Commit Graph

3709 Commits

Author SHA1 Message Date
Jens Axboe
a9381351dd Merge tag 'nvme-6.14-2025-03-13' of git://git.infradead.org/nvme into block-6.14
Pull NVMe fixes from Keith:

"nvme fixes for Linux 6.14

 - Concurrent pci error and hotplug handling fix (Keith)
 - Endpoint function fixes (Damien)"

* tag 'nvme-6.14-2025-03-13' of git://git.infradead.org/nvme:
  nvmet: pci-epf: Do not add an IRQ vector if not needed
  nvmet: pci-epf: Set NVMET_PCI_EPF_Q_LIVE when a queue is fully created
  nvme-pci: fix stuck reset on concurrent DPC and HP
2025-03-13 09:41:57 -06:00
Shin'ichiro Kawasaki
9bce6b5f89 block: change blk_mq_add_to_batch() third argument type to bool
Commit 1f47ed294a ("block: cleanup and fix batch completion adding
conditions") modified the evaluation criteria for the third argument,
'ioerror', in the blk_mq_add_to_batch() function. Initially, the
function had checked if 'ioerror' equals zero. Following the commit, it
started checking for negative error values, with the presumption that
such values, for instance -EIO, would be passed in.

However, blk_mq_add_to_batch() callers do not pass negative error
values. Instead, they pass status codes defined in various ways:

- NVMe PCI and Apple drivers pass NVMe status code
- virtio_blk driver passes the virtblk request header status byte
- null_blk driver passes blk_status_t

These codes are either zero or positive, therefore the revised check
fails to function as intended. Specifically, with the NVMe PCI driver,
this modification led to the failure of the blktests test case nvme/039.
In this test scenario, errors are artificially injected to the NVMe
driver, resulting in positive NVMe status codes passed to
blk_mq_add_to_batch(), which unexpectedly processes the failed I/O in a
batch. Hence the failure.

To correct the ioerror check within blk_mq_add_to_batch(), make all
callers to uniformly pass the argument as boolean. Modify the callers to
check their specific status codes and pass the boolean value 'is_error'.
Also describe the arguments of blK_mq_add_to_batch as kerneldoc.

Fixes: 1f47ed294a ("block: cleanup and fix batch completion adding conditions")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20250311104359.1767728-3-shinichiro.kawasaki@wdc.com
[axboe: fold in documentation update]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-03-12 08:26:36 -06:00
Shin'ichiro Kawasaki
e5c2bcc0cd nvme: move error logging from nvme_end_req() to __nvme_end_req()
Before the Commit 1f47ed294a ("block: cleanup and fix batch completion
adding conditions"), blk_mq_add_to_batch() did not add failed
passthrough requests to batch, and returned false. After the commit,
blk_mq_add_to_batch() always adds passthrough requests to batch
regardless of whether the request failed or not, and returns true. This
affected error logging feature in the NVME driver.

Before the commit, the call chain of failed passthrough request was as
follows:

nvme_handle_cqe()
 blk_mq_add_to_batch() .. false is returned, then call nvme_pci_complete_rq()
 nvme_pci_complete_rq()
  nvme_complete_rq()
   nvme_end_req()
    nvme_log_err_passthru() .. error logging
    __nvme_end_req()        .. end of the rqeuest

After the commit, the call chain is as follows:

nvme_handle_cqe()
 blk_mq_add_to_batch() .. true is returned, then set nvme_pci_complete_batch()
 ..
 nvme_pci_complete_batch()
  nvme_complete_batch()
   nvme_complete_batch_req()
    __nvme_end_req() .. end of the request, without error logging

To make the error logging feature work again for passthrough requests, move the
nvme_log_err_passthru() call from nvme_end_req() to __nvme_end_req().

While at it, move nvme_log_error() call for non-passthrough requests together
with nvme_log_err_passthru(). Even though the trigger commit does not affect
non-passthrough requests, move it together for code simplicity.

