[ Upstream commit 56c5dab20a6391604df9521f812c01d1e3fe1bd0 ]
Since gcc13, each member of an enum has the same type as the enum [1]. And
that is inherited from its members. Provided these two:
SRP_TAG_NO_REQ = ~0U,
SRP_TAG_TSK_MGMT = 1U << 31
all other members are unsigned ints.
Esp. with SRP_MAX_SGE and SRP_TSK_MGMT_SQ_SIZE and their use in min(),
this results in the following warnings:
include/linux/minmax.h:20:35: error: comparison of distinct pointer types lacks a cast
drivers/infiniband/ulp/srp/ib_srp.c:563:42: note: in expansion of macro 'min'
include/linux/minmax.h:20:35: error: comparison of distinct pointer types lacks a cast
drivers/infiniband/ulp/srp/ib_srp.c:2369:27: note: in expansion of macro 'min'
So move the large values away to a separate enum, so that they don't
affect other members.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36113
Link: https://lore.kernel.org/r/20221212120411.13750-1-jirislaby@kernel.org
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit dbc94a0fb81771a38733c0e8f2ea8c4fa6934dc1 ]
There are 2 ways to create IPoIB PKEY child interfaces:
1) Writing a PKEY to /sys/class/net/<ib parent interface>/create_child.
2) Using netlink with iproute.
While with sysfs the child interface has the same number of tx and
rx queues as the parent, with netlink there will always be 1 tx
and 1 rx queue for the child interface. That's because the
get_num_tx/rx_queues() netlink ops are missing and the default value
of 1 is taken for the number of queues (in rtnl_create_link()).
This change adds the get_num_tx/rx_queues() ops which allows for
interfaces with multiple queues to be created over netlink. This
constant only represents the max number of tx and rx queues on that
net device.
Fixes: 9baa0b0364 ("IB/ipoib: Add rtnl_link_ops support")
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Link: https://lore.kernel.org/r/f4a42c8aa43c02d5ae5559a60c3e5e0f18c82531.1670485816.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ed461b30b22c8fa85c25189c14cb89f29595cd14 ]
In the previous iteration of the while loop, the "ret" may have been
assigned a value of 0, so the error return code -EINVAL may have been
incorrectly set to 0. To fix set valid return code before calling to
goto. Also investigate each case separately as Andy suggessted.
Fixes: e711f968c4 ("IB/srp: replace custom implementation of hex2bin()")
Fixes: 2a174df0c6 ("IB/srp: Use kstrtoull() instead of simple_strtoull()")
Fixes: 19f313438c ("IB/srp: Add RDMA/CM support")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Link: https://lore.kernel.org/r/1669953638-11747-2-git-send-email-wangyufen@huawei.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 56c310de0b4b3aca1c4fdd9c1093fc48372a7335 ]
ib_dma_map_sg() augments the SGL into a 'dma mapped SGL'. This process
may change the number of entries and the lengths of each entry.
Code that touches dma_address is iterating over the 'dma mapped SGL'
and must use dma_nents which returned from ib_dma_map_sg().
We should use the return count from ib_dma_map_sg for futher usage.
Fixes: 9cb8374804 ("RDMA/rtrs: server: main functionality")
Link: https://lore.kernel.org/r/20220818105355.110344-4-haris.iqbal@ionos.com
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Aleksei Marov <aleksei.marov@ionos.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b66905e04dc714825aa6cffb950e281b46bbeafe ]
When iommu is enabled, we hit warnings like this:
WARNING: at rtrs/rtrs.c:178 rtrs_iu_post_rdma_write_imm+0x9b/0x110
rtrs warn on one sge entry length is 0, which is unexpected.
The problem is ib_dma_map_sg augments the SGL into a 'dma mapped SGL'.
This process may change the number of entries and the lengths of each
entry.
Code that touches dma_address is iterating over the 'dma mapped SGL'
and must use dma_nents which returned from ib_dma_map_sg().
