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2022-06-25xprtrdma: fix incorrect header size calculationsColin Ian King
commit 912288442cb2f431bf3c8cb097a5de83bc6dbac1 upstream. Currently the header size calculations are using an assignment operator instead of a += operator when accumulating the header size leading to incorrect sizes. Fix this by using the correct operator. Addresses-Coverity: ("Unused value") Fixes: 302d3deb2068 ("xprtrdma: Prevent inline overflow") Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> [bwh: Backported to 4.19: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-14xprtrdma: treat all calls not a bcall when bc_serv is NULLKinglong Mee
[ Upstream commit 11270e7ca268e8d61b5d9e5c3a54bd1550642c9c ] When a rdma server returns a fault format reply, nfs v3 client may treats it as a bcall when bc service is not exist. The debug message at rpcrdma_bc_receive_call are, [56579.837169] RPC: rpcrdma_bc_receive_call: callback XID 00000001, length=20 [56579.837174] RPC: rpcrdma_bc_receive_call: 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 After that, rpcrdma_bc_receive_call will meets NULL pointer as, [ 226.057890] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8 ... [ 226.058704] RIP: 0010:_raw_spin_lock+0xc/0x20 ... [ 226.059732] Call Trace: [ 226.059878] rpcrdma_bc_receive_call+0x138/0x327 [rpcrdma] [ 226.060011] __ib_process_cq+0x89/0x170 [ib_core] [ 226.060092] ib_cq_poll_work+0x26/0x80 [ib_core] [ 226.060257] process_one_work+0x1a7/0x360 [ 226.060367] ? create_worker+0x1a0/0x1a0 [ 226.060440] worker_thread+0x30/0x390 [ 226.060500] ? create_worker+0x1a0/0x1a0 [ 226.060574] kthread+0x116/0x130 [ 226.060661] ? kthread_flush_work_fn+0x10/0x10 [ 226.060724] ret_from_fork+0x35/0x40 ... Signed-off-by: Kinglong Mee <kinglongmee@gmail.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-04-15SUNRPC/call_alloc: async tasks mustn't block waiting for memoryNeilBrown
[ Upstream commit c487216bec83b0c5a8803e5c61433d33ad7b104d ] When memory is short, new worker threads cannot be created and we depend on the minimum one rpciod thread to be able to handle everything. So it must not block waiting for memory. mempools are particularly a problem as memory can only be released back to the mempool by an async rpc task running. If all available workqueue threads are waiting on the mempool, no thread is available to return anything. rpc_malloc() can block, and this might cause deadlocks. So check RPC_IS_ASYNC(), rather than RPC_IS_SWAPPER() to determine if blocking is acceptable. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-24svcrdma: disable timeouts on rdma backchannelTimo Rothenpieler
commit 6820bf77864d5894ff67b5c00d7dba8f92011e3d upstream. This brings it in line with the regular tcp backchannel, which also has all those timeouts disabled. Prevents the backchannel from timing out, getting some async operations like server side copying getting stuck indefinitely on the client side. Signed-off-by: Timo Rothenpieler <timo@rothenpieler.org> Fixes: 5d252f90a800 ("svcrdma: Add class for RDMA backwards direction transport") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-30SUNRPC: xprt_load_transport() needs to support the netid "rdma6"Trond Myklebust
[ Upstream commit d5aa6b22e2258f05317313ecc02efbb988ed6d38 ] According to RFC5666, the correct netid for an IPv6 addressed RDMA transport is "rdma6", which we've supported as a mount option since Linux-4.7. The problem is when we try to load the module "xprtrdma6", that will fail, since there is no modulealias of that name. Fixes: 181342c5ebe8 ("xprtrdma: Add rdma6 option to support NFS/RDMA IPv6") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-30svcrdma: fix bounce buffers for unaligned offsets and multiple pagesDan Aloni
[ Upstream commit c327a310ec4d6ecbea13185ed56c11def441d9ab ] This was discovered using O_DIRECT at the client side, with small unaligned file offsets or IOs that span multiple file pages. Fixes: e248aa7be86 ("svcrdma: Remove max_sge check at connect time") Signed-off-by: Dan Aloni <dan@kernelim.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-10-01svcrdma: Fix leak of transport addressesChuck Lever
[ Upstream commit 1a33d8a284b1e85e03b8c7b1ea8fb985fccd1d71 ] Kernel memory leak detected: unreferenced object 0xffff888849cdf480 (size 8): comm "kworker/u8:3", pid 2086, jiffies 4297898756 (age 4269.856s) hex dump (first 8 bytes): 30 00 cd 49 88 88 ff ff 0..I.... backtrace: [<00000000acfc370b>] __kmalloc_track_caller+0x137/0x183 [<00000000a2724354>] kstrdup+0x2b/0x43 [<0000000082964f84>] xprt_rdma_format_addresses+0x114/0x17d [rpcrdma] [<00000000dfa6ed00>] xprt_setup_rdma_bc+0xc0/0x10c [rpcrdma] [<0000000073051a83>] xprt_create_transport+0x3f/0x1a0 [sunrpc] [<0000000053531a8e>] rpc_create+0x118/0x1cd [sunrpc] [<000000003a51b5f8>] setup_callback_client+0x1a5/0x27d [nfsd] [<000000001bd410af>] nfsd4_process_cb_update.isra.7+0x16c/0x1ac [nfsd] [<000000007f4bbd56>] nfsd4_run_cb_work+0x4c/0xbd [nfsd] [<0000000055c5586b>] process_one_work+0x1b2/0x2fe [<00000000b1e3e8ef>] worker_thread+0x1a6/0x25a [<000000005205fb78>] kthread+0xf6/0xfb [<000000006d2dc057>] ret_from_fork+0x3a/0x50 Introduce a call to xprt_rdma_free_addresses() similar to the way that the TCP backchannel releases a transport's peer address strings. Fixes: 5d252f90a800 ("svcrdma: Add class for RDMA backwards direction transport") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-26svcrdma: Fix another Receive buffer leakChuck Lever
