1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index b15d8cbf630b..3c9c318f66ed 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -174,6 +174,24 @@ static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
                 sgl_bidi = sdb->table.sgl;
                 sgl_bidi_count = sdb->table.nents;
         }
+        /*
+         * Because some userspace code via scsi-generic do not memset their
+         * associated read buffers, go ahead and do that here for type
+         * SCF_SCSI_CONTROL_SG_IO_CDB.  Also note that this is currently
+         * guaranteed to be a single SGL for SCF_SCSI_CONTROL_SG_IO_CDB
+         * by target core in transport_generic_allocate_tasks() ->
+         * transport_generic_cmd_sequencer().
+         */
+        if (se_cmd->se_cmd_flags & SCF_SCSI_CONTROL_SG_IO_CDB &&
+            se_cmd->data_direction == DMA_FROM_DEVICE) {
+                struct scatterlist *sg = scsi_sglist(sc);
+                unsigned char *buf = kmap(sg_page(sg)) + sg->offset;
+
+                if (buf != NULL) {
+                        memset(buf, 0, sg->length);
+                        kunmap(sg_page(sg));
+                }
+        }
 
         /* Tell the core about our preallocated memory */
         ret = transport_generic_map_mem_to_cmd(se_cmd, scsi_sglist(sc),