2 files changed, 19 insertions, 3 deletions

diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index e0b3c379aa14..0921a64b5550 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -291,6 +291,11 @@ rd_execute_rw(struct se_cmd *cmd)
         u32 src_len;
         u64 tmp;
 
+        if (dev->rd_flags & RDF_NULLIO) {
+                target_complete_cmd(cmd, SAM_STAT_GOOD);
+                return 0;
+        }
+
         tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
         rd_offset = do_div(tmp, PAGE_SIZE);
         rd_page = tmp;
@@ -373,11 +378,12 @@ rd_execute_rw(struct se_cmd *cmd)
 }
 
 enum {
-        Opt_rd_pages, Opt_err
+        Opt_rd_pages, Opt_rd_nullio, Opt_err
 };
 
 static match_table_t tokens = {
         {Opt_rd_pages, "rd_pages=%d"},
+        {Opt_rd_nullio, "rd_nullio=%d"},
         {Opt_err, NULL}
 };
 
@@ -408,6 +414,14 @@ static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
                                 " Count: %u\n", rd_dev->rd_page_count);
                         rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
                         break;
+                case Opt_rd_nullio:
+                        match_int(args, &arg);
+                        if (arg != 1)
+                                break;
+
+                        pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
+                        rd_dev->rd_flags |= RDF_NULLIO;
+                        break;
                 default:
                         break;
                 }
@@ -424,8 +438,9 @@ static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
         ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
                         rd_dev->rd_dev_id);
         bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
-                        "  SG_table_count: %u\n", rd_dev->rd_page_count,
-                        PAGE_SIZE, rd_dev->sg_table_count);
+                        "  SG_table_count: %u  nullio: %d\n", rd_dev->rd_page_count,
+                        PAGE_SIZE, rd_dev->sg_table_count,
+                        !!(rd_dev->rd_flags & RDF_NULLIO));
         return bl;
 }
 
diff --git a/drivers/target/target_core_rd.h b/drivers/target/target_core_rd.h
index 933b38b6e563..1789d1e14395 100644
--- a/drivers/target/target_core_rd.h
+++ b/drivers/target/target_core_rd.h
@@ -22,6 +22,7 @@ struct rd_dev_sg_table {
 } ____cacheline_aligned;
 
 #define RDF_HAS_PAGE_COUNT      0x01
+#define RDF_NULLIO              0x02
 
 struct rd_dev {
         struct se_device dev;