The correct interrupt name is 'hs_phy_irq' not 'hs_phY_irq'.
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240220-dt-bindins-qcom-dwc3-fix-typo-v1-1-742bf6e49641@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Define VBUS regulator and the Type-C handling block as present on the
Qualcomm PM6150 PMIC.
Signed-off-by: Danila Tikhonov <danila@jiaxyga.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20240220202147.228911-3-danila@jiaxyga.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The PM6150 PMIC has the same Type-C register block as the PM8150B.
Define corresponding compatible string, having the qcom,pm8150b-vbus-reg
as a fallback.
Signed-off-by: Danila Tikhonov <danila@jiaxyga.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240220202147.228911-2-danila@jiaxyga.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a spelling mistake in a dev_err message. Fix it.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20240220080617.2674613-1-colin.i.king@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A call to usb_set_interface() crashes if the device is deallocated
concurrently, such as due to physical removal or a serious IO error.
It could also interfere with other drivers using the device if the
current driver is unbound before the call is finished.

Document the need to delay driver unbinding until this call returns,
which solves both issues.

Document the same regarding usb_clear_halt(), which is equally known
to be routinely called by drivers.

Explicitly mention finishing pending operations in the documentation
of the driver disconnect callback.
Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Link: https://lore.kernel.org/r/20240218092515.7635ff8c@foxbookSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently xhci_map_urb_for_dma() creates a temporary buffer and copies
the SG list to the new linear buffer. But if the kzalloc_node() fails,
then the following sg_pcopy_to_buffer() can lead to crash since it
tries to memcpy to NULL pointer.

So return -ENOMEM if kzalloc returns null pointer.

Cc: stable@vger.kernel.org # 5.11
Fixes: 2017a1e5 ("usb: xhci: Use temporary buffer to consolidate SG")
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-10-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

DbC driver starts polling for events immediately when DbC is enabled.
The current polling interval is 1ms, which keeps the CPU busy, impacting
power management even when there are no active data transfers.

Solve this by polling at a slower rate, with a 64ms interval as default
until a transfer request is queued, or if there are still are pending
unhandled transfers at event completion.
Tested-by: Uday M Bhat <uday.m.bhat@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-9-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Two NEC uPD720200 adapters have been observed to randomly misbehave:
a Stop Endpoint command fails with Context Error, the Output Context
indicates Stopped state, and the endpoint keeps running. Very often,
Set TR Dequeue Pointer is seen to fail next with Context Error too,
in addition to problems from unexpectedly completed cancelled work.

The pathology is common on fast running isoc endpoints like uvcvideo,
but has also been reproduced on a full-speed bulk endpoint of pl2303.
It seems all EPs are affected, with risk proportional to their load.

Reproduction involves receiving any kind of stream and closing it to
make the device driver cancel URBs already queued in advance.

Deal with it by retrying the command like in the Running state.
Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-8-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A trb_in_td() call is used to determine if a completion event matches
any TRB of the currently executing TD. This function is told to start
searching right after the last finished TD, which is not at all where
the currently expected TD is guaranteed to begin, because some TDs in
between may have been cancelled.

Not only is a pointless work performed, but a bug resulting in the HC
executing cancelled TDs was seen to trick the driver into associating
events from a TD just cancelled with an unrelated future TD.

Since the ring is being traversed for the specific purpose of finding
a match with the current TD, always start from its first TRB. This is
the most reliable bit of information that we posses.

Tracking of HC's work progress is not affected, except for cases when
a misattributed event would have moved dequeue past a pending TD.
Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-7-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Refactor the code to improve readability by using
'xhci_free_segments_for_ring()' function for freeing ring segments.
This replaces the custom while loop previously used within
'xhci_ring_expansion()' and 'xhci_alloc_segments_for_ring()'.

Slightly modify 'xhci_free_segments_for_ring()' to handle lists
which do not loop. This makes it possible to use it in error
paths of 'xhci_alloc_segments_for_ring()'.

This change also prepares for switching the custom xhci linked segment
list into to more standard list.h lists.

[minor commit message rewording -Mathias]
Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-6-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace a segment of code within 'xhci_clear_command_ring()' with a
function call to 'xhci_initialize_ring_info()'. This change eliminates
code duplication, as 'xhci_initialize_ring_info()' performs the same
operations as the replaced code.
Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-5-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Slot ID is a index of a virtual device in struct 'xhci_hcd->devs[]'.
Previously, to get the slot ID associated with a port, we had to loop
through all devices and compare ports, which is very inefficient.
Instead, the slot ID (of the device which is directly connected to the
port), is added to the its corresponding 'xhci_port' struct. As a result,
finding the port's device is quick and easy.

