Henrik Bjoernlund says:

====================
net: bridge: cfm: Add support for Connectivity Fault Management(CFM)

Connectivity Fault Management (CFM) is defined in 802.1Q
section 12.14.

Connectivity Fault Management (CFM) comprises capabilities for
detecting, verifying, and isolating connectivity failures in Virtual
Bridged Networks. These capabilities can be used in networks
operated by multiple independent organizations, each with restricted
management access to each other’s equipment.

CFM functions are partitioned as follows:
    — Path discovery
    — Fault detection
    — Fault verification and isolation
    — Fault notification
    — Fault recovery

The primary CFM protocol shims are called Maintenance Points (MPs).
A MP can be either a MEP or a MHF.
The MEP:
    -It is the Maintenance association End Point
     described in 802.1Q section 19.2.
    -It is created on a specific level (1-7) and is assuring
     that no CFM frames are passing through this MEP on lower levels.
    -It initiates and terminates/validates CFM frames on its level.
    -It can only exist on a port that is related to a bridge.
The MHF:
    -It is the Maintenance Domain Intermediate Point
     (MIP) Half Function (MHF) described in 802.1Q section 19.3.
    -It is created on a specific level (1-7).
    -It is extracting/injecting certain CFM frame on this level.
    -It can only exist on a port that is related to a bridge.
    -Currently not supported.

There are defined the following CFM protocol functions:
    -Continuity Check
    -Loopback. Currently not supported.
    -Linktrace. Currently not supported.

This CFM component supports create/delete of MEP instances and
configuration of the different CFM protocols. Also status information
can be fetched and delivered through notification due to defect
status change.

The user interacts with CFM using the 'cfm' user space client
program, the client talks with the kernel using netlink.

Any notification emitted by CFM from the kernel can be monitored in
user space by starting 'cfm_server' program.

Currently this 'cfm' and 'cfm_server' programs are standalone placed
in a cfm repository https://github.com/microchip-ung/cfm but it is
considered to integrate this into 'iproute2'.

v1 -> v2
    Added the CFM switchdev interface and also added utilization by
    calling the interface from the kernel CFM implementation trying
    to offload CFM functionality to HW. This offload (CFM driver) is
    currently not implemented.

    Corrections based on RCF comments:
        -The single CFM kernel implementation Patch is broken up into
         three patches.
        -Changed the list of MEP instances from list_head to
         hlist_head.
        -Removed unnecessary RCU list traversing.
        -Solved RCU unlocking problem.
        -Removed unnecessary comments.
        -Added ASSERT_RTNL() where required.
        -Shaping up on error messages.
        -Correction NETLINK br_fill_ifinfo() to be able to handle
         'filter_mask' with multiple flags asserted.

v2 -> v3
    -The switchdev definition and utilization has been removed as
     there was no switchdev implementation.
    -Some compiling issues are fixed as Reported-by:
     kernel test robot <lkp@intel.com>.

v3 -> v4
    -Fixed potential crash during hlist walk where elements are
     removed.
    -Giving all commits unique titles.
    -NETLINK implementation split into three commits.
    -Commit "bridge: cfm: Bridge port remove" is merged with
     commit "bridge: cfm: Kernel space implementation of CFM. MEP
     create/delete."

v4 -> v5
    -Reordered members in struct net_bridge to bring member
     frame_type_list to the first cache line.
    -Helper functions nla_get_mac() and nla_get_maid() are removed.
    -The NLA_POLICY_NESTED() macro is used to initialize the
     br_cfm_policy array.
    -Fixed reverse xmas tree.

v5 -> v6
    -Fixed that the SKB buffer was not freed during error handling return.
    -Removed unused struct definition.
    -Changed bool to u8 bitfields for space save.
    -Utilizing the NETLINK policy validation feature.

v6 -> v7
    -Removed check of parameters in br_cfm_mep_config_set() and
     br_cfm_cc_peer_mep_add() in first commit of MEP implementation
     (Patch 4 out of 10)
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: Henrik Bjoernlund <henrik.bjoernlund@microchip.com>
====================

Link: https://lore.kernel.org/r/20201027100251.3241719-1-henrik.bjoernlund@microchip.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

This is the implementation of Netlink notifications out of CFM.

Notifications are initiated whenever a state change happens in CFM.

IFLA_BRIDGE_CFM:
    Points to the CFM information.

IFLA_BRIDGE_CFM_MEP_STATUS_INFO:
    This indicate that the MEP instance status are following.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO:
    This indicate that the peer MEP status are following.

CFM nested attribute has the following attributes in next level.

IFLA_BRIDGE_CFM_MEP_STATUS_INSTANCE:
    The MEP instance number of the delivered status.
    The type is NLA_U32.
IFLA_BRIDGE_CFM_MEP_STATUS_OPCODE_UNEXP_SEEN:
    The MEP instance received CFM PDU with unexpected Opcode.
    The type is NLA_U32 (bool).
IFLA_BRIDGE_CFM_MEP_STATUS_VERSION_UNEXP_SEEN:
    The MEP instance received CFM PDU with unexpected version.
    The type is NLA_U32 (bool).
IFLA_BRIDGE_CFM_MEP_STATUS_RX_LEVEL_LOW_SEEN:
    The MEP instance received CCM PDU with MD level lower than
    configured level. This frame is discarded.
    The type is NLA_U32 (bool).

