<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/sunrpc, branch v4.16.4</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>rpc_pipefs: fix double-dput()</title>
<updated>2018-04-24T07:43:10+00:00</updated>
<author>
<name>Al Viro</name>
<email>viro@zeniv.linux.org.uk</email>
</author>
<published>2018-04-03T05:15:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=68a8025a3b5558c9b1603fb6da130dad294696ce'/>
<id>68a8025a3b5558c9b1603fb6da130dad294696ce</id>
<content type='text'>
commit 4a3877c4cedd95543f8726b0a98743ed8db0c0fb upstream.

if we ever hit rpc_gssd_dummy_depopulate() dentry passed to
it has refcount equal to 1.  __rpc_rmpipe() drops it and
dput() done after that hits an already freed dentry.

Cc: stable@kernel.org
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4a3877c4cedd95543f8726b0a98743ed8db0c0fb upstream.

if we ever hit rpc_gssd_dummy_depopulate() dentry passed to
it has refcount equal to 1.  __rpc_rmpipe() drops it and
dput() done after that hits an already freed dentry.

Cc: stable@kernel.org
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xprtrdma: Fix corner cases when handling device removal</title>
<updated>2018-04-24T07:43:00+00:00</updated>
<author>
<name>Chuck Lever</name>
<email>chuck.lever@oracle.com</email>
</author>
<published>2018-03-19T18:23:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=03e19286b7f3aa830a07d05efc2df47efb060d4c'/>
<id>03e19286b7f3aa830a07d05efc2df47efb060d4c</id>
<content type='text'>
commit 25524288631fc5b7d33259fca1e0dc38146be5d6 upstream.

Michal Kalderon has found some corner cases around device unload
with active NFS mounts that I didn't have the imagination to test
when xprtrdma device removal was added last year.

- The ULP device removal handler is responsible for deallocating
  the PD. That wasn't clear to me initially, and my own testing
  suggested it was not necessary, but that is incorrect.

- The transport destruction path can no longer assume that there
  is a valid ID.

- When destroying a transport, ensure that ib_free_cq() is not
  invoked on a CQ that was already released.

Reported-by: Michal Kalderon &lt;Michal.Kalderon@cavium.com&gt;
Fixes: bebd031866ca ("xprtrdma: Support unplugging an HCA from ...")
Signed-off-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 25524288631fc5b7d33259fca1e0dc38146be5d6 upstream.

Michal Kalderon has found some corner cases around device unload
with active NFS mounts that I didn't have the imagination to test
when xprtrdma device removal was added last year.

- The ULP device removal handler is responsible for deallocating
  the PD. That wasn't clear to me initially, and my own testing
  suggested it was not necessary, but that is incorrect.

- The transport destruction path can no longer assume that there
  is a valid ID.

- When destroying a transport, ensure that ib_free_cq() is not
  invoked on a CQ that was already released.

Reported-by: Michal Kalderon &lt;Michal.Kalderon@cavium.com&gt;
Fixes: bebd031866ca ("xprtrdma: Support unplugging an HCA from ...")
Signed-off-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xprtrdma: Fix latency regression on NUMA NFS/RDMA clients</title>
<updated>2018-04-24T07:43:00+00:00</updated>
<author>
<name>Chuck Lever</name>
<email>chuck.lever@oracle.com</email>
</author>
<published>2018-02-28T20:30:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=fef573a1e06a8312070749200a38f11ac31efc8b'/>
<id>fef573a1e06a8312070749200a38f11ac31efc8b</id>
<content type='text'>
commit 6720a89933739cb8dec748cd253f7c8df2c0ae4d upstream.

With v4.15, on one of my NFS/RDMA clients I measured a nearly
doubling in the latency of small read and write system calls. There
was no change in server round trip time. The extra latency appears
in the whole RPC execution path.

"git bisect" settled on commit ccede7598588 ("xprtrdma: Spread reply
processing over more CPUs") .

After some experimentation, I found that leaving the WQ bound and
allowing the scheduler to pick the dispatch CPU seems to eliminate
the long latencies, and it does not introduce any new regressions.

