Sharing DFS channel state across multiple wiphys (radios) could
be useful with multiple radios on the system. When one radio
completes CAC and markes the channel available another radio
can use this information and start beaconing without really doing
CAC.

Whenever there is a state change in dfs channel associated to
a particular wiphy the the same state change is propagated to
other wiphys having the same DFS reg domain configuration.
Also when a new wiphy is created the dfs channel state of
other existing wiphys of same DFS domain is copied.
Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qti.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

For non-ETSI regulatory domain, CAC result on DFS channel
may not be valid once moving out of that channel (as done
during remain-on-channel, scannning and off-channel tx).
Running CAC on an operating DFS channel after every off-channel
operation will only add complexity and disturb the current
link. Better do not allow any off-channel switch from a DFS
operating channel in non-ETSI domain.
Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qti.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

DFS requirement for ETSI domain (section 4.7.1.4 in
ETSI EN 301 893 V1.8.1) is the only one which explicitly
states that once DFS channel is marked as available afer
the CAC, this channel will remain in available state even
moving to a different operating channel. But the same is
not explicitly stated in FCC DFS requirement. Also, Pre-CAC
requriements are not explicitly mentioned in FCC requirement.
Current implementation in keeping DFS channel in available
state is same as described in ETSI domain.

For non-ETSI DFS domain, this patch gives a grace period of 2 seconds
since the completion of successful CAC before moving the channel's
DFS state to 'usable' from 'available' state. The same grace period
is checked against the channel's dfs_state_entered timestamp while
deciding if a DFS channel is available for operation. There is a new
radar event, NL80211_RADAR_PRE_CAC_EXPIRED, reported when DFS channel
is moved from available to usable state after the grace period. Also
make sure the DFS channel state is reset to usable once the beaconing
operation on that channel is brought down (like stop_ap, leave_ibss
and leave_mesh) in non-ETSI domain.
Signed-off-by: Vasanthakumar Thiagarajan <vthiagar@qti.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Currently, hwsim is reporting survey data (only a fake noise floor)
for the current channel. This breaks when the multi-channel support
is enabled since then there's no current channel.

Make the dummy implementation closer to a real one and only report
data while scanning, for all the scanned channels. At other times,
no survey data might be available (in real hardware) due to power-
save for example.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Use setup_timer() and setup_deferrable_timer() to set the data and
function timer fields. It makes the code cleaner and will allow for
easier change of the timer struct internals.
Signed-off-by: Ondřej Lysoněk <ondrej.lysonek@seznam.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <linux-wireless@vger.kernel.org>
Cc: <netdev@vger.kernel.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

This channel is defined in the IEEE 802.11 standard and available in
number of countries, so extend the mac80211_hwsim channel list to cover
channel 169 to enable additional testing.
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

ieee80211_alloc_hw_nm will validate the requested name (if any) before
creating the new device and may use a name different from the one
requested rather than fail.  Make sure the HWSIM_CMD_NEW_RADIO
event/response generated has the final name or userspace will receive
the wrong name.  Note that mac80211_hwsim_new_radio may now modify
params.

A check for duplicate radio name could be added separately.
Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Mesh failure average never be more than 100. Only in case of
fixed path, average will be more than threshold limit (95%).
With recent EWMA changes it may go upto 99 as it is scaled to
100. It make sense to return maximum metric when average is
greater than threshold limit.
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

The Channel Center Frequency Segment 2 field is used in
802.11-2016 for encoding the actual channel position of
the 80+80/160 MHz channel, if the max NSS is restricted.
This is used for backwards compatibility.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

We don't really need three different bits for each, since the
types are mutually exclusive. Use just two bits for it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

This function contains the HT calculations, which makes no
sense - split that out into a separate function. As a side
effect, this makes the 60G flag independent from HT_MCS so
remove the MCS one from wil6210 (also deleting a duplicate
assignment.)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

This pointer really isn't needed, so remove it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

This matches the spec, and otherwise things are really
confusing with the next patch adding CCFS2.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

