Commit Graph

369 Commits

Author SHA1 Message Date
Chuck Lever
4cf44be6f1 xprtrdma: Fix recursion into rpcrdma_xprt_disconnect()
Both Dan and I have observed two processes invoking
rpcrdma_xprt_disconnect() concurrently. In my case:

1. The connect worker invokes rpcrdma_xprt_disconnect(), which
   drains the QP and waits for the final completion
2. This causes the newly posted Receive to flush and invoke
   xprt_force_disconnect()
3. xprt_force_disconnect() sets CLOSE_WAIT and wakes up the RPC task
   that is holding the transport lock
4. The RPC task invokes xprt_connect(), which calls ->ops->close
5. xprt_rdma_close() invokes rpcrdma_xprt_disconnect(), which tries
   to destroy the QP.

Deadlock.

To prevent xprt_force_disconnect() from waking anything, handle the
clean up after a failed connection attempt in the xprt's sndtask.

The retry loop is removed from rpcrdma_xprt_connect() to ensure
that the newly allocated ep and id are properly released before
a REJECTED connection attempt can be retried.

Reported-by: Dan Aloni <dan@kernelim.com>
Fixes: e28ce90083 ("xprtrdma: kmalloc rpcrdma_ep separate from rpcrdma_xprt")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-07-13 10:50:41 -04:00
Chuck Lever
85bfd71bc3 xprtrdma: Fix double-free in rpcrdma_ep_create()
In the error paths, there's no need to call kfree(ep) after calling
rpcrdma_ep_put(ep).

Fixes: e28ce90083 ("xprtrdma: kmalloc rpcrdma_ep separate from rpcrdma_xprt")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-07-13 10:50:41 -04:00
Chuck Lever
c487eb7d8e xprtrdma: Clean up disconnect
1. Ensure that only rpcrdma_cm_event_handler() modifies
   ep->re_connect_status to avoid racy changes to that field.

2. Ensure that xprt_force_disconnect() is invoked only once as a
   transport is closed or destroyed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-06-22 09:34:35 -04:00
Chuck Lever
f423f755f4 xprtrdma: Clean up synopsis of rpcrdma_flush_disconnect()
Refactor: Pass struct rpcrdma_xprt instead of an IB layer object.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-06-22 09:34:35 -04:00
Chuck Lever
2d97f46376 xprtrdma: Use re_connect_status safely in rpcrdma_xprt_connect()
Clean up: Sometimes creating a fresh rpcrdma_ep can fail. That's why
xprt_rdma_connect() always checks if the r_xprt->rx_ep pointer is
valid before dereferencing it. Instead, xprt_rdma_connect() can
simply check rpcrdma_xprt_connect()'s return value.

Also, there's no need to set re_connect_status to zero just after
the rpcrdma_ep is created, since it is allocated with kzalloc.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-06-22 09:34:35 -04:00
Chuck Lever
2acc5cae29 xprtrdma: Prevent dereferencing r_xprt->rx_ep after it is freed
r_xprt->rx_ep is known to be good while the transport's send lock is
held.  Otherwise additional references on rx_ep must be held when it
is used outside of that lock's critical sections.

For now, bump the rx_ep reference count once whenever there is at
least one outstanding Receive WR. This avoids the memory bandwidth
overhead of taking and releasing the reference count for every
ib_post_recv() and Receive completion.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-06-22 09:34:35 -04:00
Chuck Lever
911813d7a1 SUNRPC: Trace transport lifetime events
Refactor: Hoist create/destroy/disconnect tracepoints out of
xprtrdma and into the generic RPC client. Some benefits include:

- Enable tracing of xprt lifetime events for the socket transport
  types

- Expose the different types of disconnect to help run down
  issues with lingering connections

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-06-11 13:33:48 -04:00
Chuck Lever
bdb2ce8281 xprtrdma: Fix trace point use-after-free race
It's not safe to use resources pointed to by the @send_wr of
ib_post_send() _after_ that function returns. Those resources are
typically freed by the Send completion handler, which can run before
ib_post_send() returns.

Thus the trace points currently around ib_post_send() in the
client's RPC/RDMA transport are a hazard, even when they are
disabled. Rearrange them so that they touch the Work Request only
_before_ ib_post_send() is invoked.

