diff options
| -rw-r--r-- | include/rdma/ib_verbs.h | 132 |
1 files changed, 92 insertions, 40 deletions
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index 8d59479eea4d..81740c14fdb1 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -1775,14 +1775,16 @@ static inline bool rdma_ib_or_iboe(struct ib_device *device, u8 port_num) } /** - * rdma_cap_ib_mad - Check if the port of device has the capability Infiniband + * rdma_cap_ib_mad - Check if the port of a device supports Infiniband * Management Datagrams. + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * Management Datagrams (MAD) are a required part of the InfiniBand + * specification and are supported on all InfiniBand devices. A slightly + * extended version are also supported on OPA interfaces. * - * Return false when port of the device don't support Infiniband - * Management Datagrams. + * Return: true if the port supports sending/receiving of MAD packets. */ static inline bool rdma_cap_ib_mad(struct ib_device *device, u8 port_num) { @@ -1790,14 +1792,24 @@ static inline bool rdma_cap_ib_mad(struct ib_device *device, u8 port_num) } /** - * rdma_cap_ib_smi - Check if the port of device has the capability Infiniband - * Subnet Management Interface. + * rdma_cap_ib_smi - Check if the port of a device provides an Infiniband + * Subnet Management Agent (SMA) on the Subnet Management Interface (SMI). + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * Each InfiniBand node is required to provide a Subnet Management Agent + * that the subnet manager can access. Prior to the fabric being fully + * configured by the subnet manager, the SMA is accessed via a well known + * interface called the Subnet Management Interface (SMI). This interface + * uses directed route packets to communicate with the SM to get around the + * chicken and egg problem of the SM needing to know what's on the fabric + * in order to configure the fabric, and needing to configure the fabric in + * order to send packets to the devices on the fabric. These directed + * route packets do not need the fabric fully configured in order to reach + * their destination. The SMI is the only method allowed to send + * directed route packets on an InfiniBand fabric. * - * Return false when port of the device don't support Infiniband - * Subnet Management Interface. + * Return: true if the port provides an SMI. */ static inline bool rdma_cap_ib_smi(struct ib_device *device, u8 port_num) { @@ -1807,12 +1819,17 @@ static inline bool rdma_cap_ib_smi(struct ib_device *device, u8 port_num) /** * rdma_cap_ib_cm - Check if the port of device has the capability Infiniband * Communication Manager. + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * The InfiniBand Communication Manager is one of many pre-defined General + * Service Agents (GSA) that are accessed via the General Service + * Interface (GSI). It's role is to facilitate establishment of connections + * between nodes as well as other management related tasks for established + * connections. * - * Return false when port of the device don't support Infiniband - * Communication Manager. + * Return: true if the port supports an IB CM (this does not guarantee that + * a CM is actually running however). */ static inline bool rdma_cap_ib_cm(struct ib_device *device, u8 port_num) { @@ -1822,12 +1839,14 @@ static inline bool rdma_cap_ib_cm(struct ib_device *device, u8 port_num) /** * rdma_cap_iw_cm - Check if the port of device has the capability IWARP * Communication Manager. + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * Similar to above, but specific to iWARP connections which have a different + * managment protocol than InfiniBand. * - * Return false when port of the device don't support IWARP - * Communication Manager. + * Return: true if the port supports an iWARP CM (this does not guarantee that + * a CM is actually running however). */ static inline bool rdma_cap_iw_cm(struct ib_device *device, u8 port_num) { @@ -1837,12 +1856,17 @@ static inline bool rdma_cap_iw_cm(struct ib_device *device, u8 port_num) /** * rdma_cap_ib_sa - Check if the port of device has the capability Infiniband * Subnet Administration. + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * An InfiniBand Subnet Administration (SA) service is a pre-defined General + * Service Agent (GSA) provided by the Subnet Manager (SM). On InfiniBand + * fabrics, devices should resolve routes to other hosts by contacting the + * SA to query the proper