Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- use proper markups for titles;
- use :Author: for authorship;
- identify the literal blocks.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

This file is almost on the standard format. All it needs
to be parsed by Sphinx is to fix its main title and add
a few blank lines.

Yet, it is worth to replace NOTE: by the corresponding
ReST markup.

While here, remove the extra "---" from a subtitle.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Mark titles;
- Mark literal blocks;
- Mark some literals that would otherwise produce warnings;
- Mark authorship.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Fix some title marks to match ReST;
- use :Author: for author name;
- foo_ is an hyperlink. Get rid of it;
- Mark literal blocks as such;
- Use tables on some places that are almost using the
  table format.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- comment the internal index;
- use the proper markups for titles;
- mark literal blocks.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Mark titles;
- Mark literal blocks;
- Mark table.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Add a title for the document;
- Mark literal blocks.

While here, replace a comma by a dot at the end of a paragraph.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Add a title for the document;
- mark literals;
- use table markup for existing table.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- mark literals;
- Adjust document title;
- Use a list for references.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Use section/title markups;
- Use :Author: for authorship;
- Mark literals and literal blocks;
- Mark tables;
- Use ReST notation for footnotes.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Mark titles with ReST notation;
- comment the contents table;
- Use :Author: tag for authorship;
- mark literal blocks as such;
- use valid numbered list markups;
- Don't capitalize titles.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Adjust the title format;
- use :Author: for author's name;
- mark literals as such;
- use note and important notation.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Move author info to the beginning of file and use :Author:
- use warning/note annotation;
- mark literal blocks as such;
- Add a title for the document;
- use **emphasis** instead of _emphasis_.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Use the right notation for titles;
- Use a list for image names;
- Use literal blocks where needed;
- Whitespace fixes.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Adjust titles to match the convention;
- use a literal block for ascii artwork.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Add a title for the document;
- Use a list for the listed URLs;
- mark literal blocks;
- adjust whitespaces;
- Don't capitalize section titles.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Pull NFS client updates from Anna Schumaker:
 "Stable bugfixes:
   - Fix -EACCESS on commit to DS handling
   - Fix initialization of nfs_page_array->npages
   - Only invalidate dentries that are actually invalid

  Features:
   - Enable NFSoRDMA transparent state migration
   - Add support for lookup-by-filehandle
   - Add support for nfs re-exporting

  Other bugfixes and cleanups:
   - Christoph cleaned up the way we declare NFS operations
   - Clean up various internal structures
   - Various cleanups to commits
   - Various improvements to error handling
   - Set the dt_type of . and .. entries in NFS v4
   - Make slot allocation more reliable
   - Fix fscache stat printing
   - Fix uninitialized variable warnings
   - Fix potential list overrun in nfs_atomic_open()
   - Fix a race in NFSoRDMA RPC reply handler
   - Fix return size for nfs42_proc_copy()
   - Fix against MAC forgery timing attacks"

* tag 'nfs-for-4.13-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (68 commits)
  NFS: Don't run wake_up_bit() when nobody is waiting...
  nfs: add export operations
  nfs4: add NFSv4 LOOKUPP handlers
  nfs: add a nfs_ilookup helper
  nfs: replace d_add with d_splice_alias in atomic_open
  sunrpc: use constant time memory comparison for mac
  NFSv4.2 fix size storage for nfs42_proc_copy
  xprtrdma: Fix documenting comments in frwr_ops.c
  xprtrdma: Replace PAGE_MASK with offset_in_page()
  xprtrdma: FMR does not need list_del_init()
  xprtrdma: Demote "connect" log messages
  NFSv4.1: Use seqid returned by EXCHANGE_ID after state migration
  NFSv4.1: Handle EXCHGID4_FLAG_CONFIRMED_R during NFSv4.1 migration
  xprtrdma: Don't defer MR recovery if ro_map fails
  xprtrdma: Fix FRWR invalidation error recovery
  xprtrdma: Fix client lock-up after application signal fires
  xprtrdma: Rename rpcrdma_req::rl_free
  xprtrdma: Pass only the list of registered MRs to ro_unmap_sync
  xprtrdma: Pre-mark remotely invalidated MRs
  xprtrdma: On invalidation failure, remove MWs from rl_registered
  ...

