Two cases:
1) blk_mq_alloc_request() needlessly re-runs the queue, after
calling into the tag allocation without NOWAIT set. We don't
need to do that.
2) blk_mq_map_request() should just use blk_mq_run_hw_queue() with
the async flag set to false.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
bio_free_pages is introduced in commit 1dfa0f68c0
("block: add a helper to free bio bounce buffer pages"),
we can reuse the func in other modules after it was
imported.
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Acked-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
device_add() may fail, and all callers are supposed to check the
return value, but one new user in lightnvm doesn't:
drivers/lightnvm/sysfs.c: In function 'nvm_sysfs_register_dev':
drivers/lightnvm/sysfs.c:184:2: error: ignoring return value of 'device_add',
declared with attribute warn_unused_result [-Werror=unused-result]
This changes the caller to propagate any error codes, which avoids
the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 38c9e260b9f9 ("lightnvm: expose device geometry through sysfs")
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
For a host to access an Open-Channel SSD, it has to know its geometry,
so that it writes and reads at the appropriate device bounds.
Currently, the geometry information is kept within the kernel, and not
exported to user-space for consumption. This patch exposes the
configuration through sysfs and enables user-space libraries, such as
liblightnvm, to use the sysfs implementation to get the geometry of an
Open-Channel SSD.
The sysfs entries are stored within the device hierarchy, and can be
found using the "lightnvm" device type.
An example configuration looks like this:
/sys/class/nvme/
└── nvme0n1
├── capabilities: 3
├── device_mode: 1
├── erase_max: 1000000
├── erase_typ: 1000000
├── flash_media_type: 0
├── media_capabilities: 0x00000001
├── media_type: 0
├── multiplane: 0x00010101
├── num_blocks: 1022
├── num_channels: 1
├── num_luns: 4
├── num_pages: 64
├── num_planes: 1
├── page_size: 4096
├── prog_max: 100000
├── prog_typ: 100000
├── read_max: 10000
├── read_typ: 10000
├── sector_oob_size: 0
├── sector_size: 4096
├── media_manager: gennvm
├── ppa_format: 0x380830082808001010102008
├── vendor_opcode: 0
├── max_phys_secs: 64
└── version: 1
Signed-off-by: Simon A. F. Lund <slund@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
LightNVM compatible device drivers does not have a method to expose
LightNVM specific sysfs entries.
To enable LightNVM sysfs entries to be exposed, lightnvm device
drivers require a struct device to attach it to. To allow both the
actual device driver and lightnvm sysfs entries to coexist, the device
driver tracks the lifetime of the nvm_dev structure.
This patch refactors NVMe and null_blk to handle the lifetime of struct
nvm_dev, which eliminates the need for struct gendisk when a lightnvm
compatible device is provided.
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
Enable devices without a gendisk instance to register itself with blk-mq
and expose the associated multi-queue sysfs entries.
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
With LightNVM enabled devices, the gendisk structure is not exposed
to the user. This hides the device driver specific sysfs entries, and
prevents binding of LightNVM geometry information to the device.
Refactor the device registration process, so that gendisk and
non-gendisk devices are easily managed.
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
With LightNVM enabled namespaces, the gendisk structure is not exposed
to the user. This prevents LightNVM users from accessing the NVMe device
driver specific sysfs entries, and LightNVM namespace geometry.
Refactor the revalidation process, so that a namespace, instead of a
gendisk, is revalidated. This later allows patches to wire up the
sysfs entries up to a non-gendisk namespace.
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
If NO_DMA=y:
drivers/built-in.o: In function `nvme_nvm_dev_dma_free':
lightnvm.c:(.text+0x23df1a): undefined reference to `dma_pool_free'
drivers/built-in.o: In function `nvme_nvm_dev_dma_alloc':
lightnvm.c:(.text+0x23df38): undefined reference to `dma_pool_alloc'
drivers/built-in.o: In function `nvme_nvm_destroy_dma_pool':
lightnvm.c:(.text+0x23df4c): undefined reference to `dma_pool_destroy'
drivers/built-in.o: In function `nvme_nvm_create_dma_pool':
lightnvm.c:(.text+0x23df7e): undefined reference to `dma_pool_create'
and
ERROR: "dma_pool_destroy" [drivers/nvme/host/nvme-core.ko] undefined!
ERROR: "dma_pool_free" [drivers/nvme/host/nvme-core.ko] undefined!
ERROR: "dma_pool_alloc" [drivers/nvme/host/nvme-core.ko] undefined!
ERROR: "dma_pool_create" [drivers/nvme/host/nvme-core.ko] undefined!
