Quiesce IO queues prior to disabling device HMB accesses. A controller
using HMB may relay on it to efficiently complete IO commands.
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This patch fixes nvme queue cleanup if requesting an IRQ handler for
the queue's vector fails. It does this by resetting the cq_vector to
the uninitialized value of -1 so it is ignored for a controller reset.
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
[changelog updates, removed misc whitespace changes]
Signed-off-by: NKeith Busch <keith.busch@intel.com>

We need to halt the controller immediately if we haven't completed
initialization as indicated by the new "connecting" state.

Fixes: ad70062c ("nvme-pci: introduce RECONNECTING state to mark initializing procedure")
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

The controller memory buffer is remapped into a kernel address on each
reset, but the driver was setting the submission queue base address
only on the very first queue creation. The remapped address is likely to
change after a reset, so accessing the old address will hit a kernel bug.

This patch fixes that by setting the queue's CMB base address each time
the queue is created.

Fixes: f63572df ("nvme: unmap CMB and remove sysfs file in reset path")
Reported-by: NChristian Black <christian.d.black@intel.com>
Cc: Jon Derrick <jonathan.derrick@intel.com>
Cc: <stable@vger.kernel.org> # 4.9+
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

In pci transport, this state is used to mark the initialization
process. This should be also used in other transports as well.
Signed-off-by: NMax Gurtovoy <maxg@mellanox.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>

After Sagi's commit (nvme-rdma: fix concurrent reset and reconnect),
both nvme-fc/rdma have following pattern:
RESETTING    - quiesce blk-mq queues, teardown and delete queues/
               connections, clear out outstanding IO requests...
RECONNECTING - establish new queues/connections and some other
               initializing things.
Introduce RECONNECTING to nvme-pci transport to do the same mark.
Then we get a coherent state definition among nvme pci/rdma/fc
transports.
Suggested-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NReviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The driver had been abusing the cq_vector state to know if new submissions
were safe, but that was before we could quiesce blk-mq. If the controller
happens to get an interrupt through while we're suspending those queues,
'no irq handler' warnings may occur.

This patch will disable the interrupts only after the queues are deleted.
Reported-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Tested-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The queue count says the highest queue that's been allocated, so don't
reallocate a queue lower than that.

Fixes: 147b27e4 ("nvme-pci: allocate device queues storage space at probe")
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Some iommu implementations can merge physically and/or virtually
contiguous segments inside sg_map_dma.  The NVMe SGL support does not take
this into account and will warn because of falling off a loop.  Pass the
number of mapped segments to nvme_pci_setup_sgls so that the SGL setup
can take the number of mapped segments into account.
Reported-by: NFangjian (Turing) <f.fangjian@huawei.com>
Fixes: a7a7cbe3 ("nvme-pci: add SGL support")
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@rimberg.me>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The driver needs to verify there is a payload with a command before
seeing if it should use SGLs to map it.

Fixes: 955b1b5a ("nvme-pci: move use_sgl initialization to nvme_init_iod()")
Reported-by: NPaul Menzel <pmenzel+linux-nvme@molgen.mpg.de>
Reviewed-by: NPaul Menzel <pmenzel+linux-nvme@molgen.mpg.de>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Define the bit positions instead of macros using the magic values,
and move the expanded helpers to calculate the size and size unit into
the implementation C file.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>

Refactor the call to nvme_map_cmb, and change the conditions for probing
for the CMB.  First remove the version check as NVMe TPs always apply
to earlier versions of the spec as well.  Second check for the whole CMBSZ
register for support of the CMB feature instead of just the size field
inside of it to simplify the code a bit.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>

fix comment typos in nvme_create_io_queues() like below.
  _aount_ to _amount_
  _an_    to _can_
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

It may cause race by setting 'nvmeq' in nvme_init_request()
because .init_request is called inside switching io scheduler, which
may happen when the NVMe device is being resetted and its nvme queues
are being freed and created. We don't have any sync between the two
pathes.

This patch changes the nvmeq allocation to occur at probe time so
there is no way we can dereference it at init_request.