[ Upstream commit 64d26422516b2e347b32e6d9b1d40b3c19a62aae ] During a connection tear down, the Receive queue is flushed before the device resources are freed. Typically, all the Receives flush with IB_WR_FLUSH_ERR. However, any pending successful Receives flush with IB_WR_SUCCESS, and the server automatically posts a fresh Receive to replace the completing one. This happens even after the connection has closed and the RQ is drained. Receives that are posted after the RQ is drained appear never to complete, causing a Receive resource leak. The leaked Receive buffer is left DMA-mapped. To prevent these late-posted recv_ctxt's from leaking, block new Receive posting after XPT_CLOSE is set. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-08-19svcrdma: Fix page leak in svc_rdma_recv_read_chunk()Chuck Lever
[ Upstream commit e814eecbe3bbeaa8b004d25a4b8974d232b765a9 ] Commit 07d0ff3b0cd2 ("svcrdma: Clean up Read chunk path") moved the page saver logic so that it gets executed event when an error occurs. In that case, the I/O is never posted, and those pages are then leaked. Errors in this path, however, are quite rare. Fixes: 07d0ff3b0cd2 ("svcrdma: Clean up Read chunk path") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-02svcrdma: Fix leak of svc_rdma_recv_ctxt objectsChuck Lever
commit 23cf1ee1f1869966b75518c59b5cbda4c6c92450 upstream. Utilize the xpo_release_rqst transport method to ensure that each rqstp's svc_rdma_recv_ctxt object is released even when the server cannot return a Reply for that rqstp. Without this fix, each RPC whose Reply cannot be sent leaks one svc_rdma_recv_ctxt. This is a 2.5KB structure, a 4KB DMA-mapped Receive buffer, and any pages that might be part of the Reply message. The leak is infrequent unless the network fabric is unreliable or Kerberos is in use, as GSS sequence window overruns, which result in connection loss, are more common on fast transports. Fixes: 3a88092ee319 ("svcrdma: Preserve Receive buffer until svc_rdma_sendto") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-02svcrdma: Fix trace point use-after-free raceChuck Lever
commit e28b4fc652c1830796a4d3e09565f30c20f9a2cf upstream. I hit this while testing nfsd-5.7 with kernel memory debugging enabled on my server: Mar 30 13:21:45 klimt kernel: BUG: unable to handle page fault for address: ffff8887e6c279a8 Mar 30 13:21:45 klimt kernel: #PF: supervisor read access in kernel mode Mar 30 13:21:45 klimt kernel: #PF: error_code(0x0000) - not-present page Mar 30 13:21:45 klimt kernel: PGD 3601067 P4D 3601067 PUD 87c519067 PMD 87c3e2067 PTE 800ffff8193d8060 Mar 30 13:21:45 klimt kernel: Oops: 0000 [#1] SMP DEBUG_PAGEALLOC PTI Mar 30 13:21:45 klimt kernel: CPU: 2 PID: 1933 Comm: nfsd Not tainted 5.6.0-rc6-00040-g881e87a3c6f9 #1591 Mar 30 13:21:45 klimt kernel: Hardware name: Supermicro Super Server/X10SRL-F, BIOS 1.0c 09/09/2015 Mar 30 13:21:45 klimt kernel: RIP: 0010:svc_rdma_post_chunk_ctxt+0xab/0x284 [rpcrdma] Mar 30 13:21:45 klimt kernel: Code: c1 83 34 02 00 00 29 d0 85 c0 7e 72 48 8b bb a0 02 00 00 48 8d 54 24 08 4c 89 e6 48 8b 07 48 8b 40 20 e8 5a 5c 2b e1 41 89 c6 <8b> 45 20 89 44 24 04 8b 05 02 e9 01 00 85 c0 7e 33 e9 5e 01 00 00 Mar 30 13:21:45 klimt kernel: RSP: 0018:ffffc90000dfbdd8 EFLAGS: 00010286 Mar 30 13:21:45 klimt kernel: RAX: 0000000000000000 RBX: ffff8887db8db400 RCX: 0000000000000030 Mar 30 13:21:45 klimt kernel: RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000246 Mar 30 13:21:45 klimt kernel: RBP: ffff8887e6c27988 R08: 0000000000000000 R09: 0000000000000004 Mar 30 13:21:45 klimt kernel: R10: ffffc90000dfbdd8 R11: 00c068ef00000000 R12: ffff8887eb4e4a80 Mar 30 13:21:45 klimt kernel: R13: ffff8887db8db634 R14: 0000000000000000 R15: ffff8887fc931000 Mar 30 13:21:45 klimt kernel: FS: 0000000000000000(0000) GS:ffff88885bd00000(0000) knlGS:0000000000000000 Mar 30 13:21:45 klimt kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Mar 30 13:21:45 klimt kernel: CR2: ffff8887e6c279a8 CR3: 000000081b72e002 CR4: 00000000001606e0 Mar 30 13:21:45 klimt kernel: Call Trace: Mar 30 13:21:45 klimt kernel: ? svc_rdma_vec_to_sg+0x7f/0x7f [rpcrdma] Mar 30 13:21:45 klimt kernel: svc_rdma_send_write_chunk+0x59/0xce [rpcrdma] Mar 30 13:21:45 klimt kernel: svc_rdma_sendto+0xf9/0x3ae [rpcrdma] Mar 30 13:21:45 klimt kernel: ? nfsd_destroy+0x51/0x51 [nfsd] Mar 30 13:21:45 klimt kernel: svc_send+0x105/0x1e3 [sunrpc] Mar 30 13:21:45 klimt kernel: nfsd+0xf2/0x149 [nfsd] Mar 30 13:21:45 klimt kernel: kthread+0xf6/0xfb Mar 30 13:21:45 klimt kernel: ? kthread_queue_delayed_work+0x74/0x74 Mar 30 13:21:45 klimt kernel: ret_from_fork+0x3a/0x50 Mar 30 13:21:45 klimt kernel: Modules linked in: ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm