The 9p code for some reason used to initialize variables outside of the
declaration, e.g. instead of just initializing the variable like this:

int retval = 0

We would be doing this:

int retval;
retval = 0;

This is perfectly fine and the compiler will just optimize dead stores
anyway, but scan-build seems to think this is a problem and there are
many of these warnings making the output of scan-build full of such
warnings:
fs/9p/vfs_inode.c:916:2: warning: Value stored to 'retval' is never read [deadcode.DeadStores]
        retval = 0;
        ^        ~

I have no strong opinion here, but if we want to regularly run
scan-build we should fix these just to silence the messages.

I've confirmed these all are indeed ok to remove.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>

Fix the following scan-build warning:
net/9p/trans_virtio.c:504:3: warning: Value stored to 'in' is never read [deadcode.DeadStores]
                in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
                ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I'm honestly not 100% sure about this one; I'm tempted to think we
could (should?) just check the return value of pack_sg_list_p to skip
the in_sgs++ and setting sgs[] if it didn't process anything, but I'm
not sure it should ever happen so this is probably fine as is.

Just removing the assignment at least makes it clear the return value
isn't used, so it's an improvement in terms of readability.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>

Similarly to the previous patch: offs can be used in handle_rerrors
without initializing on small payloads; in this case handle_rerrors will
not use it because of the size check, but it doesn't hurt to make sure
it is zero to please scan-build.

This fixes the following warning:
net/9p/trans_virtio.c:539:3: warning: 3rd function call argument is an uninitialized value [core.CallAndMessage]
                handle_rerror(req, in_hdr_len, offs, in_pages);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>

handle_rerror can dereference the pages pointer, but it is not
necessarily set for small payloads.
In practice these should be filtered out by the size check, but
might as well double-check explicitly.

This fixes the following scan-build warnings:
net/9p/trans_virtio.c:401:24: warning: Dereference of null pointer [core.NullDereference]
                memcpy_from_page(to, *pages++, offs, n);
                                     ^~~~~~~~
net/9p/trans_virtio.c:406:23: warning: Dereference of null pointer (loaded from variable 'pages') [core.NullDereference]
        memcpy_from_page(to, *pages, offs, size);
                             ^~~~~~

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>

Pull networking fixes from Jakub Kicinski:
 "Including fixes from netfilter.

  Current release - regressions:

   - sched: act_pedit: free pedit keys on bail from offset check

  Current release - new code bugs:

   - pds_core:
      - Kconfig fixes (DEBUGFS and AUXILIARY_BUS)
      - fix mutex double unlock in error path

  Previous releases - regressions:

   - sched: cls_api: remove block_cb from driver_list before freeing

   - nf_tables: fix ct untracked match breakage

   - eth: mtk_eth_soc: drop generic vlan rx offload

   - sched: flower: fix error handler on replace

  Previous releases - always broken:

   - tcp: fix skb_copy_ubufs() vs BIG TCP

   - ipv6: fix skb hash for some RST packets

   - af_packet: don't send zero-byte data in packet_sendmsg_spkt()

   - rxrpc: timeout handling fixes after moving client call connection
     to the I/O thread

   - ixgbe: fix panic during XDP_TX with > 64 CPUs

   - igc: RMW the SRRCTL register to prevent losing timestamp config

   - dsa: mt7530: fix corrupt frames using TRGMII on 40 MHz XTAL MT7621

   - r8152:
      - fix flow control issue of RTL8156A
      - fix the poor throughput for 2.5G devices
      - move setting r8153b_rx_agg_chg_indicate() to fix coalescing
      - enable autosuspend

   - ncsi: clear Tx enable mode when handling a Config required AEN

   - octeontx2-pf: macsec: fixes for CN10KB ASIC rev

  Misc:

   - 9p: remove INET dependency"