Fixes: ab03eff58e ("xprtrdma: Add trace points in RPC Call transmit paths")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-04-20 10:44:01 -04:00
Chuck Lever
58bd6656f8 xprtrdma: Restore wake-up-all to rpcrdma_cm_event_handler()
Commit e28ce90083 ("xprtrdma: kmalloc rpcrdma_ep separate from
rpcrdma_xprt") erroneously removed a xprt_force_disconnect()
call from the "transport disconnect" path. The result was that the
client no longer responded to server-side disconnect requests.

Restore that call.

Fixes: e28ce90083 ("xprtrdma: kmalloc rpcrdma_ep separate from rpcrdma_xprt")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-04-20 10:41:00 -04:00
Chuck Lever
e28ce90083 xprtrdma: kmalloc rpcrdma_ep separate from rpcrdma_xprt
Change the rpcrdma_xprt_disconnect() function so that it no longer
waits for the DISCONNECTED event.  This prevents blocking if the
remote is unresponsive.

In rpcrdma_xprt_disconnect(), the transport's rpcrdma_ep is
detached. Upon return from rpcrdma_xprt_disconnect(), the transport
(r_xprt) is ready immediately for a new connection.

The RDMA_CM_DEVICE_REMOVAL and RDMA_CM_DISCONNECTED events are now
handled almost identically.

However, because the lifetimes of rpcrdma_xprt structures and
rpcrdma_ep structures are now independent, creating an rpcrdma_ep
needs to take a module ref count. The ep now owns most of the
hardware resources for a transport.

Also, a kref is needed to ensure that rpcrdma_ep sticks around
long enough for the cm_event_handler to finish.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:25 -04:00
Chuck Lever
745b734c9b xprtrdma: Extract sockaddr from struct rdma_cm_id
rpcrdma_cm_event_handler() is always passed an @id pointer that is
valid. However, in a subsequent patch, we won't be able to extract
an r_xprt in every case. So instead of using the r_xprt's
presentation address strings, extract them from struct rdma_cm_id.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:25 -04:00
Chuck Lever
93aa8e0a9d xprtrdma: Merge struct rpcrdma_ia into struct rpcrdma_ep
I eventually want to allocate rpcrdma_ep separately from struct
rpcrdma_xprt so that on occasion there can be more than one ep per
xprt.

The new struct rpcrdma_ep will contain all the fields currently in
rpcrdma_ia and in rpcrdma_ep. This is all the device and CM settings
for the connection, in addition to per-connection settings
negotiated with the remote.

Take this opportunity to rename the existing ep fields from rep_* to
re_* to disambiguate these from struct rpcrdma_rep.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:25 -04:00
Chuck Lever
d6ccebf956 xprtrdma: Disconnect on flushed completion
Completion errors after a disconnect often occur much sooner than a
CM_DISCONNECT event. Use this to try to detect connection loss more
quickly.

Note that other kernel ULPs do take care to disconnect explicitly
when a WR is flushed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:25 -04:00
Chuck Lever
897b7be9bc xprtrdma: Remove rpcrdma_ia::ri_flags
Clean up:
The upper layer serializes calls to xprt_rdma_close, so there is no
need for an atomic bit operation, saving 8 bytes in rpcrdma_ia.

This enables merging rpcrdma_ia_remove directly into the disconnect
logic.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:25 -04:00
Chuck Lever
81fe0c57f4 xprtrdma: Invoke rpcrdma_ia_open in the connect worker
Move rdma_cm_id creation into rpcrdma_ep_create() so that it is now
responsible for allocating all per-connection hardware resources.

With this clean-up, all three arms of the switch statement in
rpcrdma_ep_connect are exactly the same now, thus the switch can be
removed.

Because device removal behaves a little differently than
disconnection, there is a little more work to be done before
rpcrdma_ep_destroy() can release the connection's rdma_cm_id. So
it is not quite symmetrical with rpcrdma_ep_create() yet.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:24 -04:00
Chuck Lever
9ba373ee24 xprtrdma: Allocate Protection Domain in rpcrdma_ep_create()
Make a Protection Domain (PD) a per-connection resource rather than
a per-transport resource. In other words, when the connection
terminates, the PD is destroyed.