When disassociation happens only numeric reason is printed
in ieee80211_rx_mgmt_disassoc(). Add text variant, too.
Signed-off-by: Arkadiusz Miśkiewicz <arekm@maven.pl>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Combine two instances of having two nested if statements
into a single one with a combined condition to reduce the
indentation.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Set the NL80211_EXT_FEATURE_CQM_RSSI_LIST wiphy extended feature
wholesale in all mac80211-based drivers that do not set the
IEEE80211_VIF_BEACON_FILTER flags on their interfaces.  mac80211 will
be processing supplied RSSI values in ieee80211_rx_mgmt_beacon and
will detect when the thresholds set by
ieee80211_set_cqm_rssi_range_config are crossed.  Remaining (few)
drivers need code to enable the firmware to monitor the thresholds.
This is mostly only compile-tested.
Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Support .set_cqm_rssi_range_config if the beacons are available for
processing in mac80211.  There's no reason that this couldn't be
offloaded by mac80211-based drivers but there's no driver method for
that added in this patch.
Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Change the SET CQM command's RSSI threshold attribute to accept any
number of thresholds as a sorted array.  The API should be backwards
compatible so that if one s32 threshold value is passed, the old
mechanism is enabled.  The netlink event generated is the same in both
cases.

cfg80211 handles an arbitrary number of RSSI thresholds but drivers have
to provide a method (set_cqm_rssi_range_config) that configures a range
set by a high and a low value.  Drivers have to call back when the RSSI
goes out of that range and there's no additional event for each time the
range is reconfigured as there was with the current one-threshold API.

This method doesn't have a hysteresis parameter because there's no
benefit to the cfg80211 code from having the hysteresis be handled by
hardware/driver in terms of the number of wakeups.  At the same time
it would likely be less consistent between drivers if offloaded or
done in the drivers.
Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

As moving average is not considering fractional part, it will
get stuck at the same level after certain state. For example,
with current values, it can get stuck at 96. Fortunately the
current threshold 95%, but if it were increased to 96 or more
mesh paths would never be deactivated. Fix failure average
movement by using EWMA helpers, which does take into account
fractional parts.
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
[johannes: pick a larger EWMA factor for more precision with
 the limited range that we will feed into it, adjust to new API]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Pull networking fixes from David Miller:

 1) Fix double-free in batman-adv, from Sven Eckelmann.

 2) Fix packet stats for fast-RX path, from Joannes Berg.

 3) Netfilter's ip_route_me_harder() doesn't handle request sockets
    properly, fix from Florian Westphal.

 4) Fix sendmsg deadlock in rxrpc, from David Howells.

 5) Add missing RCU locking to transport hashtable scan, from Xin Long.

 6) Fix potential packet loss in mlxsw driver, from Ido Schimmel.

 7) Fix race in NAPI handling between poll handlers and busy polling,
    from Eric Dumazet.

 8) TX path in vxlan and geneve need proper RCU locking, from Jakub
    Kicinski.

 9) SYN processing in DCCP and TCP need to disable BH, from Eric
    Dumazet.

10) Properly handle net_enable_timestamp() being invoked from IRQ
    context, also from Eric Dumazet.

11) Fix crash on device-tree systems in xgene driver, from Alban Bedel.

12) Do not call sk_free() on a locked socket, from Arnaldo Carvalho de
    Melo.

13) Fix use-after-free in netvsc driver, from Dexuan Cui.

14) Fix max MTU setting in bonding driver, from WANG Cong.

15) xen-netback hash table can be allocated from softirq context, so use
    GFP_ATOMIC. From Anoob Soman.

16) Fix MAC address change bug in bgmac driver, from Hari Vyas.

17) strparser needs to destroy strp_wq on module exit, from WANG Cong.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (69 commits)
  strparser: destroy workqueue on module exit
  sfc: fix IPID endianness in TSOv2
  sfc: avoid max() in array size
  rds: remove unnecessary returned value check
  rxrpc: Fix potential NULL-pointer exception
  nfp: correct DMA direction in XDP DMA sync
  nfp: don't tell FW about the reserved buffer space
  net: ethernet: bgmac: mac address change bug
  net: ethernet: bgmac: init sequence bug
  xen-netback: don't vfree() queues under spinlock
  xen-netback: keep a local pointer for vif in backend_disconnect()
  netfilter: nf_tables: don't call nfnetlink_set_err() if nfnetlink_send() fails
  netfilter: nft_set_rbtree: incorrect assumption on lower interval lookups
  netfilter: nf_conntrack_sip: fix wrong memory initialisation
  can: flexcan: fix typo in comment
  can: usb_8dev: Fix memory leak of priv->cmd_msg_buffer
  can: gs_usb: fix coding style
  can: gs_usb: Don't use stack memory for USB transfers
  ixgbe: Limit use of 2K buffers on architectures with 256B or larger cache lines
  ixgbe: update the rss key on h/w, when ethtool ask for it
  ...

