target: Don't allow setting WC emulation if device doesn't support
Just like for pSCSI, if the transport sets get_write_cache, then it is
not valid to enable write cache emulation for it. Return an error.
see https://bugzilla.redhat.com/show_bug.cgi?id=1082675
Reviewed-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 382b66b..26416c1 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -798,10 +798,10 @@
pr_err("emulate_write_cache not supported for pSCSI\n");
return -EINVAL;
}
- if (dev->transport->get_write_cache) {
- pr_warn("emulate_write_cache cannot be changed when underlying"
- " HW reports WriteCacheEnabled, ignoring request\n");
- return 0;
+ if (flag &&
+ dev->transport->get_write_cache) {
+ pr_err("emulate_write_cache not supported for this device\n");
+ return -EINVAL;
}
dev->dev_attrib.emulate_write_cache = flag;