Thus there is one less HW resource that remains allocated to a
transport after a connection is closed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:24 -04:00
Chuck Lever
9144a803df xprtrdma: Refactor rpcrdma_ep_connect() and rpcrdma_ep_disconnect()
Clean up: Simplify the synopses of functions in the connect and
disconnect paths in preparation for combining the rpcrdma_ia and
struct rpcrdma_ep structures.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:24 -04:00
Chuck Lever
97d0de8812 xprtrdma: Clean up the post_send path
Clean up: Simplify the synopses of functions in the post_send path
by combining the struct rpcrdma_ia and struct rpcrdma_ep arguments.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:24 -04:00
Chuck Lever
253a51622f xprtrdma: Refactor frwr_init_mr()
Clean up: prepare for combining the rpcrdma_ia and rpcrdma_ep
structures. Take the opportunity to rename the function to be
consistent with the "subsystem _ object _ verb" naming scheme.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:24 -04:00
Chuck Lever
85cd8e2b78 xprtrdma: Invoke rpcrdma_ep_create() in the connect worker
Refactor rpcrdma_ep_create(), rpcrdma_ep_disconnect(), and
rpcrdma_ep_destroy().

rpcrdma_ep_create will be invoked at connect time instead of at
transport set-up time. It will be responsible for allocating per-
connection resources. In this patch it allocates the CQs and
creates a QP. More to come.

rpcrdma_ep_destroy() is the inverse functionality that is
invoked at disconnect time. It will be responsible for releasing
the CQs and QP.

These changes should be safe to do because both connect and
disconnect is guaranteed to be serialized by the transport send
lock.

This takes us another step closer to resolving the address and route
only at connect time so that connection failover to another device
will work correctly.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-03-27 10:47:24 -04:00
Chuck Lever
e515dd9d76 xprtrdma: DMA map rr_rdma_buf as each rpcrdma_rep is created
Clean up: This simplifies the logic in rpcrdma_post_recvs.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
b7ff0185e9 xprtrdma: Destroy reps from previous connection instance
To safely get rid of all rpcrdma_reps from a particular connection
instance, xprtrdma has to wait until each of those reps is finished
being used. A rep may be backing the rq_rcv_buf of an RPC that has
just completed, for example.

Since it is safe to invoke rpcrdma_rep_destroy() only in the Receive
completion handler, simply mark reps remaining in the rb_all_reps
list after the transport is drained. These will then be deleted as
rpcrdma_post_recvs pulls them off the rep free list.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
85810388a9 xprtrdma: Destroy rpcrdma_rep when Receive is flushed
This reduces the hardware and memory footprint of an unconnected
transport.

At some point in the future, transport reconnect will allow
resolving the destination IP address through a different device. The
current change enables reps for the new connection to be allocated
on whichever NUMA node the new device affines to after a reconnect.

Note that this does not destroy _all_ the transport's reps... there
will be a few that are still part of a running RPC completion.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
b78de1dca0 xprtrdma: Allocate and map transport header buffers at connect time
Currently the underlying RDMA device is chosen at transport set-up
time. But it will soon be at connect time instead.

The maximum size of a transport header is based on device
capabilities. Thus transport header buffers have to be allocated
_after_ the underlying device has been chosen (via address and route
resolution); ie, in the connect worker.

Thus, move the allocation of transport header buffers to the connect
worker, after the point at which the underlying RDMA device has been
chosen.

This also means the RDMA device is available to do a DMA mapping of
these buffers at connect time, instead of in the hot I/O path. Make
that optimization as well.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
25868e610a xprtrdma: Refactor frwr_is_supported
Refactor: Perform the "is supported" check in rpcrdma_ep_create()
instead of in rpcrdma_ia_open(). frwr_open() is where most of the
logic to query device attributes is already located.

The current code displays a redundant error message when the device
does not support FRWR. As an additional clean-up, this patch removes
the extra message.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
18d065a5d4 xprtrdma: Eliminate per-transport "max pages"
To support device hotplug and migrating a connection between devices
of different capabilities, we have to guarantee that all in-kernel
devices can support the same max NFS payload size (1 megabyte).

This means that possibly one or two in-tree devices are no longer
supported for NFS/RDMA because they cannot support 1MB rsize/wsize.
The only one I confirmed was cxgb3, but it has already been removed
from the kernel.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
7581d90109 xprtrdma: Refactor initialization of ep->rep_max_requests
Clean up: there is no need to keep two copies of the same value.
Also, in subsequent patches, rpcrdma_ep_create() will be called in
the connect worker rather than at set-up time.

Minor fix: Initialize the transport's sendctx to the value based on
the capabilities of the underlying device, not the maximum setting.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
cb586decbb xprtrdma: Make sendctx queue lifetime the same as connection lifetime
The size of the sendctx queue depends on the value stored in
ia->ri_max_send_sges. This value is determined by querying the
underlying device.

Eventually, rpcrdma_ia_open() and rpcrdma_ep_create() will be called
in the connect worker rather than at transport set-up time. The
underlying device will not have been chosen device set-up time.