Pull SCSI target updates from Nicholas Bellinger:
 "It's been usually busy for summer, with most of the efforts centered
  around TCMU developments and various target-core + fabric driver bug
  fixing activities. Not particularly large in terms of LoC, but lots of
  smaller patches from many different folks.

  The highlights include:

   - ibmvscsis logical partition manager support (Michael Cyr + Bryant
     Ly)

   - Convert target/iblock WRITE_SAME to blkdev_issue_zeroout (hch +
     nab)

   - Add support for TMR percpu LUN reference counting (nab)

   - Fix a potential deadlock between EXTENDED_COPY and iscsi shutdown
     (Bart)

   - Fix COMPARE_AND_WRITE caw_sem leak during se_cmd quiesce (Jiang Yi)

   - Fix TMCU module removal (Xiubo Li)

   - Fix iser-target OOPs during login failure (Andrea Righi + Sagi)

   - Breakup target-core free_device backend driver callback (mnc)

   - Perform TCMU add/delete/reconfig synchronously (mnc)

   - Fix TCMU multiple UIO open/close sequences (mnc)

   - Fix TCMU CHECK_CONDITION sense handling (mnc)

   - Fix target-core SAM_STAT_BUSY + TASK_SET_FULL handling (mnc + nab)

   - Introduce TYPE_ZBC support in PSCSI (Damien Le Moal)

   - Fix possible TCMU memory leak + OOPs when recalculating cmd base
     size (Xiubo Li + Bryant Ly + Damien Le Moal + mnc)

   - Add login_keys_workaround attribute for non RFC initiators (Robert
     LeBlanc + Arun Easi + nab)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (68 commits)
  iscsi-target: Add login_keys_workaround attribute for non RFC initiators
  Revert "qla2xxx: Fix incorrect tcm_qla2xxx_free_cmd use during TMR ABORT"
  tcmu: clean up the code and with one small fix
  tcmu: Fix possbile memory leak / OOPs when recalculating cmd base size
  target: export lio pgr/alua support as device attr
  target: Fix return sense reason in target_scsi3_emulate_pr_out
  target: Fix cmd size for PR-OUT in passthrough_parse_cdb
  tcmu: Fix dev_config_store
  target: pscsi: Introduce TYPE_ZBC support
  target: Use macro for WRITE_VERIFY_32 operation codes
  target: fix SAM_STAT_BUSY/TASK_SET_FULL handling
  target: remove transport_complete
  pscsi: finish cmd processing from pscsi_req_done
  tcmu: fix sense handling during completion
  target: add helper to copy sense to se_cmd buffer
  target: do not require a transport_complete for SCF_TRANSPORT_TASK_SENSE
  target: make device_mutex and device_list static
  tcmu: Fix flushing cmd entry dcache page
  tcmu: fix multiple uio open/close sequences
  tcmu: drop configured check in destroy
  ...

"perf lock" shows fairly heavy contention for the bit waitqueue locks
when doing an I/O heavy workload.
Use a bit to tell whether or not there has been contention for a lock
so that we can optimise away the bit waitqueue options in those cases.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This support for opening files on NFS by file handle, both through the
open_by_handle syscall, and for re-exporting NFS (for example using a
different version).  The support is very basic for now, as each open by
handle will have to do an NFSv4 open operation on the wire.  In the
future this will hopefully be mitigated by an open file cache, as well
as various optimizations in NFS for this specific case.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
[hch: incorporated various changes, resplit the patches, new changelog]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Pull nfsd updates from Bruce Fields:
 "Chuck's RDMA update overhauls the "call receive" side of the
  RPC-over-RDMA transport to use the new rdma_rw API.

  Christoph cleaned the way nfs operations are declared, removing a
  bunch of function-pointer casts and declaring the operation vectors as
  const.

