1. 22 Jun, 2017 3 commits
  2. 18 Jun, 2017 37 commits
    • Johan Hovold's avatar
      NFC: nfcmrvl: allow gpio 0 for reset signalling · e33a3f84
      Johan Hovold authored
      Allow gpio 0 to be used for reset signalling, and instead use negative
      errnos to disable the reset functionality.
      Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      e33a3f84
    • Johan Hovold's avatar
      NFC: nfcmrvl_usb: use interface as phy device · 0d1ca88b
      Johan Hovold authored
      Use the USB-interface rather than parent USB-device device, which is
      what this driver binds to, when registering the nci device.
      
      Note that using the right device is important when dealing with device-
      managed resources as the interface can be unbound independently of the
      parent device.
      
      Also note that private device pointer had already been set by
      nfcmrvl_nci_register_dev() so the redundant assignment can therefore be
      removed.
      Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      0d1ca88b
    • Johan Hovold's avatar
      NFC: nfcmrvl_uart: fix device-node leak during probe · d0607aa4
      Johan Hovold authored
      Make sure to release the device-node reference when done parsing the
      node.
      
      Fixes: e097dc62 ("NFC: nfcmrvl: add UART driver")
      Cc: Vincent Cuissard <cuissard@marvell.com>
      Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      d0607aa4
    • Johan Hovold's avatar
      NFC: nfcmrvl: fix firmware-management initialisation · 45dd39b9
      Johan Hovold authored
      The nci-device was never deregistered in the event that
      fw-initialisation failed.
      
      Fix this by moving the firmware initialisation before device
      registration since the firmware work queue should be available before
      registering.
      
      Note that this depends on a recent fix that moved device-name
      initialisation back to to nci_allocate_device() as the
      firmware-workqueue name is now derived from the nfc-device name.
      
      Fixes: 3194c687 ("NFC: nfcmrvl: add firmware download support")
      Cc: stable <stable@vger.kernel.org>     # 4.4
      Cc: Vincent Cuissard <cuissard@marvell.com>
      Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      45dd39b9
    • Johan Hovold's avatar
      NFC: nfcmrvl: use nfc-device for firmware download · e5834ac2
      Johan Hovold authored
      Use the nfc- rather than phy-device in firmware-management code that
      needs a valid struct device.
      
      This specifically fixes a NULL-pointer dereference in
      nfcmrvl_fw_dnld_init() during registration when the underlying tty is
      one end of a Unix98 pty.
      
      Note that the driver still uses the phy device for any debugging, which
      is fine for now.
      
      Fixes: 3194c687 ("NFC: nfcmrvl: add firmware download support")
      Cc: stable <stable@vger.kernel.org>     # 4.4
      Cc: Vincent Cuissard <cuissard@marvell.com>
      Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      e5834ac2
    • Johan Hovold's avatar
      NFC: nfcmrvl: do not use device-managed resources · 0cbe4011
      Johan Hovold authored
      This specifically fixes resource leaks in the registration error paths.
      
      Device-managed resources is a bad fit for this driver as devices can be
      registered from the n_nci line discipline. Firstly, a tty may not even
      have a corresponding device (should it be part of a Unix98 pty)
      something which would lead to a NULL-pointer dereference when
      registering resources.
      
      Secondly, if the tty has a class device, its lifetime exceeds that of
      the line discipline, which means that resources would leak every time
      the line discipline is closed (or if registration fails).
      
      Currently, the devres interface was only being used to request a reset
      gpio despite the fact that it was already explicitly freed in
      nfcmrvl_nci_unregister_dev() (along with the private data), something
      which also prevented the resource leak at close.
      
      Note that the driver treats gpio number 0 as invalid despite it being
      perfectly valid. This will be addressed in a follow-up patch.
      
      Fixes: b2fe288e ("NFC: nfcmrvl: free reset gpio")
      Fixes: 4a2b947f ("NFC: nfcmrvl: add chip reset management")
      Cc: stable <stable@vger.kernel.org>     # 4.2: b2fe288e
      Cc: Vincent Cuissard <cuissard@marvell.com>
      Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      0cbe4011
    • Johan Hovold's avatar
      NFC: nfcmrvl_uart: add missing tty-device sanity check · 15e0c59f
      Johan Hovold authored
      Make sure to check the tty-device pointer before trying to access the
      parent device to avoid dereferencing a NULL-pointer when the tty is one
      end of a Unix98 pty.
      
