The variable status is being initialized with a value that is never
read and it is being updated later with a new value.  The initialization
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

I noticed that for callback requests, the reported backlog latency
is always zero, and the rtt value is crazy big. The problem was that
rqst->rq_xtime is never set for backchannel requests.

Fixes: 78215759 ("SUNRPC: Make RTT measurement more ... ")
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

NFSv2, v3 and NFSv4 servers often have duplicate replay caches that look
at the source port when deciding whether or not an RPC call is a replay
of a previous call. This requires clients to perform strange TCP gymnastics
in order to ensure that when they reconnect to the server, they bind
to the same source port.

NFSv4.1 and NFSv4.2 have sessions that provide proper replay semantics,
that do not look at the source port of the connection. This patch therefore
ensures they can ignore the rebind requirement.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Since commit 4f8943f8 ("SUNRPC: Replace direct task wakeups from
softirq context") there has been a race to the value of the sk_err if both
XPRT_SOCK_WAKE_ERROR and XPRT_SOCK_WAKE_DISCONNECT are set.  In that case,
we may end up losing the sk_err value that existed when xs_error_report was
called.

Fix this by reverting to the previous behavior: instead of using SO_ERROR
to retrieve the value at a later time (which might also return sk_err_soft),
copy the sk_err value onto struct sock_xprt, and use that value to wake
pending tasks.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Fixes: 4f8943f8 ("SUNRPC: Replace direct task wakeups from softirq context")
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

If we've removed the request from the receive list, and have added
it back after resetting the request receive buffer, then we should
only receive message data if it is a new reply (i.e. if
transport->recv.copied is zero).

Fixes: 277e4ab7 ("SUNRPC: Simplify TCP receive code by switching...")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

The bvec tracks the list of pages, so if the number of pages changes
due to a re-encode, we need to reset the bvec as well.

Fixes: 277e4ab7 ("SUNRPC: Simplify TCP receive code by switching...")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20+

Add a per-transport maximum limit in the socket case, and add
helpers to allow the NFSv4 code to discover that limit.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Adapt and apply changes that were made to the TCP socket connect
code. See the following commits for details on the purpose of
these changes:

Commit 7196dbb0 ("SUNRPC: Allow changing of the TCP timeout parameters on the fly")
Commit 3851f1cd ("SUNRPC: Limit the reconnect backoff timer to the max RPC message timeout")
Commit 02910177 ("SUNRPC: Fix reconnection timeouts")

Some common transport code is moved to xprt.c to satisfy the code
duplication police.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Replace the direct task wakeups from inside a softirq context with
wakeups from a process context.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

In the case where a record marker was used, xs_sendpages() needs
to return the length of the payload + record marker so that we
operate correctly in the case of a partial transmission.
When the callers check return value, they therefore need to
take into account the record marker length.

Fixes: 06b5fc3a ("Merge tag 'nfs-rdma-for-5.1-1'...")
Cc: stable@vger.kernel.org # 5.1+
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Add variables to track RPC level errors so that we can distinguish
between issue that arose in the RPC transport layer as opposed to
those arising from the reply message.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Convert the transport callback to actually put the request to sleep
instead of just setting a timeout. This is in preparation for
rpc_sleep_on_timeout().
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Avoid following compiler warning on uninitialized variable

net/sunrpc/xprtsock.c: In function ‘xs_read_stream_request.constprop’:
net/sunrpc/xprtsock.c:525:10: warning: ‘read’ may be used uninitialized in this function [-Wmaybe-uninitialized]
   return read;
          ^~~~
net/sunrpc/xprtsock.c:529:23: warning: ‘ret’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  return ret < 0 ? ret : read;
         ~~~~~~~~~~~~~~^~~~~~
Signed-off-by: NAlakesh Haloi <alakesh.haloi@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the server sends a reply that is larger than the pre-allocated
buffer, then the current code may fail to register how much of
the stream that it has finished reading. This again can lead to
hangs.

Fixes: e92053a5 ("SUNRPC: Handle zero length fragments correctly")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Convert the remaining gfp_flags arguments in sunrpc to standard reclaiming
allocations, now that we set memalloc_nofs_save() as appropriate.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

udp_poll() checks the struct file for the O_NONBLOCK flag, so we must not
call it with a NULL file pointer.