Fixes: 1f47ed294a ("block: cleanup and fix batch completion adding conditions")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250311104359.1767728-2-shinichiro.kawasaki@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-03-11 07:49:35 -06:00
Damien Le Moal
39393f5c5c nvmet: pci-epf: Do not add an IRQ vector if not needed
The function nvmet_pci_epf_create_cq() always unconditionally calls
nvmet_pci_epf_add_irq_vector() to add an IRQ vector for a completion
queue. But this is not correct if the host requested the creation of a
completion queue for polling, without an IRQ vector specified (i.e. the
flag NVME_CQ_IRQ_ENABLED is not set).

Fix this by calling nvmet_pci_epf_add_irq_vector() and setting the queue
flag NVMET_PCI_EPF_Q_IRQ_ENABLED for the cq only if NVME_CQ_IRQ_ENABLED
is set. While at it, also fix the error path to add the missing removal
of the added IRQ vector if nvmet_cq_create() fails.

Fixes: 0faa0fe6f9 ("nvmet: New NVMe PCI endpoint function target driver")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-03-10 10:12:16 -07:00
Damien Le Moal
bf9b8020a8 nvmet: pci-epf: Set NVMET_PCI_EPF_Q_LIVE when a queue is fully created
The function nvmet_pci_epf_create_sq() use test_and_set_bit() to check
that a submission queue is not already live and if not, set the
NVMET_PCI_EPF_Q_LIVE queue flag to declare the sq live (ready to use).
However, this is done on entry to the function, before the submission
queue is actually fully initialized and ready to use. This creates a
race situation with the function nvmet_pci_epf_poll_sqs_work() which
looks at the NVMET_PCI_EPF_Q_LIVE queue flag to poll the submission
queue when it is live. This race can lead to invalid DMA transfers if
nvmet_pci_epf_poll_sqs_work() runs after the NVMET_PCI_EPF_Q_LIVE flag
is set but before setting the sq pci address and doorbell ofset.

Avoid this race by only testing the NVMET_PCI_EPF_Q_LIVE flag on entry
to nvmet_pci_epf_create_sq() and setting it after the submission queue
is fully setup before nvmet_pci_epf_create_sq() returns success.
Since the function nvmet_pci_epf_create_cq() also has the same racy flag
setting pattern, also make a similar change in that function.

Fixes: 0faa0fe6f9 ("nvmet: New NVMe PCI endpoint function target driver")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-03-10 10:12:13 -07:00
Keith Busch
3f674e7b67 nvme-pci: fix stuck reset on concurrent DPC and HP
The PCIe error handling has the nvme driver quiesce the device, attempt
to restart it, then wait for that restart to complete.

A PCIe DPC event also toggles the PCIe link. If the slot doesn't have
out-of-band presence detection, this will trigger a pciehp
re-enumeration.

The error handling that calls nvme_error_resume is holding the device
lock while this happens. This lock blocks pciehp's request to disconnect
the driver from proceeding.

Meanwhile the nvme's reset can't make forward progress because its
device isn't there anymore with outstanding IO, and the timeout handler
won't do anything to fix it because the device is undergoing error
handling.

End result: deadlocked.

Fix this by having the timeout handler short cut the disabling for a
disconnected PCIe device. The downside is that we're relying on an IO
timeout to clean up this mess, which could be a minute by default.

Tested-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-03-10 09:15:48 -07:00
Dan Carpenter
528361c499 nvme-tcp: fix signedness bug in nvme_tcp_init_connection()
The kernel_recvmsg() function returns an int which could be either
negative error codes or the number of bytes received.  The problem is
that the condition:

        if (ret < sizeof(*icresp)) {

is type promoted to type unsigned long and negative values are treated
as high positive values which is success, when they should be treated as
failure.  Handle invalid positive returns separately from negative
error codes to avoid this problem.

