nvme: cancel pending I/O if nvme controller is in terminal state

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>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index e4bec200ebeb27077083995283eb9e0a746fef9c..095f59e7aa937aa3ae9d8e3fc3f1a25608c99f25 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -628,27 +628,6 @@ 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 d0ed64dc7380e51577bc6ece92db1d0a273905a7..b564c5f1450c6a506302c482882d2be31a8eb5c6 100644 (file)
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -741,6 +741,27 @@ 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 8e0bb9692685d4638bd21dad44fe1fbbbb147a77..e393f6947ce493f8674a7bb971dc4d4abae192ca 100644 (file)
--- 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)
        u32 csts = readl(dev->bar + NVME_REG_CSTS);
        u8 opcode;
 
+       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.
         */
@@ -1390,8 +1393,11 @@ 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))