      Fixes: e097dc62 ("NFC: nfcmrvl: add UART driver")
      Cc: stable <stable@vger.kernel.org>     # 4.2
      Cc: Vincent Cuissard <cuissard@marvell.com>
      Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      15e0c59f
    • Johan Hovold's avatar
      NFC: fix broken device allocation · 20777bc5
      Johan Hovold authored
      Commit 7eda8b8e ("NFC: Use IDR library to assing NFC devices IDs")
      moved device-id allocation and struct-device initialisation from
      nfc_allocate_device() to nfc_register_device().
      
      This broke just about every nfc-device-registration error path, which
      continue to call nfc_free_device() that tries to put the device
      reference of the now uninitialised (but zeroed) struct device:
      
      kobject: '(null)' (ce316420): is not initialized, yet kobject_put() is being called.
      
      The late struct-device initialisation also meant that various work
      queues whose names are derived from the nfc device name were also
      misnamed:
      
        421 root         0 SW<  [(null)_nci_cmd_]
        422 root         0 SW<  [(null)_nci_rx_w]
        423 root         0 SW<  [(null)_nci_tx_w]
      
      Move the id-allocation and struct-device initialisation back to
      nfc_allocate_device() and fix up the single call site which did not use
      nfc_free_device() in its error path.
      
      Fixes: 7eda8b8e ("NFC: Use IDR library to assing NFC devices IDs")
      Cc: stable <stable@vger.kernel.org>     # 3.8
      Cc: Samuel Ortiz <sameo@linux.intel.com>
      Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      20777bc5
    • Mark Greer's avatar
      NFC: trf7970a: Clean up coding style issues · e2f0f671
      Mark Greer authored
      Clean up coding style issues according to scripts/Lindent.
      Some scripts/Lindent changes were reverted when it appeared
      to make the code less readable or when it made the line run
      over 80 characters.
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      e2f0f671
    • Mark Greer's avatar
      NFC: trf7970a: Convert to descriptor based GPIO interface · d34e48d6
      Mark Greer authored
      The trf7970a driver uses the deprecated integer-based GPIO consumer
      interface so convert it to use the new descriptor-based GPIO
      consumer interface.
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      d34e48d6
    • Mark Greer's avatar
      NFC: trf7970a: Enable pins are active high not active low · 1877d2c5
      Mark Greer authored
      The example DTS code for the trf7970a sets the GPIOs for the EN
      and EN2 pins to active low when they are really active high so
      correct the error.
      Acked-by: default avatarRob Herring <robh@kernel.org>
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      1877d2c5
    • Mark Greer's avatar
      NFC: trf7970a: Remove support for 'vin-voltage-override' DT property · a34631c2
      Mark Greer authored
      The 'vin-voltage-override' DT property is used by the trf7970a
      driver to override the voltage presented to the driver by the
      regulator subsystem.  This is unnecessary as properly specifying
      the regulator chain via DT properties will accomplish the same
      thing.  Therefore, remove support for 'vin-voltage-override'.
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      a34631c2
    • Mark Greer's avatar
      NFC: trf7970a: Remove useless comment · fcc652f6
      Mark Greer authored
      The last entry in the trf7970a_of_match[] table must be an empty
      entry to demarcate the end of the table.  Currently, there is a
      comment indicating this but it is obvious so remove the comment.
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      fcc652f6
    • Mark Greer's avatar
      NFC: trf7970a: Only check 'en2-rf-quirk' if EN2 is specified · afcb9fbd
      Mark Greer authored
      The quirk indicated by the 'en2-rf-quirk' device tree property
      is only relevant when there is a GPIO connected to the EN2 pin
      of the trf7970a. This means we should only check for 'en2-rf-quirk'
      when EN2 is specified in the 'ti,enable-gpios' property of the
      device tree.
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      afcb9fbd
    • Mark Greer's avatar
      NFC: trf7970a: Fix inaccurate comment in trf7970a_probe() · 69f984f0
      Mark Greer authored
      As of commit ce69b95c ("NFC: Make EN2 pin optional in the
      TRF7970A driver"), only the GPIO for the 'EN' enable pin needs
      to be specified in the device tree so update the comments that
      says both 'EN' and 'EN2' must be specified.
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      69f984f0
    • Mark Greer's avatar
      NFC: trf7970a: Don't de-assert EN2 unless it was asserted · 67dec192
      Mark Greer authored
      When the trf7970a part has the bug related to 'en2-rf-quirk',
      the GPIO connected to the EN2 pin will not be asserted by the
      driver when powering up so it shouldn't be de-asserted when
      powering down.
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      67dec192
    • Mark Greer's avatar
      MAINTAINERS: NFC: trf7970a: Add Mark Greer as maintainer · 581132b6
      Mark Greer authored
      Add Mark Greer as the maintainer of the trf7970a NFC driver.
      Signed-off-by: default avatarMark Greer <mgreer@animalcreek.com>
      Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
      581132b6
    • Florian Fainelli's avatar
      net: dsa: Fix legacy probing · 06d4d450
      Florian Fainelli authored
      After commit 6d3c8c0d ("net: dsa: Remove master_netdev and
      use dst->cpu_dp->netdev") and a29342e7 ("net: dsa: Associate
      slave network device with CPU port") we would be seeing NULL pointer
      dereferences when accessing dst->cpu_dp->netdev too early. In the legacy
      code, we actually know early in advance the master network device, so
      pass it down to the relevant functions.
      