So pass the count return from ib_dma_map_sg.
Fixes: 6a98d71dae ("RDMA/rtrs: client: main functionality")
Link: https://lore.kernel.org/r/20220818105355.110344-3-haris.iqbal@ionos.com
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Aleksei Marov <aleksei.marov@ionos.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b5605148e6ce36bb21020d49010b617693933128 ]
Change the LIO port members inside struct srpt_port from regular members
into pointers. Allocate the LIO port data structures from inside
srpt_make_tport() and free these from inside srpt_make_tport(). Keep
struct srpt_device as long as either an RDMA port or a LIO target port is
associated with it. This patch decouples the lifetime of struct srpt_port
(controlled by the RDMA core) and struct srpt_port_id (controlled by LIO).
This patch fixes the following KASAN complaint:
BUG: KASAN: use-after-free in srpt_enable_tpg+0x31/0x70 [ib_srpt]
Read of size 8 at addr ffff888141cc34b8 by task check/5093
Call Trace:
<TASK>
show_stack+0x4e/0x53
dump_stack_lvl+0x51/0x66
print_address_description.constprop.0.cold+0xea/0x41e
print_report.cold+0x90/0x205
kasan_report+0xb9/0xf0
__asan_load8+0x69/0x90
srpt_enable_tpg+0x31/0x70 [ib_srpt]
target_fabric_tpg_base_enable_store+0xe2/0x140 [target_core_mod]
configfs_write_iter+0x18b/0x210
new_sync_write+0x1f2/0x2f0
vfs_write+0x3e3/0x540
ksys_write+0xbb/0x140
__x64_sys_write+0x42/0x50
do_syscall_64+0x34/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
Link: https://lore.kernel.org/r/20220727193415.1583860-4-bvanassche@acm.org
Reported-by: Li Zhijian <lizhijian@fujitsu.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Fixes: a42d985bd5 ("ib_srpt: Initial SRP Target merge for v3.3-rc1")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c14adff285ad1bb8eefc5d8fc202ceb1f7e3a2f1 ]
removes list_next_or_null_rr_rcu macro to fix below warnings.
That macro is used only twice.
CHECK:MACRO_ARG_REUSE: Macro argument reuse 'head' - possible side-effects?
CHECK:MACRO_ARG_REUSE: Macro argument reuse 'ptr' - possible side-effects?
CHECK:MACRO_ARG_REUSE: Macro argument reuse 'memb' - possible side-effects?
Replaces that macro with an inline function.
Fixes: 6a98d71dae ("RDMA/rtrs: client: main functionality")
Cc: jinpu.wang@ionos.com
Link: https://lore.kernel.org/r/20220712103113.617754-5-haris.iqbal@ionos.com
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit caa84d95c78f35168847e2ab861a3a7f87033d36 ]
rtrs_clt_sess is used for paths and not sessions on the client side. This
creates confusion so let's rename it to rtrs_clt_path. Also, rename
related variables and functions.
Coccinelle is used to do the transformations for most of the occurrences
and remaining ones were handled manually.
Link: https://lore.kernel.org/r/20220105180708.7774-4-jinpu.wang@ionos.com
Signed-off-by: Vaishali Thakkar <vaishali.thakkar@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ae4c81644e9105d9f7f713bb0d444737bb6a0cf1 ]
rtrs_srv_sess is used for paths and not sessions on the server side. This
creates confusion so let's rename it to rtrs_srv_path. Also, rename
related variables and functions.
Coccinelle is used to do the transformations for most of the occurrences
and remaining ones were handled manually.
Link: https://lore.kernel.org/r/20220105180708.7774-3-jinpu.wang@ionos.com
Signed-off-by: Vaishali Thakkar <vaishali.thakkar@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d9372794717f44b6e746d8fbab66763b6d753e71 ]
rtrs_sess is in fact a path. This makes it confusing and difficult to get
into the code. So let's rename the structure and related use cases of it.
