[PATCH 3.14 175/228] target: Allow non-supporting backends to set pi_prot_type to 0

Greg Kroah-Hartman
2014-06-05T00:11:14Z

From: Andy Grover <agrover@redhat.com>

commit 448ba904160f9d8f69217c28a1692cee5afbff88 upstream.

Userspace tools assume if a value is read from configfs, it is valid
and will not cause an error if the same value is written back. The only
valid value for pi_prot_type for backends not supporting DIF is 0, so allow
this particular value to be set without returning an error.

Reported-by: Krzysztof Chojnowski <frirajder@gmail.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -936,6 +936,10 @@ int se_dev_set_pi_prot_type(struct se_de
return 0;
}
if (!dev->transport->init_prot || !dev->transport->free_prot) {
+ /* 0 is only allowed value for non-supporting backends */
+ if (flag == 0)
+ return 0;
+
pr_err("DIF protection not supported by backend: %s\n",
dev->transport->name);
return -ENOSYS;