nvme: code command_id with a genctr for use-after-free validation

[ Upstream commit e7006de6c23803799be000a5dcce4d916a36541a ]

We cannot detect a (perhaps buggy) controller that is sending us
a com

nvme: code command_id with a genctr for use-after-free validation

[ Upstream commit e7006de6c23803799be000a5dcce4d916a36541a ]

We cannot detect a (perhaps buggy) controller that is sending us
a completion for a request that was already completed (for example
sending a completion twice), this phenomenon was seen in the wild
a few times.

So to protect against this, we use the upper 4 msbits of the nvme sqe
command_id to use as a 4-bit generation counter and verify it matches
the existing request generation that is incrementing on every execution.

The 16-bit command_id structure now is constructed by:
| xxxx | xxxxxxxxxxxx |
gen request tag

This means that we are giving up some possible queue depth as 12 bits
allow for a maximum queue depth of 4095 instead of 65536, however we
never create such long queues anyways so no real harm done.

Suggested-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Tested-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

nvme-tcp: don't check blk_mq_tag_to_rq when receiving pdu data

[ Upstream commit 3b01a9d0caa8276d9ce314e09610f7fb70f49a00 ]

We already validate it when receiving the c2hdata pdu header
and this is

nvme-tcp: don't check blk_mq_tag_to_rq when receiving pdu data

[ Upstream commit 3b01a9d0caa8276d9ce314e09610f7fb70f49a00 ]

We already validate it when receiving the c2hdata pdu header
and this is not changing so this is a redundant check.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

nvme-tcp: don't update queue count when failing to set io queues

[ Upstream commit 664227fde63844d69e9ec9e90a8a7801e6ff072d ]

We update ctrl->queue_count and schedule another reconnect when io queu

nvme-tcp: don't update queue count when failing to set io queues

[ Upstream commit 664227fde63844d69e9ec9e90a8a7801e6ff072d ]

We update ctrl->queue_count and schedule another reconnect when io queue
count is zero.But we will never try to create any io queue in next reco-
nnection, because ctrl->queue_count already set to zero.We will end up
having an admin-only session in Live state, which is exactly what we try
to avoid in the original patch.
Update ctrl->queue_count after queue_count zero checking to fix it.

Signed-off-by: Ruozhu Li <liruozhu@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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nvme-tcp: fix possible use-after-completion

commit 825619b09ad351894d2c6fb6705f5b3711d145c7 upstream.

Commit db5ad6b7f8cd ("nvme-tcp: try to send request in queue_rq
context") added a second contex

nvme-tcp: fix possible use-after-completion

commit 825619b09ad351894d2c6fb6705f5b3711d145c7 upstream.

Commit db5ad6b7f8cd ("nvme-tcp: try to send request in queue_rq
context") added a second context that may perform a network send.
This means that now RX and TX are not serialized in nvme_tcp_io_work
and can run concurrently.

While there is correct mutual exclusion in the TX path (where
the send_mutex protect the queue socket send activity) RX activity,
and more specifically request completion may run concurrently.

This means we must guarantee that any mutation of the request state
related to its lifetime, bytes sent must not be accessed when a completion
may have possibly arrived back (and processed).

The race may trigger when a request completion arrives, processed
_and_ reused as a fresh new request, exactly in the (relatively short)
window between the last data payload sent and before the request iov_iter
is advanced.

Consider the following race:
1. 16K write request is queued
2. The nvme command and the data is sent to the controller (in-capsule
or solicited by r2t)
3. After the last payload is sent but before the req.iter is advanced,
the controller sends back a completion.
4. The completion is processed, the request is completed, and reused
to transfer a new request (write or read)
5. The new request is queued, and the driver reset the request parameters
(nvme_tcp_setup_cmd_pdu).
6. Now context in (2) resumes execution and advances the req.iter

==> use-after-completion as this is already a new request.

Fix this by making sure the request is not advanced after the last
data payload send, knowing that a completion may have arrived already.

An alternative solution would have been to delay the request completion
or state change waiting for reference counting on the TX path, but besides
adding atomic operations to the hot-path, it may present challenges in
multi-stage R2T scenarios where a r2t handler needs to be deferred to
an async execution.