The fix is implemented by reverting only the part of
commit ccede7598588 ("xprtrdma: Spread reply processing over more
CPUs") that dispatches RPC replies specifically on the CPU where the
matching RPC call was made.

Interestingly, saving the CPU number and later queuing reply
processing there was effective _only_ for a NFS READ and WRITE
request. On my NUMA client, in-kernel RPC reply processing for
asynchronous RPCs was dispatched on the same CPU where the RPC call
was made, as expected. However synchronous RPCs seem to get their
reply dispatched on some other CPU than where the call was placed,
every time.

Fixes: ccede7598588 ("xprtrdma: Spread reply processing over ... ")
Signed-off-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 6720a89933739cb8dec748cd253f7c8df2c0ae4d upstream.

With v4.15, on one of my NFS/RDMA clients I measured a nearly
doubling in the latency of small read and write system calls. There
was no change in server round trip time. The extra latency appears
in the whole RPC execution path.

"git bisect" settled on commit ccede7598588 ("xprtrdma: Spread reply
processing over more CPUs") .

After some experimentation, I found that leaving the WQ bound and
allowing the scheduler to pick the dispatch CPU seems to eliminate
the long latencies, and it does not introduce any new regressions.

The fix is implemented by reverting only the part of
commit ccede7598588 ("xprtrdma: Spread reply processing over more
CPUs") that dispatches RPC replies specifically on the CPU where the
matching RPC call was made.

Interestingly, saving the CPU number and later queuing reply
processing there was effective _only_ for a NFS READ and WRITE
request. On my NUMA client, in-kernel RPC reply processing for
asynchronous RPCs was dispatched on the same CPU where the RPC call
was made, as expected. However synchronous RPCs seem to get their
reply dispatched on some other CPU than where the call was placed,
every time.

Fixes: ccede7598588 ("xprtrdma: Spread reply processing over ... ")
Signed-off-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Anna Schumaker &lt;Anna.Schumaker@Netapp.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>sunrpc: remove incorrect HMAC request initialization</title>
<updated>2018-04-19T06:54:08+00:00</updated>
<author>
<name>Eric Biggers</name>
<email>ebiggers@google.com</email>
</author>
<published>2018-03-28T17:57:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3d3a61aa49cc13387e8e84282ac740ed78b7a4b7'/>
<id>3d3a61aa49cc13387e8e84282ac740ed78b7a4b7</id>
<content type='text'>
commit f3aefb6a7066e24bfea7fcf1b07907576de69d63 upstream.

make_checksum_hmac_md5() is allocating an HMAC transform and doing
crypto API calls in the following order:

    crypto_ahash_init()
    crypto_ahash_setkey()
    crypto_ahash_digest()

This is wrong because it makes no sense to init() the request before a
key has been set, given that the initial state depends on the key.  And
digest() is short for init() + update() + final(), so in this case
there's no need to explicitly call init() at all.

Before commit 9fa68f620041 ("crypto: hash - prevent using keyed hashes
without setting key") the extra init() had no real effect, at least for
the software HMAC implementation.  (There are also hardware drivers that
implement HMAC-MD5, and it's not immediately obvious how gracefully they
handle init() before setkey().)  But now the crypto API detects this
incorrect initialization and returns -ENOKEY.  This is breaking NFS
mounts in some cases.

Fix it by removing the incorrect call to crypto_ahash_init().

Reported-by: Michael Young &lt;m.a.young@durham.ac.uk&gt;
Fixes: 9fa68f620041 ("crypto: hash - prevent using keyed hashes without setting key")
Fixes: fffdaef2eb4a ("gss_krb5: Add support for rc4-hmac encryption")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers &lt;ebiggers@google.com&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit f3aefb6a7066e24bfea7fcf1b07907576de69d63 upstream.

make_checksum_hmac_md5() is allocating an HMAC transform and doing
crypto API calls in the following order:

    crypto_ahash_init()
    crypto_ahash_setkey()
    crypto_ahash_digest()

This is wrong because it makes no sense to init() the request before a
key has been set, given that the initial state depends on the key.  And
digest() is short for init() + update() + final(), so in this case
there's no need to explicitly call init() at all.