ocfs2_nodemanager ocfs2_stackglue ib_umad ib_ipoib mlx4_ib sb_edac x86_pkg_temp_thermal iTCO_wdt iTCO_vendor_support coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel glue_helper crypto_simd cryptd pcspkr rpcrdma i2c_i801 rdma_ucm lpc_ich mfd_core ib_iser rdma_cm iw_cm ib_cm mei_me raid0 libiscsi mei sg scsi_transport_iscsi ioatdma wmi ipmi_si ipmi_devintf ipmi_msghandler acpi_power_meter nfsd nfs_acl lockd auth_rpcgss grace sunrpc ip_tables xfs libcrc32c mlx4_en sd_mod sr_mod cdrom mlx4_core crc32c_intel igb nvme i2c_algo_bit ahci i2c_core libahci nvme_core dca libata t10_pi qedr dm_mirror dm_region_hash dm_log dm_mod dax qede qed crc8 ib_uverbs ib_core Mar 30 13:21:45 klimt kernel: CR2: ffff8887e6c279a8 Mar 30 13:21:45 klimt kernel: ---[ end trace 87971d2ad3429424 ]--- It's absolutely not safe to use resources pointed to by the @send_wr argument 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 server'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: bd2abef33394 ("svcrdma: Trace key RDMA API events") Fixes: 4201c7464753 ("svcrdma: Introduce svc_rdma_send_ctxt") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-27xprtrdma: Fix use-after-free in rpcrdma_post_recvsChuck Lever
[ Upstream commit 2d0abe36cf13fb7b577949fd1539326adddcc9bc ] Dereference wr->next /before/ the memory backing wr has been released. This issue was found by code inspection. It is not expected to be a significant problem because it is in an error path that is almost never executed. Fixes: 7c8d9e7c8863 ("xprtrdma: Move Receive posting to ... ") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-17xprtrdma: Fix completion wait during device removalChuck Lever
commit 13cb886c591f341a8759f175292ddf978ef903a1 upstream. 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: bebd031866ca ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05xprtrdma: Prevent leak of rpcrdma_rep objectsChuck Lever
[ Upstream commit 07e10308ee5da8e6132e0b737ece1c99dd651fb6 ] If a reply has been processed but the RPC is later retransmitted anyway, the req->rl_reply field still contains the only pointer to the old rpcrdma rep. When the next reply comes in, the reply handler will stomp on the rl_reply field, leaking the old rep. A trace event is added to capture such leaks. This problem seems to be worsened by the restructuring of the RPC Call path in v4.20. Fully addressing this issue will require at least a re-architecture of the disconnect logic, which is not appropriate during -rc. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-11-24sunrpc: Fix connect metricsChuck Lever
[ Upstream commit 3968a8a5310404c2f0b9e4d9f28cab13a12bc4fd ] For TCP, the logic in xprt_connect_status is currently never invoked to record a successful connection. Commit 2a4919919a97 ("SUNRPC: Return EAGAIN instead of ENOTCONN when waking up xprt->pending") changed the way TCP xprt's are awoken after a connect succeeds. Instead, change connection-oriented transports to bump connect_count and compute connect_time the moment that XPRT_CONNECTED is set. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-10svcrdma: Ignore source port when computing DRC hashChuck Lever
commit 1e091c3bbf51d34d5d96337a59ce5ab2ac3ba2cc upstream. The DRC appears to be effectively empty after an RPC/RDMA transport reconnect. The problem is that each connection uses a different source port, which defeats the DRC hash. Clients always have to disconnect before they send retransmissions to reset the connection's credit accounting, thus every retransmit on NFS/RDMA will miss the DRC. An NFS/RDMA client's IP source port is meaningless for RDMA transports. The transport layer typically sets the source port value on the connection to a random ephemeral port. The server already ignores it for the "secure port" check. See commit 16e4d93f6de7 ("NFSD: Ignore client's source port on RDMA transports"). The Linux NFS server's DRC resolves XID collisions from the same source IP address by using the checksum of the first 200 bytes of the RPC call header. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-23xprtrdma: Make sure Send CQ is allocated on an existing compvecNicolas Morey-Chaisemartin
[ Upstream commit a4cb5bdb754afe21f3e9e7164213e8600cf69427 ] Make sure the device has at least 2 completion vectors before allocating to compvec#1 Fixes: a4699f5647f3 (xprtrdma: Put Send CQ in IB_POLL_WORKQUEUE mode) Signed-off-by: Nicolas Morey-Chaisemartin <nmoreychaisemartin@suse.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-02-27xprtrdma: Double free in rpcrdma_sendctxs_create()Dan Carpenter
[ Upstream commit 6e17f58c486d9554341f70aa5b63b8fbed07b3fa ] The clean up is handled by the caller, rpcrdma_buffer_create(), so this call to rpcrdma_sendctxs_destroy() leads to a double free. Fixes: ae72950abf99 ("xprtrdma: Add data structure to manage RDMA Send arguments") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-02-15svcrdma: Remove max_sge check at connect timeChuck Lever
