Now that TASK_ABORTED status is not generated for all cases by
TMR ABORT_TASK + LUN_RESET, a new TFO->abort_task() caller is
necessary in order to give fabric drivers a chance to unmap
hardware / software resources before the se_cmd descriptor is
released via the normal TFO->release_cmd() codepath.

This patch adds TFO->aborted_task() in core_tmr_abort_task()
in place of the original transport_send_task_abort(), and
also updates all fabric drivers to implement this caller.

The fabric drivers that include changes to perform cleanup
via ->aborted_task() are:

  - iscsi-target
  - iser-target
  - srpt
  - tcm_qla2xxx

The fabric drivers that currently set ->aborted_task() to
NOPs are:

  - loopback
  - tcm_fc
  - usb-gadget
  - sbp-target
  - vhost-scsi

For the latter five, there appears to be no additional cleanup
required before invoking TFO->release_cmd() to release the
se_cmd descriptor.

v2 changes:
  - Move ->aborted_task() call into transport_cmd_finish_abort (Alex)

Cc: Alex Leung <amleung21@yahoo.com>
Cc: Mark Rustad <mark.d.rustad@intel.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Vu Pham <vu@mellanox.com>
Cc: Chris Boot <bootc@bootc.net>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Cc: Saurav Kashyap <saurav.kashyap@qlogic.com>
Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes isert_conn_create_fastreg_pool() to follow
logic in iscsi_target_locate_portal() for determining how many
FRMR descriptors to allocate based upon the number of possible
per-session command slots that are available.

This addresses an OOPs in isert_reg_rdma() where due to the
use of ISCSI_DEF_XMIT_CMDS_MAX could end up returning a bogus
fast_reg_descriptor when the number of active tags exceeded
the original hardcoded max.

Note this also includes moving isert_conn_create_fastreg_pool()
from isert_connect_request() to isert_put_login_tx() before
posting the final Login Response PDU in order to determine the
se_nacl->queue_depth (eg: number of tags) per session the target
will be enforcing.

v2 changes:
  - Move isert_conn->conn_fr_pool list_head init into
    isert_conn_request()
v3 changes:
  - Drop unnecessary list_empty() check in isert_reg_rdma()
    (Sagi)

Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.12+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

If during data-transfer a data-integrity error was detected we
must fail the command with CHECK_CONDITION and not execute
the command.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Reported-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Remove code duplication from RDMA_READ and RDMA_WRITE
completions that do basically the same check.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

If protection is involved, iSER target must wait for
completion of RDMA_READ before sending SCSI response.
So we must consider that when calculating post_send_buf_count
additions, also when processing good/error completions.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

As REG_SIG_MR work request and it's LOCAL_INVALIDATE are
not accounted in post_send_buf_count we must color these
with ISER_FASTREG_LI_WRID in order to process their error
completions when the QP flushes.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

In case the Target core passed transport T10 protection
operation:

1. Register data buffer (data memory region)
2. Register protection buffer if exsists (prot memory region)
3. Register signature region (signature memory region)
   - use work request IB_WR_REG_SIG_MR
4. Execute RDMA
5. Upon RDMA completion check the signature status
   - if succeeded send good SCSI response
   - if failed send SCSI bad response with appropriate sense buffer

(Fix up compile error in isert_reg_sig_mr, and fix up incorrect
 se_cmd->prot_type -> TARGET_PROT_NORMAL comparision - nab)
(Fix failed sector assignment in isert_completion_rdma_* - Sagi + nab)
(Fix enum assignements for protection type - Sagi)
(Fix devision on 32-bit in isert_completion_rdma_* - Sagi + Fengguang)
(Fix context change for v3.14-rc6 code - nab)
(Fix iscsit_build_rsp_pdu inc_statsn flag usage - nab)
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

In case of protected transactions, we will need to check the
protection status of the transaction before sending SCSI response.
So be ready for RDMA_WRITE completions. currently we don't ask
for these completions, but for T10-PI we will.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Introduce pi_context to hold relevant RDMA protection resources.
We eliminate data_key_valid boolean and replace it with indicators
container to indicate:
- Is the descriptor protected (registered via signature MR)
- Is the data_mr key valid (can spare LOCAL_INV WR)
- Is the prot_mr key valid (can spare LOCAL_INV WR)
- Is the sig_mr key valid (can spare LOCAL_INV WR)

Upon connection establishment check if network portal is T10-PI
enabled and allocate T10-PI resources if necessary, allocate
signature enabled memory regions and mark connection queue-pair
as signature enabled.