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
Variable weight is not being initialized to zero before it is
used to compute the weight sum. Ensure it is initialized to zero.
Found with static analysis with cppcheck:
[lib/sbitmap.c:177]: (error) Uninitialized variable: weight
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
If we have a bunch of high-numbered bits allocated and then we resize
the struct sbitmap_queue, when those bits get cleared, we'll update the
hint and then have to re-randomize it repeatedly. Avoid that by checking
that the cleared bit is still a valid hint. No measurable performance
difference in the common case.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
After a struct sbitmap_queue is resized smaller, the allocation hints
may still be set to bits beyond the new depth of the bitmap. This means
that, for example, if the number of blk-mq tags is reduced through
sysfs, more requests than the nominal queue depth may be in flight.
It's tempting to fix this at resize time by doing a one-time
reinitialization of the hints, but this can race with
__sbitmap_queue_get() updating the hint. Instead, check the hint before
we use it. This caused no measurable performance difference in my
synthetic benchmarks.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
In order to get good cache behavior from a sbitmap, we want each CPU to
stick to its own cacheline(s) as much as possible. This might happen
naturally as the bitmap gets filled up and the alloc_hint values spread
out, but we really want this behavior from the start. blk-mq apparently
intended to do this, but the code to do this was never wired up. Get rid
of the dead code and make it part of the sbitmap library.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Again, there's no point in passing this in every time. Make it part of
struct sbitmap_queue and clean up the API.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Allocating your own per-cpu allocation hint separately makes for an
awkward API. Instead, allocate the per-cpu hint as part of the struct
sbitmap_queue. There's no point for a struct sbitmap_queue without the
cache, but you can still use a bare struct sbitmap.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The original bt_alloc() we converted from was using kzalloc(), not
kzalloc_node(), to allocate the wait queues. This was probably an
oversight, so fix it for sbitmap_queue_init_node().
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This is a generally useful data structure, so make it available to
anyone else who might want to use it. It's also a nice cleanup
separating the allocation logic from the rest of the tag handling logic.
The code is behind a new Kconfig option, CONFIG_SBITMAP, which is only
selected by CONFIG_BLOCK for now.
This should be a complete noop functionality-wise.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We currently account a '0' dispatch, and anything above that still falls
below the range set by BLK_MQ_MAX_DISPATCH_ORDER. If we dispatch more,
we don't account it.
Change the last bucket to be inclusive of anything above the range we
track, and have the sysfs file reflect that by including a '+' in the
output:
$ cat /sys/block/nvme0n1/mq/0/dispatched
0 1006
1 20229
2 1
4 0
8 0
16 0
32+ 0
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
blk_mq_delay_kick_requeue_list() provides the ability to kick the
q->requeue_list after a specified time. To do this the request_queue's
'requeue_work' member was changed to a delayed_work.
blk_mq_delay_kick_requeue_list() allows DM to defer processing requeued
requests while it doesn't make sense to immediately requeue them
(e.g. when all paths in a DM multipath have failed).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Since REQ_OP_BITS == 3 and __REQ_NR_BITS == 30 it is not that hard
to pass an op_flags argument to bio_set_op_attrs() that is larger
than the number of bits reserved for the op_flags argument. Complain
if this happens. Additionally, ensure that negative arguments trigger
a complaint (1 << ... is signed while 1U << ... is unsigned; adding
0U to an integer expression causes it to be promoted to an unsigned
type).
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Introduce the bio_flags() macro. Ensure that the second argument of
bio_set_op_attrs() only contains flags and no operation. This patch
does not change any functionality.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Chris Mason <clm@fb.com> (maintainer:BTRFS FILE SYSTEM)
Cc: Josef Bacik <jbacik@fb.com> (maintainer:BTRFS FILE SYSTEM)
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Make it clear that the sizeof(unsigned int) expression in BIO_OP_SHIFT
refers to the bi_opf member of struct bio.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
commit e1defc4ff0
"block: Do away with the notion of hardsect_size"
removed the notion of "hardware sector size" from
the kernel in favor of logical block size, but
references remain in comments and documentation.
Update the remaining sites mentioning hardsect.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
The blk_mq_alloc_single_hw_queue() is a prototype artifact that
should have been removed with
commit cdef54dd85
"blk-mq: remove alloc_hctx and free_hctx methods" where the last
users of it were deleted.