commit e248aa7be86e8179f20ac0931774ecd746f3f5bf upstream. Two and a half years ago, the client was changed to use gathered Send for larger inline messages, in commit 655fec6987b ("xprtrdma: Use gathered Send for large inline messages"). Several fixes were required because there are a few in-kernel device drivers whose max_sge is 3, and these were broken by the change. Apparently my memory is going, because some time later, I submitted commit 25fd86eca11c ("svcrdma: Don't overrun the SGE array in svc_rdma_send_ctxt"), and after that, commit f3c1fd0ee294 ("svcrdma: Reduce max_send_sges"). These too incorrectly assumed in-kernel device drivers would have more than a few Send SGEs available. The fix for the server side is not the same. This is because the fundamental problem on the server is that, whether or not the client has provisioned a chunk for the RPC reply, the server must squeeze even the most complex RPC replies into a single RDMA Send. Failing in the send path because of Send SGE exhaustion should never be an option. Therefore, instead of failing when the send path runs out of SGEs, switch to using a bounce buffer mechanism to handle RPC replies that are too complex for the device to send directly. That allows us to remove the max_sge check to enable drivers with small max_sge to work again. Reported-by: Don Dutile <ddutile@redhat.com> Fixes: 25fd86eca11c ("svcrdma: Don't overrun the SGE array in ...") Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-15svcrdma: Reduce max_send_sgesChuck Lever
commit f3c1fd0ee294abd4367dfa72d89f016c682202f0 upstream. There's no need to request a large number of send SGEs because the inline threshold already constrains the number of SGEs per Send. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Cc: Don Dutile <ddutile@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-13xprtrdma: Reset credit grant properly after a disconnectChuck Lever
[ Upstream commit ef739b2175dde9c05594f768cb78149f1ce2ac36 ] On a fresh connection, an RPC/RDMA client is supposed to send only one RPC Call until it gets a credit grant in the first RPC Reply from the server [RFC 8166, Section 3.3.3]. There is a bug in the Linux client's credit accounting mechanism introduced by commit e7ce710a8802 ("xprtrdma: Avoid deadlock when credit window is reset"). On connect, it simply dumps all pending RPC Calls onto the new connection. Servers have been tolerant of this bad behavior. Currently no server implementation ever changes its credit grant over reconnects, and servers always repost enough Receives before connections are fully established. To correct this issue, ensure that the client resets both the credit grant _and_ the congestion window when handling a reconnect. Fixes: e7ce710a8802 ("xprtrdma: Avoid deadlock when credit ... ") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: stable@kernel.org Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-23Merge tag 'nfs-for-4.19-1' of git://git.linux-nfs.org/projects/anna/linux-nfsLinus Torvalds
Pull NFS client updates from Anna Schumaker: "These patches include adding async support for the v4.2 COPY operation. I think Bruce is planning to send the server patches for the next release, but I figured we could get the client side out of the way now since it's been in my tree for a while. This shouldn't cause any problems, since the server will still respond with synchronous copies even if the client requests async. Features: - Add support for asynchronous server-side COPY operations Stable bufixes: - Fix an off-by-one in bl_map_stripe() (v3.17+) - NFSv4 client live hangs after live data migration recovery (v4.9+) - xprtrdma: Fix disconnect regression (v4.18+) - Fix locking in pnfs_generic_recover_commit_reqs (v4.14+) - Fix a sleep in atomic context in nfs4_callback_sequence() (v4.9+) Other bugfixes and cleanups: - Optimizations and fixes involving NFS v4.1 / pNFS layout handling - Optimize lseek(fd, SEEK_CUR, 0) on directories to avoid locking - Immediately reschedule writeback when the server replies with an error - Fix excessive attribute revalidation in nfs_execute_ok() - Add error checking to nfs_idmap_prepare_message() - Use new vm_fault_t return type - Return a delegation when reclaiming one that the server has recalled - Referrals should inherit proto setting from parents - Make rpc_auth_create_args a const - Improvements to rpc_iostats tracking - Fix a potential reference leak when there is an error processing a callback - Fix rmdir / mkdir / rename nlink accounting - Fix updating inode change attribute - Fix error handling in nfsn4_sp4_select_mode() - Use an appropriate work queue for direct-write completion - Don't busy wait if NFSv4 session draining is interrupted" * tag 'nfs-for-4.19-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (54 commits) pNFS: Remove unwanted optimisation of layoutget pNFS/flexfiles: ff_layout_pg_init_read should exit on error pNFS: Treat RECALLCONFLICT like DELAY... pNFS: When updating the stateid in layoutreturn, also update the recall range NFSv4: Fix a sleep in atomic context in nfs4_callback_sequence() NFSv4: Fix locking in pnfs_generic_recover_commit_reqs NFSv4: Fix a typo in nfs4_init_channel_attrs() NFSv4: Don't busy wait if NFSv4 session draining is interrupted NFS recover from destination server reboot for copies NFS add a simple sync nfs4_proc_commit after async COPY NFS handle COPY ERR_OFFLOAD_NO_REQS NFS send OFFLOAD_CANCEL when COPY killed NFS export nfs4_async_handle_error NFS handle COPY reply CB_OFFLOAD call race NFS add support for asynchronous COPY NFS COPY xdr handle async reply NFS OFFLOAD_CANCEL xdr NFS CB_OFFLOAD xdr NFS: Use an appropriate work queue for direct-write completion NFSv4: Fix error handling in nfs4_sp4_select_mode() ...