Reported-by: Narayan Ayalasomayajula <narayan.ayalasomayajula@wdc.com>
Tested-by: Anil Mishra <anil.mishra@wdc.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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nvme-tcp: rerun io_work if req_list is not empty

[ Upstream commit a0fdd1418007f83565d3f2e04b47923ba93a9b8c ]

A possible race condition exists where the request to send data is
enqueued from nvme_t

nvme-tcp: rerun io_work if req_list is not empty

[ Upstream commit a0fdd1418007f83565d3f2e04b47923ba93a9b8c ]

A possible race condition exists where the request to send data is
enqueued from nvme_tcp_handle_r2t()'s will not be observed by
nvme_tcp_send_all() if it happens to be running. The driver relies on
io_work to send the enqueued request when it is runs again, but the
concurrently running nvme_tcp_send_all() may not have released the
send_mutex at that time. If no future commands are enqueued to re-kick
the io_work, the request will timeout in the SEND_H2C state, resulting
in a timeout error like:

nvme nvme0: queue 1: timeout request 0x3 type 6

Ensure the io_work continues to run as long as the req_list is not empty.

Fixes: db5ad6b7f8cdd ("nvme-tcp: try to send request in queue_rq context")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

nvme-tcp: block BH in sk state_change sk callback

[ Upstream commit 8b73b45d54a14588f86792869bfb23098ea254cb ]

The TCP stack can run from process context for a long time
so we should disable BH her

nvme-tcp: block BH in sk state_change sk callback

[ Upstream commit 8b73b45d54a14588f86792869bfb23098ea254cb ]

The TCP stack can run from process context for a long time
so we should disable BH here.

Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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nvme-tcp: fix a NULL deref when receiving a 0-length r2t PDU

commit fd0823f405090f9f410fc3e3ff7efb52e7b486fa upstream.

When the controller sends us a 0-length r2t PDU we should not attempt to
try t

nvme-tcp: fix a NULL deref when receiving a 0-length r2t PDU

commit fd0823f405090f9f410fc3e3ff7efb52e7b486fa upstream.

When the controller sends us a 0-length r2t PDU we should not attempt to
try to set up a h2cdata PDU but rather conclude that this is a buggy
controller (forward progress is not possible) and simply fail it
immediately.

Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver")
Reported-by: Belanger, Martin <Martin.Belanger@dell.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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nvme-tcp: fix possible hang when failing to set io queues

commit 72f572428b83d0bc7028e7c4326d1a5f45205e44 upstream.

We only setup io queues for nvme controllers, and it makes absolutely no
sense to

nvme-tcp: fix possible hang when failing to set io queues

commit 72f572428b83d0bc7028e7c4326d1a5f45205e44 upstream.

We only setup io queues for nvme controllers, and it makes absolutely no
sense to allow a controller (re)connect without any I/O queues. If we
happen to fail setting the queue count for any reason, we should not
allow this to be a successful reconnect as I/O has no chance in going
through. Instead just fail and schedule another reconnect.

Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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nvme-tcp: fix misuse of __smp_processor_id with preemption enabled

commit bb83337058a7000644cdeffc67361d2473534756 upstream.

For our pure advisory use-case, we only rely on this call as a hint, so

nvme-tcp: fix misuse of __smp_processor_id with preemption enabled

commit bb83337058a7000644cdeffc67361d2473534756 upstream.

For our pure advisory use-case, we only rely on this call as a hint, so
fix the warning complaints of using the smp_processor_id variants with
preemption enabled.

Fixes: db5ad6b7f8cd ("nvme-tcp: try to send request in queue_rq context")
Fixes: ada831772188 ("nvme-tcp: Fix warning with CONFIG_DEBUG_PREEMPT")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

nvme-tcp: add clean action for failed reconnection

[ Upstream commit 70a99574a79f1cd4dc7ad56ea37be40844bfb97b ]

If reconnect failed after start io queues, the queues will be unquiesced
and new requ

nvme-tcp: add clean action for failed reconnection

[ Upstream commit 70a99574a79f1cd4dc7ad56ea37be40844bfb97b ]

If reconnect failed after start io queues, the queues will be unquiesced
and new requests continue to be delivered. Reconnection error handling
process directly free queues without cancel suspend requests. The
suppend request will time out, and then crash due to use the queue
after free.

Add sync queues and cancel suppend requests for reconnection error
handling.