      Fixes: 6d3c8c0d ("net: dsa: Remove master_netdev and use dst->cpu_dp->netdev")
      Fixes: a29342e7 ("net: dsa: Associate slave network device with CPU port")
      Reported-by: default avatarJason Cobham <jcobham@questertangent.com>
      Tested-by: default avatarJason Cobham <jcobham@questertangent.com>
      Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
      Reviewed-by: default avatarVivien Didelot <vivien.didelot@savoirfairelinux.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      06d4d450
    • Dave Watson's avatar
      tls: update Kconfig · d807ec65
      Dave Watson authored
      Missing crypto deps for some platforms.
      Default to n for new module.
      
      config: m68k-amcore_defconfig (attached as .config)
      compiler: m68k-linux-gcc (GCC) 4.9.0
      
      make.cross ARCH=m68k
      All errors (new ones prefixed by >>):
      
         net/built-in.o: In function `tls_set_sw_offload':
      >> (.text+0x732f8): undefined reference to `crypto_alloc_aead'
         net/built-in.o: In function `tls_set_sw_offload':
      >> (.text+0x7333c): undefined reference to `crypto_aead_setkey'
         net/built-in.o: In function `tls_set_sw_offload':
      >> (.text+0x73354): undefined reference to `crypto_aead_setauthsize'
      Reported-by: default avatarkbuild test robot <fengguang.wu@intel.com>
      Signed-off-by: default avatarDave Watson <davejwatson@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d807ec65
    • David S. Miller's avatar
      Merge branch 'net-remove-dst-garbage-collector-logic' · ffe95ecf
      David S. Miller authored
      Wei Wang says:
      
      ====================
      remove dst garbage collector logic
      
      The current mechanism of dst release is a bit complicated. It is because
      the users of dst get divided into 2 situations:
        1. Most users take the reference count when using a dst and release the
           reference count when done.
        2. Exceptional users like IPv4/IPv6/decnet/xfrm routing code do not take
           reference count when referencing to a dst due to some histotic reasons.
      
      Due to those exceptional use cases in 2, reference count being 0 is not an
      adequate evidence to indicate that no user is using this dst. So users in 1
      can't free the dst simply based on reference count being 0 because users in
      2 might still hold reference to it.
      Instead, a dst garbage list is needed to hold the dst entries that already
      get removed by the users in 2 but are still held by users in 1. And a periodic
      garbage collector task is run to check all the dst entries in the list to see
      if the users in 1 have released the reference to those dst entries.
      If so, the dst is now ready to be freed.
      