Fixes: 578539e096 ("nvme-tcp: fix connect failure on receiving partial ICResp PDU")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-03-05 10:37:01 -08:00
Meir Elisha
a16f88964c nvmet-tcp: Fix a possible sporadic response drops in weakly ordered arch
The order in which queue->cmd and rcv_state are updated is crucial.
If these assignments are reordered by the compiler, the worker might not
get queued in nvmet_tcp_queue_response(), hanging the IO. to enforce the
the correct reordering, set rcv_state using smp_store_release().

Fixes: bdaf132791 ("nvmet-tcp: fix a segmentation fault during io parsing error")

Signed-off-by: Meir Elisha <meir.elisha@volumez.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-27 18:20:27 -08:00
Maurizio Lombardi
ad95bab0cd nvme-tcp: fix potential memory corruption in nvme_tcp_recv_pdu()
nvme_tcp_recv_pdu() doesn't check the validity of the header length.
When header digests are enabled, a target might send a packet with an
invalid header length (e.g. 255), causing nvme_tcp_verify_hdgst()
to access memory outside the allocated area and cause memory corruptions
by overwriting it with the calculated digest.

Fix this by rejecting packets with an unexpected header length.

Fixes: 3f2304f8c6 ("nvme-tcp: add NVMe over TCP host driver")
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-27 18:19:08 -08:00
Maurizio Lombardi
afb41b08c4 nvme-tcp: Fix a C2HTermReq error message
In H2CTermReq, a FES with value 0x05 means "R2T Limit Exceeded"; but
in C2HTermReq the same value has a different meaning (Data Transfer Limit
Exceeded).

Fixes: 84e009042d ("nvme-tcp: add basic support for the C2HTermReq PDU")
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-27 15:13:23 -08:00
Maurizio Lombardi
0979ff3676 nvmet: remove old function prototype
nvmet_subsys_nsid_exists() doesn't exist anymore

Fixes: 74d16965d7 ("nvmet-loop: avoid using mutex in IO hotpath")
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-27 15:12:58 -08:00
Keith Busch
00817f0f1c nvme-ioctl: fix leaked requests on mapping error
All the callers assume nvme_map_user_request() frees the request on a
failure. This wasn't happening on invalid metadata or io_uring command
flags, so we've been leaking those requests.

Fixes: 23fd22e55b ("nvme: wire up fixed buffer support for nvme passthrough")
Fixes: 7c2fd76048 ("nvme: fix metadata handling in nvme-passthrough")
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-25 09:09:18 -08:00
Icenowy Zheng
56cf7ef0d4 nvme-pci: skip CMB blocks incompatible with PCI P2P DMA
The PCI P2PDMA code will register the CMB block to the memory
hot-plugging subsystem, which have an alignment requirement. Memory
blocks that do not satisfy this alignment requirement (usually 2MB) will
lead to a WARNING from memory hotplugging.

Verify the CMB block's address and size against the alignment and only
try to send CMB blocks compatible with it to prevent this warning.

Tested on Intel DC D4502 SSD, which has a 512K CMB block that is too
small for memory hotplugging (thus PCI P2PDMA).

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-24 16:23:57 -08:00
Icenowy Zheng
6a3572e10f nvme-pci: clean up CMBMSC when registering CMB fails
CMB decoding should get disabled when the CMB block isn't successfully
registered to P2P DMA subsystem.

Clean up the CMBMSC register in this error handling codepath to disable
CMB decoding (and CMBLOC/CMBSZ registers).

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-24 16:21:24 -08:00
Sagi Grimberg
8c1624b63a nvme-tcp: fix possible UAF in nvme_tcp_poll
nvme_tcp_poll() may race with the send path error handler because
it may complete the request while it is actively being polled for
completion, resulting in a UAF panic [1]:

We should make sure to stop polling when we see an error when
trying to read from the socket. Hence make sure to propagate the
error so that the block layer breaks the polling cycle.