Before commit 9fa68f620041 ("crypto: hash - prevent using keyed hashes
without setting key") the extra init() had no real effect, at least for
the software HMAC implementation.  (There are also hardware drivers that
implement HMAC-MD5, and it's not immediately obvious how gracefully they
handle init() before setkey().)  But now the crypto API detects this
incorrect initialization and returns -ENOKEY.  This is breaking NFS
mounts in some cases.

Fix it by removing the incorrect call to crypto_ahash_init().

Reported-by: Michael Young &lt;m.a.young@durham.ac.uk&gt;
Fixes: 9fa68f620041 ("crypto: hash - prevent using keyed hashes without setting key")
Fixes: fffdaef2eb4a ("gss_krb5: Add support for rc4-hmac encryption")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers &lt;ebiggers@google.com&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>vfs: do bulk POLL* -&gt; EPOLL* replacement</title>
<updated>2018-02-11T22:34:03+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-11T22:34:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a9a08845e9acbd224e4ee466f5c1275ed50054e8'/>
<id>a9a08845e9acbd224e4ee466f5c1275ed50054e8</id>
<content type='text'>
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\&lt;POLL$V\&gt;\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\&lt;POLL$V\&gt;\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'nfs-for-4.16-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs</title>
<updated>2018-02-09T22:55:30+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-09T22:55:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=82f0a41e1980318ea4cdae20cdce7b33cb9c8946'/>
<id>82f0a41e1980318ea4cdae20cdce7b33cb9c8946</id>
<content type='text'>
Pull more NFS client updates from Trond Myklebust:
 "A few bugfixes and some small sunrpc latency/performance improvements
  before the merge window closes:

  Stable fixes:

   - fix an incorrect calculation of the RDMA send scatter gather
     element limit

   - fix an Oops when attempting to free resources after RDMA device
     removal

  Bugfixes:

   - SUNRPC: Ensure we always release the TCP socket in a timely fashion
     when the connection is shut down.

   - SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context

  Latency/Performance:

   - SUNRPC: Queue latency sensitive socket tasks to the less contended
     xprtiod queue

   - SUNRPC: Make the xprtiod workqueue unbounded.

   - SUNRPC: Make the rpciod workqueue unbounded"

* tag 'nfs-for-4.16-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context
  fix parallelism for rpc tasks
  Make the xprtiod workqueue unbounded.
  SUNRPC: Queue latency-sensitive socket tasks to xprtiod
  SUNRPC: Ensure we always close the socket after a connection shuts down
  xprtrdma: Fix BUG after a device removal
  xprtrdma: Fix calculation of ri_max_send_sges
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull more NFS client updates from Trond Myklebust:
 "A few bugfixes and some small sunrpc latency/performance improvements
  before the merge window closes:

  Stable fixes:

   - fix an incorrect calculation of the RDMA send scatter gather
     element limit

   - fix an Oops when attempting to free resources after RDMA device
     removal

  Bugfixes:

   - SUNRPC: Ensure we always release the TCP socket in a timely fashion
     when the connection is shut down.

   - SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context

  Latency/Performance:

   - SUNRPC: Queue latency sensitive socket tasks to the less contended
     xprtiod queue

   - SUNRPC: Make the xprtiod workqueue unbounded.

   - SUNRPC: Make the rpciod workqueue unbounded"

* tag 'nfs-for-4.16-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context
  fix parallelism for rpc tasks
  Make the xprtiod workqueue unbounded.
  SUNRPC: Queue latency-sensitive socket tasks to xprtiod
  SUNRPC: Ensure we always close the socket after a connection shuts down
  xprtrdma: Fix BUG after a device removal
  xprtrdma: Fix calculation of ri_max_send_sges
</pre>
</div>
</content>
</entry>
<entry>
<title>SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context</title>
<updated>2018-02-09T14:39:42+00:00</updated>
<author>
<name>Trond Myklebust</name>
<email>trond.myklebust@primarydata.com</email>
</author>
<published>2018-02-09T14:39:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0afa6b4412988019db14c6bfb8c6cbdf120ca9ad'/>
<id>0afa6b4412988019db14c6bfb8c6cbdf120ca9ad</id>
<content type='text'>
Calling __UDPX_INC_STATS() from a preemptible context leads to a
warning of the form:

