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>

diff --git a/drivers/target/target_core_cdb.c b/drivers/target/target_core_cdb.c
index 9828300236619354f98a082e3670a8f9a280a2dc..145739bcf7528368b58f20b46d623a846097561e 100644 (file)
--- a/drivers/target/target_core_cdb.c
+++ b/drivers/target/target_core_cdb.c
@@ -774,6 +774,35 @@ target_modesense_control(struct se_device *dev, unsigned char *p)
        p[0] = 0x0a;
        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
         *

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index e56c39daeec601272661c7542d4c76be0fb3d592..a92176d2e1875072337a33515d823b8c80bb634e 100644 (file)
--- 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 81860ddc7cc4c4f09d67d05518e514eba354fc56..b38b6c993e6555855be8cd830451d41a0ab6e1d5 100644 (file)
--- 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 8204c76ca12b43784d1a7ab48ecc591f3e680484..86ca35539b944bb0648677cdcdf6d94b7c3bed41 100644 (file)
--- 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 f3b6ae655454e36ca0314e3b4d5fc7298aefdaf5..46571912086c1b5c7cc5592e91a4ec4ace9fd50d 100644 (file)
--- 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 54af39d8e3fbd4ba4a0fd599fe0baa33c574a4ff..f41b07c7401e432fe006ce75849ee813ba600cde 100644 (file)
--- 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