* tag 'net-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (69 commits)
  net: bcmgenet: Remove phy_stop() from bcmgenet_netif_stop()
  pds_core: fix mutex double unlock in error path
  net/sched: flower: fix error handler on replace
  Revert "net/sched: flower: Fix wrong handle assignment during filter change"
  net/sched: flower: fix filter idr initialization
  net: fec: correct the counting of XDP sent frames
  bonding: add xdp_features support
  net: enetc: check the index of the SFI rather than the handle
  sfc: Add back mailing list
  virtio_net: suppress cpu stall when free_unused_bufs
  ice: block LAN in case of VF to VF offload
  net: dsa: mt7530: fix network connectivity with multiple CPU ports
  net: dsa: mt7530: fix corrupt frames using trgmii on 40 MHz XTAL MT7621
  9p: Remove INET dependency
  netfilter: nf_tables: fix ct untracked match breakage
  af_packet: Don't send zero-byte data in packet_sendmsg_spkt().
  igc: read before write to SRRCTL register
  pds_core: add AUXILIARY_BUS and NET_DEVLINK to Kconfig
  pds_core: remove CONFIG_DEBUG_FS from makefile
  ionic: catch failure from devlink_alloc
  ...

Pull 9p updates from Eric Van Hensbergen:
 "This includes a number of patches that didn't quite make the cut last
  merge window while we addressed some outstanding issues and review
  comments. It includes some new caching modes for those that only want
  readahead caches and reworks how we do writeback caching so we are not
  keeping extra references around which both causes performance problems
  and uses lots of additional resources on the server.

  It also includes a new flag to force disabling of xattrs which can
  also cause major performance issues, particularly if the underlying
  filesystem on the server doesn't support them.

  Finally it adds a couple of additional mount options to better support
  directio and enabling caches when the server doesn't support
  qid.version.

  There was one late-breaking bug report that has also been included as
  its own patch where I forgot to propagate an embarassing bit-logic fix
  to the various variations of open"

* tag '9p-6.4-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  fs/9p: Fix bit operation logic error
  fs/9p: Rework cache modes and add new options to Documentation
  fs/9p: remove writeback fid and fix per-file modes
  fs/9p: Add new mount modes
  9p: Add additional debug flags and open modes
  fs/9p: allow disable of xattr support on mount
  fs/9p: Remove unnecessary superblock flags
  fs/9p: Consolidate file operations and add readahead and writeback

9pfs can run over assorted transports, so it doesn't have an INET
dependency.  Drop it and remove the includes of linux/inet.h.

NET_9P_FD/trans_fd.o builds without INET or UNIX and is usable over
plain file descriptors.  However, tcp and unix functionality is still
built and would generate runtime failures if used.  Add imply INET and
UNIX to NET_9P_FD, so functionality is enabled by default but can still
be explicitly disabled.

This allows configuring 9pfs over Xen with INET and UNIX disabled.

Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In xen_9pfs_front_probe, it calls xen_9pfs_front_alloc_dataring
to init priv->rings and bound &ring->work with p9_xen_response.

When it calls xen_9pfs_front_event_handler to handle IRQ requests,
it will finally call schedule_work to start the work.

When we call xen_9pfs_front_remove to remove the driver, there
may be a sequence as follows:

Fix it by finishing the work before cleanup in xen_9pfs_front_free.

Note that, this bug is found by static analysis, which might be
false positive.

CPU0                  CPU1

                     |p9_xen_response
xen_9pfs_front_remove|
  xen_9pfs_front_free|
kfree(priv)          |
//free priv          |
                     |p9_tag_lookup
                     |//use priv->client

Fixes: 71ebd71921e4 ("xen/9pfs: connect to the backend")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>

Add some additional debug flags to assist with debugging
cache changes.  Also add some additional open modes so we
can track cache state in fids more directly.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>

Pull 9p updates from Eric Van Hensbergen:

 - some fixes and cleanup setting up for a larger set of performance
   patches I've been working on

 - a contributed fixes relating to 9p/rdma

 - some contributed fixes relating to 9p/xen

* tag '9p-6.3-for-linus-part1' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  fs/9p: fix error reporting in v9fs_dir_release
  net/9p: fix bug in client create for .L
  9p/rdma: unmap receive dma buffer in rdma_request()/post_recv()
  9p/xen: fix connection sequence
  9p/xen: fix version parsing
  fs/9p: Expand setup of writeback cache to all levels
  net/9p: Adjust maximum MSIZE to account for p9 header