2018-08-23Merge tag 'nfsd-4.19-1' of git://linux-nfs.org/~bfields/linuxLinus Torvalds
Pull nfsd updates from Bruce Fields: "Chuck Lever fixed a problem with NFSv4.0 callbacks over GSS from multi-homed servers. The only new feature is a minor bit of protocol (change_attr_type) which the client doesn't even use yet. Other than that, various bugfixes and cleanup" * tag 'nfsd-4.19-1' of git://linux-nfs.org/~bfields/linux: (27 commits) sunrpc: Add comment defining gssd upcall API keywords nfsd: Remove callback_cred nfsd: Use correct credential for NFSv4.0 callback with GSS sunrpc: Extract target name into svc_cred sunrpc: Enable the kernel to specify the hostname part of service principals sunrpc: Don't use stack buffer with scatterlist rpc: remove unneeded variable 'ret' in rdma_listen_handler nfsd: use true and false for boolean values nfsd: constify write_op[] fs/nfsd: Delete invalid assignment statements in nfsd4_decode_exchange_id NFSD: Handle full-length symlinks NFSD: Refactor the generic write vector fill helper svcrdma: Clean up Read chunk path svcrdma: Avoid releasing a page in svc_xprt_release() nfsd: Mark expected switch fall-through sunrpc: remove redundant variables 'checksumlen','blocksize' and 'data' nfsd: fix leaked file lock with nfs exported overlayfs nfsd: don't advertise a SCSI layout for an unsupported request_queue nfsd: fix corrupted reply to badly ordered compound nfsd: clarify check_op_ordering ...
2018-08-09rpc: remove unneeded variable 'ret' in rdma_listen_handlerzhong jiang
The ret is not modified after initalization, So just remove the variable and return 0. Signed-off-by: zhong jiang <zhongjiang@huawei.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09svcrdma: Clean up Read chunk pathChuck Lever
Simplify the error handling at the tail of recv_read_chunk() by re-arranging rq_pages[] housekeeping and documenting it properly. NB: In this path, svc_rdma_recvfrom returns zero. Therefore no subsequent reply processing is done on the svc_rqstp, and thus the rq_respages field does not need to be updated. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09svcrdma: Avoid releasing a page in svc_xprt_release()Chuck Lever
svc_xprt_release() invokes svc_free_res_pages(), which releases pages between rq_respages and rq_next_page. Historically, the RPC/RDMA transport has set these two pointers to be different by one, which means: - one page gets released when svc_recv returns 0. This normally happens whenever one or more RDMA Reads need to be dispatched to complete construction of an RPC Call. - one page gets released after every call to svc_send. In both cases, this released page is immediately refilled by svc_alloc_arg. There does not seem to be a reason for releasing this page. To avoid this unnecessary memory allocator traffic, set rq_next_page more carefully. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09sunrpc: remove redundant variables 'checksumlen','blocksize' and 'data'YueHaibing
Variables 'checksumlen','blocksize' and 'data' are being assigned, but are never used, hence they are redundant and can be removed. Fix the following warning: net/sunrpc/auth_gss/gss_krb5_wrap.c:443:7: warning: variable ‘blocksize’ set but not used [-Wunused-but-set-variable] net/sunrpc/auth_gss/gss_krb5_crypto.c:376:15: warning: variable ‘checksumlen’ set but not used [-Wunused-but-set-variable] net/sunrpc/xprtrdma/svc_rdma.c:97:9: warning: variable ‘data’ set but not used [-Wunused-but-set-variable] Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-08xprtrdma: Fix disconnect regressionChuck Lever
I found that injecting disconnects with v4.18-rc resulted in random failures of the multi-threaded git regression test. The root cause appears to be that, after a reconnect, the RPC/RDMA transport is waking pending RPCs before the transport has posted enough Receive buffers to receive the Replies. If a Reply arrives before enough Receive buffers are posted, the connection is dropped. A few connection drops happen in quick succession as the client and server struggle to regain credit synchronization. This regression was introduced with commit 7c8d9e7c8863 ("xprtrdma: Move Receive posting to Receive handler"). The client is supposed to post a single Receive when a connection is established because it's not supposed to send more than one RPC Call before it gets a fresh credit grant in the first RPC Reply [RFC 8166, Section 3.3.3]. Unfortunately there appears to be a longstanding bug in the Linux client's credit accounting mechanism. On connect, it simply dumps all pending RPC Calls