IFLA_BRIDGE_CFM_CC_PEER_STATUS_INSTANCE:
    The MEP instance number of the delivered status.
    The type is NLA_U32.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_PEER_MEPID:
    The added Peer MEP ID of the delivered status.
    The type is NLA_U32.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_CCM_DEFECT:
    The CCM defect status.
    The type is NLA_U32 (bool).
    True means no CCM frame is received for 3.25 intervals.
    IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_RDI:
    The last received CCM PDU RDI.
    The type is NLA_U32 (bool).
IFLA_BRIDGE_CFM_CC_PEER_STATUS_PORT_TLV_VALUE:
    The last received CCM PDU Port Status TLV value field.
    The type is NLA_U8.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_IF_TLV_VALUE:
    The last received CCM PDU Interface Status TLV value field.
    The type is NLA_U8.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_SEEN:
    A CCM frame has been received from Peer MEP.
    The type is NLA_U32 (bool).
    This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_TLV_SEEN:
    A CCM frame with TLV has been received from Peer MEP.
    The type is NLA_U32 (bool).
    This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
IFLA_BRIDGE_CFM_CC_PEER_STATUS_SEQ_UNEXP_SEEN:
    A CCM frame with unexpected sequence number has been received
    from Peer MEP.
    The type is NLA_U32 (bool).
    When a sequence number is not one higher than previously received
    then it is unexpected.
    This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This is the implementation of CFM netlink status
get information interface.

Add new nested netlink attributes. These attributes are used by the
user space to get status information.

GETLINK:
    Request filter RTEXT_FILTER_CFM_STATUS:
    Indicating that CFM status information must be delivered.

    IFLA_BRIDGE_CFM:
        Points to the CFM information.

    IFLA_BRIDGE_CFM_MEP_STATUS_INFO:
        This indicate that the MEP instance status are following.
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO:
        This indicate that the peer MEP status are following.

CFM nested attribute has the following attributes in next level.

GETLINK RTEXT_FILTER_CFM_STATUS:
    IFLA_BRIDGE_CFM_MEP_STATUS_INSTANCE:
        The MEP instance number of the delivered status.
        The type is u32.
    IFLA_BRIDGE_CFM_MEP_STATUS_OPCODE_UNEXP_SEEN:
        The MEP instance received CFM PDU with unexpected Opcode.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_MEP_STATUS_VERSION_UNEXP_SEEN:
        The MEP instance received CFM PDU with unexpected version.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_MEP_STATUS_RX_LEVEL_LOW_SEEN:
        The MEP instance received CCM PDU with MD level lower than
        configured level. This frame is discarded.
        The type is u32 (bool).

    IFLA_BRIDGE_CFM_CC_PEER_STATUS_INSTANCE:
        The MEP instance number of the delivered status.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_PEER_MEPID:
        The added Peer MEP ID of the delivered status.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_CCM_DEFECT:
        The CCM defect status.
        The type is u32 (bool).
        True means no CCM frame is received for 3.25 intervals.
        IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL.
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_RDI:
        The last received CCM PDU RDI.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_PORT_TLV_VALUE:
        The last received CCM PDU Port Status TLV value field.
        The type is u8.
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_IF_TLV_VALUE:
        The last received CCM PDU Interface Status TLV value field.
        The type is u8.
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_SEEN:
        A CCM frame has been received from Peer MEP.
        The type is u32 (bool).
        This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_TLV_SEEN:
        A CCM frame with TLV has been received from Peer MEP.
        The type is u32 (bool).
        This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
    IFLA_BRIDGE_CFM_CC_PEER_STATUS_SEQ_UNEXP_SEEN:
        A CCM frame with unexpected sequence number has been received
        from Peer MEP.
        The type is u32 (bool).
        When a sequence number is not one higher than previously received
        then it is unexpected.
        This is cleared after GETLINK IFLA_BRIDGE_CFM_CC_PEER_STATUS_INFO.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This is the implementation of CFM netlink configuration
get information interface.

Add new nested netlink attributes. These attributes are used by the
user space to get configuration information.

GETLINK:
    Request filter RTEXT_FILTER_CFM_CONFIG:
    Indicating that CFM configuration information must be delivered.

    IFLA_BRIDGE_CFM:
        Points to the CFM information.

    IFLA_BRIDGE_CFM_MEP_CREATE_INFO:
        This indicate that MEP instance create parameters are following.
    IFLA_BRIDGE_CFM_MEP_CONFIG_INFO:
        This indicate that MEP instance config parameters are following.
    IFLA_BRIDGE_CFM_CC_CONFIG_INFO:
        This indicate that MEP instance CC functionality
        parameters are following.
    IFLA_BRIDGE_CFM_CC_RDI_INFO:
        This indicate that CC transmitted CCM PDU RDI
        parameters are following.
    IFLA_BRIDGE_CFM_CC_CCM_TX_INFO:
        This indicate that CC transmitted CCM PDU parameters are
        following.
    IFLA_BRIDGE_CFM_CC_PEER_MEP_INFO:
        This indicate that the added peer MEP IDs are following.

CFM nested attribute has the following attributes in next level.

GETLINK RTEXT_FILTER_CFM_CONFIG:
    IFLA_BRIDGE_CFM_MEP_CREATE_INSTANCE:
        The created MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_MEP_CREATE_DOMAIN:
        The created MEP domain.
        The type is u32 (br_cfm_domain).
        It must be BR_CFM_PORT.
        This means that CFM frames are transmitted and received
        directly on the port - untagged. Not in a VLAN.
    IFLA_BRIDGE_CFM_MEP_CREATE_DIRECTION:
        The created MEP direction.
        The type is u32 (br_cfm_mep_direction).
        It must be BR_CFM_MEP_DIRECTION_DOWN.
        This means that CFM frames are transmitted and received on
        the port. Not in the bridge.
    IFLA_BRIDGE_CFM_MEP_CREATE_IFINDEX:
        The created MEP residence port ifindex.
        The type is u32 (ifindex).

    IFLA_BRIDGE_CFM_MEP_DELETE_INSTANCE:
        The deleted MEP instance number.
        The type is u32.