The sendctx queue will thus have to be created after the underlying
device has been chosen via address and route resolution; in other
words, in the connect worker.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
2e87036814 xprtrdma: Eliminate ri_max_send_sges
Clean-up. The max_send_sge value also happens to be stored in
ep->rep_attr. Let's keep just a single copy.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-15 10:54:32 -05:00
Chuck Lever
671c450b6f xprtrdma: Fix oops in Receive handler after device removal
Since v5.4, a device removal occasionally triggered this oops:

Dec  2 17:13:53 manet kernel: BUG: unable to handle page fault for address: 0000000c00000219
Dec  2 17:13:53 manet kernel: #PF: supervisor read access in kernel mode
Dec  2 17:13:53 manet kernel: #PF: error_code(0x0000) - not-present page
Dec  2 17:13:53 manet kernel: PGD 0 P4D 0
Dec  2 17:13:53 manet kernel: Oops: 0000 [#1] SMP
Dec  2 17:13:53 manet kernel: CPU: 2 PID: 468 Comm: kworker/2:1H Tainted: G        W         5.4.0-00050-g53717e43af61 #883
Dec  2 17:13:53 manet kernel: Hardware name: Supermicro SYS-6028R-T/X10DRi, BIOS 1.1a 10/16/2015
Dec  2 17:13:53 manet kernel: Workqueue: ib-comp-wq ib_cq_poll_work [ib_core]
Dec  2 17:13:53 manet kernel: RIP: 0010:rpcrdma_wc_receive+0x7c/0xf6 [rpcrdma]
Dec  2 17:13:53 manet kernel: Code: 6d 8b 43 14 89 c1 89 45 78 48 89 4d 40 8b 43 2c 89 45 14 8b 43 20 89 45 18 48 8b 45 20 8b 53 14 48 8b 30 48 8b 40 10 48 8b 38 <48> 8b 87 18 02 00 00 48 85 c0 75 18 48 8b 05 1e 24 c4 e1 48 85 c0
Dec  2 17:13:53 manet kernel: RSP: 0018:ffffc900035dfe00 EFLAGS: 00010246
Dec  2 17:13:53 manet kernel: RAX: ffff888467290000 RBX: ffff88846c638400 RCX: 0000000000000048
Dec  2 17:13:53 manet kernel: RDX: 0000000000000048 RSI: 00000000f942e000 RDI: 0000000c00000001
Dec  2 17:13:53 manet kernel: RBP: ffff888467611b00 R08: ffff888464e4a3c4 R09: 0000000000000000
Dec  2 17:13:53 manet kernel: R10: ffffc900035dfc88 R11: fefefefefefefeff R12: ffff888865af4428
Dec  2 17:13:53 manet kernel: R13: ffff888466023000 R14: ffff88846c63f000 R15: 0000000000000010
Dec  2 17:13:53 manet kernel: FS:  0000000000000000(0000) GS:ffff88846fa80000(0000) knlGS:0000000000000000
Dec  2 17:13:53 manet kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Dec  2 17:13:53 manet kernel: CR2: 0000000c00000219 CR3: 0000000002009002 CR4: 00000000001606e0
Dec  2 17:13:53 manet kernel: Call Trace:
Dec  2 17:13:53 manet kernel: __ib_process_cq+0x5c/0x14e [ib_core]
Dec  2 17:13:53 manet kernel: ib_cq_poll_work+0x26/0x70 [ib_core]
Dec  2 17:13:53 manet kernel: process_one_work+0x19d/0x2cd
Dec  2 17:13:53 manet kernel: ? cancel_delayed_work_sync+0xf/0xf
Dec  2 17:13:53 manet kernel: worker_thread+0x1a6/0x25a
Dec  2 17:13:53 manet kernel: ? cancel_delayed_work_sync+0xf/0xf
Dec  2 17:13:53 manet kernel: kthread+0xf4/0xf9
Dec  2 17:13:53 manet kernel: ? kthread_queue_delayed_work+0x74/0x74
Dec  2 17:13:53 manet kernel: ret_from_fork+0x24/0x30

The proximal cause is that this rpcrdma_rep has a rr_rdmabuf that
is still pointing to the old ib_device, which has been freed. The
only way that is possible is if this rpcrdma_rep was not destroyed
by rpcrdma_ia_remove.

Debugging showed that was indeed the case: this rpcrdma_rep was
still in use by a completing RPC at the time of the device removal,
and thus wasn't on the rep free list. So, it was not found by
rpcrdma_reps_destroy().

