diff options
| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2011-07-17 02:57:58 -0700 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2011-07-22 09:37:49 +0000 |
| commit | 5de619a31d9cb051d1f818e661af4e54def82316 (patch) | |
| tree | bbdf282c42fe3818607fff4f3a4f7d1b74ee064e /drivers/target/target_core_cdb.c | |
| parent | 1d20bb6147954d4fbd337a3d1b40c7eeae254cd7 (diff) | |
| download | linux-5de619a31d9cb051d1f818e661af4e54def82316.tar.bz2 | |
target: Update QUEUE ALGORITHM MODIFIER control page default
This patch adds the default 'Unrestricted reordering allowed' for SCSI
control mode page QUEUE ALGORITHM MODIFIER on a per se_device basis in
target_modesense_control() following spc4r23. This includes a new
emuluate_rest_reord configfs attribute that currently (only) accepts
zero to signal 'Unrestricted reordering allowed' in control mode page
usage by the backend target device.
Reported-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@risingtidesystems.com>
Diffstat (limited to 'drivers/target/target_core_cdb.c')
| -rw-r--r-- | drivers/target/target_core_cdb.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/drivers/target/target_core_cdb.c b/drivers/target/target_core_cdb.c index 982830023661..145739bcf752 100644 --- a/drivers/target/target_core_cdb.c +++ b/drivers/target/target_core_cdb.c @@ -775,6 +775,35 @@ target_modesense_control(struct se_device *dev, unsigned char *p) p[1] = 0x0a; p[2] = 2; /* + * From spc4r23, 7.4.7 Control mode page + * + * The QUEUE ALGORITHM MODIFIER field (see table 368) specifies + * restrictions on the algorithm used for reordering commands + * having the SIMPLE task attribute (see SAM-4). + * + * Table 368 -- QUEUE ALGORITHM MODIFIER field + * Code Description + * 0h Restricted reordering + * 1h Unrestricted reordering allowed + * 2h to 7h Reserved + * 8h to Fh Vendor specific + * + * A value of zero in the QUEUE ALGORITHM MODIFIER field specifies that + * the device server shall order the processing sequence of commands + * having the SIMPLE task attribute such that data integrity is maintained + * for that I_T nexus (i.e., if the transmission of new SCSI transport protocol + * requests is halted at any time, the final value of all data observable + * on the medium shall be the same as if all the commands had been processed + * with the ORDERED task attribute). + * + * A value of one in the QUEUE ALGORITHM MODIFIER field specifies that the + * device server may reorder the processing sequence of commands having the + * SIMPLE task attribute in any manner. Any data integrity exposures related to + * command sequence order shall be explicitly handled by the application client + * through the selection of appropriate ommands and task attributes. + */ + p[3] = (dev->se_sub_dev->se_dev_attrib.emulate_rest_reord == 1) ? 0x00 : 0x10; + /* * From spc4r17, section 7.4.6 Control mode Page * * Unit Attention interlocks control (UN_INTLCK_CTRL) to code 00b |