    IFLA_BRIDGE_CFM_MEP_CONFIG_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_MEP_CONFIG_UNICAST_MAC:
        The configured MEP unicast MAC address.
        The type is 6*u8 (array).
        This is used as SMAC in all transmitted CFM frames.
    IFLA_BRIDGE_CFM_MEP_CONFIG_MDLEVEL:
        The configured MEP unicast MD level.
        The type is u32.
        It must be in the range 1-7.
        No CFM frames are passing through this MEP on lower levels.
    IFLA_BRIDGE_CFM_MEP_CONFIG_MEPID:
        The configured MEP ID.
        The type is u32.
        It must be in the range 0-0x1FFF.
        This MEP ID is inserted in any transmitted CCM frame.

    IFLA_BRIDGE_CFM_CC_CONFIG_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_CONFIG_ENABLE:
        The Continuity Check (CC) functionality is enabled or disabled.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL:
        The CC expected receive interval of CCM frames.
        The type is u32 (br_cfm_ccm_interval).
        This is also the transmission interval of CCM frames when enabled.
    IFLA_BRIDGE_CFM_CC_CONFIG_EXP_MAID:
        The CC expected receive MAID in CCM frames.
        The type is CFM_MAID_LENGTH*u8.
        This is MAID is also inserted in transmitted CCM frames.

    IFLA_BRIDGE_CFM_CC_PEER_MEP_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_PEER_MEPID:
        The CC Peer MEP ID added.
        The type is u32.
        When a Peer MEP ID is added and CC is enabled it is expected to
        receive CCM frames from that Peer MEP.

    IFLA_BRIDGE_CFM_CC_RDI_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_RDI_RDI:
        The RDI that is inserted in transmitted CCM PDU.
        The type is u32 (bool).

    IFLA_BRIDGE_CFM_CC_CCM_TX_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_CCM_TX_DMAC:
        The transmitted CCM frame destination MAC address.
        The type is 6*u8 (array).
        This is used as DMAC in all transmitted CFM frames.
    IFLA_BRIDGE_CFM_CC_CCM_TX_SEQ_NO_UPDATE:
        The transmitted CCM frame update (increment) of sequence
        number is enabled or disabled.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_CCM_TX_PERIOD:
        The period of time where CCM frame are transmitted.
        The type is u32.
        The time is given in seconds. SETLINK IFLA_BRIDGE_CFM_CC_CCM_TX
        must be done before timeout to keep transmission alive.
        When period is zero any ongoing CCM frame transmission
        will be stopped.
    IFLA_BRIDGE_CFM_CC_CCM_TX_IF_TLV:
        The transmitted CCM frame update with Interface Status TLV
        is enabled or disabled.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_CCM_TX_IF_TLV_VALUE:
        The transmitted Interface Status TLV value field.
        The type is u8.
    IFLA_BRIDGE_CFM_CC_CCM_TX_PORT_TLV:
        The transmitted CCM frame update with Port Status TLV is enabled
        or disabled.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_CCM_TX_PORT_TLV_VALUE:
        The transmitted Port Status TLV value field.
        The type is u8.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This is the implementation of CFM netlink configuration
set information interface.

Add new nested netlink attributes. These attributes are used by the
user space to create/delete/configure CFM instances.

SETLINK:
    IFLA_BRIDGE_CFM:
        Indicate that the following attributes are CFM.

    IFLA_BRIDGE_CFM_MEP_CREATE:
        This indicate that a MEP instance must be created.
    IFLA_BRIDGE_CFM_MEP_DELETE:
        This indicate that a MEP instance must be deleted.
    IFLA_BRIDGE_CFM_MEP_CONFIG:
        This indicate that a MEP instance must be configured.
    IFLA_BRIDGE_CFM_CC_CONFIG:
        This indicate that a MEP instance Continuity Check (CC)
        functionality must be configured.
    IFLA_BRIDGE_CFM_CC_PEER_MEP_ADD:
        This indicate that a CC Peer MEP must be added.
    IFLA_BRIDGE_CFM_CC_PEER_MEP_REMOVE:
        This indicate that a CC Peer MEP must be removed.
    IFLA_BRIDGE_CFM_CC_CCM_TX:
        This indicate that the CC transmitted CCM PDU must be configured.
    IFLA_BRIDGE_CFM_CC_RDI:
        This indicate that the CC transmitted CCM PDU RDI must be
        configured.

CFM nested attribute has the following attributes in next level.

SETLINK RTEXT_FILTER_CFM_CONFIG:
    IFLA_BRIDGE_CFM_MEP_CREATE_INSTANCE:
        The created MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_MEP_CREATE_DOMAIN:
        The created MEP domain.
        The type is u32 (br_cfm_domain).
        It must be BR_CFM_PORT.
        This means that CFM frames are transmitted and received
        directly on the port - untagged. Not in a VLAN.
    IFLA_BRIDGE_CFM_MEP_CREATE_DIRECTION:
        The created MEP direction.
        The type is u32 (br_cfm_mep_direction).
        It must be BR_CFM_MEP_DIRECTION_DOWN.
        This means that CFM frames are transmitted and received on
        the port. Not in the bridge.
    IFLA_BRIDGE_CFM_MEP_CREATE_IFINDEX:
        The created MEP residence port ifindex.
        The type is u32 (ifindex).

    IFLA_BRIDGE_CFM_MEP_DELETE_INSTANCE:
        The deleted MEP instance number.
        The type is u32.