 BUG: using __this_cpu_add() in preemptible [00000000] code: kworker/u5:0/31
 caller is xs_udp_data_receive_workfn+0x194/0x270
 CPU: 1 PID: 31 Comm: kworker/u5:0 Not tainted 4.15.0-rc8-00076-g90ea9f1 #2
 Workqueue: xprtiod xs_udp_data_receive_workfn
 Call Trace:
  dump_stack+0x85/0xc1
  check_preemption_disabled+0xce/0xe0
  xs_udp_data_receive_workfn+0x194/0x270
  process_one_work+0x318/0x620
  worker_thread+0x20a/0x390
  ? process_one_work+0x620/0x620
  kthread+0x120/0x130
  ? __kthread_bind_mask+0x60/0x60
  ret_from_fork+0x24/0x30

Since we're taking a spinlock in those functions anyway, let's fix the
issue by moving the call so that it occurs under the spinlock.

Reported-by: kernel test robot &lt;fengguang.wu@intel.com&gt;
Signed-off-by: Trond Myklebust &lt;trond.myklebust@primarydata.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Calling __UDPX_INC_STATS() from a preemptible context leads to a
warning of the form:

 BUG: using __this_cpu_add() in preemptible [00000000] code: kworker/u5:0/31
 caller is xs_udp_data_receive_workfn+0x194/0x270
 CPU: 1 PID: 31 Comm: kworker/u5:0 Not tainted 4.15.0-rc8-00076-g90ea9f1 #2
 Workqueue: xprtiod xs_udp_data_receive_workfn
 Call Trace:
  dump_stack+0x85/0xc1
  check_preemption_disabled+0xce/0xe0
  xs_udp_data_receive_workfn+0x194/0x270
  process_one_work+0x318/0x620
  worker_thread+0x20a/0x390
  ? process_one_work+0x620/0x620
  kthread+0x120/0x130
  ? __kthread_bind_mask+0x60/0x60
  ret_from_fork+0x24/0x30

Since we're taking a spinlock in those functions anyway, let's fix the
issue by moving the call so that it occurs under the spinlock.

Reported-by: kernel test robot &lt;fengguang.wu@intel.com&gt;
Signed-off-by: Trond Myklebust &lt;trond.myklebust@primarydata.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'nfsd-4.16' of git://linux-nfs.org/~bfields/linux</title>
<updated>2018-02-08T23:18:32+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-08T23:18:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f1517df8701c9f12dae9ce7f43a5d300a6917619'/>
<id>f1517df8701c9f12dae9ce7f43a5d300a6917619</id>
<content type='text'>
Pull nfsd update from Bruce Fields:
 "A fairly small update this time around. Some cleanup, RDMA fixes,
  overlayfs fixes, and a fix for an NFSv4 state bug.

  The bigger deal for nfsd this time around was Jeff Layton's
  already-merged i_version patches"

* tag 'nfsd-4.16' of git://linux-nfs.org/~bfields/linux:
  svcrdma: Fix Read chunk round-up
  NFSD: hide unused svcxdr_dupstr()
  nfsd: store stat times in fill_pre_wcc() instead of inode times
  nfsd: encode stat-&gt;mtime for getattr instead of inode-&gt;i_mtime
  nfsd: return RESOURCE not GARBAGE_ARGS on too many ops
  nfsd4: don't set lock stateid's sc_type to CLOSED
  nfsd: Detect unhashed stids in nfsd4_verify_open_stid()
  sunrpc: remove dead code in svc_sock_setbufsize
  svcrdma: Post Receives in the Receive completion handler
  nfsd4: permit layoutget of executable-only files
  lockd: convert nlm_rqst.a_count from atomic_t to refcount_t
  lockd: convert nlm_lockowner.count from atomic_t to refcount_t
  lockd: convert nsm_handle.sm_count from atomic_t to refcount_t
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull nfsd update from Bruce Fields:
 "A fairly small update this time around. Some cleanup, RDMA fixes,
  overlayfs fixes, and a fix for an NFSv4 state bug.