Function 'xhci_find_slot_id_by_port()' is removed, as it is no longer
needed.
Signed-off-by: Niklas Neronin <niklas.neronin@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-4-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Variables real & fake port do not convey their purpose, thus they are
replaced with a pointer to the root hub port 'struct xhci_port *rhub_port'.
'rhub_port' contains real & fake ports in zero-based format, which happens
to be more widely used inside the xHCI driver:
 - 'real_port' is ('rhub_port->hw_portnum' + 1)
 - 'fake_port' is ('rhub_port->hcd_portnum' + 1)

One reason for real port being one-based, is to signal other functions in
case struct 'xhci_virt_device' initialization failed, in this case the
value will remain 0. This is no longer needed, instead we check whether
or not 'rhub_port' is 'NULL'.
Signed-off-by: Niklas Neronin <niklas.neronin@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-3-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

xHC hardware needs to know which roothub port a USB device is attached to
when controlling the device, so the xHCI driver stores in each device the
roothub port which it's connected behind. This is done with two different
port index values, the 'real_port' which is an index to the xHC hardware
port register array, and the 'fake_port' which is the per hub port index
used by the hub driver.

Instead of finding real & fake port separately, find the root hub port
'xhci_port' structure which contains both real & fake port values:
    - 'real_port' is ('hw_portnum' + 1)
    - 'fake_port' is ('hcd_portnum' + 1)
i.e. real & fake port are 'hw_portnum' & 'hcd_portnum' in one-based
format.

The 'xhci_port' structure is a better way to refer to roothub ports than
the 'real_port' & 'fake_port'. As a result, these port indexes are slated
to be replaced with a direct pointer to the root hub port. This patch
setups the ground work for the future changes.
Signed-off-by: Niklas Neronin <niklas.neronin@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240229141438.619372-2-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 43a7206b ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the structures typec_mux_class, retimer_class and
typec_class to be declared at build time placing them into read-only
memory, instead of having to be dynamically allocated at boot time.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Link: https://lore.kernel.org/r/20240301-class_cleanup-usb-v1-1-50309e325095@marliere.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We have a macro. It should be used.
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20240229132401.3270-1-oneukum@suse.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Merge tag 'thunderbolt-for-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt into usb-next

Mika writes:

thunderbolt: Changes for v6.9 merge window

This includes following USB4/Thunderbolt changes for the v6.9 merge
window:

  - Reset the topology also for USB4 v1 routers on driver load
  - DisplayPort tunneling and bandwidth allocation mode improvements
  - Tracepoint support for the control channel
  - Couple of minor fixes and cleanups.

All these have been in linux-next with no reported issues.

* tag 'thunderbolt-for-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt: (23 commits)
  thunderbolt: Constify the struct device_type usage
  thunderbolt: Add trace events support for the control channel
  thunderbolt: Keep the domain powered when USB4 port is in redrive mode
  thunderbolt: Improve DisplayPort tunnel setup process to be more robust
  thunderbolt: Calculate DisplayPort tunnel bandwidth after DPRX capabilities read
  thunderbolt: Reserve released DisplayPort bandwidth for a group for 10 seconds
  thunderbolt: Introduce tb_tunnel_direction_downstream()
  thunderbolt: Re-order bandwidth group functions
  thunderbolt: Fail the failed bandwidth request properly
  thunderbolt: Log an error if DPTX request is not cleared
  thunderbolt: Handle bandwidth allocation mode disable request
  thunderbolt: Re-calculate estimated bandwidth when allocation mode is enabled
  thunderbolt: Use DP_LOCAL_CAP for maximum bandwidth calculation
  thunderbolt: Correct typo in host_reset parameter
  thunderbolt: Skip discovery also in USB4 v2 host
  thunderbolt: Reset only non-USB4 host routers in resume
  thunderbolt: Remove usage of the deprecated ida_simple_xx() API
  thunderbolt: Fix rollback in tb_port_lane_bonding_enable() for lane 1
  thunderbolt: Fix XDomain rx_lanes_show and tx_lanes_show
  thunderbolt: Reset topology created by the boot firmware
  ...