(Fix context change for v3.14-rc6 code - nab)
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

export map/unmap data buffer to a routine that may
be used in various places in the code and keep the
mapping data in a designated descriptor. Also, let
isert_fast_reg_mr to decide weather to use global
MR or do fast registration.

This commit does not change any functionality.

(Fix context change for v3.14-rc6 code - nab)
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch addresses a number of active I/O shutdown issues
related to isert_cmd descriptors being leaked that are part
of a completion interrupt coalescing batch.

This includes adding logic in isert_cq_tx_comp_err() to
drain any associated tx_desc->comp_llnode_batch, as well
as isert_cq_drain_comp_llist() to drain any associated
isert_conn->conn_comp_llist.

Also, set tx_desc->llnode_active in isert_init_send_wr()
in order to determine when work requests need to be skipped
in isert_cq_tx_work() exception path code.

Finally, update isert_init_send_wr() to only allow interrupt
coalescing when ISER_CONN_UP.
Acked-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.13+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes IB_WR_FAST_REG_MR + IB_WR_LOCAL_INV related
work requests to include a ISER_FRWR_LI_WRID value in order to
signal isert_cq_tx_work() that these requests should be ignored.

This is necessary because even though IB_SEND_SIGNALED is not
set for either work request, during a QP failure event the work
requests will be returned with exception status from the TX
completion queue.

v2 changes:
 - Rename ISER_FRWR_LI_WRID -> ISER_FASTREG_LI_WRID (Sagi)
Acked-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.12+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes the incorrect setting of ->post_send_buf_count
related to RDMA WRITEs + READs where isert_rdma_rw->send_wr_num
was not being taken into account.

This includes incrementing ->post_send_buf_count within
isert_put_datain() + isert_get_dataout(), decrementing within
__isert_send_completion() + isert_response_completion(), and
clearing wr->send_wr_num within isert_completion_rdma_read()

This is necessary because even though IB_SEND_SIGNALED is
not set for RDMA WRITEs + READs, during a QP failure event
the work requests will be returned with exception status
from the TX completion queue.
Acked-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch addresses a couple of different hug shutdown issues
related to wait_event() + isert_conn->state.  First, it changes
isert_conn->conn_wait + isert_conn->conn_wait_comp_err from
waitqueues to completions, and sets ISER_CONN_TERMINATING from
within isert_disconnect_work().

Second, it splits isert_free_conn() into isert_wait_conn() that
is called earlier in iscsit_close_connection() to ensure that
all outstanding commands have completed before continuing.

Finally, it breaks isert_cq_comp_err() into seperate TX / RX
related code, and adds logic in isert_cq_rx_comp_err() to wait
for outstanding commands to complete before setting ISER_CONN_DOWN
and calling complete(&isert_conn->conn_wait_comp_err).
Acked-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

There are a handful of uses of list_empty() for cmd->i_conn_node
within iser-target code that expect to return false once a cmd
has been removed from the per connect list.

This patch changes all uses of list_del -> list_del_init in order
to ensure that list_empty() returns false as expected.
Acked-by: NSagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

We use "tx_desc" again after we free it.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Fix a possible NULL pointer dereference in disconnection flow. This
can happen if the target disconnected/rejected the connection request,
e.g before the binding stage between iscsi connection to the transport
connection.
Signed-off-by: NAlex Tabachnik <alext@mellanox.com>
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

The usage of strict_strtoul() is not preferred, because
strict_strtoul() is obsolete. Thus, kstrtoul() should be
used.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch fixes a memory leak for fr_desc upon failure of
isert_create_fr_desc() in isert_conn_create_fastreg_pool()
code.

As reported by Coverity 1166659:

*** CID 1166659:  Resource leak  (RESOURCE_LEAK)
/drivers/infiniband/ulp/isert/ib_isert.c: 470 in isert_conn_create_fastreg_pool()
464                      isert_conn, isert_conn->conn_fr_pool_size);
465
466             return 0;
467
468     err:
469             isert_conn_free_fastreg_pool(isert_conn);
>>>     CID 1166659:  Resource leak  (RESOURCE_LEAK)
>>>     Variable "fr_desc" going out of scope leaks the storage it points to.
470             return ret;
471     }
472
473     static int
474     isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
475     {

Cc: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch propigates the use of task state bitmask now used by
percpu_ida_alloc() up the iscsi-target callchain, replacing the
use of GFP_ATOMIC for TASK_RUNNING, and GFP_KERNEL for
TASK_INTERRUPTIBLE.