    IFLA_BRIDGE_CFM_MEP_CONFIG_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_MEP_CONFIG_UNICAST_MAC:
        The configured MEP unicast MAC address.
        The type is 6*u8 (array).
        This is used as SMAC in all transmitted CFM frames.
    IFLA_BRIDGE_CFM_MEP_CONFIG_MDLEVEL:
        The configured MEP unicast MD level.
        The type is u32.
        It must be in the range 1-7.
        No CFM frames are passing through this MEP on lower levels.
    IFLA_BRIDGE_CFM_MEP_CONFIG_MEPID:
        The configured MEP ID.
        The type is u32.
        It must be in the range 0-0x1FFF.
        This MEP ID is inserted in any transmitted CCM frame.

    IFLA_BRIDGE_CFM_CC_CONFIG_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_CONFIG_ENABLE:
        The Continuity Check (CC) functionality is enabled or disabled.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_CONFIG_EXP_INTERVAL:
        The CC expected receive interval of CCM frames.
        The type is u32 (br_cfm_ccm_interval).
        This is also the transmission interval of CCM frames when enabled.
    IFLA_BRIDGE_CFM_CC_CONFIG_EXP_MAID:
        The CC expected receive MAID in CCM frames.
        The type is CFM_MAID_LENGTH*u8.
        This is MAID is also inserted in transmitted CCM frames.

    IFLA_BRIDGE_CFM_CC_PEER_MEP_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_PEER_MEPID:
        The CC Peer MEP ID added.
        The type is u32.
        When a Peer MEP ID is added and CC is enabled it is expected to
        receive CCM frames from that Peer MEP.

    IFLA_BRIDGE_CFM_CC_RDI_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_RDI_RDI:
        The RDI that is inserted in transmitted CCM PDU.
        The type is u32 (bool).

    IFLA_BRIDGE_CFM_CC_CCM_TX_INSTANCE:
        The configured MEP instance number.
        The type is u32.
    IFLA_BRIDGE_CFM_CC_CCM_TX_DMAC:
        The transmitted CCM frame destination MAC address.
        The type is 6*u8 (array).
        This is used as DMAC in all transmitted CFM frames.
    IFLA_BRIDGE_CFM_CC_CCM_TX_SEQ_NO_UPDATE:
        The transmitted CCM frame update (increment) of sequence
        number is enabled or disabled.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_CCM_TX_PERIOD:
        The period of time where CCM frame are transmitted.
        The type is u32.
        The time is given in seconds. SETLINK IFLA_BRIDGE_CFM_CC_CCM_TX
        must be done before timeout to keep transmission alive.
        When period is zero any ongoing CCM frame transmission
        will be stopped.
    IFLA_BRIDGE_CFM_CC_CCM_TX_IF_TLV:
        The transmitted CCM frame update with Interface Status TLV
        is enabled or disabled.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_CCM_TX_IF_TLV_VALUE:
        The transmitted Interface Status TLV value field.
        The type is u8.
    IFLA_BRIDGE_CFM_CC_CCM_TX_PORT_TLV:
        The transmitted CCM frame update with Port Status TLV is enabled
        or disabled.
        The type is u32 (bool).
    IFLA_BRIDGE_CFM_CC_CCM_TX_PORT_TLV_VALUE:
        The transmitted Port Status TLV value field.
        The type is u8.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This is the third commit of the implementation of the CFM protocol
according to 802.1Q section 12.14.

Functionality is extended with CCM frame reception.
The MEP instance now contains CCM based status information.
Most important is the CCM defect status indicating if correct
CCM frames are received with the expected interval.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This is the second commit of the implementation of the CFM protocol
according to 802.1Q section 12.14.

Functionality is extended with CCM frame transmission.

Interface is extended with these functions:
br_cfm_cc_rdi_set()
br_cfm_cc_ccm_tx()
br_cfm_cc_config_set()

A MEP Continuity Check feature can be configured by
br_cfm_cc_config_set()
    The Continuity Check parameters can be configured to be used when
    transmitting CCM.

A MEP can be configured to start or stop transmission of CCM frames by
br_cfm_cc_ccm_tx()
    The CCM will be transmitted for a selected period in seconds.
    Must call this function before timeout to keep transmission alive.

A MEP transmitting CCM can be configured with inserted RDI in PDU by
br_cfm_cc_rdi_set()
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This is the first commit of the implementation of the CFM protocol
according to 802.1Q section 12.14.

It contains MEP instance create, delete and configuration.

Connectivity Fault Management (CFM) comprises capabilities for
detecting, verifying, and isolating connectivity failures in
Virtual Bridged Networks. These capabilities can be used in
networks operated by multiple independent organizations, each
with restricted management access to each others equipment.

CFM functions are partitioned as follows:
    - Path discovery
    - Fault detection
    - Fault verification and isolation
    - Fault notification
    - Fault recovery

Interface consists of these functions:
br_cfm_mep_create()
br_cfm_mep_delete()
br_cfm_mep_config_set()
br_cfm_cc_config_set()
br_cfm_cc_peer_mep_add()
br_cfm_cc_peer_mep_remove()

A MEP instance is created by br_cfm_mep_create()
    -It is the Maintenance association End Point
     described in 802.1Q section 19.2.
    -It is created on a specific level (1-7) and is assuring
     that no CFM frames are passing through this MEP on lower levels.
    -It initiates and validates CFM frames on its level.
    -It can only exist on a port that is related to a bridge.
    -Attributes given cannot be changed until the instance is
     deleted.

A MEP instance can be deleted by br_cfm_mep_delete().

A created MEP instance has attributes that can be
configured by br_cfm_mep_config_set().