Since commit aed65af1 ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
tb_domain_type, tb_retimer_type, tb_switch_type, usb4_port_device_type,
tb_service_type and tb_xdomain_type variables to be constant structures as
well, placing it into read-only memory which can not be modified at
runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Sometimes it is useful to see the traffic happening inside the control
channel, especially when debugging a possible problem. This adds
tracepoints close to the hardware which can be enabled dynamically as
needed using the standard Linux trace events facility.
Signed-off-by: Gil Fine <gil.fine@linux.intel.com>
Co-developed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

If a DiplayPort cable is directly connected to the host routers USB4
port, there is no tunnel involved but the port is in "redrive" mode
meaning that it is re-driving the DisplayPort signals from its
DisplayPort source. In this case we need to keep the domain powered on
otherwise once the domain enters D3cold the connected monitor blanks
too.

Since this happens only on Intel Barlow Ridge add a quirk that takes
runtime PM reference if we detect that the USB4 port entered redrive
mode (and release it once it exits the mode).
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

We need it here for the USB fixes, and it resolves a merge conflict as
reported in linux-next in drivers/usb/roles/class.c
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull bcachefs fixes from Kent Overstreet:
 "Some more mostly boring fixes, but some not

  User reported ones:

   - the BTREE_ITER_FILTER_SNAPSHOTS one fixes a really nasty
     performance bug; user reported an untar initially taking two
     seconds and then ~2 minutes

   - kill a __GFP_NOFAIL in the buffered read path; this was a leftover
     from the trickier fix to kill __GFP_NOFAIL in readahead, where we
     can't return errors (and have to silently truncate the read
     ourselves).

     bcachefs can't use GFP_NOFAIL for folio state unlike iomap based
     filesystems because our folio state is just barely too big, 2MB
     hugepages cause us to exceed the 2 page threshhold for GFP_NOFAIL.

     additionally, the flags argument was just buggy, we weren't
     supplying GFP_KERNEL previously (!)"

* tag 'bcachefs-2024-02-25' of https://evilpiepirate.org/git/bcachefs:
  bcachefs: fix bch2_save_backtrace()
  bcachefs: Fix check_snapshot() memcpy
  bcachefs: Fix bch2_journal_flush_device_pins()
  bcachefs: fix iov_iter count underflow on sub-block dio read
  bcachefs: Fix BTREE_ITER_FILTER_SNAPSHOTS on inodes btree
  bcachefs: Kill __GFP_NOFAIL in buffered read path
  bcachefs: fix backpointer_to_text() when dev does not exist

Missed a call in the previous fix.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

Pull two documentation build fixes from Jonathan Corbet:

 - The XFS online fsck documentation uses incredibly deeply nested
   subsection and list nesting; that broke the PDF docs build. Tweak a
   parameter to tell LaTeX to allow the deeper nesting.

 - Fix a 6.8 PDF-build regression

* tag 'docs-6.8-fixes3' of git://git.lwn.net/linux:
  docs: translations: use attribute to store current language
  docs: Instruct LaTeX to cope with deeper nesting

Pull USB fixes from Greg KH:
 "Here are some small USB fixes for 6.8-rc6 to resolve some reported
  problems. These include:

   - regression fixes with typec tpcm code as reported by many

   - cdnsp and cdns3 driver fixes

   - usb role setting code bugfixes

   - build fix for uhci driver

   - ncm gadget driver bugfix

   - MAINTAINERS entry update

  All of these have been in linux-next all week with no reported issues
  and there is at least one fix in here that is in Thorsten's regression
  list that is being tracked"

* tag 'usb-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: typec: tpcm: Fix issues with power being removed during reset
  MAINTAINERS: Drop myself as maintainer of TYPEC port controller drivers
  usb: gadget: ncm: Avoid dropping datagrams of properly parsed NTBs
  Revert "usb: typec: tcpm: reset counter when enter into unattached state after try role"
  usb: gadget: omap_udc: fix USB gadget regression on Palm TE
  usb: dwc3: gadget: Don't disconnect if not started
  usb: cdns3: fix memory double free when handle zero packet
  usb: cdns3: fixed memory use after free at cdns3_gadget_ep_disable()
  usb: roles: don't get/set_role() when usb_role_switch is unregistered
  usb: roles: fix NULL pointer issue when put module's reference
  usb: cdnsp: fixed issue with incorrect detecting CDNSP family controllers
  usb: cdnsp: blocked some cdns3 specific code
  usb: uhci-grlib: Explicitly include linux/platform_device.h