Also, drop the unnecessary gfp_t parameter to isert_allocate_cmd(),
and just pass TASK_INTERRUPTIBLE into iscsit_allocate_cmd().
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

After booting without a working link, "ip link" shows:

 5: mlx4_ib1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 2044 qdisc pfifo_fast
 state DOWN qlen 256
    ...
 7: mlx4_ib1.8003@mlx4_ib1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 2044 qdisc
 pfifo_fast state DOWN qlen 256
    ...

Then after connecting and disconnecting the link, which should result
in exactly the same state as before, it shows:

 5: mlx4_ib1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 2044 qdisc pfifo_fast
 state DOWN qlen 256
    ...
 7: mlx4_ib1.8003@mlx4_ib1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 2044 qdisc
 pfifo_fast state LOWERLAYERDOWN qlen 256
    ...

Notice the (now correct) LOWERLAYERDOWN operstate shown for the
mlx4_ib1.8003 interface. Ideally the identical state would be shown
right after boot.

The problem is related to the calling of netif_carrier_off() in
network drivers.  For a long time it was known that doing
netif_carrier_off() before registering the netdevice would result in
the interface's operstate being shown as UNKNOWN if the device was
brought up without a working link. This problem was fixed in commit
8f4cccbb ('net: Set device operstate at registration time'), but
still there remains the minor inconsistency demonstrated above.

This patch fixes it by moving ipoib's call to netif_carrier_off() into
the .ndo_open method, which is where network drivers ordinarily do it.
With the patch when doing the same test as above, the operstate of
mlx4_ib1.8003 is shown as LOWERLAYERDOWN right after boot.
Signed-off-by: NMichal Schmidt <mschmidt@redhat.com>
Acked-by: NErez Shitrit <erezsh@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

The rport timers must be stopped before the SRP initiator destroys the
resources associated with the SCSI host. This is necessary because
otherwise the callback functions invoked from the SRP transport layer
could trigger a use-after-free. Stopping the rport timers before
invoking scsi_remove_host() can trigger long delays in the SCSI error
handler if a transport layer failure occurs while scsi_remove_host()
is in progress. Hence move the code for stopping the rport timers from
srp_rport_release() into a new function and invoke that function after
scsi_remove_host() has finished. This patch fixes the following
sporadic kernel crash:

     kernel BUG at include/asm-generic/dma-mapping-common.h:64!
     invalid opcode: 0000 [#1] SMP
     RIP: 0010:[<ffffffffa03b20b1>]  [<ffffffffa03b20b1>] srp_unmap_data+0x121/0x130 [ib_srp]
     Call Trace:
     [<ffffffffa03b20fc>] srp_free_req+0x3c/0x80 [ib_srp]
     [<ffffffffa03b2188>] srp_finish_req+0x48/0x70 [ib_srp]
     [<ffffffffa03b21fb>] srp_terminate_io+0x4b/0x60 [ib_srp]
     [<ffffffffa03a6fb5>] __rport_fail_io_fast+0x75/0x80 [scsi_transport_srp]
     [<ffffffffa03a7438>] rport_fast_io_fail_timedout+0x88/0xc0 [scsi_transport_srp]
     [<ffffffff8108b370>] worker_thread+0x170/0x2a0
     [<ffffffff81090876>] kthread+0x96/0xa0
     [<ffffffff8100c0ca>] child_rip+0xa/0x20
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This routine may help for protection registration as well.
This patch does not change any functionality.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This routine may be called both by fast registration
descriptors for data and for integrity buffers.

This patch does not change any functionality.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Use fast registration lingo. fast registration will
also incorporate signature/DIF registration.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

It is more correct to seperate connections protection domains
and dma_mr handles. protection information support requires to
do so.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

When creating an IPoIB UD QP, provide a hint to the low level driver
that the QP should support flow-steering.  This means that privileged
user space applications can steer TCP/IP IPoIB traffic from the
network stack, in a similar manner done with Ethernet RAW_PACKET QPs.

The hint is provided through new QP creation flag called NETIF_QP.
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

When we create a new infiniband link with uninfiniband device, e.g. `ip link
add link em1 type ipoib pkey 0x8001`. We will get a NULL pointer dereference
cause other dev like Ethernet don't have struct ib_device.