      This logic introduces unnecessary complications in the dst code which makes it
      hard to understand and to debug.
      
      In order to get rid of the whole dst garbage collector (gc) and make the dst
      code more unified and simplified, we can make the users in 2 also take reference
      count on the dst and release it properly when done.
      This way, dst can be safely freed once the refcount drops to 0 and no gc
      thread is needed anymore.
      
      This patch series' target is to completely get rid of dst gc logic and free
      dst based on reference count only.
      Patch 1-3 are preparation patches to do some cleanup/improvement on the existing
      code to make later work easier.
      Patch 4-21 are real implementations.
      In these patches, a temporary flag DST_NOGC is used to help transition
      those exceptional users one by one. Once every component is transitioned,
      this temporary flag is removed.
      By the end of this patch series, all dst are refcounted when being used
      and released when done. And dst will be freed when its refcount drops to 0.
      No dst gc task is running anymore.
      
      Note: This patch series depends on the decnet fix that was sent right before:
            "decnet: always not take dst->__refcnt when inserting dst into hash table"
      
      v2:
        add curly braces in udp_v4/6_early_demux() in patch 02
        add EXPORT_SYMBOL() for dst_dev_put() in patch 05
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ffe95ecf
    • Wei Wang's avatar
      net: add debug atomic_inc_not_zero() in dst_hold() · 44ebe791
      Wei Wang authored
      This patch is meant to add a debug warning on the situation where dst is
      being held during its destroy phase. This could potentially cause double
      free issue on the dst.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      44ebe791
    • Wei Wang's avatar
      net: reorder all the dst flags · 1eb04e7c
      Wei Wang authored
      As some dst flags are removed, reorder the dst flags to fill in the
      blanks.
      Note: these flags are not exposed into user space. So it is safe to
      reorder.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1eb04e7c
    • Wei Wang's avatar
      net: remove DST_NOCACHE flag · a4c2fd7f
      Wei Wang authored
      DST_NOCACHE flag check has been removed from dst_release() and
      dst_hold_safe() in a previous patch because all the dst are now ref
      counted properly and can be released based on refcnt only.
      Looking at the rest of the DST_NOCACHE use, all of them can now be
      removed or replaced with other checks.
      So this patch gets rid of all the DST_NOCACHE usage and remove this flag
      completely.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a4c2fd7f
    • Wei Wang's avatar
      net: remove DST_NOGC flag · b2a9c0ed
      Wei Wang authored
      Now that all the components have been changed to release dst based on
      refcnt only and not depend on dst gc anymore, we can remove the
      temporary flag DST_NOGC.
      
      Note that we also need to remove the DST_NOCACHE check in dst_release()
      and dst_hold_safe() because now all the dst are released based on refcnt
      and behaves as DST_NOCACHE.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b2a9c0ed
    • Wei Wang's avatar
      net: remove dst gc related code · 5b7c9a8f
      Wei Wang authored
      This patch removes all dst gc related code and all the dst free
      functions
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5b7c9a8f
    • Wei Wang's avatar
      decnet: take dst->__refcnt when struct dn_route is created · 560fd93b
      Wei Wang authored
      struct dn_route is inserted into dn_rt_hash_table but no dst->__refcnt
      is taken.
      This patch makes sure the dn_rt_hash_table's reference to the dst is ref
      counted.
      
      As the dst is always ref counted properly, we can safely mark
      DST_NOGC flag so dst_release() will release dst based on refcnt only.
      And dst gc is no longer needed and all dst_free() or its related
      function calls should be replaced with dst_release() or
      dst_release_immediate(). And dst_dev_put() is called when removing dst
      from the hash table to release the reference on dst->dev before we lose
      pointer to it.
      