Pull tty/serial driver fixes from Greg KH:
 "Here are three small serial/tty driver fixes for 6.8-rc6 that resolve
  the following reported errors:

   - riscv hvc console driver fix that was reported by many

   - amba-pl011 serial driver fix for RS485 mode

   - stm32 serial driver fix for RS485 mode

  All of these have been in linux-next all week with no reported
  problems"

* tag 'tty-6.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: amba-pl011: Fix DMA transmission in RS485 mode
  serial: stm32: do not always set SER_RS485_RX_DURING_TX if RS485 is enabled
  tty: hvc: Don't enable the RISC-V SBI console by default

Pull x86 fixes from Borislav Petkov:

 - Make sure clearing CPU buffers using VERW happens at the latest
   possible point in the return-to-userspace path, otherwise memory
   accesses after the VERW execution could cause data to land in CPU
   buffers again

* tag 'x86_urgent_for_v6.8_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  KVM/VMX: Move VERW closer to VMentry for MDS mitigation
  KVM/VMX: Use BT+JNC, i.e. EFLAGS.CF to select VMRESUME vs. VMLAUNCH
  x86/bugs: Use ALTERNATIVE() instead of mds_user_clear static key
  x86/entry_32: Add VERW just before userspace transition
  x86/entry_64: Add VERW just before userspace transition
  x86/bugs: Add asm helpers for executing VERW

Pull irq fixes from Borislav Petkov:

 - Make sure GICv4 always gets initialized to prevent a kexec-ed kernel
   from silently failing to set it up

 - Do not call bus_get_dev_root() for the mbigen irqchip as it always
   returns NULL - use NULL directly

 - Fix hardware interrupt number truncation when assigning MSI
   interrupts

 - Correct sending end-of-interrupt messages to disabled interrupts
   lines on RISC-V PLIC

* tag 'irq_urgent_for_v6.8_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3-its: Do not assume vPE tables are preallocated
  irqchip/mbigen: Don't use bus_get_dev_root() to find the parent
  PCI/MSI: Prevent MSI hardware interrupt number truncation
  irqchip/sifive-plic: Enable interrupt if needed before EOI

Pull erofs fix from Gao Xiang:

 - Fix page refcount leak when looking up specific inodes
   introduced by metabuf reworking

* tag 'erofs-for-6.8-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: fix refcount on the metabuf used for inode lookup

Pull RCU pathwalk fixes from Al Viro:
 "We still have some races in filesystem methods when exposed to RCU
  pathwalk. This series is a result of code audit (the second round of
  it) and it should deal with most of that stuff.

  Still pending: ntfs3 ->d_hash()/->d_compare() and ceph_d_revalidate().
  Up to maintainers (a note for NTFS folks - when documentation says
  that a method may not block, it *does* imply that blocking allocations
  are to be avoided. Really)"

[ More explanations for people who aren't familiar with the vagaries of
  RCU path walking: most of it is hidden from filesystems, but if a
  filesystem actively participates in the low-level path walking it
  needs to make sure the fields involved in that walk are RCU-safe.

  That "actively participate in low-level path walking" includes things
  like having its own ->d_hash()/->d_compare() routines, or by having
  its own directory permission function that doesn't just use the common
  helpers.  Having a ->d_revalidate() function will also have this issue.

  Note that instead of making everything RCU safe you can also choose to
  abort the RCU pathwalk if your operation cannot be done safely under
  RCU, but that obviously comes with a performance penalty. One common
  pattern is to allow the simple cases under RCU, and abort only if you
  need to do something more complicated.

  So not everything needs to be RCU-safe, and things like the inode etc
  that the VFS itself maintains obviously already are. But these fixes
  tend to be about properly RCU-delaying things like ->s_fs_info that
  are maintained by the filesystem and that got potentially released too
  early.   - Linus ]