A MEP Continuity Check feature can be configured by
br_cfm_cc_config_set()
    The Continuity Check Receiver state machine can be
    enabled and disabled.
    According to 802.1Q section 19.2.8

A MEP can have Peer MEPs added and removed by
br_cfm_cc_peer_mep_add() and br_cfm_cc_peer_mep_remove()
    The Continuity Check feature can maintain connectivity
    status on each added Peer MEP.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This EtherType is used by all CFM protocal frames transmitted
according to 802.1Q section 12.14.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This makes it possible to include or exclude the CFM
protocol according to 802.1Q section 12.14.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This patch extends the processing of frames in the bridge. Currently MRP
frames needs special processing and the current implementation doesn't
allow a nice way to process different frame types. Therefore try to
improve this by adding a list that contains frame types that need
special processing. This list is iterated for each input frame and if
there is a match based on frame type then these functions will be called
and decide what to do with the frame. It can process the frame then the
bridge doesn't need to do anything or don't process so then the bridge
will do normal forwarding.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Colin Ian King says:

====================
vsock: minor clean up of ioctl error handling

Two minor changes to the ioctl error handling.
====================

Link: https://lore.kernel.org/r/20201027090942.14916-1-colin.king@canonical.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Currently when an invalid ioctl command is used the error return
is -EINVAL.  Fix this by returning the correct error -ENOIOCTLCMD.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

When exercising the kernel with stress-ng with some ioctl tests the
"Unknown ioctl" error message is spamming the kernel log at a high
rate. Remove this message.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Merge tag 'fallthrough-fixes-clang-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull fallthrough fix from Gustavo A. R. Silva:
 "This fixes a ton of fall-through warnings when building with Clang
  12.0.0 and -Wimplicit-fallthrough"

* tag 'fallthrough-fixes-clang-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  include: jhash/signal: Fix fall-through warnings for Clang

Pull networking fixes from Jakub Kicinski:
 "Current release regressions:

   - r8169: fix forced threading conflicting with other shared
     interrupts; we tried to fix the use of raise_softirq_irqoff from an
     IRQ handler on RT by forcing hard irqs, but this driver shares
     legacy PCI IRQs so drop the _irqoff() instead

   - tipc: fix memory leak caused by a recent syzbot report fix to
     tipc_buf_append()

  Current release - bugs in new features:

   - devlink: Unlock on error in dumpit() and fix some error codes

   - net/smc: fix null pointer dereference in smc_listen_decline()

  Previous release - regressions:

   - tcp: Prevent low rmem stalls with SO_RCVLOWAT.

   - net: protect tcf_block_unbind with block lock

   - ibmveth: Fix use of ibmveth in a bridge; the self-imposed filtering
     to only send legal frames to the hypervisor was too strict

   - net: hns3: Clear the CMDQ registers before unmapping BAR region;
     incorrect cleanup order was leading to a crash

   - bnxt_en - handful of fixes to fixes:
      - Send HWRM_FUNC_RESET fw command unconditionally, even if there
        are PCIe errors being reported
      - Check abort error state in bnxt_open_nic().
      - Invoke cancel_delayed_work_sync() for PFs also.
      - Fix regression in workqueue cleanup logic in bnxt_remove_one().

   - mlxsw: Only advertise link modes supported by both driver and
     device, after removal of 56G support from the driver 56G was not
     cleared from advertised modes

   - net/smc: fix suppressed return code

  Previous release - always broken:

   - netem: fix zero division in tabledist, caused by integer overflow

   - bnxt_en: Re-write PCI BARs after PCI fatal error.

   - cxgb4: set up filter action after rewrites

   - net: ipa: command payloads already mapped

  Misc:

   - s390/ism: fix incorrect system EID, it's okay to change since it
     was added in current release

   - vsock: use ns_capable_noaudit() on socket create to suppress false
     positive audit messages"

* tag 'net-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (36 commits)
  r8169: fix issue with forced threading in combination with shared interrupts
  netem: fix zero division in tabledist
  ibmvnic: fix ibmvnic_set_mac
  mptcp: add missing memory scheduling in the rx path
  tipc: fix memory leak caused by tipc_buf_append()
  gtp: fix an use-before-init in gtp_newlink()
  net: protect tcf_block_unbind with block lock
  ibmveth: Fix use of ibmveth in a bridge.
  net/sched: act_mpls: Add softdep on mpls_gso.ko
  ravb: Fix bit fields checking in ravb_hwtstamp_get()
  devlink: Unlock on error in dumpit()
  devlink: Fix some error codes
  chelsio/chtls: fix memory leaks in CPL handlers
  chelsio/chtls: fix deadlock issue
  net: hns3: Clear the CMDQ registers before unmapping BAR region
  bnxt_en: Send HWRM_FUNC_RESET fw command unconditionally.
  bnxt_en: Check abort error state in bnxt_open_nic().
  bnxt_en: Re-write PCI BARs after PCI fatal error.
  bnxt_en: Invoke cancel_delayed_work_sync() for PFs also.
  bnxt_en: Fix regression in workqueue cleanup logic in bnxt_remove_one().
  ...

Pull rdma fixes from Jason Gunthorpe:
 "The good news is people are testing rc1 in the RDMA world - the bad
  news is testing of the for-next area is not as good as I had hoped, as
  we really should have caught at least the rdma_connect_locked() issue
  before now.

  Notable merge window regressions that didn't get caught/fixed in time
  for rc1:

   - Fix in kernel users of rxe, they were broken by the rapid fix to
     undo the uABI breakage in rxe from another patch

   - EFA userspace needs to read the GID table but was broken with the
     new GID table logic

   - Fix user triggerable deadlock in mlx5 using devlink reload

   - Fix deadlock in several ULPs using rdma_connect from the CM handler
     callbacks

   - Memory leak in qedr"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/qedr: Fix memory leak in iWARP CM
  RDMA: Add rdma_connect_locked()
  RDMA/uverbs: Fix false error in query gid IOCTL
  RDMA/mlx5: Fix devlink deadlock on net namespace deletion
  RDMA/rxe: Fix small problem in network_type patch

As reported by Serge flag IRQF_NO_THREAD causes an error if the
interrupt is actually shared and the other driver(s) don't have this
flag set. This situation can occur if a PCI(e) legacy interrupt is
used in combination with forced threading.
There's no good way to deal with this properly, therefore we have to
remove flag IRQF_NO_THREAD. For fixing the original forced threading
issue switch to napi_schedule().