Pull more KVM updates from Radim Krčmář:
 "Second batch of KVM changes for the 4.11 merge window:

  PPC:
   - correct assumption about ASDR on POWER9
   - fix MMIO emulation on POWER9

  x86:
   - add a simple test for ioperm
   - cleanup TSS (going through KVM tree as the whole undertaking was
     caused by VMX's use of TSS)
   - fix nVMX interrupt delivery
   - fix some performance counters in the guest

  ... and two cleanup patches"

* tag 'kvm-4.11-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: nVMX: Fix pending events injection
  x86/kvm/vmx: remove unused variable in segment_base()
  selftests/x86: Add a basic selftest for ioperm
  x86/asm: Tidy up TSS limit code
  kvm: convert kvm.users_count from atomic_t to refcount_t
  KVM: x86: never specify a sample period for virtualized in_tx_cp counters
  KVM: PPC: Book3S HV: Don't use ASDR for real-mode HPT faults on POWER9
  KVM: PPC: Book3S HV: Fix software walk of guest process page tables

Pull documentation fixes from Jonathan Corbet:
 "A few fixes for the docs tree, including one for a 4.11 build
  regression"

* tag 'docs-4.11-fixes' of git://git.lwn.net/linux:
  Documentation/sphinx: fix primary_domain configuration
  docs: Fix htmldocs build failure
  doc/ko_KR/memory-barriers: Update control-dependencies section
  pcieaer doc: update the link
  Documentation: Update path to sysrq.txt

Pull staging/IIO driver fixes from Greg KH:
 "Here are a few small staging and IIO driver fixes for issues that
  showed up after the big set if changes you merged last week.

  Nothing major, just small bugs resolved in some IIO drivers, a lustre
  allocation fix, and some RaspberryPi driver fixes for reported
  problems, as well as a MAINTAINERS entry update.

  All of these have been in linux-next for a week with no reported
  issues"

* tag 'staging-4.11-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: fsl-mc: fix warning in DT ranges parser
  MAINTAINERS: Remove Noralf Trønnes as fbtft maintainer
  staging: vchiq_2835_arm: Make cache-line-size a required DT property
  staging: bcm2835/mmal-vchiq: unlock on error in buffer_from_host()
  staging/lustre/lnet: Fix allocation size for sv_cpt_data
  iio: adc: xilinx: Fix error handling
  iio: 104-quad-8: Fix off-by-one error when addressing flag register
  iio: adc: handle unknow of_device_id data

Pull crypto fixes from Herbert Xu:

 - vmalloc stack regression in CCM

 - Build problem in CRC32 on ARM

 - Memory leak in cavium

 - Missing Kconfig dependencies in atmel and mediatek

 - XTS Regression on some platforms (s390 and ppc)

 - Memory overrun in CCM test vector

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: vmx - Use skcipher for xts fallback
  crypto: vmx - Use skcipher for cbc fallback
  crypto: testmgr - Pad aes_ccm_enc_tv_template vector
  crypto: arm/crc32 - add build time test for CRC instruction support
  crypto: arm/crc32 - fix build error with outdated binutils
  crypto: ccm - move cbcmac input off the stack
  crypto: xts - Propagate NEED_FALLBACK bit
  crypto: api - Add crypto_requires_off helper
  crypto: atmel - CRYPTO_DEV_MEDIATEK should depend on HAS_DMA
  crypto: atmel - CRYPTO_DEV_ATMEL_TDES and CRYPTO_DEV_ATMEL_SHA should depend on HAS_DMA
  crypto: cavium - fix leak on curr if curr->head fails to be allocated
  crypto: cavium - Fix couple of static checker errors

Pull misc final vfs updates from Al Viro:
 "A few unrelated patches that got beating in -next.

