>From the initial implementation of NVMe SGL kernel support
commit a7a7cbe3 ("nvme-pci: add SGL support") with addition of the
commit 943e942e ("nvme-pci: limit max IO size and segments to avoid
high order allocations") now there is only caller left for
nvme_pci_iod_alloc_size() which statically passes true for last
parameter that calculates allocation size based on SGL since we need
size of biggest command supported for mempool allocation.

This patch modifies the helper functions nvme_pci_iod_alloc_size() such
that it is now uses maximum of PRP and SGL size for iod allocation size
calculation.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Saving the nvme controller's page size was from a time when the driver
tried to use different sized pages, but this value is always set to
a constant, and has been this way for some time. Remove the 'page_size'
field and replace its usage with the constant value.

This also lets the compiler make some micro-optimizations in the io
path, and that's always a good thing.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The nvme_pci_iod_alloc_size() should return 'size_t' type to be
consistent with the sizeof return value.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Add a blank line after declarations to make code more readable.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Fix comment typos and remove whitespaces before tabs to cleanup
checkpatch errors.
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We've validated the segment counts before calling nvme_map_data(),
so there is no need to validate again in nvme_pci_use_sgls(, which is
only called from nvme_map_data().
Signed-off-by: NBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Documented model names of Intel SSDs requiring quirks.
Signed-off-by: NDavid Fugate <david.fugate@linux.intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Just cleanup by removing the empty line.
Signed-off-by: NDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Although use of for loop is preferred it is not a common practice to
have 80 char long for loop initialization and comparison section.

Use temp variables for calculating values and replace them in the
for loop with size of all variables to set to u64 since preferred
variable is declared as u64.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The NVMe PCIe declares module parameter io_queue_depth as int. Change
this to u16 as queue depth can never be negative. Now to reflect this
update module parameter getter function from param_get_int() ->
param_get_uint() and respective setter function with type of n changed
from int to u16 with param_set_int() to param_set_ushort(). Finally
update struct nvme_dev q_depth member to u16 and use u16 in min_t()
when calculating dev->q_depth in the nvme_pci_enable() (since q_depth is
now u16) and use unsigned int instead of int when calculating
dev->tagset.queue_depth as target variable tagset->queue_depth is of type
unsigned int in nvme_dev_add().
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Both admin's and drive's tagsets should be set according the numa node
of the controller.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Set the node value according to the PCI device numa node.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Use the new blk_mq_complete_request_remote helper to avoid an indirect
function call in the completion fast path.
Reviewed-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

While the NVMe specification allows the device to access the host memory
buffer in host DRAM from all power states, hosts will fail access to
DRAM during S3 and similar power states.

Fixes: d916b1be ("nvme-pci: use host managed power state for suspend")
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

There may be a race between nvme_reap_pending_cqes() and nvme_poll(), e.g.,
when doing live reset while polling the nvme device.

      CPU X                        CPU Y
                               nvme_poll()
nvme_dev_disable()
-> nvme_stop_queues()
-> nvme_suspend_io_queues()
-> nvme_suspend_queue()
                               -> spin_lock(&nvmeq->cq_poll_lock);
-> nvme_reap_pending_cqes()
   -> nvme_process_cq()        -> nvme_process_cq()

In the above scenario, the nvme_process_cq() for the same queue may be
running on both CPU X and CPU Y concurrently.

It is much more easier to reproduce the issue when CONFIG_PREEMPT is
enabled in kernel. When CONFIG_PREEMPT is disabled, it would take longer
time for nvme_stop_queues()-->blk_mq_quiesce_queue() to wait for grace
period.

This patch protects nvme_process_cq() with nvmeq->cq_poll_lock in
nvme_reap_pending_cqes().

Fixes: fa46c6fb ("nvme/pci: move cqe check after device shutdown")
Signed-off-by: NDongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch doesn't change any logic, and is needed as a preparation
for adding PI support for fabrics drivers that will use an extended
LBA format for metadata and will support more than 1 integrity segment.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Check module parameter write/poll_queues before using it to catch
too large values.

