On 03/27/2017 04:07 AM, lixiubo@xxxxxxxxxxxxxxxxxxxx wrote:
> From: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
>
> The t_data_nents and t_bidi_data_nents are the numbers of the
> segments, but it couldn't be sure the block size equals to size
> of the segment.
>
> For the worst case, all the blocks are discontiguous and there
> will need the same number of iovecs, that's to say: blocks == iovs.
> So here just set the number of iovs to block count needed by tcmu
> cmd.
>
> Signed-off-by: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
> Tested-by: Ilias Tsitsimpis <iliastsi@xxxxxxxxxxx>
> ---
> drivers/target/target_core_user.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
> index 65d475f..ede815c 100644
> --- a/drivers/target/target_core_user.c
> +++ b/drivers/target/target_core_user.c
> @@ -408,6 +408,13 @@ static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
> return data_length;
> }
>
> +static inline uint32_t tcmu_cmd_get_block_cnt(struct tcmu_cmd *tcmu_cmd)
> +{
> + size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
> +
> + return data_length / DATA_BLOCK_SIZE;
> +}
> +
> static sense_reason_t
> tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
> {
> @@ -435,8 +442,7 @@ static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
> * expensive to tell how many regions are freed in the bitmap
> */
> base_command_size = max(offsetof(struct tcmu_cmd_entry,
> - req.iov[se_cmd->t_bidi_data_nents +
> - se_cmd->t_data_nents]),
> + req.iov[tcmu_cmd_get_block_cnt(tcmu_cmd)]),
> sizeof(struct tcmu_cmd_entry));
> command_size = base_command_size
> + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
>
Looks ok to me. Thanks.
Reviewed-by: Mike Christie <mchristi@xxxxxxxxxx>
