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Make polled request timeout less invasive.

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Instead of panic after one second of polling, make the normal timeout
handler to activate, reset the controller and abort the outstanding
requests.  If all of it won't happen within 10 seconds then something
in the driver is likely stuck bad and panic is the only way out.

In particular this fixed device hot unplug during execution of those
polled commands, allowing clean device detach instead of panic.

MFC after:	1 week
Sponsored by:	iXsystems, Inc.
This commit is contained in:
Alexander Motin 2020-06-18 19:16:03 +00:00
parent 3b3e9cfb1b
commit ead7e10308
3 changed files with 17 additions and 9 deletions
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2
sys/dev/nvme/nvme_ctrlr.c
View File

@ -520,7 +520,7 @@ nvme_ctrlr_create_qpairs(struct nvme_controller *ctrlr)
}
status.done = 0;
nvme_ctrlr_cmd_create_io_sq(qpair->ctrlr, qpair,
nvme_ctrlr_cmd_create_io_sq(ctrlr, qpair,
nvme_completion_poll_cb, &status);
nvme_completion_poll(&status);
if (nvme_completion_is_error(&status.cpl)) {

12
sys/dev/nvme/nvme_private.h
View File

@ -463,20 +463,22 @@ int nvme_detach(device_t dev);
* Wait for a command to complete using the nvme_completion_poll_cb.
* Used in limited contexts where the caller knows it's OK to block
* briefly while the command runs. The ISR will run the callback which
* will set status->done to true.usually within microseconds. A 1s
* pause means something is seriously AFU and we should panic to
* provide the proper context to diagnose.
* will set status->done to true, usually within microseconds. If not,
* then after one second timeout handler should reset the controller
* and abort all outstanding requests including this polled one. If
* still not after ten seconds, then something is wrong with the driver,
* and panic is the only way to recover.
*/
static __inline
void
nvme_completion_poll(struct nvme_completion_poll_status *status)
{
int sanity = hz * 1;
int sanity = hz * 10;
while (!atomic_load_acq_int(&status->done) && --sanity > 0)
pause("nvme", 1);
if (sanity <= 0)
panic("NVME polled command failed to complete within 1s.");
panic("NVME polled command failed to complete within 10s.");
}
static __inline void

12
sys/dev/nvme/nvme_qpair.c
View File

@ -956,6 +956,7 @@ nvme_qpair_submit_tracker(struct nvme_qpair *qpair, struct nvme_tracker *tr)
{
struct nvme_request *req;
struct nvme_controller *ctrlr;
int timeout;
mtx_assert(&qpair->lock, MA_OWNED);
@ -964,9 +965,14 @@ nvme_qpair_submit_tracker(struct nvme_qpair *qpair, struct nvme_tracker *tr)
qpair->act_tr[tr->cid] = tr;
ctrlr = qpair->ctrlr;
if (req->timeout)
callout_reset_on(&tr->timer, ctrlr->timeout_period * hz,
nvme_timeout, tr, qpair->cpu);
if (req->timeout) {
if (req->cb_fn == nvme_completion_poll_cb)
timeout = hz;
else
timeout = ctrlr->timeout_period * hz;
callout_reset_on(&tr->timer, timeout, nvme_timeout, tr,
qpair->cpu);
}
/* Copy the command from the tracker to the submission queue. */
memcpy(&qpair->cmd[qpair->sq_tail], &req->cmd, sizeof(req->cmd));