  Christoph's changes touch both client and server, and both client and
  server pulls this time around should be based on the same commits from
  Christoph"

* tag 'nfsd-4.13' of git://linux-nfs.org/~bfields/linux: (53 commits)
  svcrdma: fix an incorrect check on -E2BIG and -EINVAL
  nfsd4: factor ctime into change attribute
  svcrdma: Remove svc_rdma_chunk_ctxt::cc_dir field
  svcrdma: use offset_in_page() macro
  svcrdma: Clean up after converting svc_rdma_recvfrom to rdma_rw API
  svcrdma: Clean-up svc_rdma_unmap_dma
  svcrdma: Remove frmr cache
  svcrdma: Remove unused Read completion handlers
  svcrdma: Properly compute .len and .buflen for received RPC Calls
  svcrdma: Use generic RDMA R/W API in RPC Call path
  svcrdma: Add recvfrom helpers to svc_rdma_rw.c
  sunrpc: Allocate up to RPCSVC_MAXPAGES per svc_rqst
  svcrdma: Don't account for Receive queue "starvation"
  svcrdma: Improve Reply chunk sanity checking
  svcrdma: Improve Write chunk sanity checking
  svcrdma: Improve Read chunk sanity checking
  svcrdma: Remove svc_rdma_marshal.c
  svcrdma: Avoid Send Queue overflow
  svcrdma: Squelch disconnection messages
  sunrpc: Disable splice for krb5i
  ...

Pull ext2, udf, reiserfs fixes from Jan Kara:
 "Several ext2, udf, and reiserfs fixes"

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: Fix memory leak when truncate races ext2_get_blocks
  reiserfs: fix race in prealloc discard
  reiserfs: don't preallocate blocks for extended attributes
  udf: Convert udf_disk_stamp_to_time() to use mktime64()
  udf: Use time64_to_tm for timestamp conversion
  udf: Fix deadlock between writeback and udf_setsize()
  udf: Use i_size_read() in udf_adinicb_writepage()
  udf: Fix races with i_size changes during readpage
  udf: Remove unused UDF_DEFAULT_BLOCKSIZE

Pull documentation fixes from Jonathan Corbet:
 "A set of fixes for various warnings, including the one caused by the
  removal of kernel/rcu/srcu.c. Also correct a stray pointer in
  memory-barriers.txt"

* tag '4.13-fixes' of git://git.lwn.net/linux:
  kokr/memory-barriers.txt: Fix obsolete link to atomic_ops.txt
  memory-barriers.txt: Fix broken link to atomic_ops.txt
  docs: Turn off section numbering for the input docs
  docs: Include uaccess docs from the right file
  docs: Do not include from kernel/rcu/srcu.c

Pull more Kbuild updates from Masahiro Yamada:

 - Move generic-y of exported headers to uapi/asm/Kbuild for complete
   de-coupling of UAPI

 - Clean up scripts/Makefile.headersinst

 - Fix host programs for 32 bit machine with XFS file system

* tag 'kbuild-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (29 commits)
  kbuild: Enable Large File Support for hostprogs
  kbuild: remove wrapper files handling from Makefile.headersinst
  kbuild: split exported generic header creation into uapi-asm-generic
  kbuild: do not include old-kbuild-file from Makefile.headersinst
  xtensa: move generic-y of exported headers to uapi/asm/Kbuild
  unicore32: move generic-y of exported headers to uapi/asm/Kbuild
  tile: move generic-y of exported headers to uapi/asm/Kbuild
  sparc: move generic-y of exported headers to uapi/asm/Kbuild
  sh: move generic-y of exported headers to uapi/asm/Kbuild
  parisc: move generic-y of exported headers to uapi/asm/Kbuild
  openrisc: move generic-y of exported headers to uapi/asm/Kbuild
  nios2: move generic-y of exported headers to uapi/asm/Kbuild
  nios2: remove unneeded arch/nios2/include/(generated/)asm/signal.h
  microblaze: move generic-y of exported headers to uapi/asm/Kbuild
  metag: move generic-y of exported headers to uapi/asm/Kbuild
  m68k: move generic-y of exported headers to uapi/asm/Kbuild
  m32r: move generic-y of exported headers to uapi/asm/Kbuild
  ia64: remove redundant generic-y += kvm_para.h from asm/Kbuild
  hexagon: move generic-y of exported headers to uapi/asm/Kbuild
  h8300: move generic-y of exported headers to uapi/asm/Kbuild
  ...