* tag 'pull-fixes.pathwalk-rcu-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ext4_get_link(): fix breakage in RCU mode
  cifs_get_link(): bail out in unsafe case
  fuse: fix UAF in rcu pathwalks
  procfs: make freeing proc_fs_info rcu-delayed
  procfs: move dropping pde and pid from ->evict_inode() to ->free_inode()
  nfs: fix UAF on pathwalk running into umount
  nfs: make nfs_set_verifier() safe for use in RCU pathwalk
  afs: fix __afs_break_callback() / afs_drop_open_mmap() race
  hfsplus: switch to rcu-delayed unloading of nls and freeing ->s_fs_info
  exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper
  affs: free affs_sb_info with kfree_rcu()
  rcu pathwalk: prevent bogus hard errors from may_lookup()
  fs/super.c: don't drop ->s_user_ns until we free struct super_block itself

Pull vfs fixes from Al Viro:
 "A couple of fixes - revert of regression from this cycle and a fix for
  erofs failure exit breakage (had been there since way back)"

* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  erofs: fix handling kern_mount() failure
  Revert "get rid of DCACHE_GENOCIDE"

1) errors from ext4_getblk() should not be propagated to caller
unless we are really sure that we would've gotten the same error
in non-RCU pathwalk.
2) we leak buffer_heads if ext4_getblk() is successful, but bh is
not uptodate.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

->d_revalidate() bails out there, anyway.  It's not enough
to prevent getting into ->get_link() in RCU mode, but that
could happen only in a very contrieved setup.  Not worth
trying to do anything fancy here unless ->d_revalidate()
stops kicking out of RCU mode at least in some cases.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

->permission(), ->get_link() and ->inode_get_acl() might dereference
->s_fs_info (and, in case of ->permission(), ->s_fs_info->fc->user_ns
as well) when called from rcu pathwalk.

Freeing ->s_fs_info->fc is rcu-delayed; we need to make freeing ->s_fs_info
and dropping ->user_ns rcu-delayed too.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

makes proc_pid_ns() safe from rcu pathwalk (put_pid_ns()
is still synchronous, but that's not a problem - it does
rcu-delay everything that needs to be)
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

that keeps both around until struct inode is freed, making access
to them safe from rcu-pathwalk
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

NFS ->d_revalidate(), ->permission() and ->get_link() need to access
some parts of nfs_server when called in RCU mode:
	server->flags
	server->caps
	*(server->io_stats)
and, worst of all, call
	server->nfs_client->rpc_ops->have_delegation
(the last one - as NFS_PROTO(inode)->have_delegation()).  We really
don't want to RCU-delay the entire nfs_free_server() (it would have
to be done with schedule_work() from RCU callback, since it can't
be made to run from interrupt context), but actual freeing of
nfs_server and ->io_stats can be done via call_rcu() just fine.
nfs_client part is handled simply by making nfs_free_client() use
kfree_rcu().
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

nfs_set_verifier() relies upon dentry being pinned; if that's
the case, grabbing ->d_lock stabilizes ->d_parent and guarantees
that ->d_parent points to a positive dentry.  For something
we'd run into in RCU mode that is *not* true - dentry might've
been through dentry_kill() just as we grabbed ->d_lock, with
its parent going through the same just as we get to into
nfs_set_verifier_locked().  It might get to detaching inode
(and zeroing ->d_inode) before nfs_set_verifier_locked() gets
to fetching that; we get an oops as the result.

That can happen in nfs{,4} ->d_revalidate(); the call chain in
question is nfs_set_verifier_locked() <- nfs_set_verifier() <-
nfs_lookup_revalidate_delegated() <- nfs{,4}_do_lookup_revalidate().
We have checked that the parent had been positive, but that's
done before we get to nfs_set_verifier() and it's possible for
memory pressure to pick our dentry as eviction candidate by that
time.  If that happens, back-to-back attempts to kill dentry and
its parent are quite normal.  Sure, in case of eviction we'll
fail the ->d_seq check in the caller, but we need to survive
until we return there...
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

In __afs_break_callback() we might check ->cb_nr_mmap and if it's non-zero
do queue_work(&vnode->cb_work).  In afs_drop_open_mmap() we decrement
->cb_nr_mmap and do flush_work(&vnode->cb_work) if it reaches zero.

The trouble is, there's nothing to prevent __afs_break_callback() from
seeing ->cb_nr_mmap before the decrement and do queue_work() after both
the decrement and flush_work().  If that happens, we might be in trouble -
vnode might get freed before the queued work runs.

__afs_break_callback() is always done under ->cb_lock, so let's make
sure that ->cb_nr_mmap can change from non-zero to zero while holding
->cb_lock (the spinlock component of it - it's a seqlock and we don't
need to mess with the counter).
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>