~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/Documentation/scsi/cxgb3i.rst

Version: ~ [ linux-6.12-rc7 ] ~ [ linux-6.11.7 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.60 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.116 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.171 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.229 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.285 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.323 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.12 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

Diff markup

Differences between /Documentation/scsi/cxgb3i.rst (Version linux-6.12-rc7) and /Documentation/scsi/cxgb3i.rst (Version linux-6.11.7)


  1 .. SPDX-License-Identifier: GPL-2.0                 1 .. SPDX-License-Identifier: GPL-2.0
  2                                                     2 
  3 =================================                   3 =================================
  4 Chelsio S3 iSCSI Driver for Linux                   4 Chelsio S3 iSCSI Driver for Linux
  5 =================================                   5 =================================
  6                                                     6 
  7 Introduction                                        7 Introduction
  8 ============                                        8 ============
  9                                                     9 
 10 The Chelsio T3 ASIC based Adapters (S310, S320     10 The Chelsio T3 ASIC based Adapters (S310, S320, S302, S304, Mezz cards, etc.
 11 series of products) support iSCSI acceleration     11 series of products) support iSCSI acceleration and iSCSI Direct Data Placement
 12 (DDP) where the hardware handles the expensive     12 (DDP) where the hardware handles the expensive byte touching operations, such
 13 as CRC computation and verification, and direc     13 as CRC computation and verification, and direct DMA to the final host memory
 14 destination:                                       14 destination:
 15                                                    15 
 16         - iSCSI PDU digest generation and veri     16         - iSCSI PDU digest generation and verification
 17                                                    17 
 18           On transmitting, Chelsio S3 h/w comp     18           On transmitting, Chelsio S3 h/w computes and inserts the Header and
 19           Data digest into the PDUs.               19           Data digest into the PDUs.
 20           On receiving, Chelsio S3 h/w compute     20           On receiving, Chelsio S3 h/w computes and verifies the Header and
 21           Data digest of the PDUs.                 21           Data digest of the PDUs.
 22                                                    22 
 23         - Direct Data Placement (DDP)              23         - Direct Data Placement (DDP)
 24                                                    24 
 25           S3 h/w can directly place the iSCSI      25           S3 h/w can directly place the iSCSI Data-In or Data-Out PDU's
 26           payload into pre-posted final destin     26           payload into pre-posted final destination host-memory buffers based
 27           on the Initiator Task Tag (ITT) in D     27           on the Initiator Task Tag (ITT) in Data-In or Target Task Tag (TTT)
 28           in Data-Out PDUs.                        28           in Data-Out PDUs.
 29                                                    29 
 30         - PDU Transmit and Recovery                30         - PDU Transmit and Recovery
 31                                                    31 
 32           On transmitting, S3 h/w accepts the      32           On transmitting, S3 h/w accepts the complete PDU (header + data)
 33           from the host driver, computes and i     33           from the host driver, computes and inserts the digests, decomposes
 34           the PDU into multiple TCP segments i     34           the PDU into multiple TCP segments if necessary, and transmit all
 35           the TCP segments onto the wire. It h     35           the TCP segments onto the wire. It handles TCP retransmission if
 36           needed.                                  36           needed.
 37                                                    37 
 38           On receiving, S3 h/w recovers the iS     38           On receiving, S3 h/w recovers the iSCSI PDU by reassembling TCP
 39           segments, separating the header and      39           segments, separating the header and data, calculating and verifying
 40           the digests, then forwarding the hea     40           the digests, then forwarding the header to the host. The payload data,
 41           if possible, will be directly placed     41           if possible, will be directly placed into the pre-posted host DDP
 42           buffer. Otherwise, the payload data      42           buffer. Otherwise, the payload data will be sent to the host too.
 43                                                    43 
 44 The cxgb3i driver interfaces with open-iscsi i     44 The cxgb3i driver interfaces with open-iscsi initiator and provides the iSCSI
 45 acceleration through Chelsio hardware wherever     45 acceleration through Chelsio hardware wherever applicable.
 46                                                    46 
 47 Using the cxgb3i Driver                            47 Using the cxgb3i Driver
 48 =======================                            48 =======================
 49                                                    49 
 50 The following steps need to be taken to accele     50 The following steps need to be taken to accelerates the open-iscsi initiator:
 51                                                    51 
 52 1. Load the cxgb3i driver: "modprobe cxgb3i"       52 1. Load the cxgb3i driver: "modprobe cxgb3i"
 53                                                    53 
 54    The cxgb3i module registers a new transport     54    The cxgb3i module registers a new transport class "cxgb3i" with open-iscsi.
 55                                                    55 
 56    * in the case of recompiling the kernel, th     56    * in the case of recompiling the kernel, the cxgb3i selection is located at::
 57                                                    57 
 58         Device Drivers                             58         Device Drivers
 59                 SCSI device support --->           59                 SCSI device support --->
 60                         [*] SCSI low-level dri     60                         [*] SCSI low-level drivers  --->
 61                                 <M>   Chelsio      61                                 <M>   Chelsio S3xx iSCSI support
 62                                                    62 
 63 2. Create an interface file located under /etc     63 2. Create an interface file located under /etc/iscsi/ifaces/ for the new
 64    transport class "cxgb3i".                       64    transport class "cxgb3i".
 65                                                    65 
 66    The content of the file should be in the fo     66    The content of the file should be in the following format::
 67                                                    67 
 68         iface.transport_name = cxgb3i              68         iface.transport_name = cxgb3i
 69         iface.net_ifacename = <ethX>               69         iface.net_ifacename = <ethX>
 70         iface.ipaddress = <iscsi ip address>       70         iface.ipaddress = <iscsi ip address>
 71                                                    71 
 72    * if iface.ipaddress is specified, <iscsi i     72    * if iface.ipaddress is specified, <iscsi ip address> needs to be either the
 73      same as the ethX's ip address or an addre     73      same as the ethX's ip address or an address on the same subnet. Make
 74      sure the ip address is unique in the netw     74      sure the ip address is unique in the network.
 75                                                    75 
 76 3. edit /etc/iscsi/iscsid.conf                     76 3. edit /etc/iscsi/iscsid.conf
 77    The default setting for MaxRecvDataSegmentL     77    The default setting for MaxRecvDataSegmentLength (131072) is too big;
 78    replace with a value no bigger than 15360 (     78    replace with a value no bigger than 15360 (for example 8192)::
 79                                                    79 
 80         node.conn[0].iscsi.MaxRecvDataSegmentL     80         node.conn[0].iscsi.MaxRecvDataSegmentLength = 8192
 81                                                    81 
 82    * The login would fail for a normal session     82    * The login would fail for a normal session if MaxRecvDataSegmentLength is
 83      too big.  A error message in the format o     83      too big.  A error message in the format of
 84      "cxgb3i: ERR! MaxRecvSegmentLength <X> to     84      "cxgb3i: ERR! MaxRecvSegmentLength <X> too big. Need to be <= <Y>."
 85      would be logged to dmesg.                     85      would be logged to dmesg.
 86                                                    86 
 87 4. To direct open-iscsi traffic to go through      87 4. To direct open-iscsi traffic to go through cxgb3i's accelerated path,
 88    "-I <iface file name>" option needs to be s     88    "-I <iface file name>" option needs to be specified with most of the
 89    iscsiadm command. <iface file name> is the      89    iscsiadm command. <iface file name> is the transport interface file created
 90    in step 2.                                      90    in step 2.
                                                      

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

sflogo.php