Reproducer:

modprobe -r nvme
modprobe nvme write_queues=`nproc`
echo $((`nproc`+1)) > /sys/module/nvme/parameters/write_queues
echo 1 > /sys/block/nvme0n1/device/reset_controller

[  657.069000] ------------[ cut here ]------------
[  657.069022] WARNING: CPU: 10 PID: 1163 at kernel/irq/affinity.c:390 irq_create_affinity_masks+0x47c/0x4a0
[  657.069056]  dm_region_hash dm_log dm_mod
[  657.069059] CPU: 10 PID: 1163 Comm: kworker/u193:9 Kdump: loaded Tainted: G        W         5.6.0+ #8
[  657.069060] Hardware name: Inspur SA5212M5/YZMB-00882-104, BIOS 4.0.9 08/27/2019
[  657.069064] Workqueue: nvme-reset-wq nvme_reset_work [nvme]
[  657.069066] RIP: 0010:irq_create_affinity_masks+0x47c/0x4a0
[  657.069067] Code: fe ff ff 48 c7 c0 b0 89 14 95 48 89 46 20 e9 e9 fb ff ff 31 c0 e9 90 fc ff ff 0f 0b 48 c7 44 24 08 00 00 00 00 e9 e9 fc ff ff <0f> 0b e9 87 fe ff ff 48 8b 7c 24 28 e8 33 a0 80 00 e9 b6 fc ff ff
[  657.069068] RSP: 0018:ffffb505ce1ffc78 EFLAGS: 00010202
[  657.069069] RAX: 0000000000000060 RBX: ffff9b97921fe5c0 RCX: 0000000000000000
[  657.069069] RDX: ffff9b67bad80000 RSI: 00000000ffffffa0 RDI: 0000000000000000
[  657.069070] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff9b97921fe718
[  657.069070] R10: ffff9b97921fe710 R11: 0000000000000001 R12: 0000000000000064
[  657.069070] R13: 0000000000000060 R14: 0000000000000000 R15: 0000000000000001
[  657.069071] FS:  0000000000000000(0000) GS:ffff9b67c0880000(0000) knlGS:0000000000000000
[  657.069072] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  657.069072] CR2: 0000559eac6fc238 CR3: 000000057860a002 CR4: 00000000007606e0
[  657.069073] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  657.069073] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  657.069073] PKRU: 55555554
[  657.069074] Call Trace:
[  657.069080]  __pci_enable_msix_range+0x233/0x5a0
[  657.069085]  ? kernfs_put+0xec/0x190
[  657.069086]  pci_alloc_irq_vectors_affinity+0xbb/0x130
[  657.069089]  nvme_reset_work+0x6e6/0xeab [nvme]
[  657.069093]  ? __switch_to_asm+0x34/0x70
[  657.069094]  ? __switch_to_asm+0x40/0x70
[  657.069095]  ? nvme_irq_check+0x30/0x30 [nvme]
[  657.069098]  process_one_work+0x1a7/0x370
[  657.069101]  worker_thread+0x1c9/0x380
[  657.069102]  ? max_active_store+0x80/0x80
[  657.069103]  kthread+0x112/0x130
[  657.069104]  ? __kthread_parkme+0x70/0x70
[  657.069105]  ret_from_fork+0x35/0x40
[  657.069106] ---[ end trace f4f06b7d24513d06 ]---
[  657.077110] nvme nvme0: 95/1/0 default/read/poll queues
Signed-off-by: NWeiping Zhang <zhangweiping@didiglobal.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Control dependencies do not guarantee load order across the condition,
allowing a CPU to predict and speculate memory reads.

Commit 324b494c inlined verifying a new completion with its
handling. At least one architecture was observed to access the contents
out of order, resulting in the driver using stale data for the
completion.

Add a dma read barrier before reading the completion queue entry and
after the condition its contents depend on to ensure the read order is
determinsitic.
Reported-by: NJohn Garry <john.garry@huawei.com>
Suggested-by: NWill Deacon <will@kernel.org>
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Tested-by: NJohn Garry <john.garry@huawei.com>
Acked-by: NWill Deacon <will@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Since commit 147b27e4 ("nvme-pci: allocate device queues storage
space at probe"), nvme_alloc_queue does not alloc the nvme queues
itself anymore.

