kernel.org/all/199be893-5dfa-41e5-b6f2-40ac90ebccc4@linux.ibm.com/
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/core.c | 21 ---------------------
drivers/nvme/host/nvme.h | 21 +++++++++++++++++++++
drivers/nvme/host/pci.c | 8 +++++++-
3 files changed, 28 insertions(+), 22 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 012c8b3f5f9c9..02d9d1b973494 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -587,27 +587,6 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
}
EXPORT_SYMBOL_GPL(nvme_change_ctrl_state);

-/*
- * Returns true for sink states that can't ever transition back to live.
- */
-static bool nvme_state_terminal(struct nvme_ctrl *ctrl)
-{
- switch (nvme_ctrl_state(ctrl)) {
- case NVME_CTRL_NEW:
- case NVME_CTRL_LIVE:
- case NVME_CTRL_RESETTING:
- case NVME_CTRL_CONNECTING:
- return false;
- case NVME_CTRL_DELETING:
- case NVME_CTRL_DELETING_NOIO:
- case NVME_CTRL_DEAD:
- return true;
- default:
- WARN_ONCE(1, "Unhandled ctrl state:%d", ctrl->state);
- return true;
- }
-}
-
/*
* Waits for the controller state to be resetting, or returns false if it is
* not possible to ever transition to that state.
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index ba62d42d2a8b7..43cff851ac5ae 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -735,6 +735,27 @@ static inline bool nvme_is_aen_req(u16 qid, __u16 command_id)
nvme_tag_from_cid(command_id) >= NVME_AQ_BLK_MQ_DEPTH;
}

+/*
+ * Returns true for sink states that can't ever transition back to live.
+ */
+static inline bool nvme_state_terminal(struct nvme_ctrl *ctrl)
+{
+ switch (nvme_ctrl_state(ctrl)) {
+ case NVME_CTRL_NEW:
+ case NVME_CTRL_LIVE:
+ case NVME_CTRL_RESETTING:
+ case NVME_CTRL_CONNECTING:
+ return false;
+ case NVME_CTRL_DELETING:
+ case NVME_CTRL_DELETING_NOIO:
+ case NVME_CTRL_DEAD:
+ return true;
+ default:
+ WARN_ONCE(1, "Unhandled ctrl state:%d", ctrl->state);
+ return true;
+ }
+}
+
void nvme_complete_rq(struct request *req);
void nvme_complete_batch_req(struct request *req);

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index b985142fb84b9..4352206533ede 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1286,6 +1286,9 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req)
struct nvme_command cmd = { };
u32 csts = readl(dev->bar + NVME_REG_CSTS);

+ if (nvme_state_terminal(&dev->ctrl))
+ goto disable;
+
/* If PCI error recovery process is happening, we cannot reset or
* the recovery mechanism will surely fail.
*/
@@ -1388,8 +1391,11 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req)
return BLK_EH_RESET_TIMER;

disable:
- if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_RESETTING))
+ if (!nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_RESETTING)) {
+ if (nvme_state_terminal(&dev->ctrl))
+ nvme_dev_disable(dev, true);
return BLK_EH_DONE;
+ }

nvme_dev_disable(dev, false);
if (nvme_try_sched_reset(&dev->ctrl))
--
2.43.0