      Also, correct the logic in dn_dst_check_expire() and dn_dst_gc() to
      check dst->__refcnt to be > 1 to indicate it is referenced by other
      users.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      560fd93b
    • Wei Wang's avatar
      xfrm: take refcnt of dst when creating struct xfrm_dst bundle · 52df157f
      Wei Wang authored
      During the creation of xfrm_dst bundle, always take ref count when
      allocating the dst. This way, xfrm_bundle_create() will form a linked
      list of dst with dst->child pointing to a ref counted dst child. And
      the returned dst pointer is also ref counted. This makes the link from
      the flow cache to this dst now ref counted properly.
      As the dst is always ref counted properly, we can safely mark
      DST_NOGC flag so dst_release() will release dst based on refcnt only.
      And dst gc is no longer needed and all dst_free() and its related
      function calls should be replaced with dst_release() or
      dst_release_immediate().
      
      The special handling logic for dst->child in dst_destroy() can be
      replaced with a simple dst_release_immediate() call on the child to
      release the whole list linked by dst->child pointer.
      Previously used DST_NOHASH flag is not needed anymore as well. The
      reason that DST_NOHASH is used in the existing code is mainly to prevent
      the dst inserted in the fib tree to be wrongly destroyed during the
      deletion of the xfrm_dst bundle. So in the existing code, DST_NOHASH
      flag is marked in all the dst children except the one which is in the
      fib tree.
      However, with this patch series to remove dst gc logic and release dst
      only based on ref count, it is safe to release all the children from a
      xfrm_dst bundle as long as the dst children are all ref counted
      properly which is already the case in the existing code.
      So, this patch removes the use of DST_NOHASH flag.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      52df157f
    • Wei Wang's avatar
      ipv6: get rid of icmp6 dst garbage collector · db916649
      Wei Wang authored
      icmp6 dst route is currently ref counted during creation and will be
      freed by user during its call of dst_release(). So no need of a garbage
      collector for it.
      Remove all icmp6 dst garbage collector related code.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      db916649
    • Wei Wang's avatar
      ipv6: mark DST_NOGC and remove the operation of dst_free() · 587fea74
      Wei Wang authored
      With the previous preparation patches, we are ready to get rid of the
      dst gc operation in ipv6 code and release dst based on refcnt only.
      So this patch adds DST_NOGC flag for all IPv6 dst and remove the calls
      to dst_free() and its related functions.
      At this point, all dst created in ipv6 code do not use the dst gc
      anymore and will be destroyed at the point when refcnt drops to 0.
      
      Also, as icmp6 dst route is refcounted during creation and will be freed
      by user during its call of dst_release(), there is no need to add this
      dst to the icmp6 gc list as well.
      Instead, we need to add it into uncached list so that when a
      NETDEV_DOWN/NETDEV_UNREGISRER event comes, we can properly go through
      these icmp6 dst as well and release the net device properly.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      587fea74
    • Wei Wang's avatar
      ipv6: call dst_hold_safe() properly · ad65a2f0
      Wei Wang authored
      Similar as ipv4, ipv6 path also needs to call dst_hold_safe() when
      necessary to avoid double free issue on the dst.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ad65a2f0
    • Wei Wang's avatar
      ipv6: call dst_dev_put() properly · 9514528d
      Wei Wang authored
      As the intend of this patch series is to completely remove dst gc,
      we need to call dst_dev_put() to release the reference to dst->dev
      when removing routes from fib because we won't keep the gc list anymore
      and will lose the dst pointer right after removing the routes.
      Without the gc list, there is no way to find all the dst's that have
      dst->dev pointing to the going-down dev.
      Hence, we are doing dst_dev_put() immediately before we lose the last
      reference of the dst from the routing code. The next dst_check() will
      trigger a route re-lookup to find another route (if there is any).
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9514528d
    • Wei Wang's avatar
      ipv6: take dst->__refcnt for insertion into fib6 tree · 1cfb71ee
      Wei Wang authored
      In IPv6 routing code, struct rt6_info is created for each static route
      and RTF_CACHE route and inserted into fib6 tree. In both cases, dst
      ref count is not taken.
      As explained in the previous patch, this leads to the need of the dst
      garbage collector.
      
      This patch holds ref count of dst before inserting the route into fib6
      tree and properly releases the dst when deleting it from the fib6 tree
      as a preparation in order to fully get rid of dst gc later.
      