If the write/poll_queues module parameters are changed at runtime to
values larger than the number of allocated queues in nvme_probe,
nvme_alloc_queue will access unallocated memory.

Add a new nr_allocated_queues member to struct nvme_dev to record how
many queues were alloctated in nvme_probe to avoid using more than the
allocated queues after a reset following a change to the
write/poll_queues module parameters.

Also add nr_write_queues and nr_poll_queues members to allow refreshing
the number of write and poll queues based on a change to the module
parameters when resetting the controller.

Fixes: 147b27e4 ("nvme-pci: allocate device queues storage space at probe")
Signed-off-by: NWeiping Zhang <zhangweiping@didiglobal.com>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
[hch: add nvme_max_io_queues, update the commit message]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The nvme driver does not have enough tags to wrap the queue, and blk-mq
will no longer call commit_rqs() when there are no new submissions to
notify.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The completion queue entry is not volatile once the phase is confirmed.
Remove the volatile keywords and check the phase using the appropriate
READ_ONCE() accessor, allowing the compiler to optimize the remaining
completion path.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Pre-incrementing ->cq_head can't be done in memory because OOB value
can be observed by another context.

This devalues space savings compared to original code :-\

	$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux
	add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-32 (-32)
	Function                                     old     new   delta
	nvme_poll_irqdisable                         464     456      -8
	nvme_poll                                    455     447      -8
	nvme_irq                                     388     380      -8
	nvme_dev_disable                             955     947      -8

But the code is minimal now: one read for head, one read for q_depth,
one increment, one comparison, single instruction phase bit update and
one write for new head.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Reported-by: NJohn Garry <john.garry@huawei.com>
Tested-by: NJohn Garry <john.garry@huawei.com>
Fixes: e2a366a4 ("nvme-pci: slimmer CQ head update")
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Put the ctrl reference count at nvme_uninit_ctrl as opposed to
nvme_init_ctrl which takes it. This decrease the reference count at the
core layer instead of decreasing it on each transport separately.
Also move the call of nvme_uninit_ctrl at PCI driver after calling to
nvme_release_prp_pools and nvme_dev_unmap, in order to put the reference
count after using the dev. This is safe because those functions use
nvme_dev which is freed only later at nvme_pci_free_ctrl.
Signed-off-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

In case nvme_sysfs_delete() is called by the user before taking the ctrl
reference count, the ctrl may be freed during the creation and cause the
bug. Take the reference as soon as the controller is externally visible,
which is done by cdev_device_add() in nvme_init_ctrl(). Also take the
reference count at the core layer instead of taking it on each transport
separately.
Signed-off-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

Destroy the resources in the same order like in nvme_probe error flow to
improve code readability.
Signed-off-by: NIsrael Rukshin <israelr@mellanox.com>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

Align PCI address print with fabrics address that is printed with
newline character.

Before:
[root@server40 linux]# cat /sys/class/nvme/nvme2/address
0000:0b:00.0[root@server40 linux]#

After:
[root@server40 linux]# cat /sys/class/nvme/nvme2/address
0000:0b:00.0
[root@server40 linux]#
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>

The timeout handler can use the existing nvme_poll() if it needs to
check a polled queue, allowing nvme_poll_irqdisable() to handle only
irq driven queues for the remaining callers.
Signed-off-by: NKeith Busch <kbusch@kernel.org>

Completion handling had been done in two steps: find all new completions
under a lock, then handle those completions outside the lock. This was
done to make the locked section as short as possible so that other
threads using the same lock wait less time.

The driver no longer shares locks during completion, and is in fact
lockless for interrupt driven queues, so the optimization no longer
serves its original purpose. Replace the two-pass completion queue
handler with a single pass that completes entries immediately.
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

The only user for tagged completion was for timeout handling. That user,
though, really only cares if the timed out command is completed, which
we can safely check within the timeout handler.