Fixes: cdef54dd85 ("blk-mq: remove alloc_hctx and free_hctx methods")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
DAX support for block devices was removed in commits 03cdad
("block: disable block device DAX by default") and 99a01cd
("block: remove BLK_DEV_DAX config option"), but we still kept a call to
dax_do_io and some uneeded i_flags manipulations introduced in commit
bbab37 ("block: Add support for DAX reads/writes to block devices").
Remove those leftovers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Allow the io_poll statistics to be zeroed to make for easier logging
of polling event.
Signed-off-by: Stephen Bates <sbates@raithlin.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
In order to help determine the effectiveness of polling in a running
system it is usful to determine the ratio of how often the poll
function is called vs how often the completion is checked. For this
reason we add a poll_considered variable and add it to the sysfs entry
for io_poll.
Signed-off-by: Stephen Bates <sbates@raithlin.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Instead of rolling our own timer, just utilize the blk mq req timeout and do the
disconnect if any of our commands timeout.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
In preparation for some future changes, change a few of the state bools over to
normal bits to set/clear properly.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We hit a warning when shutting down the nbd connection because we have irq's
disabled. We don't really need to do the shutdown under the lock, just clear
the nbd->sock. So do the shutdown outside of the irq. This gets rid of the
warning.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This moves NBD over to using blkmq, which allows us to get rid of the NBD
wide queue lock and the async submit kthread. We will start with 1 hw
queue for now, but I plan to add multiple tcp connection support in the
future and we'll fix how we set the hwqueue's.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
We get 1 warning when biuld kernel with W=1:
drivers/block/mtip32xx/mtip32xx.c:3689:6: warning: no previous prototype for
'mtip_block_release' [-Wmissing-prototypes]
In fact, this function is only used in the file in which it is declared
and don't need a declaration, but can be made static.
so this patch marks it 'static'.
Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
When drivers or the core calls this function, they usually
dereference the request shortly there after. Prefetch the first
cache line.
Profiling IO workloads shows that this is the most common cache
miss on the block side of things.
Signed-off-by: Jens Axboe <axboe@fb.com>
Various cache line optimizations:
- Move delay_work towards the end. It's huge, and we don't use it
a lot (only SCSI).
- Move the atomic state into the same cacheline as the the dispatch
list and lock.
- Rearrange a few members to pack it better.
- Shrink the max-order for dispatch accounting from 10 to 7. This
means that ->dispatched[] and ->run now take up their own
cacheline.
This shrinks struct blk_mq_hw_ctx down to 8 cachelines.
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull drm fixes from Dave Airlie:
"A bunch of fixes covering i915, amdgpu, one tegra and some core DRM
ones. Nothing too strange at this point"
* tag 'drm-fixes-for-4.8-rc4' of git://people.freedesktop.org/~airlied/linux: (21 commits)
drm/atomic: Don't potentially reset color_mgmt_changed on successive property updates.
drm: Protect fb_defio in drivers with CONFIG_KMS_FBDEV_EMULATION
drm/amdgpu: skip TV/CV in display parsing
drm/amdgpu: avoid a possible array overflow
drm/amdgpu: fix lru size grouping v2
drm/tegra: dsi: Enhance runtime power management
drm/i915: Fix botched merge that downgrades CSR versions.
drm/i915/skl: Ensure pipes with changed wms get added to the state
drm/i915/gen9: Only copy WM results for changed pipes to skl_hw
drm/i915/skl: Add support for the SAGV, fix underrun hangs
drm/i915/gen6+: Interpret mailbox error flags
drm/i915: Reattach comment, complete type specification
drm/i915: Unconditionally flush any chipset buffers before execbuf
drm/i915/gen9: Drop invalid WARN() during data rate calculation
drm/i915/gen9: Initialize intel_state->active_crtcs during WM sanitization (v2)
drm: Reject page_flip for !DRIVER_MODESET
drm/amdgpu: fix timeout value check in amd_sched_job_recovery
drm/amdgpu: fix sdma_v2_4_ring_test_ib
drm/amdgpu: fix amdgpu_move_blit on 32bit systems
drm/radeon: fix radeon_move_blit on 32bit systems
...