Signed-off-by: Chao Leng <lengchao@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

nvme-tcp: avoid request double completion for concurrent nvme_tcp_timeout

[ Upstream commit 9ebbfe495ecd2e51bc92ac21ed5817c3b9e223ce ]

Each name space has a request queue, if complete request long

nvme-tcp: avoid request double completion for concurrent nvme_tcp_timeout

[ Upstream commit 9ebbfe495ecd2e51bc92ac21ed5817c3b9e223ce ]

Each name space has a request queue, if complete request long time,
multi request queues may have time out requests at the same time,
nvme_tcp_timeout will execute concurrently. Multi requests in different
request queues may be queued in the same tcp queue, multi
nvme_tcp_timeout may call nvme_tcp_stop_queue at the same time.
The first nvme_tcp_stop_queue will clear NVME_TCP_Q_LIVE and continue
stopping the tcp queue(cancel io_work), but the others check
NVME_TCP_Q_LIVE is already cleared, and then directly complete the
requests, complete request before the io work is completely canceled may
lead to a use-after-free condition.
Add a multex lock to serialize nvme_tcp_stop_queue.

Signed-off-by: Chao Leng <lengchao@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

nvme-tcp: Fix warning with CONFIG_DEBUG_PREEMPT

commit ada831772188192243f9ea437c46e37e97a5975d upstream.

We shouldn't call smp_processor_id() in a preemptible
context, but this is advisory at best

nvme-tcp: Fix warning with CONFIG_DEBUG_PREEMPT

commit ada831772188192243f9ea437c46e37e97a5975d upstream.

We shouldn't call smp_processor_id() in a preemptible
context, but this is advisory at best, so instead
call __smp_processor_id().

Fixes: db5ad6b7f8cd ("nvme-tcp: try to send request in queue_rq context")
Reported-by: Or Gerlitz <gerlitz.or@gmail.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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nvme-tcp: fix possible data corruption with bio merges

commit ca1ff67d0fb14f39cf0cc5102b1fbcc3b14f6fb9 upstream.

When a bio merges, we can get a request that spans multiple
bios, and the overall re

nvme-tcp: fix possible data corruption with bio merges

commit ca1ff67d0fb14f39cf0cc5102b1fbcc3b14f6fb9 upstream.

When a bio merges, we can get a request that spans multiple
bios, and the overall request payload size is the sum of
all bios. When we calculate how much we need to send
from the existing bio (and bvec), we did not take into
account the iov_iter byte count cap.

Since multipage bvecs support, bvecs can split in the middle
which means that when we account for the last bvec send we
should also take the iov_iter byte count cap as it might be
lower than the last bvec size.

Reported-by: Hao Wang <pkuwangh@gmail.com>
Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver")
Tested-by: Hao Wang <pkuwangh@gmail.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

nvme-tcp: Fix possible race of io_work and direct send

commit 5c11f7d9f843bdd24cd29b95401938bc3f168070 upstream.

We may send a request (with or without its data) from two paths:

1. From our I/O

nvme-tcp: Fix possible race of io_work and direct send

commit 5c11f7d9f843bdd24cd29b95401938bc3f168070 upstream.

We may send a request (with or without its data) from two paths:

1. From our I/O context nvme_tcp_io_work which is triggered from:
- queue_rq
- r2t reception
- socket data_ready and write_space callbacks
2. Directly from queue_rq if the send_list is empty (because we want to
save the context switch associated with scheduling our io_work).

However, given that now we have the send_mutex, we may run into a race
condition where none of these contexts will send the pending payload to
the controller. Both io_work send path and queue_rq send path
opportunistically attempt to acquire the send_mutex however queue_rq only
attempts to send a single request, and if io_work context fails to
acquire the send_mutex it will complete without rescheduling itself.

The race can trigger with the following sequence:

1. queue_rq sends request (no incapsule data) and blocks
2. RX path receives r2t - prepares data PDU to send, adds h2cdata PDU
to the send_list and schedules io_work
3. io_work triggers and cannot acquire the send_mutex - because of (1),
ends without self rescheduling
4. queue_rq completes the send, and completes

==> no context will send the h2cdata - timeout.

Fix this by having queue_rq sending as much as it can from the send_list
such that if it still has any left, its because the socket buffer is
full and the socket write_space callback will trigger, thus guaranteeing
that a context will be scheduled to send the h2cdata PDU.