[1]:
--
[35665.692310] nvme nvme2: failed to send request -13
[35665.702265] nvme nvme2: unsupported pdu type (3)
[35665.702272] BUG: kernel NULL pointer dereference, address: 0000000000000000
[35665.702542] nvme nvme2: queue 1 receive failed:  -22
[35665.703209] #PF: supervisor write access in kernel mode
[35665.703213] #PF: error_code(0x0002) - not-present page
[35665.703214] PGD 8000003801cce067 P4D 8000003801cce067 PUD 37e6f79067 PMD 0
[35665.703220] Oops: 0002 [#1] SMP PTI
[35665.703658] nvme nvme2: starting error recovery
[35665.705809] Hardware name: Inspur aaabbb/YZMB-00882-104, BIOS 4.1.26 09/22/2022
[35665.705812] Workqueue: kblockd blk_mq_requeue_work
[35665.709172] RIP: 0010:_raw_spin_lock+0xc/0x30
[35665.715788] Call Trace:
[35665.716201]  <TASK>
[35665.716613]  ? show_trace_log_lvl+0x1c1/0x2d9
[35665.717049]  ? show_trace_log_lvl+0x1c1/0x2d9
[35665.717457]  ? blk_mq_request_bypass_insert+0x2c/0xb0
[35665.717950]  ? __die_body.cold+0x8/0xd
[35665.718361]  ? page_fault_oops+0xac/0x140
[35665.718749]  ? blk_mq_start_request+0x30/0xf0
[35665.719144]  ? nvme_tcp_queue_rq+0xc7/0x170 [nvme_tcp]
[35665.719547]  ? exc_page_fault+0x62/0x130
[35665.719938]  ? asm_exc_page_fault+0x22/0x30
[35665.720333]  ? _raw_spin_lock+0xc/0x30
[35665.720723]  blk_mq_request_bypass_insert+0x2c/0xb0
[35665.721101]  blk_mq_requeue_work+0xa5/0x180
[35665.721451]  process_one_work+0x1e8/0x390
[35665.721809]  worker_thread+0x53/0x3d0
[35665.722159]  ? process_one_work+0x390/0x390
[35665.722501]  kthread+0x124/0x150
[35665.722849]  ? set_kthread_struct+0x50/0x50
[35665.723182]  ret_from_fork+0x1f/0x30

Reported-by: Zhang Guanghui <zhang.guanghui@cestc.cn>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-24 14:29:00 -08:00
Daniel Wagner
d2fe192348 nvme: only allow entering LIVE from CONNECTING state
The fabric transports and also the PCI transport are not entering the
LIVE state from NEW or RESETTING. This makes the state machine more
restrictive and allows to catch not supported state transitions, e.g.
directly switching from RESETTING to LIVE.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-20 09:14:25 -08:00
Daniel Wagner
f13409bb3f nvme-fc: rely on state transitions to handle connectivity loss
It's not possible to call nvme_state_ctrl_state with holding a spin
lock, because nvme_state_ctrl_state calls cancel_delayed_work_sync
when fastfail is enabled.

Instead syncing the ASSOC_FLAG and state transitions using a lock, it's
possible to only rely on the state machine transitions. That means
nvme_fc_ctrl_connectivity_loss should unconditionally call
nvme_reset_ctrl which avoids the read race on the ctrl state variable.
Actually, it's not necessary to test in which state the ctrl is, the
reset work will only scheduled when the state machine is in LIVE state.

In nvme_fc_create_association, the LIVE state can only be entered if it
was previously CONNECTING. If this is not possible then the reset
handler got triggered. Thus just error out here.

Fixes: ee59e3820c ("nvme-fc: do not ignore connectivity loss during connecting")
Closes: https://lore.kernel.org/all/denqwui6sl5erqmz2gvrwueyxakl5txzbbiu3fgebryzrfxunm@iwxuthct377m/
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-20 09:13:55 -08:00
Hector Martin
3f22421f6a apple-nvme: Support coprocessors left idle
iBoot on at least some firmwares/machines leaves ANS2 running, requiring
a wake command instead of a CPU boot (and if we reset ANS2 in that
state, everything breaks).