      Also, correct fib6_age() logic to check dst->__refcnt to be 1 to indicate
      no user is referencing the dst.
      
      And remove dst_hold() in vrf_rt6_create() as ip6_dst_alloc() already puts
      dst->__refcnt to 1.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1cfb71ee
    • Wei Wang's avatar
      ipv4: mark DST_NOGC and remove the operation of dst_free() · b838d5e1
      Wei Wang authored
      With the previous preparation patches, we are ready to get rid of the
      dst gc operation in ipv4 code and release dst based on refcnt only.
      So this patch adds DST_NOGC flag for all IPv4 dst and remove the calls
      to dst_free().
      At this point, all dst created in ipv4 code do not use the dst gc
      anymore and will be destroyed at the point when refcnt drops to 0.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b838d5e1
    • Wei Wang's avatar
      ipv4: call dst_hold_safe() properly · 9df16efa
      Wei Wang authored
      This patch checks all the calls to
      dst_hold()/skb_dst_force()/dst_clone()/dst_use() to see if
      dst_hold_safe() is needed to avoid double free issue if dst
      gc is removed and dst_release() directly destroys dst when
      dst->__refcnt drops to 0.
      
      In tx path, TCP hold sk->sk_rx_dst ref count and also hold sock_lock().
      UDP and other similar protocols always hold refcount for
      skb->_skb_refdst. So both paths seem to be safe.
      
      In rx path, as it is lockless and skb_dst_set_noref() is likely to be
      used, dst_hold_safe() should always be used when trying to hold dst.
      
      In the routing code, if dst is held during an rcu protected session, it
      is necessary to call dst_hold_safe() as the current dst might be in its
      rcu grace period.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9df16efa
    • Wei Wang's avatar
      ipv4: call dst_dev_put() properly · 95c47f9c
      Wei Wang authored
      As the intend of this patch series is to completely remove dst gc,
      we need to call dst_dev_put() to release the reference to dst->dev
      when removing routes from fib because we won't keep the gc list anymore
      and will lose the dst pointer right after removing the routes.
      Without the gc list, there is no way to find all the dst's that have
      dst->dev pointing to the going-down dev.
      Hence, we are doing dst_dev_put() immediately before we lose the last
      reference of the dst from the routing code. The next dst_check() will
      trigger a route re-lookup to find another route (if there is any).
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      95c47f9c
    • Wei Wang's avatar
      ipv4: take dst->__refcnt when caching dst in fib · 0830106c
      Wei Wang authored
      In IPv4 routing code, fib_nh and fib_nh_exception can hold pointers
      to struct rtable but they never increment dst->__refcnt.
      This leads to the need of the dst garbage collector because when user
      is done with this dst and calls dst_release(), it can only decrement
      dst->__refcnt and can not free the dst even it sees dst->__refcnt
      drops from 1 to 0 (unless DST_NOCACHE flag is set) because the routing
      code might still hold reference to it.
      And when the routing code tries to delete a route, it has to put the
      dst to the gc_list if dst->__refcnt is not yet 0 and have a gc thread
      running periodically to check on dst->__refcnt and finally to free dst
      when refcnt becomes 0.
      
      This patch increments dst->__refcnt when
      fib_nh/fib_nh_exception holds reference to this dst and properly release
      the dst when fib_nh/fib_nh_exception has been updated with a new dst.
      
      This patch is a preparation in order to fully get rid of dst gc later.
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0830106c
    • Wei Wang's avatar
      net: introduce a new function dst_dev_put() · 4a6ce2b6
      Wei Wang authored
      This function should be called when removing routes from fib tree after
      the dst gc is no longer in use.
      We first mark DST_OBSOLETE_DEAD on this dst to make sure next
      dst_ops->check() fails and returns NULL.
      Secondly, as we no longer keep the gc_list, we need to properly
      release dst->dev right at the moment when the dst is removed from
      the fib/fib6 tree.
      It does the following:
      1. change dst->input and output pointers to dst_discard/dst_dscard_out to
         discard all packets
      2. replace dst->dev with loopback interface
      Signed-off-by: default avatarWei Wang <weiwan@google.com>
      Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4a6ce2b6