Fixes: db5ad6b7f8cd ("nvme-tcp: try to send request in queue_rq context")
Reported-by: Potnuri Bharat Teja <bharat@chelsio.com>
Reported-by: Samuel Jones <sjones@kalrayinc.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

nvme-tcp: avoid repeated request completion

The request may be executed asynchronously, and rq->state may be
changed to IDLE. To avoid repeated request completion, only
MQ_RQ_COMPLETE of rq->state i

nvme-tcp: avoid repeated request completion

The request may be executed asynchronously, and rq->state may be
changed to IDLE. To avoid repeated request completion, only
MQ_RQ_COMPLETE of rq->state is checked in nvme_tcp_complete_timed_out.
It is not safe, so need adding check IDLE for rq->state.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Chao Leng <lengchao@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

show more ...

nvme-tcp: avoid race between time out and tear down

Now use teardown_lock to serialize for time out and tear down. This may
cause abnormal: first cancel all request in tear down, then time out may
c

nvme-tcp: avoid race between time out and tear down

Now use teardown_lock to serialize for time out and tear down. This may
cause abnormal: first cancel all request in tear down, then time out may
complete the request again, but the request may already be freed or
restarted.

To avoid race between time out and tear down, in tear down process,
first we quiesce the queue, and then delete the timer and cancel
the time out work for the queue. At the same time we need to delete
teardown_lock.

Signed-off-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

show more ...

nvme-tcp: check page by sendpage_ok() before calling kernel_sendpage()

Currently nvme_tcp_try_send_data() doesn't use kernel_sendpage() to
send slab pages. But for pages allocated by __get_free_page

nvme-tcp: check page by sendpage_ok() before calling kernel_sendpage()

Currently nvme_tcp_try_send_data() doesn't use kernel_sendpage() to
send slab pages. But for pages allocated by __get_free_pages() without
__GFP_COMP, which also have refcount as 0, they are still sent by
kernel_sendpage() to remote end, this is problematic.

The new introduced helper sendpage_ok() checks both PageSlab tag and
page_count counter, and returns true if the checking page is OK to be
sent by kernel_sendpage().

This patch fixes the page checking issue of nvme_tcp_try_send_data()
with sendpage_ok(). If sendpage_ok() returns true, send this page by
kernel_sendpage(), otherwise use sock_no_sendpage to handle this page.

Signed-off-by: Coly Li <colyli@suse.de>
Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jan Kara <jack@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mikhail Skorzhinskii <mskorzhinskiy@solarflare.com>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Vlastimil Babka <vbabka@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

nvme-tcp: cancel async events before freeing event struct

Cancel async event work in case async event has been queued up, and
nvme_tcp_submit_async_event() runs after event has been freed.

Signed-o

nvme-tcp: cancel async events before freeing event struct

Cancel async event work in case async event has been queued up, and
nvme_tcp_submit_async_event() runs after event has been freed.

Signed-off-by: David Milburn <dmilburn@redhat.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

show more ...

nvme-tcp: fix reset hang if controller died in the middle of a reset

If the controller becomes unresponsive in the middle of a reset, we will
hang because we are waiting for the freeze to complete,

nvme-tcp: fix reset hang if controller died in the middle of a reset

If the controller becomes unresponsive in the middle of a reset, we will
hang because we are waiting for the freeze to complete, but that cannot
happen since we have commands that are inflight holding the
q_usage_counter, and we can't blindly fail requests that times out.

So give a timeout and if we cannot wait for queue freeze before
unfreezing, fail and have the error handling take care how to proceed
(either schedule a reconnect of remove the controller).

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

show more ...

nvme-tcp: fix timeout handler

When a request times out in a LIVE state, we simply trigger error
recovery and let the error recovery handle the request cancellation,
however when a request times out

nvme-tcp: fix timeout handler

When a request times out in a LIVE state, we simply trigger error
recovery and let the error recovery handle the request cancellation,
however when a request times out in a non LIVE state, we make sure to
complete it immediately as it might block controller setup or teardown
and prevent forward progress.

However tearing down the entire set of I/O and admin queues causes
freeze/unfreeze imbalance (q->mq_freeze_depth) because and is really
an overkill to what we actually need, which is to just fence controller
teardown that may be running, stop the queue, and cancel the request if
it is not already completed.