Only stop the CPU if RTKit was running, and only do the reset dance if
the CPU is stopped.

Normal shutdown handoff:
- RTKit not yet running
- CPU detected not running
- Reset
- CPU powerup
- RTKit boot wait

ANS2 left running/idle:
- RTKit not yet running
- CPU detected running
- RTKit wake message

Sleep/resume cycle:
- RTKit shutdown
- CPU stopped
- (sleep here)
- CPU detected not running
- Reset
- CPU powerup
- RTKit boot wait

Shutdown or device removal:
- RTKit shutdown
- CPU stopped

Therefore, the CPU running bit serves as a consistent flag of whether
the coprocessor is fully stopped or just idle.

Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Sven Peter <sven@svenpeter.dev>
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-18 07:41:10 -08:00
Hector Martin
eefa72a15e apple-nvme: Release power domains when probe fails
Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Sven Peter <sven@svenpeter.dev>
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-18 07:41:10 -08:00
Damien Le Moal
2ba8cf918f nvmet: Use enum definitions instead of hardcoded values
Change the definition of the inline functions nvmet_cc_en(),
nvmet_cc_css(), nvmet_cc_mps(), nvmet_cc_ams(), nvmet_cc_shn(),
nvmet_cc_iosqes(), and nvmet_cc_iocqes() to use the enum difinitions in
include/linux/nvme.h instead of hardcoded values.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-18 07:39:42 -08:00
Caleb Sander Mateos
487a3ea7b1 nvme/ioctl: add missing space in err message
nvme_validate_passthru_nsid() logs an err message whose format string is
split over 2 lines. There is a missing space between the two pieces,
resulting in log lines like "... does not match nsid (1)of namespace".
Add the missing space between ")" and "of". Also combine the format
string pieces onto a single line to make the err message easier to grep.

Fixes: e7d4b5493a ("nvme: factor out a nvme_validate_passthru_nsid helper")
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-18 07:37:31 -08:00
Caleb Sander Mateos
578539e096 nvme-tcp: fix connect failure on receiving partial ICResp PDU
nvme_tcp_init_connection() attempts to receive an ICResp PDU but only
checks that the return value from recvmsg() is non-negative. If the
sender closes the TCP connection or sends fewer than 128 bytes, this
check will pass even though the full PDU wasn't received.

Ensure the full ICResp PDU is received by checking that recvmsg()
returns the expected 128 bytes.

Additionally set the MSG_WAITALL flag for recvmsg(), as a sender could
split the ICResp over multiple TCP frames. Without MSG_WAITALL,
recvmsg() could return prematurely with only part of the PDU.

Fixes: 3f2304f8c6 ("nvme-tcp: add NVMe over TCP host driver")
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-18 07:37:02 -08:00
Damien Le Moal
cd513e0434 nvme: tcp: Fix compilation warning with W=1
When compiling with W=1, a warning result for the function
nvme_tcp_set_queue_io_cpu():

host/tcp.c:1578: warning: Function parameter or struct member 'queue'
not described in 'nvme_tcp_set_queue_io_cpu'
host/tcp.c:1578: warning: expecting prototype for Track the number of
queues assigned to each cpu using a global per(). Prototype was for
nvme_tcp_set_queue_io_cpu() instead

Avoid this warning by using the regular comment format for the function
nvme_tcp_set_queue_io_cpu() instead of the kdoc comment format.

