target: Add emulation for MODE SELECT

This is another thing that compliance tests try, and it's easy to
implement on top of the MODE SENSE refactoring; since we don't claim
to support any changeable values, all we need to do is check that
the page contents sent by the initiator match what we would return.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index 6c10fce9ef09..33022a3f31fc 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -975,6 +975,57 @@ out:
         return 0;
 }
 
+static int spc_emulate_modeselect(struct se_cmd *cmd)
+{
+        struct se_device *dev = cmd->se_dev;
+        char *cdb = cmd->t_task_cdb;
+        bool ten = cdb[0] == MODE_SELECT_10;
+        int off = ten ? 8 : 4;
+        bool pf = !!(cdb[1] & 0x10);
+        u8 page, subpage;
+        unsigned char *buf;
+        unsigned char tbuf[SE_MODE_PAGE_BUF];
+        int length;
+        int ret = 0;
+        int i;
+
+        buf = transport_kmap_data_sg(cmd);
+
+        if (!pf) {
+                cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
+                ret = -EINVAL;
+                goto out;
+        }
+
+        page = buf[off] & 0x3f;
+        subpage = buf[off] & 0x40 ? buf[off + 1] : 0;
+
+        for (i = 0; i < ARRAY_SIZE(modesense_handlers); ++i)
+                if (modesense_handlers[i].page == page &&
+                    modesense_handlers[i].subpage == subpage) {
+                        memset(tbuf, 0, SE_MODE_PAGE_BUF);
+                        length = modesense_handlers[i].emulate(dev, 0, tbuf);
+                        goto check_contents;
+                }
+
+        cmd->scsi_sense_reason = TCM_UNKNOWN_MODE_PAGE;
+        ret = -EINVAL;
+        goto out;
+
+check_contents:
+        if (memcmp(buf + off, tbuf, length)) {
+                cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
+                ret = -EINVAL;
+        }
+
+out:
+        transport_kunmap_data_sg(cmd);
+
+        if (!ret)
+                target_complete_cmd(cmd, GOOD);
+        return ret;
+}
+
 static int spc_emulate_request_sense(struct se_cmd *cmd)
 {
         unsigned char *cdb = cmd->t_task_cdb;
@@ -1113,9 +1164,11 @@ int spc_parse_cdb(struct se_cmd *cmd, unsigned int *size)
         switch (cdb[0]) {
         case MODE_SELECT:
                 *size = cdb[4];
+                cmd->execute_cmd = spc_emulate_modeselect;
                 break;
         case MODE_SELECT_10:
                 *size = (cdb[7] << 8) + cdb[8];
+                cmd->execute_cmd = spc_emulate_modeselect;
                 break;
         case MODE_SENSE:
                 *size = cdb[4];