Fixes: 424a646e ("r8169: fix operation under forced interrupt threading")
Link: https://www.spinics.net/lists/netdev/msg694960.htmlReported-by: Serge Belyshev <belyshev@depni.sinp.msu.ru>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Serge Belyshev <belyshev@depni.sinp.msu.ru>
Link: https://lore.kernel.org/r/b5b53bfe-35ac-3768-85bf-74d1290cf394@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Currently it is possible to craft a special netlink RTM_NEWQDISC
command that can result in jitter being equal to 0x80000000. It is
enough to set the 32 bit jitter to 0x02000000 (it will later be
multiplied by 2^6) or just set the 64 bit jitter via
TCA_NETEM_JITTER64. This causes an overflow during the generation of
uniformly distributed numbers in tabledist(), which in turn leads to
division by zero (sigma != 0, but sigma * 2 is 0).

The related fragment of code needs 32-bit division - see commit
9b0ed89 ("netem: remove unnecessary 64 bit modulus"), so switching to
64 bit is not an option.

Fix the issue by keeping the value of jitter within the range that can
be adequately handled by tabledist() - [0;INT_MAX]. As negative std
deviation makes no sense, take the absolute value of the passed value
and cap it at INT_MAX. Inside tabledist(), switch to unsigned 32 bit
arithmetic in order to prevent overflows.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
Reported-by: syzbot+ec762a6342ad0d3c0d8f@syzkaller.appspotmail.com
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Link: https://lore.kernel.org/r/20201028170731.1383332-1-aleksandrnogikh@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Jakub Kicinski brought up a concern in ibmvnic_set_mac().
ibmvnic_set_mac() does this:

	ether_addr_copy(adapter->mac_addr, addr->sa_data);
	if (adapter->state != VNIC_PROBED)
		rc = __ibmvnic_set_mac(netdev, addr->sa_data);

So if state == VNIC_PROBED, the user can assign an invalid address to
adapter->mac_addr, and ibmvnic_set_mac() will still return 0.

The fix is to validate ethernet address at the beginning of
ibmvnic_set_mac(), and move the ether_addr_copy to
the case of "adapter->state != VNIC_PROBED".

Fixes: c26eba03 ("ibmvnic: Update reset infrastructure to support tunable parameters")
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Link: https://lore.kernel.org/r/20201027220456.71450-1-ljp@linux.ibm.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

When moving the skbs from the subflow into the msk receive
queue, we must schedule there the required amount of memory.

Try to borrow the required memory from the subflow, if needed,
so that we leverage the existing TCP heuristic.

Fixes: 6771bfd9 ("mptcp: update mptcp ack sequence from work queue")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/f6143a6193a083574f11b00dbf7b5ad151bc4ff4.1603810630.git.pabeni@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

In preparation to enable -Wimplicit-fallthrough for Clang, explicitly
add break statements instead of letting the code fall through to the
next case.

This patch adds four break statements that, together, fix almost 40,000
warnings when building Linux 5.10-rc1 with Clang 12.0.0 and this[1] change
reverted. Notice that in order to enable -Wimplicit-fallthrough for Clang,
such change[1] is meant to be reverted at some point. So, this patch helps
to move in that direction.

Something important to mention is that there is currently a discrepancy
between GCC and Clang when dealing with switch fall-through to empty case
statements or to cases that only contain a break/continue/return
statement[2][3][4].

Now that the -Wimplicit-fallthrough option has been globally enabled[5],
any compiler should really warn on missing either a fallthrough annotation
or any of the other case-terminating statements (break/continue/return/
goto) when falling through to the next case statement. Making exceptions
to this introduces variation in case handling which may continue to lead
to bugs, misunderstandings, and a general lack of robustness. The point
of enabling options like -Wimplicit-fallthrough is to prevent human error
and aid developers in spotting bugs before their code is even built/
submitted/committed, therefore eliminating classes of bugs. So, in order
to really accomplish this, we should, and can, move in the direction of
addressing any error-prone scenarios and get rid of the unintentional
fallthrough bug-class in the kernel, entirely, even if there is some minor
redundancy. Better to have explicit case-ending statements than continue to
have exceptions where one must guess as to the right result. The compiler
will eliminate any actual redundancy.

[1] commit e2079e93 ("kbuild: Do not enable -Wimplicit-fallthrough for clang for now")
[2] https://github.com/ClangBuiltLinux/linux/issues/636
[3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91432
[4] https://godbolt.org/z/xgkvIh
[5] commit a035d552 ("Makefile: Globally enable fall-through warning")
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Pull AFS fixes from David Howells:

 - Fix copy_file_range() to an afs file now returning EINVAL if the
   splice_write file op isn't supplied.

 - Fix a deref-before-check in afs_unuse_cell().

 - Fix a use-after-free in afs_xattr_get_acl().

 - Fix afs to not try to clear PG_writeback when laundering a page.

 - Fix afs to take a ref on a page that it sets PG_private on and to
   drop that ref when clearing PG_private. This is done through recently
   added helpers.

 - Fix a page leak if write_begin() fails.

 - Fix afs_write_begin() to not alter the dirty region info stored in
   page->private, but rather do this in afs_write_end() instead when we
   know what we actually changed.

 - Fix afs_invalidatepage() to alter the dirty region info on a page
   when partial page invalidation occurs so that we don't inadvertantly
   include a span of zeros that will get written back if a page gets
   laundered due to a remote 3rd-party induced invalidation.