  Everything else will have to go into the next window ;-/"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  hfs: fix hfs_readdir()
  selftest for default_file_splice_read() infoleak
  9p: constify ->d_name handling

Pull more SCSI updates from James Bottomley:
 "This is the set of stuff that didn't quite make the initial pull and a
  set of fixes for stuff which did.

  The new stuff is basically lpfc (nvme), qedi and aacraid. The fixes
  cover a lot of previously submitted stuff, the most important of which
  probably covers some of the failing irq vectors allocation and other
  fallout from having the SCSI command allocated as part of the block
  allocation functions"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (59 commits)
  scsi: qedi: Fix memory leak in tmf response processing.
  scsi: aacraid: remove redundant zero check on ret
  scsi: lpfc: use proper format string for dma_addr_t
  scsi: lpfc: use div_u64 for 64-bit division
  scsi: mac_scsi: Fix MAC_SCSI=m option when SCSI=m
  scsi: cciss: correct check map error.
  scsi: qla2xxx: fix spelling mistake: "seperator" -> "separator"
  scsi: aacraid: Fixed expander hotplug for SMART family
  scsi: mpt3sas: switch to pci_alloc_irq_vectors
  scsi: qedf: fixup compilation warning about atomic_t usage
  scsi: remove scsi_execute_req_flags
  scsi: merge __scsi_execute into scsi_execute
  scsi: simplify scsi_execute_req_flags
  scsi: make the sense header argument to scsi_test_unit_ready mandatory
  scsi: sd: improve TUR handling in sd_check_events
  scsi: always zero sshdr in scsi_normalize_sense
  scsi: scsi_dh_emc: return success in clariion_std_inquiry()
  scsi: fix memory leak of sdpk on when gd fails to allocate
  scsi: sd: make sd_devt_release() static
  scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.
  ...

Fixes: 43a0c675 ("strparser: Stream parser for messages")
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for your net tree,
they are:

1) Missing check for full sock in ip_route_me_harder(), from
   Florian Westphal.

2) Incorrect sip helper structure initilization that breaks it when
   several ports are used, from Christophe Leroy.

3) Fix incorrect assumption when looking up for matching with adjacent
   intervals in the nft_set_rbtree.

4) Fix broken netlink event error reporting in nf_tables that results
   in misleading ESRCH errors propagated to userspace listeners.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull libnvdimm fixes from Dan Williams:
 "A fix and regression test case for nvdimm namespace label
  compatibility.

  Details:

   - An "nvdimm namespace label" is metadata on an nvdimm that
     provisions dimm capacity into a "namespace" that can host a block
     device / dax-filesytem, or a device-dax character device.

     A namespace is an object that other operating environment and
     platform firmware needs to comprehend for capabilities like booting
     from an nvdimm.

     The label metadata contains a checksum that Linux was not
     calculating correctly leading to other environments rejecting the
     Linux label.

   These have received a build success notification from the kbuild
   robot, and a positive test result from Nick who reported the problem"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  nfit, libnvdimm: fix interleave set cookie calculation
  tools/testing/nvdimm: make iset cookie predictable

Pull PCI fixes from Bjorn Helgaas:

 - fix NULL pointer dereferences in many DesignWare-based drivers due to
   refactoring error

 - fix Altera config write breakage due to my refactoring error

* tag 'pci-v4.11-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: altera: Fix TLP_CFG_DW0 for TLP write
  PCI: dwc: Fix crashes seen due to missing assignments

Pull parisc fixes and cleanups from Helge Deller:
 "Nothing really important in this patchset: fix resource leaks in error
  paths, coding style cleanups and code removal"

* 'parisc-4.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Remove flush_user_dcache_range and flush_user_icache_range
  parisc: fix a printk
  parisc: ccio-dma: Handle return NULL error from ioremap_nocache
  parisc: Define access_ok() as macro
  parisc: eisa: Fix resource leaks in error paths
  parisc: eisa: Remove coding style errors

Pull Xtensa updates from Max Filippov:

 - clean up bootable image build targets: provide separate 'Image',
   'zImage' and 'uImage' make targets that only build corresponding
   image type. Make 'all' build all images appropriate for a platform

 - allow merging vectors code into .text section as a preparation step
   for XIP support

 - fix handling external FDT when the kernel is built without
   BLK_DEV_INITRD support

* tag 'xtensa-20170303' of git://github.com/jcmvbkbc/linux-xtensa:
  xtensa: allow merging vectors into .text section
  xtensa: clean up bootable image build targets
  xtensa: move parse_tag_fdt out of #ifdef CONFIG_BLK_DEV_INITRD

Pull ARM SoC late DT updates from Arnd Bergmann:
 "These updates have been kept in a separate branch mostly because they
  rely on updates to the respective clk drivers to keep the shared
  header files in sync.