route. * - * Return false when port of the device don't support Infiniband - * Subnet Administration. + * Return: true if the port should act as a client to the fabric Subnet + * Administration interface. This does not imply that the SA service is + * running locally. */ static inline bool rdma_cap_ib_sa(struct ib_device *device, u8 port_num) { @@ -1852,12 +1876,19 @@ static inline bool rdma_cap_ib_sa(struct ib_device *device, u8 port_num) /** * rdma_cap_ib_mcast - Check if the port of device has the capability Infiniband * Multicast. + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * InfiniBand multicast registration is more complex than normal IPv4 or + * IPv6 multicast registration. Each Host Channel Adapter must register + * with the Subnet Manager when it wishes to join a multicast group. It + * should do so only once regardless of how many queue pairs it subscribes + * to this group. And it should leave the group only after all queue pairs + * attached to the group have been detached. * - * Return false when port of the device don't support Infiniband - * Multicast. + * Return: true if the port must undertake the additional adminstrative + * overhead of registering/unregistering with the SM and tracking of the + * total number of queue pairs attached to the multicast group. */ static inline bool rdma_cap_ib_mcast(struct ib_device *device, u8 port_num) { @@ -1867,12 +1898,15 @@ static inline bool rdma_cap_ib_mcast(struct ib_device *device, u8 port_num) /** * rdma_cap_af_ib - Check if the port of device has the capability * Native Infiniband Address. + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * InfiniBand addressing uses a port's GUID + Subnet Prefix to make a default + * GID. RoCE uses a different mechanism, but still generates a GID via + * a prescribed mechanism and port specific data. * - * Return false when port of the device don't support - * Native Infiniband Address. + * Return: true if the port uses a GID address to identify devices on the + * network. */ static inline bool rdma_cap_af_ib(struct ib_device *device, u8 port_num) { @@ -1881,13 +1915,19 @@ static inline bool rdma_cap_af_ib(struct ib_device *device, u8 port_num) /** * rdma_cap_eth_ah - Check if the port of device has the capability - * Ethernet Address Handler. + * Ethernet Address Handle. + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * RoCE is InfiniBand over Ethernet, and it uses a well defined technique + * to fabricate GIDs over Ethernet/IP specific addresses native to the + * port. Normally, packet headers are generated by the sending host + * adapter, but when sending connectionless datagrams, we must manually + * inject the proper headers for the fabric we are communicating over. * - * Return false when port of the device don't support - * Ethernet Address Handler. + * Return: true if we are running as a RoCE port and must force the + * addition of a Global Route Header built from our Ethernet Address + * Handle into our header list for connectionless packets. */ static inline bool rdma_cap_eth_ah(struct ib_device *device, u8 port_num) { @@ -1897,12 +1937,24 @@ static inline bool rdma_cap_eth_ah(struct ib_device *device, u8 port_num) /** * rdma_cap_read_multi_sge - Check if the port of device has the capability * RDMA Read Multiple Scatter-Gather Entries. + * @device: Device to check + * @port_num: Port number to check * - * @device: Device to be checked - * @port_num: Port number of the device + * iWARP has a restriction that RDMA READ requests may only have a single + * Scatter/Gather Entry (SGE) in the work request. * - * Return false when port of the device don't support - * RDMA Read Multiple Scatter-Gather Entries. + * NOTE: although the linux kernel currently assumes all devices are either + * single SGE RDMA READ devices or identical SGE maximums for RDMA READs and + * WRITEs, according to Tom Talpey, this is not accurate. There are some + * devices out there that support more than a single SGE on RDMA READ + * requests, but do not support the same number of SGEs as they do on + * RDMA WRITE requests. The linux kernel would need rearchitecting to + * support these imbalanced READ/WRITE SGEs allowed devices. So, for now, + * suffice with either the device supports the same READ/WRITE SGEs, or + * it only gets one READ sge. + * + * Return: true for any device that allows more than one SGE in RDMA READ + * requests. */ static inline bool rdma_cap_read_multi_sge(struct ib_device *device, u8 port_num) |