target: Fail XCOPY for non matching source + destination block_size

This patch adds an explicit check + failure for XCOPY I/O to source +
destination devices with a non-matching block_size.

This limitiation is currently due to the fact that the scatterlist
memory allocated for the XCOPY READ operation is passed zero-copy
to the XCOPY WRITE operation.

Reported-by: Thomas Glanzmann <thomas@glanzmann.de>
Reported-by: Douglas Gilbert <dgilbert@interlog.com>
Cc: Thomas Glanzmann <thomas@glanzmann.de>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/target/target_core_xcopy.c b/drivers/target/target_core_xcopy.c
index 0e41143fc16e..474cd44fac14 100644
--- a/drivers/target/target_core_xcopy.c
+++ b/drivers/target/target_core_xcopy.c
@@ -893,6 +893,7 @@ sense_reason_t target_do_xcopy(struct se_cmd *se_cmd)
         struct xcopy_op *xop = NULL;
         unsigned char *p = NULL, *seg_desc;
         unsigned int list_id, list_id_usage, sdll, inline_dl, sa;
+        sense_reason_t ret = TCM_INVALID_PARAMETER_LIST;
         int rc;
         unsigned short tdll;
 
@@ -944,6 +945,17 @@ sense_reason_t target_do_xcopy(struct se_cmd *se_cmd)
         if (rc <= 0)
                 goto out;
 
+        if (xop->src_dev->dev_attrib.block_size !=
+            xop->dst_dev->dev_attrib.block_size) {
+                pr_err("XCOPY: Non matching src_dev block_size: %u + dst_dev"
+                       " block_size: %u currently unsupported\n",
+                        xop->src_dev->dev_attrib.block_size,
+                        xop->dst_dev->dev_attrib.block_size);
+                xcopy_pt_undepend_remotedev(xop);
+                ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+                goto out;
+        }
+
         pr_debug("XCOPY: Processed %d target descriptors, length: %u\n", rc,
                                 rc * XCOPY_TARGET_DESC_LEN);
         seg_desc = &p[16];
@@ -966,7 +978,7 @@ out:
         if (p)
                 transport_kunmap_data_sg(se_cmd);
         kfree(xop);
-        return TCM_INVALID_PARAMETER_LIST;
+        return ret;
 }
 
 static sense_reason_t target_rcr_operating_parameters(struct se_cmd *se_cmd)