From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/target/target_core_cdb.c | 29 +++++++++++++++++++++++++++++
drivers/target/target_core_configfs.c | 4 ++++
drivers/target/target_core_device.c | 15 ++++++++++++++-
include/target/target_core_base.h | 1 +
include/target/target_core_device.h | 1 +
include/target/target_core_transport.h | 2 ++
6 files changed, 51 insertions(+), 1 deletions(-)
diff --git a/drivers/target/target_core_cdb.c b/drivers/target/target_core_cdb.c
index 9828300..145739b 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
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index e56c39d..a92176d 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -701,6 +701,9 @@ SE_DEV_ATTR(enforce_pr_isids, S_IRUGO | S_IWUSR);
DEF_DEV_ATTRIB(is_nonrot);
SE_DEV_ATTR(is_nonrot, S_IRUGO | S_IWUSR);
+DEF_DEV_ATTRIB(emulate_rest_reord);
+SE_DEV_ATTR(emulate_rest_reord, S_IRUGO | S_IWUSR);
+
DEF_DEV_ATTRIB_RO(hw_block_size);
SE_DEV_ATTR_RO(hw_block_size);
@@ -750,6 +753,7 @@ static struct configfs_attribute *target_core_dev_attrib_attrs[] = {
&target_core_dev_attrib_emulate_tpws.attr,
&target_core_dev_attrib_enforce_pr_isids.attr,
&target_core_dev_attrib_is_nonrot.attr,
+ &target_core_dev_attrib_emulate_rest_reord.attr,
&target_core_dev_attrib_hw_block_size.attr,
&target_core_dev_attrib_block_size.attr,
&target_core_dev_attrib_hw_max_sectors.attr,
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 81860dd..b38b6c9 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -857,6 +857,7 @@ void se_dev_set_default_attribs(
dev->se_sub_dev->se_dev_attrib.emulate_alua = DA_EMULATE_ALUA;
dev->se_sub_dev->se_dev_attrib.enforce_pr_isids = DA_ENFORCE_PR_ISIDS;
dev->se_sub_dev->se_dev_attrib.is_nonrot = DA_IS_NONROT;
+ dev->se_sub_dev->se_dev_attrib.emulate_rest_reord = DA_EMULATE_REST_REORD;
/*
* The TPU=1 and TPWS=1 settings will be set in TCM/IBLOCK
* iblock_create_virtdevice() from struct queue_limits values
@@ -1128,11 +1129,23 @@ int se_dev_set_is_nonrot(struct se_device *dev, int flag)
return -EINVAL;
}
dev->se_sub_dev->se_dev_attrib.is_nonrot = flag;
- printk(KERN_INFO "dev[%p]: SE Device is_nonrot bit: %d\n",
+ pr_debug("dev[%p]: SE Device is_nonrot bit: %d\n",
dev, flag);
return 0;
}
+int se_dev_set_emulate_rest_reord(struct se_device *dev, int flag)
+{
+ if (flag != 0) {
+ printk(KERN_ERR "dev[%p]: SE Device emulatation of restricted"
+ " reordering not implemented\n", dev);
+ return -ENOSYS;
+ }
+ dev->se_sub_dev->se_dev_attrib.emulate_rest_reord = flag;
+ pr_debug("dev[%p]: SE Device emulate_rest_reord: %d\n", dev, flag);
+ return 0;
+}
+
/*
* Note, this can only be called on unexported SE Device Object.
*/
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 8204c76..86ca355 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -662,6 +662,7 @@ struct se_dev_attrib {
int emulate_alua;
int enforce_pr_isids;
int is_nonrot;
+ int emulate_rest_reord;
u32 hw_block_size;
u32 block_size;
u32 hw_max_sectors;
diff --git a/include/target/target_core_device.h b/include/target/target_core_device.h
index f3b6ae6..4657191 100644
--- a/include/target/target_core_device.h
+++ b/include/target/target_core_device.h
@@ -40,6 +40,7 @@ extern int se_dev_set_emulate_tpu(struct se_device *, int);
extern int se_dev_set_emulate_tpws(struct se_device *, int);
extern int se_dev_set_enforce_pr_isids(struct se_device *, int);
extern int se_dev_set_is_nonrot(struct se_device *, int);
+extern int se_dev_set_emulate_rest_reord(struct se_device *dev, int);
extern int se_dev_set_queue_depth(struct se_device *, u32);
extern int se_dev_set_max_sectors(struct se_device *, u32);
extern int se_dev_set_optimal_sectors(struct se_device *, u32);
diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h
index 54af39d..f41b07c 100644
--- a/include/target/target_core_transport.h
+++ b/include/target/target_core_transport.h
@@ -103,6 +103,8 @@
#define DA_STATUS_MAX_SECTORS_MAX 8192
/* By default don't report non-rotating (solid state) medium */
#define DA_IS_NONROT 0
+/* Queue Algorithm Modifier default for restricted reordering in control mode page */
+#define DA_EMULATE_REST_REORD 0
#define SE_MODE_PAGE_BUF 512
--
1.7.6
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