onto the new connection. It's possible it has done this ever since the RPC/RDMA transport was added to the kernel ten years ago. Servers have so far been tolerant of this bad behavior. Currently no server implementation ever changes its credit grant over reconnects, and servers always repost enough Receives before connections are fully established. The Linux client implementation used to post a Receive before each of these Calls. This has covered up the flooding send behavior. I could try to correct this old bug so that the client sends exactly one RPC Call and waits for a Reply. Since we are so close to the next merge window, I'm going to instead provide a simple patch to post enough Receives before a reconnect completes (based on the number of credits granted to the previous connection). The spurious disconnects will be gone, but the client will still send multiple RPC Calls immediately after a reconnect. Addressing the latter problem will wait for a merge window because a) I expect it to be a large change requiring lots of testing, and b) obviously the Linux client has interoperated successfully since day zero while still being broken. Fixes: 7c8d9e7c8863 ("xprtrdma: Move Receive posting to ... ") Cc: stable@vger.kernel.org # v4.18+ Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-07-30RDMA, core and ULPs: Declare ib_post_send() and ib_post_recv() arguments constBart Van Assche
Since neither ib_post_send() nor ib_post_recv() modify the data structure their second argument points at, declare that argument const. This change makes it necessary to declare the 'bad_wr' argument const too and also to modify all ULPs that call ib_post_send(), ib_post_recv() or ib_post_srq_recv(). This patch does not change any functionality but makes it possible for the compiler to verify whether the ib_post_(send|recv|srq_recv) really do not modify the posted work request. To make this possible, only one cast had to be introduce that casts away constness, namely in rpcrdma_post_recvs(). The only way I can think of to avoid that cast is to introduce an additional loop in that function or to change the data type of bad_wr from struct ib_recv_wr ** into int (an index that refers to an element in the work request list). However, both approaches would require even more extensive changes than this patch. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-07-26net/xprtrdma: Restore needed argument to ib_post_sendJason Gunthorpe
The call in svc_rdma_post_chunk_ctxt() does actually use bad_wr. Fixes: ed288d74a9e5 ("net/xprtrdma: Simplify ib_post_(send|recv|srq_recv)() calls") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-07-24net/xprtrdma: Simplify ib_post_(send|recv|srq_recv)() callsBart Van Assche
Instead of declaring and passing a dummy 'bad_wr' pointer, pass NULL as third argument to ib_post_(send|recv|srq_recv)(). Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Acked-by: Anna Schumaker <Anna.Schumaker@netapp.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-06-18IB/core: add max_send_sge and max_recv_sge attributesSteve Wise
This patch replaces the ib_device_attr.max_sge with max_send_sge and max_recv_sge. It allows ulps to take advantage of devices that have very different send and recv sge depths. For example cxgb4 has a max_recv_sge of 4, yet a max_send_sge of 16. Splitting out these attributes allows much more efficient use of the SQ for cxgb4 with ulps that use the RDMA_RW API. Consider a large RDMA WRITE that has 16 scattergather entries. With max_sge of 4, the ulp would send 4 WRITE WRs, but with max_sge of 16, it can be done with 1 WRITE WR. Acked-by: Sagi Grimberg <sagi@grimberg.me> Acked-by: Christoph Hellwig <hch@lst.de> Acked-by: Selvin Xavier <selvin.xavier@broadcom.com> Acked-by: Shiraz Saleem <shiraz.saleem@intel.com> Acked-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2018-06-12Merge tag 'nfs-for-4.18-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds
Pull NFS client updates from Trond Myklebust: "Highlights include: Stable fixes: - Fix a 1-byte stack overflow in nfs_idmap_read_and_verify_message - Fix a hang due to incorrect error returns in rpcrdma_convert_iovs() - Revert an incorrect change to the NFSv4.1 callback channel - Fix a bug in the NFSv4.1 sequence error handling Features and optimisations: - Support for piggybacking a LAYOUTGET operation to the OPEN compound - RDMA performance enhancements to deal with transport congestion - Add proper SPDX tags for NetApp-contributed RDMA source - Do not request delegated file attributes (size+change) from the server - Optimise away a GETATTR in the lookup revalidate code when doing NFSv4 OPEN - Optimise away unnecessary lookups for rename targets - Misc performance improvements when freeing NFSv4 delegations Bugfixes and cleanups: - Try to fail quickly if proto=rdma - Clean up RDMA receive trace points - Fix sillyrename to return the delegation when appropriate - Misc attribute revalidation fixes - Immediately clear the pNFS layout on a file when the server returns ESTALE - Return NFS4ERR_DELAY when delegation/layout recalls fail due to