Pull more tracing updates from Steven Rostedt:
 "A few more minor updates:

   - Show the tgid mappings for user space trace tools to use

   - Fix and optimize the comm and tgid cache recording

   - Sanitize derived kprobe names

   - Ftrace selftest updates

   - trace file header fix

   - Update of Documentation/trace/ftrace.txt

   - Compiler warning fixes

   - Fix possible uninitialized variable"

* tag 'trace-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix uninitialized variable in match_records()
  ftrace: Remove an unneeded NULL check
  ftrace: Hide cached module code for !CONFIG_MODULES
  tracing: Do note expose stack_trace_filter without DYNAMIC_FTRACE
  tracing: Update Documentation/trace/ftrace.txt
  tracing: Fixup trace file header alignment
  selftests/ftrace: Add a testcase for kprobe event naming
  selftests/ftrace: Add a test to probe module functions
  selftests/ftrace: Update multiple kprobes test for powerpc
  trace/kprobes: Sanitize derived event names
  tracing: Attempt to record other information even if some fail
  tracing: Treat recording tgid for idle task as a success
  tracing: Treat recording comm for idle task as a success
  tracing: Add saved_tgids file to show cached pid to tgid mappings

This will be needed in order to implement the get_parent export op
for nfsd.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This helper will allow to find an existing NFS inode by the file handle
and fattr.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

It's a trival change but follows knfsd export document that asks
for d_splice_alias during lookup.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Otherwise, we enable a MAC forgery via timing attack.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: linux-nfs@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Return size of COPY is u64 but it was assigned to an "int" status.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.

FASTREG and LOCAL_INV WRs are typically not signaled. localinv_wake
is used for the last LOCAL_INV WR in a chain, which is always
signaled. The documenting comments should reflect that.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.

Reported by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.

Commit 38f1932e ("xprtrdma: Remove FMRs from the unmap list
after unmapping") utilized list_del_init() to try to prevent some
list corruption. The corruption was actually caused by the reply
handler racing with a signal. Now that MR invalidation is properly
serialized, list_del_init() can safely be replaced.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Some have complained about the log messages generated when xprtrdma
opens or closes a connection to a server. When an NFS mount is
mostly idle these can appear every few minutes as the client idles
out the connection and reconnects.

Connection and disconnection is a normal part of operation, and not
exceptional, so change these to dprintk's for now. At some point
all of these will be converted to tracepoints, but that's for
another day.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Transparent State Migration copies a client's lease state from the
server where a filesystem used to reside to the server where it now
resides. When an NFSv4.1 client first contacts that destination
server, it uses EXCHANGE_ID to detect trunking relationships.

The lease that was copied there is returned to that client, but the
destination server sets EXCHGID4_FLAG_CONFIRMED_R when replying to
the client. This is because the lease was confirmed on the source
server (before it was copied).

When CONFIRMED_R is set, the client throws away the sequence ID
returned by the server. During a Transparent State Migration, however
there's no other way for the client to know what sequence ID to use
with a lease that's been migrated.

Therefore, the client must save and use the contrived slot sequence
value returned by the destination server even when CONFIRMED_R is
set.

Note that some servers always return a seqid of 1 after a migration.
Reported-by: Xuan Qi <xuan.qi@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Xuan Qi <xuan.qi@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Transparent State Migration copies a client's lease state from the
server where a filesystem used to reside to the server where it now
resides. When an NFSv4.1 client first contacts that destination
server, it uses EXCHANGE_ID to detect trunking relationships.

