target: Don't call TFO->write_pending if data_length == 0
If an initiator sends a zero-length command (e.g. TEST UNIT READY) but
sets the transfer direction in the transport layer to indicate a
data-out phase, we still shouldn't try to transfer data. At best it's
a NOP, and depending on the transport, we might crash on an
uninitialized sg list.
Reported-by: Craig Watson <craig.watson@vanguard-rugged.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: <stable@vger.kernel.org> # 3.1
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 9ea0d5f..be877bf 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2292,7 +2292,7 @@
* and let it call back once the write buffers are ready.
*/
target_add_to_state_list(cmd);
- if (cmd->data_direction != DMA_TO_DEVICE) {
+ if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
target_execute_cmd(cmd);
return 0;
}