igrab() - Fix the client behaviour on NFS4ERR_SEQ_FALSE_RETRY" * tag 'nfs-for-4.18-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (80 commits) skip LAYOUTRETURN if layout is invalid NFSv4.1: Fix the client behaviour on NFS4ERR_SEQ_FALSE_RETRY NFSv4: Fix a typo in nfs41_sequence_process NFSv4: Revert commit 5f83d86cf531d ("NFSv4.x: Fix wraparound issues..") NFSv4: Return NFS4ERR_DELAY when a layout recall fails due to igrab() NFSv4: Return NFS4ERR_DELAY when a delegation recall fails due to igrab() NFSv4.0: Remove transport protocol name from non-UCS client ID NFSv4.0: Remove cl_ipaddr from non-UCS client ID NFSv4: Fix a compiler warning when CONFIG_NFS_V4_1 is undefined NFS: Filter cache invalidation when holding a delegation NFS: Ignore NFS_INO_REVAL_FORCED in nfs_check_inode_attributes() NFS: Improve caching while holding a delegation NFS: Fix attribute revalidation NFS: fix up nfs_setattr_update_inode NFSv4: Ensure the inode is clean when we set a delegation NFSv4: Ignore NFS_INO_REVAL_FORCED in nfs4_proc_access NFSv4: Don't ask for delegated attributes when adding a hard link NFSv4: Don't ask for delegated attributes when revalidating the inode NFS: Pass the inode down to the getattr() callback NFSv4: Don't request size+change attribute if they are delegated to us ...
2018-06-12Merge tag 'nfsd-4.18' of git://linux-nfs.org/~bfields/linuxLinus Torvalds
Pull nfsd updates from Bruce Fields: "A relatively quiet cycle for nfsd. The largest piece is an RDMA update from Chuck Lever with new trace points, miscellaneous cleanups, and streamlining of the send and receive paths. Other than that, some miscellaneous bugfixes" * tag 'nfsd-4.18' of git://linux-nfs.org/~bfields/linux: (26 commits) nfsd: fix error handling in nfs4_set_delegation() nfsd: fix potential use-after-free in nfsd4_decode_getdeviceinfo Fix 16-byte memory leak in gssp_accept_sec_context_upcall svcrdma: Fix incorrect return value/type in svc_rdma_post_recvs svcrdma: Remove unused svc_rdma_op_ctxt svcrdma: Persistently allocate and DMA-map Send buffers svcrdma: Simplify svc_rdma_send() svcrdma: Remove post_send_wr svcrdma: Don't overrun the SGE array in svc_rdma_send_ctxt svcrdma: Introduce svc_rdma_send_ctxt svcrdma: Clean up Send SGE accounting svcrdma: Refactor svc_rdma_dma_map_buf svcrdma: Allocate recv_ctxt's on CPU handling Receives svcrdma: Persistently allocate and DMA-map Receive buffers svcrdma: Preserve Receive buffer until svc_rdma_sendto svcrdma: Simplify svc_rdma_recv_ctxt_put svcrdma: Remove sc_rq_depth svcrdma: Introduce svc_rdma_recv_ctxt svcrdma: Trace key RDMA API events svcrdma: Trace key RPC/RDMA protocol events ...
2018-06-08svcrdma: Fix incorrect return value/type in svc_rdma_post_recvsChuck Lever
This crept in during the development process and wasn't caught before I posted the "final" version. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: 0b2613c5883f ('svcrdma: Allocate recv_ctxt's on CPU ... ') Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-06-04Merge tag 'nfs-rdma-for-4.18-1' of ↵Trond Myklebust
git://git.linux-nfs.org/projects/anna/linux-nfs NFS-over-RDMA client updates for Linux 4.18 Stable patches: - xprtrdma: Return -ENOBUFS when no pages are available New features: - Add ->alloc_slot() and ->free_slot() functions Bugfixes and cleanups: - Add missing SPDX tags to some files - Try to fail mount quickly if client has no RDMA devices - Create transport IDs in the correct network namespace - Fix max_send_wr computation - Clean up receive tracepoints - Refactor receive handling - Remove unused functions
2018-06-01xprtrdma: Remove transfertypes arrayChuck Lever
Clean up: This array was used in a dprintk that was replaced by a trace point in commit ab03eff58eb5 ("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>
2018-06-01xprtrdma: Add trace_xprtrdma_dma_map(mr)Chuck Lever
Matches trace_xprtrdma_dma_unmap(mr). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-06-01xprtrdma: Wait on empty sendctx queueChuck Lever
Currently, when the sendctx queue is exhausted during marshaling, the RPC/RDMA transport places the RPC task on the delayq, which forces a wait for HZ >> 2 before the marshal and send is retried. With this change, the transport now places such an RPC task on the pending queue, and wakes it just as soon as more sendctxs become available. This typically takes less than a millisecond, and the write_space waking mechanism is less deadlock-prone. Moreover, the waiting RPC task is holding the transport's write lock, which blocks the transport from sending RPCs. Therefore faster recovery from sendctx queue exhaustion is desirable. Cf. commit 5804891455d5 ("xprtrdma: ->send_request returns -EAGAIN when there are no free MRs"). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-06-01xprtrdma: Move common wait_for_buffer_space call to parent functionChuck Lever
Clean up: The logic to wait for write space is common to a bunch of the encoding helper functions. Lift it out and put it in the tail of rpcrdma_marshal_req(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-06-01xprtrdma: Return -ENOBUFS when no pages are availableChuck Lever