The code path is:
rtnl_newlink
  |-- ipoib_new_child_link
        |-- __ipoib_vlan_add
              |-- ipoib_set_dev_features
                    |-- ib_query_device

Fix this bug by make sure the src net is infiniband when create new link.
Signed-off-by: NHangbin Liu <liuhangbin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch moves INIT_WORK setup for cq_desc->cq_[rx,tx]_work into
isert_create_device_ib_res(), instead of being done each callback
invocation in isert_cq_[rx,tx]_callback().

This also fixes a 'INFO: trying to register non-static key' warning
when cancel_work_sync() is called before INIT_WORK has setup the
struct work_struct.
Reported-by: NOr Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.12+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: <stable@vger.kernel.org> #3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch avoids a duplicate iscsit_increment_maxcmdsn() call for
ISER_IB_RDMA_WRITE within isert_map_rdma() + isert_reg_rdma_frwr(),
which will already be occuring once during isert_put_datain() ->
iscsit_build_rsp_pdu() operation.

It also removes the local conn->stat_sn assignment + increment,
and changes the third parameter to iscsit_build_rsp_pdu() to
signal this should be done by iscsi_target_mode code.
Tested-by: NMoussa Ba <moussaba@micron.com>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This patch changes isert_reg_rdma_frwr() to not use FRMR for single
dma entry requests from small I/Os, in order to avoid the associated
memory registration overhead.

Using DMA MR is sufficient here for the single dma entry requests,
and addresses a >= v3.12 performance regression.
Signed-off-by: NVu Pham <vu@mellanox.com>
Cc: <stable@vger.kernel.org> # v3.12+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The IB spec does not guarantee that the opcode is available in error
completions.  Hence do not rely on it.  See also commit 948d1e88
("IB/srp: Introduce srp_handle_qp_err()").
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Cc: <stable@vger.kernel.org> # v3.8
Signed-off-by: NRoland Dreier <roland@purestorage.com>

If SCSI commands are submitted with a SCSI request timeout that is
lower than the the IB RC timeout, it can happen that the SCSI error
handler has already started device recovery before transport layer
error handling starts.  So it can happen that the SCSI error handler
tries to abort a SCSI command after it has been reset by
srp_rport_reconnect().

Tell the SCSI error handler that such commands have finished and that
it is not necessary to continue its recovery strategy for commands
that have been reset by srp_rport_reconnect().
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Remove an SRP target from the SRP target list before invoking the last
scsi_host_put() call.  This change is necessary because that last put
frees the memory that holds the srp_target_port structure.

This patch prevents the following kernel oops:

    RIP: 0010:[<ffffffff810b00d0>] __lock_acquire+0x500/0x1570
    Call Trace:
     [<ffffffff810b11e4>] lock_acquire+0xa4/0x120
     [<ffffffff81531206>] _spin_lock+0x36/0x70
     [<ffffffffa01b6d8f>] srp_remove_work+0xef/0x180 [ib_srp]
     [<ffffffff8109125c>] worker_thread+0x21c/0x3d0
     [<ffffffff81096e86>] kthread+0x96/0xa0
     [<ffffffff8100c20a>] child_rip+0xa/0x20
Signed-off-by: NVu Pham <vuhuong@mellanox.com>

[ bvanassche - Modified path description and CC'ed stable. ]
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Currently, it's not possible to change queue depth for a device behind
SRP host. Sometimes, we need to adjust queue_depth for performance
reason (eg storage busy, we need lower queue_depth to avoid running
into SCSI error handler), so this patch add support for SRP driver.
Signed-off-by: NJack Wang <jinpu.wang@profitbricks.com>
Tested-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Certain storage configurations, e.g. a sufficiently large array of
hard disks in a RAID configuration, need a queue depth above 64 to
achieve optimal performance. Hence make the queue depth configurable.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Tested-by: NJack Wang <xjtuwjp@gmail.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This patch does not change any functionality.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Vu Pham <vu@mellanox.com>
Cc: Sebastian Riemer <sebastian.riemer@profitbricks.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

On an initiator system with multiple IB ports it is not yet possible
to figure out what the originating port of an SRP connection is. Hence
make the source GID available in sysfs.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

After a transport layer occurred, periodically try to reconnect
to the target until the dev_loss timer expires.  Protect the
callback functions that can be invoked from inside the SCSI EH
against concurrent invocation with srp_reconnect_rport() via the
rport mutex. Change the default dev_loss_tmo from 60s into 600s
to give the reconnect mechanism a chance to kick in.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <roland@purestorage.com>