The fix is to introduce a list of all rpcrdma_reps so that they all
can be found when a device is removed. That list is used to perform
only regbuf DMA unmapping, replacing that call to
rpcrdma_reps_destroy().

Meanwhile, to prevent corruption of this list, I've moved the
destruction of temp rpcrdma_rep objects to rpcrdma_post_recvs().
rpcrdma_xprt_drain() ensures that post_recvs (and thus rep_destroy) is
not invoked while rpcrdma_reps_unmap is walking rb_all_reps, thus
protecting the rb_all_reps list.

Fixes: b0b227f071 ("xprtrdma: Use an llist to manage free rpcrdma_reps")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-14 13:30:24 -05:00
Chuck Lever
13cb886c59 xprtrdma: Fix completion wait during device removal
I've found that on occasion, "rmmod <dev>" will hang while if an NFS
is under load.

Ensure that ri_remove_done is initialized only just before the
transport is woken up to force a close. This avoids the completion
possibly getting initialized again while the CM event handler is
waiting for a wake-up.

Fixes: bebd031866 ("xprtrdma: Support unplugging an HCA from under an NFS mount")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-14 13:30:24 -05:00
Chuck Lever
b32b9ed493 xprtrdma: Fix create_qp crash on device unload
On device re-insertion, the RDMA device driver crashes trying to set
up a new QP:

Nov 27 16:32:06 manet kernel: BUG: kernel NULL pointer dereference, address: 00000000000001c0
Nov 27 16:32:06 manet kernel: #PF: supervisor write access in kernel mode
Nov 27 16:32:06 manet kernel: #PF: error_code(0x0002) - not-present page
Nov 27 16:32:06 manet kernel: PGD 0 P4D 0
Nov 27 16:32:06 manet kernel: Oops: 0002 [#1] SMP
Nov 27 16:32:06 manet kernel: CPU: 1 PID: 345 Comm: kworker/u28:0 Tainted: G        W         5.4.0 #852
Nov 27 16:32:06 manet kernel: Hardware name: Supermicro SYS-6028R-T/X10DRi, BIOS 1.1a 10/16/2015
Nov 27 16:32:06 manet kernel: Workqueue: xprtiod xprt_rdma_connect_worker [rpcrdma]
Nov 27 16:32:06 manet kernel: RIP: 0010:atomic_try_cmpxchg+0x2/0x12
Nov 27 16:32:06 manet kernel: Code: ff ff 48 8b 04 24 5a c3 c6 07 00 0f 1f 40 00 c3 31 c0 48 81 ff 08 09 68 81 72 0c 31 c0 48 81 ff 83 0c 68 81 0f 92 c0 c3 8b 06 <f0> 0f b1 17 0f 94 c2 84 d2 75 02 89 06 88 d0 c3 53 ba 01 00 00 00
Nov 27 16:32:06 manet kernel: RSP: 0018:ffffc900035abbf0 EFLAGS: 00010046
Nov 27 16:32:06 manet kernel: RAX: 0000000000000000 RBX: 00000000000001c0 RCX: 0000000000000000
Nov 27 16:32:06 manet kernel: RDX: 0000000000000001 RSI: ffffc900035abbfc RDI: 00000000000001c0
Nov 27 16:32:06 manet kernel: RBP: ffffc900035abde0 R08: 000000000000000e R09: ffffffffffffc000
Nov 27 16:32:06 manet kernel: R10: 0000000000000000 R11: 000000000002e800 R12: ffff88886169d9f8
Nov 27 16:32:06 manet kernel: R13: ffff88886169d9f4 R14: 0000000000000246 R15: 0000000000000000
Nov 27 16:32:06 manet kernel: FS:  0000000000000000(0000) GS:ffff88846fa40000(0000) knlGS:0000000000000000
Nov 27 16:32:06 manet kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Nov 27 16:32:06 manet kernel: CR2: 00000000000001c0 CR3: 0000000002009006 CR4: 00000000001606e0
Nov 27 16:32:06 manet kernel: Call Trace:
Nov 27 16:32:06 manet kernel: do_raw_spin_lock+0x2f/0x5a
Nov 27 16:32:06 manet kernel: create_qp_common.isra.47+0x856/0xadf [mlx4_ib]
Nov 27 16:32:06 manet kernel: ? slab_post_alloc_hook.isra.60+0xa/0x1a
Nov 27 16:32:06 manet kernel: ? __kmalloc+0x125/0x139
Nov 27 16:32:06 manet kernel: mlx4_ib_create_qp+0x57f/0x972 [mlx4_ib]

The fix is to copy the qp_init_attr struct that was just created by
rpcrdma_ep_create() instead of using the one from the previous
connection instance.