[   93.268391] kernel BUG at drivers/nvme/host/pci.c:408!
[   93.274146] invalid opcode: 0000 [#1] SMP
[   93.278618] Modules linked in: nfsv3 nfs_acl rpcsec_gss_krb5 auth_rpcgss
nfsv4 dns_resolver nfs lockd grace fscache sunrpc ipmi_ssif vfat fat
intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel
kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel iTCO_wdt
intel_cstate ipmi_si iTCO_vendor_support intel_uncore mxm_wmi mei_me
ipmi_devintf intel_rapl_perf pcspkr sg ipmi_msghandler lpc_ich dcdbas mei
shpchp acpi_power_meter wmi dm_multipath ip_tables xfs libcrc32c sd_mod
mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt
fb_sys_fops ttm drm ahci libahci nvme libata crc32c_intel nvme_core tg3
megaraid_sas ptp i2c_core pps_core dm_mirror dm_region_hash dm_log dm_mod
[   93.349071] CPU: 5 PID: 1842 Comm: sh Not tainted 4.15.0-rc2.ming+ #4
[   93.356256] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.5.5 08/16/2017
[   93.364801] task: 00000000fb8abf2a task.stack: 0000000028bd82d1
[   93.371408] RIP: 0010:nvme_init_request+0x36/0x40 [nvme]
[   93.377333] RSP: 0018:ffffc90002537ca8 EFLAGS: 00010246
[   93.383161] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000008
[   93.391122] RDX: 0000000000000000 RSI: ffff880276ae0000 RDI: ffff88047bae9008
[   93.399084] RBP: ffff88047bae9008 R08: ffff88047bae9008 R09: 0000000009dabc00
[   93.407045] R10: 0000000000000004 R11: 000000000000299c R12: ffff880186bc1f00
[   93.415007] R13: ffff880276ae0000 R14: 0000000000000000 R15: 0000000000000071
[   93.422969] FS:  00007f33cf288740(0000) GS:ffff88047ba80000(0000) knlGS:0000000000000000
[   93.431996] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   93.438407] CR2: 00007f33cf28e000 CR3: 000000047e5bb006 CR4: 00000000001606e0
[   93.446368] Call Trace:
[   93.449103]  blk_mq_alloc_rqs+0x231/0x2a0
[   93.453579]  blk_mq_sched_alloc_tags.isra.8+0x42/0x80
[   93.459214]  blk_mq_init_sched+0x7e/0x140
[   93.463687]  elevator_switch+0x5a/0x1f0
[   93.467966]  ? elevator_get.isra.17+0x52/0xc0
[   93.472826]  elv_iosched_store+0xde/0x150
[   93.477299]  queue_attr_store+0x4e/0x90
[   93.481580]  kernfs_fop_write+0xfa/0x180
[   93.485958]  __vfs_write+0x33/0x170
[   93.489851]  ? __inode_security_revalidate+0x4c/0x60
[   93.495390]  ? selinux_file_permission+0xda/0x130
[   93.500641]  ? _cond_resched+0x15/0x30
[   93.504815]  vfs_write+0xad/0x1a0
[   93.508512]  SyS_write+0x52/0xc0
[   93.512113]  do_syscall_64+0x61/0x1a0
[   93.516199]  entry_SYSCALL64_slow_path+0x25/0x25
[   93.521351] RIP: 0033:0x7f33ce96aab0
[   93.525337] RSP: 002b:00007ffe57570238 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[   93.533785] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f33ce96aab0
[   93.541746] RDX: 0000000000000006 RSI: 00007f33cf28e000 RDI: 0000000000000001
[   93.549707] RBP: 00007f33cf28e000 R08: 000000000000000a R09: 00007f33cf288740
[   93.557669] R10: 00007f33cf288740 R11: 0000000000000246 R12: 00007f33cec42400
[   93.565630] R13: 0000000000000006 R14: 0000000000000001 R15: 0000000000000000
[   93.573592] Code: 4c 8d 40 08 4c 39 c7 74 16 48 8b 00 48 8b 04 08 48 85 c0
74 16 48 89 86 78 01 00 00 31 c0 c3 8d 4a 01 48 63 c9 48 c1 e1 03 eb de <0f>
0b 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 f6 53 48 89
[   93.594676] RIP: nvme_init_request+0x36/0x40 [nvme] RSP: ffffc90002537ca8
[   93.602273] ---[ end trace 810dde3993e5f14e ]---
Reported-by: NYi Zhang <yi.zhang@redhat.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

When the io queues setup or tagset allocation failed, ctrl.tagset is
NULL.  But the scan work will still be queued and executed, then panic
comes up due to NULL pointer reference of ctrl.tagset.