Remove the tag check to simplify completion handling.
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

Update CQ head with pre-increment operator. This saves subtraction of 1
and a few registers.

Also update phase with "^= 1". This generates only one RMW instruction.

	ffffffff815ba150 <nvme_update_cq_head>:
	ffffffff815ba150:       0f b7 47 70             movzx  eax,WORD PTR [rdi+0x70]
	ffffffff815ba154:       83 c0 01                add    eax,0x1
	ffffffff815ba157:       66 89 47 70             mov    WORD PTR [rdi+0x70],ax
	ffffffff815ba15b:       66 3b 47 68             cmp    ax,WORD PTR [rdi+0x68]
	ffffffff815ba15f:       74 01                   je     ffffffff815ba162 <nvme_update_cq_head+0x12>
	ffffffff815ba161:       c3                      ret
	ffffffff815ba162:       31 c0                   xor    eax,eax
	ffffffff815ba164:       80 77 74 01      ===>   xor    BYTE PTR [rdi+0x74],0x1
	ffffffff815ba168:       66 89 47 70             mov    WORD PTR [rdi+0x70],ax
	ffffffff815ba16c:       c3                      ret

	add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-119 (-119)
	Function                                     old     new   delta
	nvme_poll                                    690     678     -12
	nvme_dev_disable                            1230    1177     -53
	nvme_irq                                     613     559     -54
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>

Completions need to consumed in the same order the controller submitted
them, otherwise future completion entries may overwrite ones we haven't
handled yet. Hold the nvme queue's poll lock while completing new CQEs to
prevent another thread from freeing command tags for reuse out-of-order.

Fixes: dabcefab ("nvme: provide optimized poll function for separate poll queues")
Signed-off-by: NBijan Mottahedeh <bijan.mottahedeh@oracle.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

People reported that old Apple machines are not working properly
if the non-first IRQ vector is in use.

Set quirk for that models to limit IRQ to use first vector only.

Based on original patch by GitHub user npx001.

Link: https://github.com/Dunedan/mbp-2016-linux/issues/9
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Leif Liddy <leif.liddy@gmail.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

The Samsung SSD SM981/PM981 and Toshiba SSD KBG40ZNT256G on the Lenovo
C640 platform experience runtime resume issues when the SSDs are kept in
sleep/suspend mode for long time.

This patch applies the 'Simple Suspend' quirk to these configurations.
With this patch, the issue had not been observed in a 1+ day test.
Reviewed-by: NJon Derrick <jonathan.derrick@intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NShyjumon N <shyjumon.n@intel.com>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

Many users have reported nvme triggered irq_startup() warnings during
shutdown. The driver uses the nvme queue's irq to synchronize scanning
for completions, and enabling an interrupt affined to only offline CPUs
triggers the alarming warning.

Move the final CQE check to after disabling the device and all
registered interrupts have been torn down so that we do not have any
IRQ to synchronize.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206509Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

There is no real need to have a pointer to the tagset in
struct nvme_queue, as we only need it in a single place, and that place
can derive the used tagset from the device and qid trivially.  This
fixes a problem with stale pointer exposure when tagsets are reset,
and also shrinks the nvme_queue structure.  It also matches what most
other transports have done since day 1.
Reported-by: NEdmund Nadolski <edmund.nadolski@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

If nvme.write_queues equals the number of CPUs, the driver had decreased
the number of interrupts available such that there could only be one read
queue even if the controller could support more. Remove the interrupt
count reduction in this case. The driver wouldn't request more IRQs than
it wants queues anyway.
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

The driver can never use more queues of any type than the number of
possible CPUs, so a higher value causes the driver to allocate more
memory for IO queues than it could ever use. Limit the parameter at
module load time to the number of possible cpus.
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

The number of poll or write queues should never be negative. Use unsigned
types so that it's not possible to break have the driver not allocate
any queues.
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NKeith Busch <kbusch@kernel.org>

We had been saving the last_cq_head seen from an interrupt so that a
polled queue wouldn't mistakenly trigger spruious interrupt detection. We
don't poll interrupt driven queues any more, so saving this value is
pointless.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKeith Busch <kbusch@kernel.org>