Now that we have the controller teardown_lock, we can safely serialize
request cancellation. This addresses a hang caused by calling extra
queue freeze on controller namespaces, causing unfreeze to not complete
correctly.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

show more ...

nvme-tcp: serialize controller teardown sequences

In the timeout handler we may need to complete a request because the
request that timed out may be an I/O that is a part of a serial sequence
of con

nvme-tcp: serialize controller teardown sequences

In the timeout handler we may need to complete a request because the
request that timed out may be an I/O that is a part of a serial sequence
of controller teardown or initialization. In order to complete the
request, we need to fence any other context that may compete with us
and complete the request that is timing out.

In this case, we could have a potential double completion in case
a hard-irq or a different competing context triggered error recovery
and is running inflight request cancellation concurrently with the
timeout handler.

Protect using a ctrl teardown_lock to serialize contexts that may
complete a cancelled request due to error recovery or a reset.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

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treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through mar

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

show more ...

nvme: rename and document nvme_end_request

nvme_end_request is a bit misnamed, as it wraps around the
blk_mq_complete_* API. It's semantics also are non-trivial, so give it
a more descriptive name

nvme: rename and document nvme_end_request

nvme_end_request is a bit misnamed, as it wraps around the
blk_mq_complete_* API. It's semantics also are non-trivial, so give it
a more descriptive name and add a comment explaining the semantics.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

show more ...

nvme-tcp: fix controller reset hang during traffic

commit fe35ec58f0d3 ("block: update hctx map when use multiple maps")
exposed an issue where we may hang trying to wait for queue freeze
during I/O

nvme-tcp: fix controller reset hang during traffic

commit fe35ec58f0d3 ("block: update hctx map when use multiple maps")
exposed an issue where we may hang trying to wait for queue freeze
during I/O. We call blk_mq_update_nr_hw_queues which in case of multiple
queue maps (which we have now for default/read/poll) is attempting to
freeze the queue. However we never started queue freeze when starting the
reset, which means that we have inflight pending requests that entered the
queue that we will not complete once the queue is quiesced.

So start a freeze before we quiesce the queue, and unfreeze the queue
after we successfully connected the I/O queues (and make sure to call
blk_mq_update_nr_hw_queues only after we are sure that the queue was
already frozen).

This follows to how the pci driver handles resets.

Fixes: fe35ec58f0d3 ("block: update hctx map when use multiple maps")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

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nvme: fix deadlock in disconnect during scan_work and/or ana_work

A deadlock happens in the following scenario with multipath:
1) scan_work(nvme0) detects a new nsid while nvme0
is an optimized

nvme: fix deadlock in disconnect during scan_work and/or ana_work

A deadlock happens in the following scenario with multipath:
1) scan_work(nvme0) detects a new nsid while nvme0
is an optimized path to it, path nvme1 happens to be
inaccessible.

2) Before scan_work is complete nvme0 disconnect is initiated
nvme_delete_ctrl_sync() sets nvme0 state to NVME_CTRL_DELETING

3) scan_work(1) attempts to submit IO,
but nvme_path_is_optimized() observes nvme0 is not LIVE.
Since nvme1 is a possible path IO is requeued and scan_work hangs.

--
Workqueue: nvme-wq nvme_scan_work [nvme_core]
kernel: Call Trace:
kernel: __schedule+0x2b9/0x6c0
kernel: schedule+0x42/0xb0
kernel: io_schedule+0x16/0x40
kernel: do_read_cache_page+0x438/0x830
kernel: read_cache_page+0x12/0x20
kernel: read_dev_sector+0x27/0xc0
kernel: read_lba+0xc1/0x220
kernel: efi_partition+0x1e6/0x708
kernel: check_partition+0x154/0x244
kernel: rescan_partitions+0xae/0x280
kernel: __blkdev_get+0x40f/0x560
kernel: blkdev_get+0x3d/0x140
kernel: __device_add_disk+0x388/0x480
kernel: device_add_disk+0x13/0x20
kernel: nvme_mpath_set_live+0x119/0x140 [nvme_core]
kernel: nvme_update_ns_ana_state+0x5c/0x60 [nvme_core]
kernel: nvme_set_ns_ana_state+0x1e/0x30 [nvme_core]
kernel: nvme_parse_ana_log+0xa1/0x180 [nvme_core]
kernel: nvme_mpath_add_disk+0x47/0x90 [nvme_core]
kernel: nvme_validate_ns+0x396/0x940 [nvme_core]
kernel: nvme_scan_work+0x24f/0x380 [nvme_core]
kernel: process_one_work+0x1db/0x380
kernel: worker_thread+0x249/0x400
kernel: kthread+0x104/0x140
--

4) Delete also hangs in flush_work(ctrl->scan_work)
from nvme_remove_namespaces().