   We mustn't, however, reduce the dirty region if the page has been
   seen to be mapped (ie. we got called through the page_mkwrite vector)
   as the page might still be mapped and we might lose data if the file
   is extended again.

 - Fix the dirty region info to have a lower resolution if the size of
   the page is too large for this to be encoded (e.g. powerpc32 with 64K
   pages).

   Note that this might not be the ideal way to handle this, since it
   may allow some leakage of undirtied zero bytes to the server's copy
   in the case of a 3rd-party conflict.

To aid the last two fixes, two additional changes:

 - Wrap the manipulations of the dirty region info stored in
   page->private into helper functions.

 - Alter the encoding of the dirty region so that the region bounds can
   be stored with one fewer bit, making a bit available for the
   indication of mappedness.

* tag 'afs-fixes-20201029' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix dirty-region encoding on ppc32 with 64K pages
  afs: Fix afs_invalidatepage to adjust the dirty region
  afs: Alter dirty range encoding in page->private
  afs: Wrap page->private manipulations in inline functions
  afs: Fix where page->private is set during write
  afs: Fix page leak on afs_write_begin() failure
  afs: Fix to take ref on page when PG_private is set
  afs: Fix afs_launder_page to not clear PG_writeback
  afs: Fix a use after free in afs_xattr_get_acl()
  afs: Fix tracing deref-before-check
  afs: Fix copy_file_range()

Commit ed42989e ("tipc: fix the skb_unshare() in tipc_buf_append()")
replaced skb_unshare() with skb_copy() to not reduce the data reference
counter of the original skb intentionally. This is not the correct
way to handle the cloned skb because it causes memory leak in 2
following cases:
 1/ Sending multicast messages via broadcast link
  The original skb list is cloned to the local skb list for local
  destination. After that, the data reference counter of each skb
  in the original list has the value of 2. This causes each skb not
  to be freed after receiving ACK:
  tipc_link_advance_transmq()
  {
   ...
   /* release skb */
   __skb_unlink(skb, &l->transmq);
   kfree_skb(skb); <-- memory exists after being freed
  }

 2/ Sending multicast messages via replicast link
  Similar to the above case, each skb cannot be freed after purging
  the skb list:
  tipc_mcast_xmit()
  {
   ...
   __skb_queue_purge(pkts); <-- memory exists after being freed
  }

This commit fixes this issue by using skb_unshare() instead. Besides,
to avoid use-after-free error reported by KASAN, the pointer to the
fragment is set to NULL before calling skb_unshare() to make sure that
the original skb is not freed after freeing the fragment 2 times in
case skb_unshare() returns NULL.

Fixes: ed42989e ("tipc: fix the skb_unshare() in tipc_buf_append()")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Reported-by: Thang Hoang Ngo <thang.h.ngo@dektech.com.au>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Link: https://lore.kernel.org/r/20201027032403.1823-1-tung.q.nguyen@dektech.com.auSigned-off-by: Jakub Kicinski <kuba@kernel.org>

*_pdp_find() from gtp_encap_recv() would trigger a crash when a peer
sends GTP packets while creating new GTP device.

RIP: 0010:gtp1_pdp_find.isra.0+0x68/0x90 [gtp]
<SNIP>
Call Trace:
 <IRQ>
 gtp_encap_recv+0xc2/0x2e0 [gtp]
 ? gtp1_pdp_find.isra.0+0x90/0x90 [gtp]
 udp_queue_rcv_one_skb+0x1fe/0x530
 udp_queue_rcv_skb+0x40/0x1b0
 udp_unicast_rcv_skb.isra.0+0x78/0x90
 __udp4_lib_rcv+0x5af/0xc70
 udp_rcv+0x1a/0x20
 ip_protocol_deliver_rcu+0xc5/0x1b0
 ip_local_deliver_finish+0x48/0x50
 ip_local_deliver+0xe5/0xf0
 ? ip_protocol_deliver_rcu+0x1b0/0x1b0

gtp_encap_enable() should be called after gtp_hastable_new() otherwise
*_pdp_find() will access the uninitialized hash table.

Fixes: 1e3a3abd ("gtp: make GTP sockets in gtp_newlink optional")
Signed-off-by: Masahiro Fujiwara <fujiwara.masahiro@gmail.com>
Link: https://lore.kernel.org/r/20201027114846.3924-1-fujiwara.masahiro@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Pull ext4 fixes from Ted Ts'o:
 "Bug fixes for the new ext4 fast commit feature, plus a fix for the
  'data=journal' bug fix.

  Also use the generic casefolding support which has now landed in
  fs/libfs.c for 5.10"

* tag 'ext4_for_linus_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: indicate that fast_commit is available via /sys/fs/ext4/feature/...
  ext4: use generic casefolding support
  ext4: do not use extent after put_bh
  ext4: use IS_ERR() for error checking of path
  ext4: fix mmap write protection for data=journal mode
  jbd2: fix a kernel-doc markup
  ext4: use s_mount_flags instead of s_mount_state for fast commit state
  ext4: make num of fast commit blocks configurable
  ext4: properly check for dirty state in ext4_inode_datasync_dirty()
  ext4: fix double locking in ext4_fc_commit_dentry_updates()

The dirty region bounds stored in page->private on an afs page are 15 bits
on a 32-bit box and can, at most, represent a range of up to 32K within a
32K page with a resolution of 1 byte.  This is a problem for powerpc32 with
64K pages enabled.

Further, transparent huge pages may get up to 2M, which will be a problem
for the afs filesystem on all 32-bit arches in the future.