Fixes: 98ef77d1aa ("xprtrdma: Send Queue size grows after a reconnect")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2020-01-14 13:30:24 -05:00
Chuck Lever
f54c870d32 xprtrdma: Replace dprintk() in rpcrdma_update_connect_private()
Clean up: Use a single trace point to record each connection's
negotiated inline thresholds and the computed maximum byte size
of transport headers.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:40 -04:00
Chuck Lever
7b020f17bb xprtrdma: Report the computed connect delay
For debugging, the op_connect trace point should report the computed
connect delay. We can then ensure that the delay is computed at the
proper times, for example.

As a further clean-up, remove a few low-value "heartbeat" trace
points in the connect path.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:40 -04:00
Chuck Lever
614f3c96d7 xprtrdma: Pull up sometimes
On some platforms, DMA mapping part of a page is more costly than
copying bytes. Restore the pull-up code and use that when we
think it's going to be faster. The heuristic for now is to pull-up
when the size of the RPC message body fits in the buffer underlying
the head iovec.

Indeed, not involving the I/O MMU can help the RPC/RDMA transport
scale better for tiny I/Os across more RDMA devices. This is because
interaction with the I/O MMU is eliminated, as is handling a Send
completion, for each of these small I/Os. Without the explicit
unmapping, the NIC no longer needs to do a costly internal TLB shoot
down for buffers that are just a handful of bytes.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:40 -04:00
Chuck Lever
dc15c3d5f1 xprtrdma: Move the rpcrdma_sendctx::sc_wr field
Clean up: This field is not needed in the Send completion handler,
so it can be moved to struct rpcrdma_req to reduce the size of
struct rpcrdma_sendctx, and to reduce the amount of memory that
is sloshed between the sending process and the Send completion
process.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:40 -04:00
Chuck Lever
f995879ec4 xprtrdma: Remove rpcrdma_sendctx::sc_xprt
Micro-optimization: Save eight bytes in a frequently allocated
structure.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:40 -04:00
Chuck Lever
9d2da4ff00 xprtrdma: Manage MRs in context of a single connection
MRs are now allocated on demand so we can safely throw them away on
disconnect. This way an idle transport can disconnect and it won't
pin hardware MR resources.

Two additional changes:

- Now that all MRs are destroyed on disconnect, there's no need to
  check during header marshaling if a req has MRs to recycle. Each
  req is sent only once per connection, and now rl_registered is
  guaranteed to be empty when rpcrdma_marshal_req is invoked.

- Because MRs are now destroyed in a WQ_MEM_RECLAIM context, they
  also must be allocated in a WQ_MEM_RECLAIM context. This reduces
  the likelihood that device driver memory allocation will trigger
  memory reclaim during NFS writeback.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:40 -04:00
Chuck Lever
c3700780a0 xprtrdma: Fix MR list handling
Close some holes introduced by commit 6dc6ec9e04 ("xprtrdma: Cache
free MRs in each rpcrdma_req") that could result in list corruption.

In addition, the result that is tabulated in @count is no longer
used, so @count is removed.

Fixes: 6dc6ec9e04 ("xprtrdma: Cache free MRs in each rpcrdma_req")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:40 -04:00
Chuck Lever
2ae50ad68c xprtrdma: Close window between waking RPC senders and posting Receives
A recent clean up attempted to separate Receive handling and RPC
Reply processing, in the name of clean layering.

Unfortunately, we can't do this because the Receive Queue has to be
refilled _after_ the most recent credit update from the responder
is parsed from the transport header, but _before_ we wake up the
next RPC sender. That is right in the middle of
rpcrdma_reply_handler().

Usually this isn't a problem because current responder
implementations don't vary their credit grant. The one exception is
when a connection is established: the grant goes from one to a much
larger number on the first Receive. The requester MUST post enough
Receives right then so that any outstanding requests can be sent
without risking RNR and connection loss.

Fixes: 6ceea36890 ("xprtrdma: Refactor Receive accounting")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:40 -04:00
Chuck Lever
eea63ca7ff xprtrdma: Initialize rb_credits in one place
Clean up/code de-duplication.