Coccinelle was used to do the transformation for most of the occurrences
and remaining ones were handled manually.
Link: https://lore.kernel.org/r/20220105180708.7774-2-jinpu.wang@ionos.com
Signed-off-by: Vaishali Thakkar <vaishali.thakkar@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4b6afe9bc955bee44c0527005c3fb0edac91ac30 ]
When testing with poll mode, it will fail and lead to warning below on
client side:
$ echo "sessname=bla path=gid:fe80::2:c903:4e:d0b3@gid:fe80::2:c903:8:ca17 device_path=/dev/nullb2 nr_poll_queues=-1" | \
sudo tee /sys/devices/virtual/rnbd-client/ctl/map_device
rnbd_client L597: Mapping device /dev/nullb2 on session bla, (access_mode: rw, nr_poll_queues: 8)
WARNING: CPU: 3 PID: 9886 at drivers/infiniband/core/cq.c:447 ib_cq_pool_get+0x26f/0x2a0 [ib_core]
The problem is in case of poll queue, we need to still call
ib_alloc_cq/ib_free_cq, we can't use cq_poll api for poll queue.
As both client and server use shared function from rtrs, set irq_con_num
to con_num on server side, which is number of total connection of the
session, this way we can differ if the rtrs_con requires pollqueue.
Following up patches will replace the duplicate code with helpers.
Link: https://lore.kernel.org/r/20210922125333.351454-4-haris.iqbal@ionos.com
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@cloud.ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 31500e902759322ba3c64b60dabae2704e738df8 ]
When the system is shutting down, iscsid is not running so we will not get
a response to the ISCSI_ERR_INVALID_HOST error event. The system shutdown
will then hang waiting on userspace to remove the session.
This has libiscsi force the destruction of the session from the kernel when
iscsi_host_remove() is called from a driver's shutdown callout.
This fixes a regression added in qedi boot with commit d1f2ce7763 ("scsi:
qedi: Fix host removal with running sessions") which made qedi use the
common session removal function that waits on userspace instead of rolling
its own kernel based removal.
Link: https://lore.kernel.org/r/20220616222738.5722-7-michael.christie@oracle.com
Fixes: d1f2ce7763 ("scsi: qedi: Fix host removal with running sessions")
Tested-by: Nilesh Javali <njavali@marvell.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c46fa8911b17e3f808679061a8af8bee219f4602 ]
Error path of rtrs_clt_open() calls free_clt(), where free_permit is
called. This is wrong since error path of rtrs_clt_open() does not need
to call free_permit().
Also, moving free_permits() call to rtrs_clt_close(), makes it more
aligned with the call to alloc_permit() in rtrs_clt_open().
Fixes: 6a98d71dae ("RDMA/rtrs: client: main functionality")
Link: https://lore.kernel.org/r/20220217030929.323849-2-haris.iqbal@ionos.com
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8700af2cc18c919b2a83e74e0479038fd113c15d ]
Callback function rtrs_clt_dev_release() for put_device() calls kfree(clt)
to free memory. We shouldn't call kfree(clt) again, and we can't use the
clt after kfree too.
Replace device_register() with device_initialize() and device_add() so that
dev_set_name can() be used appropriately.
Move mutex_destroy() to the release function so it can be called in
the alloc_clt err path.
Fixes: eab0982466 ("RDMA/rtrs-clt: Refactor the failure cases in alloc_clt")
Link: https://lore.kernel.org/r/20220217030929.323849-1-haris.iqbal@ionos.com
Reported-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Pull SCSI updates from James Bottomley:
"This series consists of the usual driver updates (ufs, qla2xxx,
target, smartpqi, lpfc, mpt3sas).
The core change causing the most churn was replacing the command
request field request with a macro, allowing us to offset map to it
and remove the redundant field; the same was also done for the tag
field.