The use of -EAGAIN in rpcrdma_convert_iovs() is a latent bug: the transport never calls xprt_write_space() when more pages become available. -ENOBUFS will trigger the correct "delay briefly and call again" logic. Fixes: 7a89f9c626e3 ("xprtrdma: Honor ->send_request API contract") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: stable@vger.kernel.org # 4.8+ Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-05-11Merge tag 'nfs-for-4.17-2' of git://git.linux-nfs.org/projects/anna/linux-nfsLinus Torvalds
Pull NFS client fixes from Anna Schumaker: "These patches fix both a possible corruption during NFSoRDMA MR recovery, and a sunrpc tracepoint crash. Additionally, Trond has a new email address to put in the MAINTAINERS file" * tag 'nfs-for-4.17-2' of git://git.linux-nfs.org/projects/anna/linux-nfs: Change Trond's email address in MAINTAINERS sunrpc: Fix latency trace point crashes xprtrdma: Fix list corruption / DMAR errors during MR recovery
2018-05-11svcrdma: Persistently allocate and DMA-map Send buffersChuck Lever
While sending each RPC Reply, svc_rdma_sendto allocates and DMA- maps a separate buffer where the RPC/RDMA transport header is constructed. The buffer is unmapped and released in the Send completion handler. This is significant per-RPC overhead, especially for small RPCs. Instead, allocate and DMA-map a buffer, and cache it in each svc_rdma_send_ctxt. This buffer and its mapping can be re-used for each RPC, saving the cost of memory allocation and DMA mapping. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-05-11svcrdma: Simplify svc_rdma_send()Chuck Lever
Clean up: No current caller of svc_rdma_send's passes in a chained WR. The logic that counts the chain length can be replaced with a constant (1). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-05-11svcrdma: Remove post_send_wrChuck Lever
Clean up: Now that the send_wr is part of the svc_rdma_send_ctxt, svc_rdma_post_send_wr is nearly empty. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-05-11svcrdma: Don't overrun the SGE array in svc_rdma_send_ctxtChuck Lever
Receive buffers are always the same size, but each Send WR has a variable number of SGEs, based on the contents of the xdr_buf being sent. While assembling a Send WR, keep track of the number of SGEs so that we don't exceed the device's maximum, or walk off the end of the Send SGE array. For now the Send path just fails if it exceeds the maximum. The current logic in svc_rdma_accept bases the maximum number of Send SGEs on the largest NFS request that can be sent or received. In the transport layer, the limit is actually based on the capabilities of the underlying device, not on properties of the Upper Layer Protocol. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-05-11svcrdma: Introduce svc_rdma_send_ctxtChuck Lever
svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt free list. This eliminates the overhead of calling kmalloc / kfree, both of which grab a globally shared lock that disables interrupts. Introduce a replacement to svc_rdma_op_ctxt's that is built especially for the svcrdma Send path. Subsequent patches will take advantage of this new structure by allocating real resources which are then cached in these objects. The allocations are freed when the transport is torn down. I've renamed the structure so that static type checking can be used to ensure that uses of op_ctxt and send_ctxt are not confused. As an additional clean up, structure fields are renamed to conform with kernel coding conventions. Additional clean ups: - Handle svc_rdma_send_ctxt_get allocation failure at each call site, rather than pre-allocating and hoping we guessed correctly - All send_ctxt_put call-sites request page freeing, so remove the @free_pages argument - All send_ctxt_put call-sites unmap SGEs, so fold that into svc_rdma_send_ctxt_put Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-05-11svcrdma: Clean up Send SGE accountingChuck Lever
Clean up: Since there's already a svc_rdma_op_ctxt being passed around with the running count of mapped SGEs, drop unneeded parameters to svc_rdma_post_send_wr(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-05-11svcrdma: Refactor svc_rdma_dma_map_bufChuck Lever
Clean up: svc_rdma_dma_map_buf does mostly the same thing as svc_rdma_dma_map_page, so let's fold these together. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-05-11svcrdma: Allocate recv_ctxt's on CPU handling ReceivesChuck Lever
There is a significant latency penalty when processing an ingress Receive if the Receive buffer resides in memory that is not on the same NUMA node as the the CPU handling completions for a CQ. The system administrator and the device driver determine which CPU handles completions. This CPU does not change during life of the CQ. Further the Upper Layer does not have any visibility of which CPU it is. Allocating Receive buffers in the Receive completion handler guarantees that Receive buffers are allocated on the preferred NUMA node for that CQ. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>