Fixes: 0ffe86f4 ("SUNRPC: Use poll() to fix up the socket requeue races")
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Now that we send the pages using a struct msghdr, instead of
using sendpage(), we no longer need to 'prime the socket' with
an address for unconnected UDP messages.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Simplify the page send code using iov_iter and bvecs.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Prepare to the socket transmission code to use iov_iter.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the client stream receive code receives an ESHUTDOWN error either
because the server closed the connection, or because it sent a
callback which cannot be processed, then we should shut down
the connection.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the message read completes, but the socket returned an error
condition, we should ensure to propagate that error.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

A zero length fragment is really a bug, but let's ensure we don't
go nuts when one turns up.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

To ensure that the receive worker has exclusive access to the stream record
info, we must not reset the contents other than when holding the
transport->recv_mutex.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

When we resend a request, ensure that the 'rq_bytes_sent' is reset
to zero.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Because we clear XPRT_SOCK_DATA_READY before reading, we can end up
with a situation where new data arrives, causing xs_data_ready() to
queue up a second receive worker job for the same socket, which then
immediately gets stuck waiting on the transport receive mutex.
The fix is to only clear XPRT_SOCK_DATA_READY once we're done reading,
and then to use poll() to check if we might need to queue up a new
job in order to deal with any new data.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Set memalloc_nofs_save() on all the rpciod/xprtiod jobs so that we
ensure memory allocations for asynchronous rpc calls don't ever end
up recursing back to the NFS layer for memory reclaim.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

tsh_size was added to accommodate transports that send a pre-amble
before each RPC message. However, this assumes the pre-amble is
fixed in size, which isn't true for some transports. That makes
tsh_size not very generic.

Also I'd like to make the estimation of RPC send and receive
buffer sizes more precise. tsh_size doesn't currently appear to be
accounted for at all by call_allocate.

Therefore let's just remove the tsh_size concept, and make the only
transports that have a non-zero tsh_size employ a direct approach.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

After receiving data into the page cache, we need to call flush_dcache_page()
for the architectures that define it.

Fixes: 277e4ab7 ("SUNRPC: Simplify TCP receive code by switching...")
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20
Tested-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Clean up some warnings observed when building with "make W=1".
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

If we want /proc/sys/sunrpc the current kernel also drags in other debug
features which we don't really want. Instead, we should always show the
following entries:

/proc/sys/sunrpc/udp_slot_table_entries
/proc/sys/sunrpc/tcp_slot_table_entries
/proc/sys/sunrpc/tcp_max_slot_table_entries
/proc/sys/sunrpc/min_resvport
/proc/sys/sunrpc/max_resvport
/proc/sys/sunrpc/tcp_fin_timeout
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: NThomas Preston <thomas.preston@codethink.co.uk>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

Ensure that we clear XPRT_CONNECTING before releasing the XPRT_LOCK so that
we don't have races between the (asynchronous) socket setup code and
tasks in xprt_connect().
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: NChuck Lever <chuck.lever@oracle.com>

When the socket is closed, we need to call xprt_disconnect_done() in order
to clean up the XPRT_WRITE_SPACE flag, and wake up the sleeping tasks.

However, we also want to ensure that we don't wake them up before the socket
is closed, since that would cause thundering herd issues with everyone
piling up to retransmit before the TCP shutdown dance has completed.
Only the task that holds XPRT_LOCKED needs to wake up early in order to
allow the close to complete.
Reported-by: NDave Wysochanski <dwysocha@redhat.com>
Reported-by: NScott Mayhew <smayhew@redhat.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: NChuck Lever <chuck.lever@oracle.com>

If the connection is broken, then xs_tcp_state_change() will take care
of scheduling the socket close as soon as appropriate. xs_read_stream()
just needs to report the error.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Ensure that we do not exit the socket read callback without clearing
XPRT_SOCK_DATA_READY.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

When discarding message data from the stream, we're better off using
the discard iterator, since that will work with non-TCP streams.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>

If the allocator fails before it has reached the target number of pages,
then we need to recheck that we're not seeking past the page buffer.
Signed-off-by: NTrond Myklebust <trond.myklebust@hammerspace.com>