FreeBSD src
67360f7bb0
T6 makes several changes relative to T5 for receive of iSCSI PDUs. First, earlier adapters issue either 2 or 3 messages to the host for each PDU received: CPL_ISCSI_HDR contains the BHS of the PDU, CPL_ISCSI_DATA (when DDP is not used for zero-copy receive) contains the PDU data as buffers on the freelist, and CPL_RX_ISCSI_DDP with status of the PDU such as result of CRC checks. In T6, a new CPL_RX_ISCSI_CMP combines CPL_ISCSI_HDR and CPL_RX_ISCSI_DDP. Data PDUs which are directly placed via DDP only report a single CPL_RX_ISCSI_CMP message. Data PDUs received on the free lists are reported as CPL_ISCSI_DATA followed by CPL_RX_ISCSI_CMP. Control PDUs such as R2T are still reported via CPL_ISCSI_HDR and CPL_RX_ISCSI_DDP. Supporting this requires changing the CPL_ISCSI_DATA handler to allocate a PDU structure if it is not preceded by a CPL_ISCSI_HDR as well as support for the new CPL_RX_ISCSI_CMP. Second, when using DDP for zero-copy receive, T6 will only issue a CPL_RX_ISCSI_CMP after a burst of PDUs have been received (indicated by the F flag in the BHS). In this case, the CPL_RX_ISCSI_CMP can reflect the completion of multiple PDUs and the BHS and TCP sequence number included in the message are from the last PDU received in the burst. Notably, the message does not include any information about earlier PDUs received as part of the burst. Instead, the driver must track the amount of data already received for a given transfer and use this to compute the amount of data received in a burst. In addition, the iSCSI layer currently has no way to permit receiving a logical PDU which spans multiple PDUs. Instead, the driver presents each burst as a single, "large" PDU to the iSCSI target and initiators. This is done by rewriting the buffer offset and data length fields in the BHS of the final PDU as well as rewriting the DataSN so that the received PDUs appear to be in order. To track all this, cxgbei maintains a hash table of 'cxgbei_cmp' structures indexed by transfer tags for each offloaded iSCSI connection. When a SCSI_DATA_IN message is received, the ITT from the received BHS is used to find the necessary state in the hash table, whereas SCSI_DATA_OUT replies use the TTT as the key. The structure tracks the expected starting offset and DataSN of the next burst as well as the rewritten DataSN value used for the previously received PDU. Discussed with: np Sponsored by: Chelsio Communications Differential Revision: https://reviews.freebsd.org/D30458 |
||
|---|---|---|
| .github/workflows | ||
| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| stand | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| .cirrus.yml | ||
| .clang-format | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| Makefile.sys.inc | ||
| ObsoleteFiles.inc | ||
| README.md | ||
| RELNOTES | ||
| UPDATING | ||
FreeBSD Source:
This is the top level of the FreeBSD source directory.
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), FreeBSD handbook on building userland, and Handbook for kernels for more information, including setting make(1) variables.
Source Roadmap:
| Directory | Description |
|---|---|
| bin | System/user commands. |
| cddl | Various commands and libraries under the Common Development and Distribution License. |
| contrib | Packages contributed by 3rd parties. |
| crypto | Cryptography stuff (see crypto/README). |
| etc | Template files for /etc. |
| gnu | Various commands and libraries under the GNU Public License. Please see gnu/COPYING and gnu/COPYING.LIB for more information. |
| include | System include files. |
| kerberos5 | Kerberos5 (Heimdal) package. |
| lib | System libraries. |
| libexec | System daemons. |
| release | Release building Makefile & associated tools. |
| rescue | Build system for statically linked /rescue utilities. |
| sbin | System commands. |
| secure | Cryptographic libraries and commands. |
| share | Shared resources. |
| stand | Boot loader sources. |
| sys | Kernel sources. |
sys/arch/conf |
Kernel configuration files. GENERIC is the configuration used in release builds. NOTES contains documentation of all possible entries. |
| tests | Regression tests which can be run by Kyua. See tests/README for additional information. |
| tools | Utilities for regression testing and miscellaneous tasks. |
| usr.bin | User commands. |
| usr.sbin | System administration commands. |
For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see FreeBSD Handbook.