The most impactful change is the final removal of scsi_ioctl, which
has been deprecated for over a decade"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (293 commits)
scsi: ufs: Fix ufshcd_request_sense_async() for Samsung KLUFG8RHDA-B2D1
scsi: ufs: ufs-exynos: Fix static checker warning
scsi: mpt3sas: Use the proper SCSI midlayer interfaces for PI
scsi: lpfc: Use the proper SCSI midlayer interfaces for PI
scsi: lpfc: Copyright updates for 14.0.0.1 patches
scsi: lpfc: Update lpfc version to 14.0.0.1
scsi: lpfc: Add bsg support for retrieving adapter cmf data
scsi: lpfc: Add cmf_info sysfs entry
scsi: lpfc: Add debugfs support for cm framework buffers
scsi: lpfc: Add support for maintaining the cm statistics buffer
scsi: lpfc: Add rx monitoring statistics
scsi: lpfc: Add support for the CM framework
scsi: lpfc: Add cmfsync WQE support
scsi: lpfc: Add support for cm enablement buffer
scsi: lpfc: Add cm statistics buffer support
scsi: lpfc: Add EDC ELS support
scsi: lpfc: Expand FPIN and RDF receive logging
scsi: lpfc: Add MIB feature enablement support
scsi: lpfc: Add SET_HOST_DATA mbox cmd to pass date/time info to firmware
scsi: fc: Add EDC ELS definition
...
Pull rdma updates from Jason Gunthorpe:
"This is quite a small cycle, no major series stands out. The HNS and
rxe drivers saw the most activity this cycle, with rxe being broken
for a good chunk of time. The significant deleted line count is due to
a SPDX cleanup series.
Summary:
- Various cleanup and small features for rtrs
- kmap_local_page() conversions
- Driver updates and fixes for: efa, rxe, mlx5, hfi1, qed, hns
- Cache the IB subnet prefix
- Rework how CRC is calcuated in rxe
- Clean reference counting in iwpm's netlink
- Pull object allocation and lifecycle for user QPs to the uverbs
core code
- Several small hns features and continued general code cleanups
- Fix the scatterlist confusion of orig_nents/nents introduced in an
earlier patch creating the append operation"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (90 commits)
RDMA/mlx5: Relax DCS QP creation checks
RDMA/hns: Delete unnecessary blank lines.
RDMA/hns: Encapsulate the qp db as a function
RDMA/hns: Adjust the order in which irq are requested and enabled
RDMA/hns: Remove RST2RST error prints for hw v1
RDMA/hns: Remove dqpn filling when modify qp from Init to Init
RDMA/hns: Fix QP's resp incomplete assignment
RDMA/hns: Fix query destination qpn
RDMA/hfi1: Convert to SPDX identifier
IB/rdmavt: Convert to SPDX identifier
RDMA/hns: Bugfix for incorrect association between dip_idx and dgid
RDMA/hns: Bugfix for the missing assignment for dip_idx
RDMA/hns: Bugfix for data type of dip_idx
RDMA/hns: Fix incorrect lsn field
RDMA/irdma: Remove the repeated declaration
RDMA/core/sa_query: Retry SA queries
RDMA: Use the sg_table directly and remove the opencoded version from umem
lib/scatterlist: Fix wrong update of orig_nents
lib/scatterlist: Provide a dedicated function to support table append
RDMA/hns: Delete unused hns bitmap interface
...
In order to support more coalesce parameters through netlink,
add two new parameter kernel_coal and extack for .set_coalesce
and .get_coalesce, then some extra info can return to user with
the netlink API.
Signed-off-by: Yufeng Mo <moyufeng@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
There are mis-match at counting inflight IO after changing the multipath
policy.
For example, we started fio test with round-robin policy and then we
changed the policy to min-inflight. IOs created under the RR policy is
finished under the min-inflight policy and inflight counter only
decreased. So the counter would be negative value. And also we started
fio test with min-inflight policy and changed the policy to the
round-robin. IOs created under the min-inflight policy increased the
inflight IO counter but the inflight IO counter was not decreased because
the policy was the round-robin when IO was finished.