The lease that was copied there is returned to that client, but the
destination server sets EXCHGID4_FLAG_CONFIRMED_R when replying to
the client. This is because the lease was confirmed on the source
server (before it was copied).

Normally, when CONFIRMED_R is set, a client purges the lease and
creates a new one. However, that throws away the entire benefit of
Transparent State Migration.

Therefore, the client must not purge that lease when it is possible
that Transparent State Migration has occurred.
Reported-by: Xuan Qi <xuan.qi@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Xuan Qi <xuan.qi@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Deferred MR recovery does a DMA-unmapping of the MW. However, ro_map
invokes rpcrdma_defer_mr_recovery in some error cases where the MW
has not even been DMA-mapped yet.

Avoid a DMA-unmapping error replacing rpcrdma_defer_mr_recovery.

Also note that if ib_dma_map_sg is asked to map 0 nents, it will
return 0. So the extra "if (i == 0)" check is no longer needed.

Fixes: 42fe28f6 ("xprtrdma: Do not leak an MW during a DMA ...")
Fixes: 505bbe64 ("xprtrdma: Refactor MR recovery work queues")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

When ib_post_send() fails, all LOCAL_INV WRs past @bad_wr have to be
examined, and the MRs reset by hand.

I'm not sure how the existing code can work by comparing R_keys.
Restructure the logic so that instead it walks the chain of WRs,
starting from the first bad one.

Make sure to wait for completion if at least one WR was actually
posted. Otherwise, if the ib_post_send fails, we can end up
DMA-unmapping the MR while LOCAL_INV operations are in flight.

Commit 7a89f9c6 ("xprtrdma: Honor ->send_request API contract")
added the rdma_disconnect() call site. The disconnect actually
causes more problems than it solves, and SQ overruns happen only as
a result of software bugs. So remove it.

Fixes: d7a21c1b ("xprtrdma: Reset MRs in frwr_op_unmap_sync()")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

After a signal, the RPC client aborts synchronous RPCs running on
behalf of the signaled application.

The server is still executing those RPCs, and will write the results
back into the client's memory when it's done. By the time the server
writes the results, that memory is likely being used for other
purposes. Therefore xprtrdma has to immediately invalidate all
memory regions used by those aborted RPCs to prevent the server's
writes from clobbering that re-used memory.

With FMR memory registration, invalidation takes a relatively long
time. In fact, the invalidation is often still running when the
server tries to write the results into the memory regions that are
being invalidated.

This sets up a race between two processes:

1.  After the signal, xprt_rdma_free calls ro_unmap_safe.
2.  While ro_unmap_safe is still running, the server replies and
    rpcrdma_reply_handler runs, calling ro_unmap_sync.

Both processes invoke ib_unmap_fmr on the same FMR.

The mlx4 driver allows two ib_unmap_fmr calls on the same FMR at
the same time, but HCAs generally don't tolerate this. Sometimes
this can result in a system crash.

If the HCA happens to survive, rpcrdma_reply_handler continues. It
removes the rpc_rqst from rq_list and releases the transport_lock.
This enables xprt_rdma_free to run in another process, and the
rpc_rqst is released while rpcrdma_reply_handler is still waiting
for the ib_unmap_fmr call to finish.

But further down in rpcrdma_reply_handler, the transport_lock is
taken again, and "rqst" is dereferenced. If "rqst" has already been
released, this triggers a general protection fault. Since bottom-
halves are disabled, the system locks up.

Address both issues by reversing the order of the xprt_lookup_rqst
call and the ro_unmap_sync call. Introduce a separate lookup
mechanism for rpcrdma_req's to enable calling ro_unmap_sync before
xprt_lookup_rqst. Now the handler takes the transport_lock once
and holds it for the XID lookup and RPC completion.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=305
Fixes: 68791649 ('xprtrdma: Invalidate in the RPC reply ... ')
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: I'm about to use the rl_free field for purposes other than
a free list. So use a more generic name.

This is a refactoring change only.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=305
Fixes: 68791649 ('xprtrdma: Invalidate in the RPC reply ... ')
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>