Due to assigning the 'replaced' value instead of or'ing it,
if drm_atomic_crtc_set_property() gets called multiple times,
the last call will define the color_mgmt_changed flag, so
a non-updating call to a property can reset the flag and
prevent actual hw state updates required by preceding
property updates.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: <stable@vger.kernel.org> # v4.6+
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Pull perf fixes from Thomas Gleixner:
"A few fixes from the perf departement
- prevent a imbalanced preemption disable in the events teardown code
- prevent out of bound acces in perf userspace
- make perf tools compile with UCLIBC again
- a fix for the userspace unwinder utility"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Use this_cpu_ptr() when stopping AUX events
perf evsel: Do not access outside hw cache name arrays
tools lib: Reinstate strlcpy() header guard with __UCLIBC__
perf unwind: Use addr_location::addr instead of ip for entries
Pull x86 fix from Thomas Gleixner:
"A single bugfix to prevent irq remapping when the ioapic is disabled"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic: Do not init irq remapping if ioapic is disabled
Pull irq fixes from Thomas Gleixner:
"This lot provides:
- plug a hotplug race in the new affinity infrastructure
- a fix for the trigger type of chained interrupts
- plug a potential memory leak in the core code
- a few fixes for ARM and MIPS GICs"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/mips-gic: Implement activate op for device domain
irqchip/mips-gic: Cleanup chip and handler setup
genirq/affinity: Use get/put_online_cpus around cpumask operations
genirq: Fix potential memleak when failing to get irq pm
irqchip/gicv3-its: Disable the ITS before initializing it
irqchip/gicv3: Remove disabling redistributor and group1 non-secure interrupts
irqchip/gic: Allow self-SGIs for SMP on UP configurations
genirq: Correctly configure the trigger on chained interrupts
Pull timer fixes from Thomas Gleixner:
"A few updates for timers & co:
- prevent a livelock in the timekeeping code when debugging is
enabled
- prevent out of bounds access in the timekeeping debug code
- various fixes in clocksource drivers
- a new maintainers entry"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function
drivers/clocksource/pistachio: Fix memory corruption in init
clocksource/drivers/timer-atmel-pit: Enable mck clock
clocksource/drivers/pxa: Fix include files for compilation
MAINTAINERS: Add ARM ARCHITECTED TIMER entry
timekeeping: Cap array access in timekeeping_debug
timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING
** fixes for ITS init issues, error handling, IRQ leakage, race conditions
** An erratum workaround for timers
** Some removal of misleading use of errors and comments
** A fix for GICv3 on 32-bit guests
* MIPS fix where the guest could wrongly map the first page of physical memory
* x86 nested virtualization fixes
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)
iQEcBAABAgAGBQJXtyfVAAoJEL/70l94x66Dhe4IAIOGI/OYVWU5IfUQ01oeRgD3
7wN222OmyC/K0/hSZc7ndRdcQfr5ombgM9XsS/EbkcRacWxAUHDX2FaYMpKgjT2M
Dnh2tJHuPz/4VtByGQ2fZ4hziK7amn18/MtPFCee+mIj0ya2fcWZ4qHVU8pKC6Ps
mVVZ0kxXsdV4pw9y6XgBLz/4bTLeASKvhFZrWOnjJoa+GeH2MFwocS0xaEI0HwxP
HVwcgoRdGXJuKUB9jE9FDWmWOgdoLnCG1bNUOvXKPcE0ZaFQDT4I4dImkBys3rqz
jbqnhLrpGEY2ZC3Rj+VyD2MOXbYOOSi59GRwYmCkqD96ZarHxSu3PdyCxmIFWzM=
=+4WK
-----END PGP SIGNATURE-----
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM fixes from Paolo Bonzini:
"ARM:
- fixes for ITS init issues, error handling, IRQ leakage, race
conditions
- an erratum workaround for timers
- some removal of misleading use of errors and comments
- a fix for GICv3 on 32-bit guests
MIPS:
- fix for where the guest could wrongly map the first page of
physical memory
x86:
- nested virtualization fixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
MIPS: KVM: Check for pfn noslot case
kvm: nVMX: fix nested tsc scaling
KVM: nVMX: postpone VMCS changes on MSR_IA32_APICBASE write
KVM: nVMX: fix msr bitmaps to prevent L2 from accessing L0 x2APIC
arm64: KVM: report configured SRE value to 32-bit world
arm64: KVM: remove misleading comment on pmu status
KVM: arm/arm64: timer: Workaround misconfigured timer interrupt
arm64: Document workaround for Cortex-A72 erratum #853709
KVM: arm/arm64: Change misleading use of is_error_pfn
KVM: arm64: ITS: avoid re-mapping LPIs
KVM: arm64: check for ITS device on MSI injection
KVM: arm64: ITS: move ITS registration into first VCPU run
KVM: arm64: vgic-its: Make updates to propbaser/pendbaser atomic
KVM: arm64: vgic-its: Plug race in vgic_put_irq
KVM: arm64: vgic-its: Handle errors from vgic_add_lpi
KVM: arm64: ITS: return 1 on successful MSI injection
Jens Axboe