On 5/20/20 10:10 AM, Dongli Zhang wrote:
>
>
> On 5/20/20 4:56 AM, Ming Lei wrote:
>> During waiting for in-flight IO completion in reset handler, timeout
>> or controller failure still may happen, then the controller is deleted
>> and all inflight IOs are failed. This way is too violent.
>>
>> Improve the reset handling by replacing nvme_wait_freeze with query
>> & check controller. If all ns queues are frozen, the controller is reset
>> successfully, otherwise check and see if the controller has been disabled.
>> If yes, break from the current recovery and schedule a fresh new reset.
>>
>> This way avoids to failing IO & removing controller unnecessarily.
>>
>> Cc: Christoph Hellwig <hch@xxxxxx>
>> Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
>> Cc: Keith Busch <kbusch@xxxxxxxxxx>
>> Cc: Max Gurtovoy <maxg@xxxxxxxxxxxx>
>> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
>> ---
>> drivers/nvme/host/pci.c | 37 ++++++++++++++++++++++++++++++-------
>> 1 file changed, 30 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
>> index ce0d1e79467a..b5aeed33a634 100644
>> --- a/drivers/nvme/host/pci.c
>> +++ b/drivers/nvme/host/pci.c
>> @@ -24,6 +24,7 @@
>> #include <linux/io-64-nonatomic-lo-hi.h>
>> #include <linux/sed-opal.h>
>> #include <linux/pci-p2pdma.h>
>> +#include <linux/delay.h>
>>
>> #include "trace.h"
>> #include "nvme.h"
>> @@ -1235,9 +1236,6 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
>> * shutdown, so we return BLK_EH_DONE.
>> */
>> switch (dev->ctrl.state) {
>> - case NVME_CTRL_CONNECTING:
>> - nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING);
>> - /* fall through */
>> case NVME_CTRL_DELETING:
>> dev_warn_ratelimited(dev->ctrl.device,
>> "I/O %d QID %d timeout, disable controller\n",
>> @@ -2393,7 +2391,8 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown)
>> u32 csts = readl(dev->bar + NVME_REG_CSTS);
>>
>> if (dev->ctrl.state == NVME_CTRL_LIVE ||
>> - dev->ctrl.state == NVME_CTRL_RESETTING) {
>> + dev->ctrl.state == NVME_CTRL_RESETTING ||
>> + dev->ctrl.state == NVME_CTRL_CONNECTING) {
>> freeze = true;
>> nvme_start_freeze(&dev->ctrl);
>> }
>> @@ -2504,12 +2503,29 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev)
>> nvme_put_ctrl(&dev->ctrl);
>> }
>>
>> +static bool nvme_wait_freeze_and_check(struct nvme_dev *dev)
>> +{
>> + bool frozen;
>> +
>> + while (true) {
>> + frozen = nvme_frozen(&dev->ctrl);
>> + if (frozen)
>> + break;
>> + if (!dev->online_queues)
>> + break;
>> + msleep(5);
>> + }
>> +
>> + return frozen;
>> +}
>> +
>> static void nvme_reset_work(struct work_struct *work)
>> {
>> struct nvme_dev *dev =
>> container_of(work, struct nvme_dev, ctrl.reset_work);
>> bool was_suspend = !!(dev->ctrl.ctrl_config & NVME_CC_SHN_NORMAL);
>> int result;
>> + bool reset_done = true;
>>
>> if (WARN_ON(dev->ctrl.state != NVME_CTRL_RESETTING)) {
>> result = -ENODEV;
>> @@ -2606,8 +2622,9 @@ static void nvme_reset_work(struct work_struct *work)
>> nvme_free_tagset(dev);
>> } else {
>> nvme_start_queues(&dev->ctrl);
>> - nvme_wait_freeze(&dev->ctrl);
>> - nvme_dev_add(dev);
>> + reset_done = nvme_wait_freeze_and_check(dev);
>
> Once we arrive at here, it indicates "dev->online_queues >= 2".
>
> 2601 if (dev->online_queues < 2) {
> 2602 dev_warn(dev->ctrl.device, "IO queues not created\n");
> 2603 nvme_kill_queues(&dev->ctrl);
> 2604 nvme_remove_namespaces(&dev->ctrl);
> 2605 nvme_free_tagset(dev);
> 2606 } else {
> 2607 nvme_start_queues(&dev->ctrl);
> 2608 nvme_wait_freeze(&dev->ctrl);
> 2609 nvme_dev_add(dev);
> 2610 nvme_unfreeze(&dev->ctrl);
> 2611 }
>
> Is there any reason to check "if (!dev->online_queues)" in
> nvme_wait_freeze_and_check()?
>
I think you meant another nvme_dev_disable() during reset?
Sorry for the misunderstanding in previous email.
Dongli Zhang