Nit: RPC_CWNDSHIFT is incorrect as the initial value for xprt->cwnd.
This mistake does not appear to have operational consequences, since
the cwnd value is replaced with a valid value upon the first Receive
completion.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:39 -04:00
Chuck Lever
a31b2f9392 xprtrdma: Connection becomes unstable after a reconnect
This is because xprt_request_get_cong() is allowing more than one
RPC Call to be transmitted before the first Receive on the new
connection. The first Receive fills the Receive Queue based on the
server's credit grant. Before that Receive, there is only a single
Receive WR posted because the client doesn't know the server's
credit grant.

Solution is to clear rq_cong on all outstanding rpc_rqsts when the
the cwnd is reset. This is because an RPC/RDMA credit is good for
one connection instance only.

Fixes: 75891f502f ("SUNRPC: Support for congestion control ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-10-24 10:30:39 -04:00
Linus Torvalds
972a2bf7df NFS Client Updates for Linux 5.3
Stable bugfixes:
 - Dequeue the request from the receive queue while we're re-encoding # v4.20+
 - Fix buffer handling of GSS MIC without slack # 5.1
 
 Features:
 - Increase xprtrdma maximum transport header and slot table sizes
 - Add support for nfs4_call_sync() calls using a custom rpc_task_struct
 - Optimize the default readahead size
 - Enable pNFS filelayout LAYOUTGET on OPEN
 
 Other bugfixes and cleanups:
 - Fix possible null-pointer dereferences and memory leaks
 - Various NFS over RDMA cleanups
 - Various NFS over RDMA comment updates
 - Don't receive TCP data into a reset request buffer
 - Don't try to parse incomplete RPC messages
 - Fix congestion window race with disconnect
 - Clean up pNFS return-on-close error handling
 - Fixes for NFS4ERR_OLD_STATEID handling
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEnZ5MQTpR7cLU7KEp18tUv7ClQOsFAl2NC04ACgkQ18tUv7Cl
 QOs4Tg//bAlGs+dIKixAmeMKmTd6I34laUnuyV/12yPQDgo6bryLrTngfe2BYvmG
 2l+8H7yHfR4/gQE4vhR0c15xFgu6pvjBGR0/nNRaXienIPXO4xsQkcaxVA7SFRY2
 HjffZwyoBfjyRps0jL+2sTsKbRtSkf9Dn+BONRgesg51jK1jyWkXqXpmgi4uMO4i
 ojpTrW81dwo7Yhv08U2A/Q1ifMJ8F9dVYuL5sm+fEbVI/Nxoz766qyB8rs8+b4Xj
 3gkfyh/Y1zoMmu6c+r2Q67rhj9WYbDKpa6HH9yX1zM/RLTiU7czMX+kjuQuOHWxY
 YiEk73NjJ48WJEep3odess1q/6WiAXX7UiJM1SnDFgAa9NZMdfhqMm6XduNO1m60
 sy0i8AdxdQciWYexOXMsBuDUCzlcoj4WYs1QGpY3uqO1MznQS/QUfu65fx8CzaT5
 snm6ki5ivqXH/js/0Z4MX2n/sd1PGJ5ynMkekxJ8G3gw+GC/oeSeGNawfedifLKK
 OdzyDdeiel5Me1p4I28j1WYVLHvtFmEWEU9oytdG0D/rjC/pgYgW/NYvAao8lQ4Z
 06wdcyAM66ViAPrbYeE7Bx4jy8zYRkiw6Y3kIbLgrlMugu3BhIW5Mi3BsgL4f4am
 KsqkzUqPZMCOVwDuUILSuPp4uHaR+JTJttywiLniTL6reF5kTiA=
 =4Ey6
 -----END PGP SIGNATURE-----

Merge tag 'nfs-for-5.4-1' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client updates from Anna Schumaker:
 "Stable bugfixes:
   - Dequeue the request from the receive queue while we're re-encoding
     # v4.20+
   - Fix buffer handling of GSS MIC without slack # 5.1

  Features:
   - Increase xprtrdma maximum transport header and slot table sizes
   - Add support for nfs4_call_sync() calls using a custom
     rpc_task_struct
   - Optimize the default readahead size
   - Enable pNFS filelayout LAYOUTGET on OPEN

  Other bugfixes and cleanups:
   - Fix possible null-pointer dereferences and memory leaks
   - Various NFS over RDMA cleanups
   - Various NFS over RDMA comment updates
   - Don't receive TCP data into a reset request buffer
   - Don't try to parse incomplete RPC messages
   - Fix congestion window race with disconnect
   - Clean up pNFS return-on-close error handling
   - Fixes for NFS4ERR_OLD_STATEID handling"

