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Improve performance by using multiple RDMA/RC channels per SCSI host for communication with an SRP target. About the implementation: - Introduce a loop over all channels in the code that uses target->ch. - Set the SRP_MULTICHAN_MULTI flag during login for the creation of the second and subsequent channels. - RDMA completion vectors are chosen such that RDMA completion interrupts are handled by the CPU socket that submitted the I/O request. As one can see in this patch it has been assumed if a system contains n CPU sockets and m RDMA completion vectors have been assigned to an RDMA HCA that IRQ affinity has been configured such that completion vectors [i*m/n..(i+1)*m/n) are bound to CPU socket i with 0 <= i < n. - Modify srp_free_ch_ib() and srp_free_req_data() such that it becomes safe to invoke these functions after the corresponding allocation function failed. - Add a ch_count sysfs attribute per target port. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
190 lines
7.6 KiB
Plaintext
190 lines
7.6 KiB
Plaintext
What: /sys/class/infiniband_srp/srp-<hca>-<port_number>/add_target
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Date: January 2, 2006
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KernelVersion: 2.6.15
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Contact: linux-rdma@vger.kernel.org
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Description: Interface for making ib_srp connect to a new target.
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One can request ib_srp to connect to a new target by writing
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a comma-separated list of login parameters to this sysfs
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attribute. The supported parameters are:
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* id_ext, a 16-digit hexadecimal number specifying the eight
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byte identifier extension in the 16-byte SRP target port
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identifier. The target port identifier is sent by ib_srp
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to the target in the SRP_LOGIN_REQ request.
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* ioc_guid, a 16-digit hexadecimal number specifying the eight
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byte I/O controller GUID portion of the 16-byte target port
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identifier.
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* dgid, a 32-digit hexadecimal number specifying the
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destination GID.
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* pkey, a four-digit hexadecimal number specifying the
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InfiniBand partition key.
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* service_id, a 16-digit hexadecimal number specifying the
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InfiniBand service ID used to establish communication with
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the SRP target. How to find out the value of the service ID
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is specified in the documentation of the SRP target.
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* max_sect, a decimal number specifying the maximum number of
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512-byte sectors to be transferred via a single SCSI command.
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* max_cmd_per_lun, a decimal number specifying the maximum
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number of outstanding commands for a single LUN.
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* io_class, a hexadecimal number specifying the SRP I/O class.
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Must be either 0xff00 (rev 10) or 0x0100 (rev 16a). The I/O
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class defines the format of the SRP initiator and target
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port identifiers.
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* initiator_ext, a 16-digit hexadecimal number specifying the
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identifier extension portion of the SRP initiator port
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identifier. This data is sent by the initiator to the target
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in the SRP_LOGIN_REQ request.
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* cmd_sg_entries, a number in the range 1..255 that specifies
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the maximum number of data buffer descriptors stored in the
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SRP_CMD information unit itself. With allow_ext_sg=0 the
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parameter cmd_sg_entries defines the maximum S/G list length
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for a single SRP_CMD, and commands whose S/G list length
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exceeds this limit after S/G list collapsing will fail.
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* allow_ext_sg, whether ib_srp is allowed to include a partial
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memory descriptor list in an SRP_CMD instead of the entire
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list. If a partial memory descriptor list has been included
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in an SRP_CMD the remaining memory descriptors are
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communicated from initiator to target via an additional RDMA
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transfer. Setting allow_ext_sg to 1 increases the maximum
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amount of data that can be transferred between initiator and
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target via a single SCSI command. Since not all SRP target
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implementations support partial memory descriptor lists the
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default value for this option is 0.
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* sg_tablesize, a number in the range 1..2048 specifying the
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maximum S/G list length the SCSI layer is allowed to pass to
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ib_srp. Specifying a value that exceeds cmd_sg_entries is
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only safe with partial memory descriptor list support enabled
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(allow_ext_sg=1).
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* comp_vector, a number in the range 0..n-1 specifying the
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MSI-X completion vector of the first RDMA channel. Some
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HCA's allocate multiple (n) MSI-X vectors per HCA port. If
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the IRQ affinity masks of these interrupts have been
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configured such that each MSI-X interrupt is handled by a
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different CPU then the comp_vector parameter can be used to
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spread the SRP completion workload over multiple CPU's.
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* tl_retry_count, a number in the range 2..7 specifying the
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IB RC retry count.
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* queue_size, the maximum number of commands that the
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initiator is allowed to queue per SCSI host. The default
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value for this parameter is 62. The lowest supported value
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is 2.