  The bigger deal for nfsd this time around was Jeff Layton's
  already-merged i_version patches"

* tag 'nfsd-4.16' of git://linux-nfs.org/~bfields/linux:
  svcrdma: Fix Read chunk round-up
  NFSD: hide unused svcxdr_dupstr()
  nfsd: store stat times in fill_pre_wcc() instead of inode times
  nfsd: encode stat-&gt;mtime for getattr instead of inode-&gt;i_mtime
  nfsd: return RESOURCE not GARBAGE_ARGS on too many ops
  nfsd4: don't set lock stateid's sc_type to CLOSED
  nfsd: Detect unhashed stids in nfsd4_verify_open_stid()
  sunrpc: remove dead code in svc_sock_setbufsize
  svcrdma: Post Receives in the Receive completion handler
  nfsd4: permit layoutget of executable-only files
  lockd: convert nlm_rqst.a_count from atomic_t to refcount_t
  lockd: convert nlm_lockowner.count from atomic_t to refcount_t
  lockd: convert nsm_handle.sm_count from atomic_t to refcount_t
</pre>
</div>
</content>
</entry>
<entry>
<title>fix parallelism for rpc tasks</title>
<updated>2018-02-08T21:24:35+00:00</updated>
<author>
<name>Olga Kornievskaia</name>
<email>aglo@umich.edu</email>
</author>
<published>2017-06-29T13:25:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f515f86b34b2e7d4b24cc9b7375c9e749895088e'/>
<id>f515f86b34b2e7d4b24cc9b7375c9e749895088e</id>
<content type='text'>
Hi folks,

On a multi-core machine, is it expected that we can have parallel RPCs
handled by each of the per-core workqueue?

In testing a read workload, observing via "top" command that a single
"kworker" thread is running servicing the requests (no parallelism).
It's more prominent while doing these operations over krb5p mount.

What has been suggested by Bruce is to try this and in my testing I
see then the read workload spread among all the kworker threads.

Signed-off-by: Olga Kornievskaia &lt;kolga@netapp.com&gt;
Signed-off-by: Trond Myklebust &lt;trond.myklebust@primarydata.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Hi folks,

On a multi-core machine, is it expected that we can have parallel RPCs
handled by each of the per-core workqueue?

In testing a read workload, observing via "top" command that a single
"kworker" thread is running servicing the requests (no parallelism).
It's more prominent while doing these operations over krb5p mount.

What has been suggested by Bruce is to try this and in my testing I
see then the read workload spread among all the kworker threads.

Signed-off-by: Olga Kornievskaia &lt;kolga@netapp.com&gt;
Signed-off-by: Trond Myklebust &lt;trond.myklebust@primarydata.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>svcrdma: Fix Read chunk round-up</title>
<updated>2018-02-08T18:40:17+00:00</updated>
<author>
<name>Chuck Lever</name>
<email>chuck.lever@oracle.com</email>
</author>
<published>2018-02-02T19:28:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=175e03101d36c3034f3c80038d4c28838351a7f2'/>
<id>175e03101d36c3034f3c80038d4c28838351a7f2</id>
<content type='text'>
A single NFSv4 WRITE compound can often have three operations:
PUTFH, WRITE, then GETATTR.

When the WRITE payload is sent in a Read chunk, the client places
the GETATTR in the inline part of the RPC/RDMA message, just after
the WRITE operation (sans payload). The position value in the Read
chunk enables the receiver to insert the Read chunk at the correct
place in the received XDR stream; that is between the WRITE and
GETATTR.

According to RFC 8166, an NFS/RDMA client does not have to add XDR
round-up to the Read chunk that carries the WRITE payload. The
receiver adds XDR round-up padding if it is absent and the
receiver's XDR decoder requires it to be present.