  This includes two branches for arm64 dt updates, both following up on
  earlier changes for the same platforms that are already merged:

  Samsung:
   - add USB3 support in Exynos7
   - minor PM related updates

  Amlogic:
   - new machines: WeTek Set-top-boxes
   - various devices added to DT

  There are also a couple of bugfixes that trickled in since the start
  of the merge window:

   - The moxart_defconfig was not building the intended platform
   - CPU-hotplug was broken on ux500
   - Coresight was broken on Juno (never worked)"

* tag 'armsoc-late' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (26 commits)
  ARM: deconfig: fix the moxart defconfig
  ARM: ux500: resume the second core properly
  arm64: dts: juno: update definition for programmable replicator
  arm64: dts: exynos: Add regulators for Vbus and Vbus-Boost
  arm64: dts: exynos: Add USB 3.0 controller node for Exynos7
  arm64: dts: exynos: Use macros for pinctrl configuration on Exynos7
  pinctrl: dt-bindings: samsung: Add Exynos7 specific pinctrl macro definitions
  arm64: dts: exynos: Add initial configuration for DISP clocks for TM2/TM2e
  ARM64: dts: meson-gxbb-p200: add ADC laddered keys
  ARM64: dts: meson: meson-gx: add the SAR ADC
  ARM64: dts: meson-gxl: add the pwm_ao_b pin
  ARM64: dts: meson-gx: add the missing pwm_AO_ab node
  clk: gxbb: fix CLKID_ETH defined twice
  ARM64: dts: meson-gxl: rename Nexbox A95x for consistency
  clk: gxbb: add the SAR ADC clocks and expose them
  dt-bindings: amlogic: Add WeTek boards
  ARM64: dts: meson-gxbb: Add support for WeTek Hub and Play
  dt-bindings: vendor-prefix: Add wetek vendor prefix
  ARM64: dts: meson-gxm: Rename q200 and q201 DT files for consistency
  ARM64: dts: meson-gx: Add HDMI HPD/DDC pinctrl nodes
  ...

Pull SMB3 fixes from Steve French:
 "Some small bug fixes as well as SMB2.1/SMB3 enablement for DFS (global
  namespace) which previously was only enabled for CIFS"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  smb2: Enforce sec= mount option
  CIFS: Fix sparse warnings
  CIFS: implement get_dfs_refer for SMB2+
  CIFS: use DFS pathnames in SMB2+ Create requests
  CIFS: set signing flag in SMB2+ TreeConnect if needed
  CIFS: let ses->ipc_tid hold smb2 TreeIds
  CIFS: add use_ipc flag to SMB2_ioctl()
  CIFS: add build_path_from_dentry_optional_prefix()
  CIFS: move DFS response parsing out of SMB1 code
  CIFS: Fix possible use after free in demultiplex thread

With Sphinx 1.5.3 I get the warning:

	WARNING: primary_domain 'C' not found, ignored.

It seems that domain names in Sphinx are case-sensitive and for the C
domain the name must be lower case.
Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Build of HTML docs failing due to conversion of deviceiobook.tmpl in
8a8a602f and regulator.tmpl in 028f2533 to RST without removing from
DOCBOOKS in Makefile, resulting (in the case of deviceiobook) the
following error:

make[1]: *** No rule to make target 'Documentation/DocBook/deviceiobook.xml', needed by 'Documentation/DocBook/deviceiobook.aux.xml'.  Stop.
Makefile:1452: recipe for target 'htmldocs' failed
make: *** [htmldocs] Error 2

Update DOCBOOKS to reflect available books.
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This commit applies upstream change, commit c8241f85 ("doc: Update
control-dependencies section of memory-barriers.txt"), to Korean
translation.
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The original link is empty, replace it.
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>