[PATCH 3.10 088/103] target: Dont allow setting WC emulation if device doesnt support

From: Greg Kroah-Hartman
Date: Wed Jun 04 2014 - 19:27:48 EST

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


From: Andy Grover <agrover@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Andy Grover <agrover@xxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/target/target_core_device.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -796,10 +796,10 @@ int se_dev_set_emulate_write_cache(struc
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;

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