So it should count IOs only if the IO is created under the min-inflight
policy. It should not care the policy when the IO is finished.
This patch adds a field mp_policy in struct rtrs_clt_io_req and stores the
multipath policy when an object of rtrs_clt_io_req is created. Then
rtrs-clt checks the mp_policy of only struct rtrs_clt_io_req instead of
the struct rtrs_clt.
Link: https://lore.kernel.org/r/20210806112112.124313-6-haris.iqbal@ionos.com
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
The IO performance test with fio after swapping the likely and unlikely
macros in all if-statement shows no difference. They do not help for the
performance of rtrs.
Thanks to Haakon Bugge for the test scenario.
The fio test did random read on 32 rnbd devices and 64 processes.
Test environment:
- Intel(R) Xeon(R) Gold 6130 CPU @ 2.10GHz
- 376G memory
- kernel version: 5.4.86
- gcc version: gcc (Debian 8.3.0-6) 8.3.0
- Infiniband controller: Mellanox Technologies MT27800 Family [ConnectX-5]
Test result:
- before swapping: IOPS=829k, BW=3239MiB/s
- after swapping: IOPS=829k, BW=3238MiB/s
- remove all (un)likely: IOPS=829k, BW=3238MiB/s
Link: https://lore.kernel.org/r/20210806112112.124313-5-haris.iqbal@ionos.com
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
On idle session, because we do not do signal for heartbeat, it will
overflow the send queue after sometime.
To avoid that, we need to enable the signal for heartbeat. To do that, add
a new member signal_interval in rtrs_path, which will set min of
queue_depth and SERVICE_CON_QUEUE_DEPTH, and track it for both heartbeat
and IO, so the sq queue full accounting is correct.
Fixes: b38041d50a ("RDMA/rtrs: Do not signal for heatbeat")
Link: https://lore.kernel.org/r/20210712060750.16494-4-jinpu.wang@ionos.com
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Aleksei Marov <aleksei.marov@ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Pull SCSI updates from James Bottomley:
"This series consists of the usual driver updates (ufs, ibmvfc,
megaraid_sas, lpfc, elx, mpi3mr, qedi, iscsi, storvsc, mpt3sas) with
elx and mpi3mr being new drivers.
The major core change is a rework to drop the status byte handling
macros and the old bit shifted definitions and the rest of the updates
are minor fixes"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (287 commits)
scsi: aha1740: Avoid over-read of sense buffer
scsi: arcmsr: Avoid over-read of sense buffer
scsi: ips: Avoid over-read of sense buffer
scsi: ufs: ufs-mediatek: Add missing of_node_put() in ufs_mtk_probe()
scsi: elx: libefc: Fix IRQ restore in efc_domain_dispatch_frame()
scsi: elx: libefc: Fix less than zero comparison of a unsigned int
scsi: elx: efct: Fix pointer error checking in debugfs init
scsi: elx: efct: Fix is_originator return code type
scsi: elx: efct: Fix link error for _bad_cmpxchg
scsi: elx: efct: Eliminate unnecessary boolean check in efct_hw_command_cancel()
scsi: elx: efct: Do not use id uninitialized in efct_lio_setup_session()
scsi: elx: efct: Fix error handling in efct_hw_init()
scsi: elx: efct: Remove redundant initialization of variable lun
scsi: elx: efct: Fix spelling mistake "Unexected" -> "Unexpected"
scsi: lpfc: Fix build error in lpfc_scsi.c
scsi: target: iscsi: Remove redundant continue statement
scsi: qla4xxx: Remove redundant continue statement
scsi: ppa: Switch to use module_parport_driver()
scsi: imm: Switch to use module_parport_driver()
scsi: mpt3sas: Fix error return value in _scsih_expander_add()
...
Linux 5.13-rc7
Needed for dependencies in following patches. Merge conflict in rxe_cmop.c
resolved by compining both patches.
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>