Fix this by decreasing the resolution.  For the moment, a 64K page will
have a resolution determined from PAGE_SIZE.  In the future, the page will
need to be passed in to the helper functions so that the page size can be
assessed and the resolution determined dynamically.

Note that this might not be the ideal way to handle this, since it may
allow some leakage of undirtied zero bytes to the server's copy in the case
of a 3rd-party conflict.  Fixing that would require a separately allocated
record and is a more complicated fix.

Fixes: 4343d008 ("afs: Get rid of the afs_writeback record")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Fix afs_invalidatepage() to adjust the dirty region recorded in
page->private when truncating a page.  If the dirty region is entirely
removed, then the private data is cleared and the page dirty state is
cleared.

Without this, if the page is truncated and then expanded again by truncate,
zeros from the expanded, but no-longer dirty region may get written back to
the server if the page gets laundered due to a conflicting 3rd-party write.

It mustn't, however, shorten the dirty region of the page if that page is
still mmapped and has been marked dirty by afs_page_mkwrite(), so a flag is
stored in page->private to record this.

Fixes: 4343d008 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>

Currently, page->private on an afs page is used to store the range of
dirtied data within the page, where the range includes the lower bound, but
excludes the upper bound (e.g. 0-1 is a range covering a single byte).

This, however, requires a superfluous bit for the last-byte bound so that
on a 4KiB page, it can say 0-4096 to indicate the whole page, the idea
being that having both numbers the same would indicate an empty range.
This is unnecessary as the PG_private bit is clear if it's an empty range
(as is PG_dirty).

Alter the way the dirty range is encoded in page->private such that the
upper bound is reduced by 1 (e.g. 0-0 is then specified the same single
byte range mentioned above).

Applying this to both bounds frees up two bits, one of which can be used in
a future commit.

This allows the afs filesystem to be compiled on ppc32 with 64K pages;
without this, the following warnings are seen:

../fs/afs/internal.h: In function 'afs_page_dirty_to':
../fs/afs/internal.h:881:15: warning: right shift count >= width of type [-Wshift-count-overflow]
  881 |  return (priv >> __AFS_PAGE_PRIV_SHIFT) & __AFS_PAGE_PRIV_MASK;
      |               ^~
../fs/afs/internal.h: In function 'afs_page_dirty':
../fs/afs/internal.h:886:28: warning: left shift count >= width of type [-Wshift-count-overflow]
  886 |  return ((unsigned long)to << __AFS_PAGE_PRIV_SHIFT) | from;
      |                            ^~

Fixes: 4343d008 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>

The afs filesystem uses page->private to store the dirty range within a
page such that in the event of a conflicting 3rd-party write to the server,
we write back just the bits that got changed locally.

However, there are a couple of problems with this:

 (1) I need a bit to note if the page might be mapped so that partial
     invalidation doesn't shrink the range.

 (2) There aren't necessarily sufficient bits to store the entire range of
     data altered (say it's a 32-bit system with 64KiB pages or transparent
     huge pages are in use).

So wrap the accesses in inline functions so that future commits can change
how this works.

Also move them out of the tracing header into the in-directory header.
There's not really any need for them to be in the tracing header.
Signed-off-by: David Howells <dhowells@redhat.com>

In afs, page->private is set to indicate the dirty region of a page.  This
is done in afs_write_begin(), but that can't take account of whether the
copy into the page actually worked.

Fix this by moving the change of page->private into afs_write_end().

Fixes: 4343d008 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>

Fix the leak of the target page in afs_write_begin() when it fails.

Fixes: 15b4650e ("afs: convert to new aops")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Nick Piggin <npiggin@gmail.com>

Fix afs to take a ref on a page when it sets PG_private on it and to drop
the ref when removing the flag.

Note that in afs_write_begin(), a lot of the time, PG_private is already
set on a page to which we're going to add some data.  In such a case, we
leave the bit set and mustn't increment the page count.

As suggested by Matthew Wilcox, use attach/detach_page_private() where
possible.

Fixes: 31143d5d ("AFS: implement basic file write support")
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Pull tracing fix from Steven Rostedt:
 "Fix synthetic event "strcat" overrun

  New synthetic event code used strcat() and miscalculated the ending,
  causing the concatenation to write beyond the allocated memory.

  Instead of using strncat(), the code is switched over to seq_buf which
  has all the mechanisms in place to protect against writing more than
  what is allocated, and cleans up the code a bit"

* tag 'trace-v5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing, synthetic events: Replace buggy strcat() with seq_buf operations

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This switches ext4 over to the generic support provided in libfs.

Since casefolded dentries behave the same in ext4 and f2fs, we decrease
the maintenance burden by unifying them, and any optimizations will
immediately apply to both.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20201028050820.1636571-1-drosen@google.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

ext4_ext_search_right() will read more extent blocks and call put_bh
after we get the information we need.  However, ret_ex will break this
and may cause use-after-free once pagecache has been freed.  Fix it by
copying the extent structure if needed.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20201028055617.2569255-1-yangerkun@huawei.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

With this fix, fast commit recovery code uses IS_ERR() for path
returned by ext4_find_extent.

Fixes: 8016e29f ("ext4: fast commit recovery path")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027204342.2794949-1-harshadshirwadkar@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

Commit afb585a9 "ext4: data=journal: write-protect pages on
j_submit_inode_data_buffers()") added calls ext4_jbd2_inode_add_write()
to track inode ranges whose mappings need to get write-protected during
transaction commits.  However the added calls use wrong start of a range
(0 instead of page offset) and so write protection is not necessarily
effective.  Use correct range start to fix the problem.

Fixes: afb585a9 ("ext4: data=journal: write-protect pages on j_submit_inode_data_buffers()")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201027132751.29858-1-jack@suse.czSigned-off-by: Theodore Ts'o <tytso@mit.edu>