Fixes: 3219378987 ("nvme-tcp: Fix I/O queue cpu spreading for multiple controllers")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-18 07:25:15 -08:00
Damien Le Moal
01ef7ff7dd nvmet: pci-epf: Avoid RCU stalls under heavy workload
The delayed work item function nvmet_pci_epf_poll_sqs_work() polls all
submission queues and keeps running in a loop as long as commands are
being submitted by the host. Depending on the preemption configuration
of the kernel, under heavy command workload, this function can thus run
for more than RCU_CPU_STALL_TIMEOUT seconds, leading to a RCU stall:

 rcu: INFO: rcu_sched self-detected stall on CPU
 rcu:   5-....: (20998 ticks this GP) idle=4244/1/0x4000000000000000 softirq=301/301 fqs=5132
 rcu:   (t=21000 jiffies g=-443 q=12 ncpus=8)
 CPU: 5 UID: 0 PID: 82 Comm: kworker/5:1 Not tainted 6.14.0-rc2 #1
 Hardware name: Radxa ROCK 5B (DT)
 Workqueue: events nvmet_pci_epf_poll_sqs_work [nvmet_pci_epf]
 pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
 pc : dw_edma_device_tx_status+0xb8/0x130
 lr : dw_edma_device_tx_status+0x9c/0x130
 sp : ffff800080b5bbb0
 x29: ffff800080b5bbb0 x28: ffff0331c5c78400 x27: ffff0331c1cd1960
 x26: ffff0331c0e39010 x25: ffff0331c20e4000 x24: ffff0331c20e4a90
 x23: 0000000000000000 x22: 0000000000000001 x21: 00000000005aca33
 x20: ffff800080b5bc30 x19: ffff0331c123e370 x18: 000000000ab29e62
 x17: ffffb2a878c9c118 x16: ffff0335bde82040 x15: 0000000000000000
 x14: 000000000000017b x13: 00000000ee601780 x12: 0000000000000018
 x11: 0000000000000000 x10: 0000000000000001 x9 : 0000000000000040
 x8 : 00000000ee601780 x7 : 0000000105c785c0 x6 : ffff0331c1027d80
 x5 : 0000000001ee7ad6 x4 : ffff0335bdea16c0 x3 : ffff0331c123e438
 x2 : 00000000005aca33 x1 : 0000000000000000 x0 : ffff0331c123e410
 Call trace:
  dw_edma_device_tx_status+0xb8/0x130 (P)
  dma_sync_wait+0x60/0xbc
  nvmet_pci_epf_dma_transfer+0x128/0x264 [nvmet_pci_epf]
  nvmet_pci_epf_poll_sqs_work+0x2a0/0x2e0 [nvmet_pci_epf]
  process_one_work+0x144/0x390
  worker_thread+0x27c/0x458
  kthread+0xe8/0x19c
  ret_from_fork+0x10/0x20

The solution for this is simply to explicitly allow rescheduling using
cond_resched(). However, since doing so for every loop of
nvmet_pci_epf_poll_sqs_work() significantly degrades performance
(for 4K random reads using 4 I/O queues, the maximum IOPS goes down from
137 KIOPS to 110 KIOPS), call cond_resched() every second to avoid the
RCU stalls.

Fixes: 0faa0fe6f9 ("nvmet: New NVMe PCI endpoint function target driver")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-18 07:25:15 -08:00
Damien Le Moal
ffa3556763 nvmet: pci-epf: Do not uselessly write the CSTS register
The function nvmet_pci_epf_poll_cc_work() will do nothing if there are
no changes to the controller configuration (CC) register. However, even
for such case, this function still calls nvmet_update_cc() and uselessly
writes the CSTS register. Avoid this by simply rescheduling the poll_cc
work if the CC register has not changed.

Also reschedule the poll_cc work if the function
nvmet_pci_epf_enable_ctrl() fails to allow the host the chance to try
again enabling the controller.

While at it, since there is no point in trying to handle the CC register
as quickly as possible, change the poll_cc work scheduling interval to
10 ms (from 5ms), to avoid excessive read accesses to that register.

Fixes: 0faa0fe6f9 ("nvmet: New NVMe PCI endpoint function target driver")
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2025-02-18 07:25:15 -08:00