[PATCH 3.12 118/146] target: Don't allow setting WC emulation if device doesn't support

Jiri Slaby
2014-06-09T09:27:48Z

From: Andy Grover <agrover@redhat.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 07b8dae38b09bcfede7e726f172e39b5ce8390d9 upstream.

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>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/target/target_core_device.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index e5e39658034c..e31ec5cf0c36 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -799,10 +799,10 @@ int se_dev_set_emulate_write_cache(struct se_device *dev, int flag)
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;
--
1.9.3