To fix this, add a new ctrl state NVME_CTRL_ADMIN_ONLY to inidcate only
admin queue is live. When non io queues or tagset allocation failed, ctrl
enters into this state, scan work will not be started.  But async event
work and nvme dev ioctl will be still available.  This will be helpful to
do further investigation and recovery.
Suggested-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The local variable __size__ will be set a bit later in a for-loop.
Remove the explicit initialization at the beginning of this function.
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

A flag "use_sgl" of "struct nvme_iod" has been used in nvme_init_iod()
without being set to any value. It seems like "use_sgl" has been set
in either nvme_pci_setup_prps() or nvme_pci_setup_sgls() which occur
later than nvme_init_iod().

Make "iod->use_sgl" being set in a proper place, nvme_init_iod().
Also move nvme_pci_use_sgls() up above nvme_init_iod() to make it
possible to be called by nvme_init_iod().
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Following condition which will cause NULL pointer dereference will
occur in nvme_free_host_mem() when it tries to remove pci device via
nvme_remove() especially after a failure of host memory allocation for HMB.

    "(host_mem_descs == NULL) && (nr_host_mem_descs != 0)"

It's because __nr_host_mem_descs__ is not cleared to 0 unlike
__host_mem_descs__ is so.
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

And increase the existing delay to cover this device as well.

Cc: stable@vger.kernel.org
Signed-off-by: NJeff Lien <jeff.lien@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

hmb descriptor idx out-of-bound occurs in case of below conditions.
preferred = 128MiB
chunk_size = 4MiB
hmmaxd = 1

Current code will not allow rmmod which will free hmb descriptors
to be done successfully in above case.

"descs[i]" will be set in for-loop without seeing any conditions
related to "max_entries" after a single "descs" was allocated by
(max_entries = 1) in this case.

Added a condition into for-loop to check index of descriptors.

Fixes: 044a9df1("nvme-pci: implement the HMB entry number and size limitations")
Signed-off-by: NMinwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The NVMe device in question drops off the PCIe bus after system suspend.
I've tried several approaches to workaround this issue, but none of them
works:
- NVME_QUIRK_DELAY_BEFORE_CHK_RDY
- NVME_QUIRK_NO_DEEPEST_PS
- Disable APST before controller shutdown
- Delay between controller shutdown and system suspend
- Explicitly set power state to 0 before controller shutdown

Fortunately it's a desktop, so disable APST won't hurt the battery.

Also, change the quirk function name to reflect it's for vendor
combination quirks.

BugLink: https://bugs.launchpad.net/bugs/1705748Signed-off-by: NKai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The 'remove_work' may be scheduled to run after nvme_remove()
returns since we can't simply cancel it in nvme_remove() for
avoiding deadlock. Once nvme_remove() returns, this module(nvme)
can be unloaded.

On the other hand, nvme_put_ctrl() calls ctr->ops->free_ctrl
which may point to nvme_pci_free_ctrl() in unloaded module.

This patch avoids this issue by queuing 'remove_work' via 'nvme_wq',
and flush this worqueue in nvme_exit() as suggested by Sagi.
Suggested-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The driver can handle tracking only one AEN request, so this patch
removes handling for multiple ones.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJames Smart  <james.smart@broadcom.com>
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

All the transports were unnecessarilly duplicating the AEN request
accounting. This patch defines everything in one place.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NGuan Junxiong <guanjunxiong@huawei.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Instead of allocating a separate struct device for the character device
handle embedd it into struct nvme_ctrl and use it for the main controller
refcounting.  This removes double refcounting and gets us an automatic
reference for the character device operations.  We keep ctrl->device as a
pointer for now to avoid chaning printks all over, but in the future we
could look into message printing helpers that take a controller structure
similar to what other subsystems do.

Note the delete_ctrl operation always already has a reference (either
through sysfs due this change, or because every open file on the
/dev/nvme-fabrics node has a refernece) when it is entered now, so we
don't need to do the unless_zero variant there.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>

This adds SGL support for NVMe PCIe driver, based on an earlier patch
from Rajiv Shanmugam Madeswaran <smrajiv15 at gmail.com>. This patch
refactors the original code and adds new module parameter sgl_threshold
to determine whether to use SGL or PRP for IOs.

The usage of SGLs is controlled by the sgl_threshold module parameter,
which allows to conditionally use SGLs if average request segment
size (avg_seg_size) is greater than sgl_threshold. In the original patch,
the decision of using SGLs was dependent only on the IO size,
with the new approach we consider not only IO size but also the
number of physical segments present in the IO.