Similiarly a deadlock with ana_work may happen: if ana_work has started
and calls nvme_mpath_set_live and device_add_disk, it will
trigger I/O. When we trigger disconnect I/O will block because
our accessible (optimized) path is disconnecting, but the alternate
path is inaccessible, so I/O blocks. Then disconnect tries to flush
the ana_work and hangs.

[ 605.550896] Workqueue: nvme-wq nvme_ana_work [nvme_core]
[ 605.552087] Call Trace:
[ 605.552683] __schedule+0x2b9/0x6c0
[ 605.553507] schedule+0x42/0xb0
[ 605.554201] io_schedule+0x16/0x40
[ 605.555012] do_read_cache_page+0x438/0x830
[ 605.556925] read_cache_page+0x12/0x20
[ 605.557757] read_dev_sector+0x27/0xc0
[ 605.558587] amiga_partition+0x4d/0x4c5
[ 605.561278] check_partition+0x154/0x244
[ 605.562138] rescan_partitions+0xae/0x280
[ 605.563076] __blkdev_get+0x40f/0x560
[ 605.563830] blkdev_get+0x3d/0x140
[ 605.564500] __device_add_disk+0x388/0x480
[ 605.565316] device_add_disk+0x13/0x20
[ 605.566070] nvme_mpath_set_live+0x5e/0x130 [nvme_core]
[ 605.567114] nvme_update_ns_ana_state+0x2c/0x30 [nvme_core]
[ 605.568197] nvme_update_ana_state+0xca/0xe0 [nvme_core]
[ 605.569360] nvme_parse_ana_log+0xa1/0x180 [nvme_core]
[ 605.571385] nvme_read_ana_log+0x76/0x100 [nvme_core]
[ 605.572376] nvme_ana_work+0x15/0x20 [nvme_core]
[ 605.573330] process_one_work+0x1db/0x380
[ 605.574144] worker_thread+0x4d/0x400
[ 605.574896] kthread+0x104/0x140
[ 605.577205] ret_from_fork+0x35/0x40
[ 605.577955] INFO: task nvme:14044 blocked for more than 120 seconds.
[ 605.579239] Tainted: G OE 5.3.5-050305-generic #201910071830
[ 605.580712] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 605.582320] nvme D 0 14044 14043 0x00000000
[ 605.583424] Call Trace:
[ 605.583935] __schedule+0x2b9/0x6c0
[ 605.584625] schedule+0x42/0xb0
[ 605.585290] schedule_timeout+0x203/0x2f0
[ 605.588493] wait_for_completion+0xb1/0x120
[ 605.590066] __flush_work+0x123/0x1d0
[ 605.591758] __cancel_work_timer+0x10e/0x190
[ 605.593542] cancel_work_sync+0x10/0x20
[ 605.594347] nvme_mpath_stop+0x2f/0x40 [nvme_core]
[ 605.595328] nvme_stop_ctrl+0x12/0x50 [nvme_core]
[ 605.596262] nvme_do_delete_ctrl+0x3f/0x90 [nvme_core]
[ 605.597333] nvme_sysfs_delete+0x5c/0x70 [nvme_core]
[ 605.598320] dev_attr_store+0x17/0x30

Fix this by introducing a new state: NVME_CTRL_DELETE_NOIO, which will
indicate the phase of controller deletion where I/O cannot be allowed
to access the namespace. NVME_CTRL_DELETING still allows mpath I/O to
be issued to the bottom device, and only after we flush the ana_work
and scan_work (after nvme_stop_ctrl and nvme_prep_remove_namespaces)
we change the state to NVME_CTRL_DELETING_NOIO. Also we prevent ana_work
from re-firing by aborting early if we are not LIVE, so we should be safe
here.

In addition, change the transport drivers to follow the updated state
machine.

Fixes: 0d0b660f214d ("nvme: add ANA support")
Reported-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

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