On Fri, Jun 07, 2013 at 09:34:24PM +0000, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
>
> This patch coverts vhost/scsi to se_cmd->cmd_kref TARGET_SCF_ACK_KREF
> usage, instead of assuming that vhost_scsi_free_cmd() is always called
> before TCM processing is completed in the response fast path.
>
> This includes adding vhost_scsi_check_stop_free() -> target_put_sess_cmd()
> to perform the second se_cmd->cmd_kref put, and moving vhost_scsi_free_cmd()
> resource release into tcm_vhost_release_cmd() that is invoked once the last
> se_cmd->cmd_kref put occurs.
>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Roland Dreier <roland@xxxxxxxxxx>
> Cc: Kent Overstreet <koverstreet@xxxxxxxxxx>
> Cc: Asias He <asias@xxxxxxxxxx>
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
> Cc: Moussa Ba <moussaba@xxxxxxxxxx>
> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Acked-by: Asias He <asias@xxxxxxxxxx>
> ---
> drivers/vhost/scsi.c | 31 +++++++++++++++++++------------
> 1 files changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index aacf71e..1e5e820 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -446,7 +446,19 @@ static u32 tcm_vhost_tpg_get_inst_index(struct se_portal_group *se_tpg)
>
> static void tcm_vhost_release_cmd(struct se_cmd *se_cmd)
> {
> - return;
> + struct tcm_vhost_cmd *tv_cmd = container_of(se_cmd,
> + struct tcm_vhost_cmd, tvc_se_cmd);
> +
> + if (tv_cmd->tvc_sgl_count) {
> + u32 i;
> + for (i = 0; i < tv_cmd->tvc_sgl_count; i++)
> + put_page(sg_page(&tv_cmd->tvc_sgl[i]));
> +
> + kfree(tv_cmd->tvc_sgl);
> + }
> +
> + tcm_vhost_put_inflight(tv_cmd->inflight);
> + kfree(tv_cmd);
> }
>
> static int tcm_vhost_shutdown_session(struct se_session *se_sess)
> @@ -559,17 +571,11 @@ static void vhost_scsi_free_cmd(struct tcm_vhost_cmd *tv_cmd)
> /* TODO locking against target/backend threads? */
> transport_generic_free_cmd(se_cmd, 0);
>
> - if (tv_cmd->tvc_sgl_count) {
> - u32 i;
> - for (i = 0; i < tv_cmd->tvc_sgl_count; i++)
> - put_page(sg_page(&tv_cmd->tvc_sgl[i]));
> -
> - kfree(tv_cmd->tvc_sgl);
> - }
> -
> - tcm_vhost_put_inflight(tv_cmd->inflight);
> +}
>
> - kfree(tv_cmd);
> +static int vhost_scsi_check_stop_free(struct se_cmd *se_cmd)
> +{
> + return target_put_sess_cmd(se_cmd->se_sess, se_cmd);
> }
>
> static void tcm_vhost_do_evt_work(struct vhost_scsi *vs,
> @@ -847,7 +853,7 @@ static void tcm_vhost_submission_work(struct work_struct *work)
> tv_cmd->tvc_cdb, &tv_cmd->tvc_sense_buf[0],
> tv_cmd->tvc_lun, tv_cmd->tvc_exp_data_len,
> tv_cmd->tvc_task_attr, tv_cmd->tvc_data_direction,
> - 0, sg_ptr, tv_cmd->tvc_sgl_count,
> + TARGET_SCF_ACK_KREF, sg_ptr, tv_cmd->tvc_sgl_count,
> sg_bidi_ptr, sg_no_bidi);
> if (rc < 0) {
> transport_send_check_condition_and_sense(se_cmd,
> @@ -2008,6 +2014,7 @@ static struct target_core_fabric_ops tcm_vhost_ops = {
> .tpg_release_fabric_acl = tcm_vhost_release_fabric_acl,
> .tpg_get_inst_index = tcm_vhost_tpg_get_inst_index,
> .release_cmd = tcm_vhost_release_cmd,
> + .check_stop_free = vhost_scsi_check_stop_free,
> .shutdown_session = tcm_vhost_shutdown_session,
> .close_session = tcm_vhost_close_session,
> .sess_get_index = tcm_vhost_sess_get_index,
> --
> 1.7.2.5
>
--
Asias
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