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What: /sys/class/infiniband_srp/srp-<hca>-<port_number>/ibdev
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Date: January 2, 2006
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KernelVersion: 2.6.15
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Contact: linux-rdma@vger.kernel.org
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Description: HCA name (<hca>).
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What: /sys/class/infiniband_srp/srp-<hca>-<port_number>/port
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Date: January 2, 2006
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KernelVersion: 2.6.15
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Contact: linux-rdma@vger.kernel.org
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Description: HCA port number (<port_number>).
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What: /sys/class/scsi_host/host<n>/allow_ext_sg
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Date: May 19, 2011
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KernelVersion: 2.6.39
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Contact: linux-rdma@vger.kernel.org
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Description: Whether ib_srp is allowed to include a partial memory
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descriptor list in an SRP_CMD when communicating with an SRP
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target.
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What: /sys/class/scsi_host/host<n>/ch_count
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Date: April 1, 2015
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KernelVersion: 3.19
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Contact: linux-rdma@vger.kernel.org
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Description: Number of RDMA channels used for communication with the SRP
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target.
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What: /sys/class/scsi_host/host<n>/cmd_sg_entries
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Date: May 19, 2011
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KernelVersion: 2.6.39
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Contact: linux-rdma@vger.kernel.org
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Description: Maximum number of data buffer descriptors that may be sent to
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the target in a single SRP_CMD request.
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What: /sys/class/scsi_host/host<n>/comp_vector
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Date: September 2, 2013
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KernelVersion: 3.11
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Contact: linux-rdma@vger.kernel.org
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Description: Completion vector used for the first RDMA channel.
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What: /sys/class/scsi_host/host<n>/dgid
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Date: June 17, 2006
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KernelVersion: 2.6.17
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Contact: linux-rdma@vger.kernel.org
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Description: InfiniBand destination GID used for communication with the SRP
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target. Differs from orig_dgid if port redirection has happened.
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What: /sys/class/scsi_host/host<n>/id_ext
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Date: June 17, 2006
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KernelVersion: 2.6.17
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Contact: linux-rdma@vger.kernel.org
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Description: Eight-byte identifier extension portion of the 16-byte target
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port identifier.
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What: /sys/class/scsi_host/host<n>/ioc_guid
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Date: June 17, 2006
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KernelVersion: 2.6.17
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Contact: linux-rdma@vger.kernel.org
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Description: Eight-byte I/O controller GUID portion of the 16-byte target
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port identifier.
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What: /sys/class/scsi_host/host<n>/local_ib_device
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Date: November 29, 2006
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KernelVersion: 2.6.19
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Contact: linux-rdma@vger.kernel.org
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Description: Name of the InfiniBand HCA used for communicating with the
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SRP target.
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What: /sys/class/scsi_host/host<n>/local_ib_port
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Date: November 29, 2006
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KernelVersion: 2.6.19
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Contact: linux-rdma@vger.kernel.org
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Description: Number of the HCA port used for communicating with the
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SRP target.
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What: /sys/class/scsi_host/host<n>/orig_dgid
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Date: June 17, 2006
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KernelVersion: 2.6.17
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Contact: linux-rdma@vger.kernel.org
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Description: InfiniBand destination GID specified in the parameters
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written to the add_target sysfs attribute.
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What: /sys/class/scsi_host/host<n>/pkey
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Date: June 17, 2006
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KernelVersion: 2.6.17
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Contact: linux-rdma@vger.kernel.org
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Description: A 16-bit number representing the InfiniBand partition key used
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for communication with the SRP target.
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What: /sys/class/scsi_host/host<n>/req_lim
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Date: October 20, 2010
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KernelVersion: 2.6.36
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Contact: linux-rdma@vger.kernel.org
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Description: Number of requests ib_srp can send to the target before it has
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to wait for more credits. For more information see also the
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SRP credit algorithm in the SRP specification.
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What: /sys/class/scsi_host/host<n>/service_id
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Date: June 17, 2006
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KernelVersion: 2.6.17
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Contact: linux-rdma@vger.kernel.org
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Description: InfiniBand service ID used for establishing communication with
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the SRP target.
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What: /sys/class/scsi_host/host<n>/sgid
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Date: February 1, 2014
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KernelVersion: 3.13
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Contact: linux-rdma@vger.kernel.org
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Description: InfiniBand GID of the source port used for communication with
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the SRP target.
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What: /sys/class/scsi_host/host<n>/zero_req_lim
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Date: September 20, 2006
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KernelVersion: 2.6.18
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Contact: linux-rdma@vger.kernel.org
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Description: Number of times the initiator had to wait before sending a
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request to the target because it ran out of credits. For more
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information see also the SRP credit algorithm in the SRP
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specification.
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