Commit 193bcb7b3719 ("svcrdma: Populate tail iovec when receiving")
attempted to add support for receiving such a compound so that just
the WRITE payload appears in rq_arg's page list, and the trailing
GETATTR is placed in rq_arg's tail iovec. (TCP just strings the
whole compound into the head iovec and page list, without regard
to the alignment of the WRITE payload).

The server transport logic also had to accommodate the optional XDR
round-up of the Read chunk, which it did simply by lengthening the
tail iovec when round-up was needed. This approach is adequate for
the NFSv2 and NFSv3 WRITE decoders.

Unfortunately it is not sufficient for nfsd4_decode_write. When the
Read chunk length is a couple of bytes less than PAGE_SIZE, the
computation at the end of nfsd4_decode_write allows argp-&gt;pagelen to
go negative, which breaks the logic in read_buf that looks for the
tail iovec.

The result is that a WRITE operation whose payload length is just
less than a multiple of a page succeeds, but the subsequent GETATTR
in the same compound fails with NFS4ERR_OP_ILLEGAL because the XDR
decoder can't find it. Clients ignore the error, but they must
update their attribute cache via a separate round trip.

As nfsd4_decode_write appears to expect the payload itself to always
have appropriate XDR round-up, have svc_rdma_build_normal_read_chunk
add the Read chunk XDR round-up to the page_len rather than
lengthening the tail iovec.

Reported-by: Olga Kornievskaia &lt;kolga@netapp.com&gt;
Fixes: 193bcb7b3719 ("svcrdma: Populate tail iovec when receiving")
Signed-off-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Tested-by: Olga Kornievskaia &lt;kolga@netapp.com&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
A single NFSv4 WRITE compound can often have three operations:
PUTFH, WRITE, then GETATTR.

When the WRITE payload is sent in a Read chunk, the client places
the GETATTR in the inline part of the RPC/RDMA message, just after
the WRITE operation (sans payload). The position value in the Read
chunk enables the receiver to insert the Read chunk at the correct
place in the received XDR stream; that is between the WRITE and
GETATTR.

According to RFC 8166, an NFS/RDMA client does not have to add XDR
round-up to the Read chunk that carries the WRITE payload. The
receiver adds XDR round-up padding if it is absent and the
receiver's XDR decoder requires it to be present.

Commit 193bcb7b3719 ("svcrdma: Populate tail iovec when receiving")
attempted to add support for receiving such a compound so that just
the WRITE payload appears in rq_arg's page list, and the trailing
GETATTR is placed in rq_arg's tail iovec. (TCP just strings the
whole compound into the head iovec and page list, without regard
to the alignment of the WRITE payload).

The server transport logic also had to accommodate the optional XDR
round-up of the Read chunk, which it did simply by lengthening the
tail iovec when round-up was needed. This approach is adequate for
the NFSv2 and NFSv3 WRITE decoders.

Unfortunately it is not sufficient for nfsd4_decode_write. When the
Read chunk length is a couple of bytes less than PAGE_SIZE, the
computation at the end of nfsd4_decode_write allows argp-&gt;pagelen to
go negative, which breaks the logic in read_buf that looks for the
tail iovec.

The result is that a WRITE operation whose payload length is just
less than a multiple of a page succeeds, but the subsequent GETATTR
in the same compound fails with NFS4ERR_OP_ILLEGAL because the XDR
decoder can't find it. Clients ignore the error, but they must
update their attribute cache via a separate round trip.

As nfsd4_decode_write appears to expect the payload itself to always
have appropriate XDR round-up, have svc_rdma_build_normal_read_chunk
add the Read chunk XDR round-up to the page_len rather than
lengthening the tail iovec.

Reported-by: Olga Kornievskaia &lt;kolga@netapp.com&gt;
Fixes: 193bcb7b3719 ("svcrdma: Populate tail iovec when receiving")
Signed-off-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Tested-by: Olga Kornievskaia &lt;kolga@netapp.com&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
