On Thu, 2017-05-04 at 15:50 -0700, Bart Van Assche wrote:
> 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@xxxxxxxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Andy Grover <agrover@xxxxxxxxxx>
> Cc: David Disseldorp <ddiss@xxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> ---
> 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;
> }
>
Applied, with a commit log to reflect that zero-length commands used to
be handled by target-core, but since commit d81cb447 (v3.7) they are now
submitted to backend drivers.