[PATCH 04/19] target/fileio: Avoid that zero-length READ and WRITE commands hang

[Bart Van Assche <bart.vanassche@sandisk.com>]

>From __target_execute_cmd() (simplified):

	ret = cmd->execute_cmd(cmd);
	if (ret != 0)
		transport_generic_request_failure(cmd, ret);

>From sbc_execute_rw():

	return ops->execute_rw(cmd, cmd->t_data_sg, cmd->t_data_nents,
			       cmd->data_direction);

This means that sbc_ops.execute_rw() must either return a non-zero
value or call target_complete_cmd() and return zero or command
execution stalls. Make sure that fd_execute_rw() calls
target_complete_cmd() even for zero-length commands.

Fixes: commit c66ac9db8d4a ("[SCSI] target: Add LIO target core v4.0.0-rc6")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: David Disseldorp <ddiss@suse.de>
Cc: <stable@vger.kernel.org>
---
 drivers/target/target_core_file.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 1bf6c31e4c21..73b8f93a5fef 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -608,8 +608,7 @@ fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 	if (ret < 0)
 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 
-	if (ret)
-		target_complete_cmd(cmd, SAM_STAT_GOOD);
+	target_complete_cmd(cmd, SAM_STAT_GOOD);
 	return 0;
 }
 
-- 
2.12.2