* tag 'nfs-for-5.4-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (53 commits)
  pNFS/filelayout: enable LAYOUTGET on OPEN
  NFS: Optimise the default readahead size
  NFSv4: Handle NFS4ERR_OLD_STATEID in LOCKU
  NFSv4: Handle NFS4ERR_OLD_STATEID in CLOSE/OPEN_DOWNGRADE
  NFSv4: Fix OPEN_DOWNGRADE error handling
  pNFS: Handle NFS4ERR_OLD_STATEID on layoutreturn by bumping the state seqid
  NFSv4: Add a helper to increment stateid seqids
  NFSv4: Handle RPC level errors in LAYOUTRETURN
  NFSv4: Handle NFS4ERR_DELAY correctly in return-on-close
  NFSv4: Clean up pNFS return-on-close error handling
  pNFS: Ensure we do clear the return-on-close layout stateid on fatal errors
  NFS: remove unused check for negative dentry
  NFSv3: use nfs_add_or_obtain() to create and reference inodes
  NFS: Refactor nfs_instantiate() for dentry referencing callers
  SUNRPC: Fix congestion window race with disconnect
  SUNRPC: Don't try to parse incomplete RPC messages
  SUNRPC: Rename xdr_buf_read_netobj to xdr_buf_read_mic
  SUNRPC: Fix buffer handling of GSS MIC without slack
  SUNRPC: RPC level errors should always set task->tk_rpc_status
  SUNRPC: Don't receive TCP data into a request buffer that has been reset
  ...
2019-09-26 12:20:14 -07:00
Chuck Lever
98ef77d1aa xprtrdma: Send Queue size grows after a reconnect
Eli Dorfman reports that after a series of idle disconnects, an
RPC/RDMA transport becomes unusable (rdma_create_qp returns
-ENOMEM). Problem was tracked down to increasing Send Queue size
after each reconnect.

The rdma_create_qp() API does not promise to leave its @qp_init_attr
parameter unaltered. In fact, some drivers do modify one or more of
its fields. Thus our calls to rdma_create_qp must use a fresh copy
of ib_qp_init_attr each time.

This fix is appropriate for kernels dating back to late 2007, though
it will have to be adapted, as the connect code has changed over the
years.

Reported-by: Eli Dorfman <eli@vastdata.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-26 15:45:38 -04:00
Chuck Lever
f9e1afe0fa xprtrdma: Clear xprt->reestablish_timeout on close
Ensure that the re-establishment delay does not grow exponentially
on each good reconnect. This probably should have been part of
commit 675dd90ad0 ("xprtrdma: Modernize ops->connect").

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-26 15:34:59 -04:00
Chuck Lever
435eba4ae0 xprtrdma: Optimize rpcrdma_post_recvs()
Micro-optimization: In rpcrdma_post_recvs, since commit e340c2d6ef
("xprtrdma: Reduce the doorbell rate (Receive)"), the common case is
to return without doing anything. Found with perf.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-21 15:04:59 -04:00
Chuck Lever
b0b227f071 xprtrdma: Use an llist to manage free rpcrdma_reps
rpcrdma_rep objects are removed from their free list by only a
single thread: the Receive completion handler. Thus that free list
can be converted to an llist, where a single-threaded consumer and
a multi-threaded producer (rpcrdma_buffer_put) can both access the
llist without the need for any serialization.

This eliminates spin lock contention between the Receive completion
handler and rpcrdma_buffer_get, and makes the rep consumer wait-
free.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-21 11:45:27 -04:00
Chuck Lever
4d6b8890dd xprtrdma: Remove rpcrdma_buffer::rb_mrlock
Clean up: Now that the free list is used sparingly, get rid of the
separate spin lock protecting it.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-21 11:40:00 -04:00
Chuck Lever
6dc6ec9e04 xprtrdma: Cache free MRs in each rpcrdma_req
Instead of a globally-contended MR free list, cache MRs in each
rpcrdma_req as they are released. This means acquiring and releasing
an MR will be lock-free in the common case, even outside the
transport send lock.

The original idea of per-rpcrdma_req MR free lists was suggested by
Shirley Ma <shirley.ma@oracle.com> several years ago. I just now
figured out how to make that idea work with on-demand MR allocation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-21 11:06:24 -04:00
Chuck Lever
805a1f620b xprtrdma: Ensure creating an MR does not trigger FS writeback
Probably would be good to also pass GFP flags to ib_alloc_mr.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-08-20 16:35:30 -04:00