We calculate avg_seg_size based on request payload bytes and number
of physical segments present in the request.

For e.g.:-

1. blk_rq_nr_phys_segments = 2 blk_rq_payload_bytes = 8k
avg_seg_size = 4K use sgl if avg_seg_size >= sgl_threshold.

2. blk_rq_nr_phys_segments = 2 blk_rq_payload_bytes = 64k
avg_seg_size = 32K use sgl if avg_seg_size >= sgl_threshold.

3. blk_rq_nr_phys_segments = 16 blk_rq_payload_bytes = 64k
avg_seg_size = 4K use sgl if avg_seg_size >= sgl_threshold.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

fixed comment typos in adapter_alloc_cq() and adapter_alloc_sq().
'the the' duplications are replaced with 'that the'.
Signed-off-by: NMinwoo Im <dn3108@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Currently, NVMe PCI host driver is programming CMB dma address as
I/O SQs addresses. This results in failures on systems where 1:1
outbound mapping is not used (example Broadcom iProc SOCs) because
CMB BAR will be progammed with PCI bus address but NVMe PCI EP will
try to access CMB using dma address.

To have CMB working on systems without 1:1 outbound mapping, we
program PCI bus address for I/O SQs instead of dma address. This
approach will work on systems with/without 1:1 outbound mapping.

Based on a report and previous patch from Abhishek Shah.

Fixes: 8ffaadf7 ("NVMe: Use CMB for the IO SQes if available")
Cc: stable@vger.kernel.org
Reported-by: NAbhishek Shah <abhishek.shah@broadcom.com>
Tested-by: NAbhishek Shah <abhishek.shah@broadcom.com>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The WARN_ONCE macro returns true if the condition is true, not if the
warn was raised, so we're printing the scatter list every time it's
invalid. This is excessive and makes debugging harder, so this patch
prints it just once.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

A spurious interrupt before the nvme driver has initialized the completion
queue may inadvertently cause the driver to believe it has a completion
to process. This may result in a NULL dereference since the nvmeq's tags
are not set at this point.

The patch initializes the host's CQ memory so that a spurious interrupt
isn't mistaken for a real completion.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Adds support for the new Host Memory Buffer Minimum Descriptor Entry Size
and Host Memory Maximum Descriptors Entries field that were added in
TP 4002 HMB Enhancements.  These allow the controller to advertise
limits for the usual number of segments in the host memory buffer, as
well as a minimum usable per-segment size.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>

We want to catch command execution errors when resetting the device, so
propagate errors from the Set Features when setting up the host memory
buffer.  We keep ignoring memory allocation failures, as the spec
clearly says that the controller must work without a host memory buffer.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Cc: stable@vger.kernel.org

The initial chunk size for host memory buffer allocation is currently
PAGE_SIZE << MAX_ORDER.  MAX_ORDER order allocation is usually failed
without CONFIG_DMA_CMA.  So the HMB allocation is retried with chunk size
PAGE_SIZE << (MAX_ORDER - 1) in general, but there is no problem if the
retry allocation works correctly.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
[hch: rebased]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Cc: stable@vger.kernel.org

nvme_alloc_host_mem currently contains two loops that are interwinded,
and the outer retry loop turns out to be broken.  Fix this by untangling
the two.

Based on a report an initial patch from Akinobu Mita.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NAkinobu Mita <akinobu.mita@gmail.com>
Tested-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Cc: stable@vger.kernel.org

nvme_nvm_ns_supported assumes every device is a pci_dev, which leads to
reading an incorrect field, or possible even a dereference of unallocated
memory for fabrics controllers.

Fix this by introducing a quirk for lighnvm capable devices instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMatias Bjørling <mb@lightnvm.io>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>

Only read and write commands need DIF remapping. Everything else uses
a passthrough integrity payload.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The NVMe 1.3 specification says in section 5.21.1.13:

"After a successful completion of a Set Features enabling the host memory
 buffer, the host shall not write to the associated host memory region,
 buffer size, or descriptor list until the host memory buffer has been
 disabled."

While this doesn't state that the descriptor list must remain accessible
to the device it certainly implies it must remaing readable by the device.

So switch to a dma coherent allocation for the descriptor list just to be
safe - it's not like the cost for it matters compared to the actual
memory buffers.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Fixes: 87ad72a5 ("nvme-pci: implement host memory buffer support")