[PATCH v2 24/25] usb: gadget: f_tcm: Check overlapped command

Thinh Nguyen
2022-07-19T01:54:30Z

If there's an overlapped command tag, cancel the command and respond
with RC_OVERLAPPED_TAG to host.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
Changes in v2:
- New patch. It was part of TASK MANAGEMENT change.
- Directly respond to host on overlapped tag instead of reporting to target
core.

drivers/usb/gadget/function/f_tcm.c | 75 ++++++++++++++++++++++++++++-
1 file changed, 73 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_tcm.c b/drivers/usb/gadget/function/f_tcm.c
index 8b99ee07df87..dfa3e7c043a3 100644
--- a/drivers/usb/gadget/function/f_tcm.c
+++ b/drivers/usb/gadget/function/f_tcm.c
@@ -692,6 +692,15 @@ static void uasp_status_data_cmpl(struct usb_ep *ep, struct usb_request *req)
break;

case UASP_QUEUE_COMMAND:
+ /*
+ * Overlapped command detected and cancelled.
+ * So send overlapped attempted status.
+ */
+ if (cmd->tmr_rsp == RC_OVERLAPPED_TAG &&
+ req->status == -ECONNRESET) {
+ uasp_send_tm_response(cmd);
+ return;
+ }

stream->cmd = NULL;

@@ -700,7 +709,8 @@ static void uasp_status_data_cmpl(struct usb_ep *ep, struct usb_request *req)
* bitmap index. This is for the cases where f_tcm handles
* status response instead of the target core.
*/
- if (cmd->tmr_rsp != RC_RESPONSE_UNKNOWN) {
+ if (cmd->tmr_rsp != RC_OVERLAPPED_TAG &&
+ cmd->tmr_rsp != RC_RESPONSE_UNKNOWN) {
struct se_session *se_sess;

se_sess = fu->tpg->tpg_nexus->tvn_se_sess;
@@ -1080,6 +1090,14 @@ static void usbg_data_write_cmpl(struct usb_ep *ep, struct usb_request *req)

cleanup:
target_put_sess_cmd(se_cmd);
+
+ /* Command was aborted due to overlapped tag */
+ if (cmd->state == UASP_QUEUE_COMMAND &&
+ cmd->tmr_rsp == RC_OVERLAPPED_TAG) {
+ uasp_send_tm_response(cmd);
+ return;
+ }
+
transport_send_check_condition_and_sense(se_cmd,
TCM_CHECK_CONDITION_ABORT_CMD, 0);
}
@@ -1148,9 +1166,10 @@ static int usbg_send_read_response(struct se_cmd *se_cmd)
return uasp_send_read_response(cmd);
}

+static void usbg_aborted_task(struct se_cmd *se_cmd);
+
static void usbg_submit_tmr(struct usbg_cmd *cmd)
{
- struct usbg_cmd *cmd = container_of(work, struct usbg_cmd, work);
struct se_session *se_sess;
struct se_cmd *se_cmd;
int flags = TARGET_SCF_ACK_KREF;
@@ -1214,6 +1233,51 @@ static void usbg_cmd_work(struct work_struct *work)
return;

skip:
+ if (cmd->tmr_rsp == RC_OVERLAPPED_TAG) {
+ struct se_session *se_sess;
+ struct uas_stream *stream;
+
+ se_sess = cmd->fu->tpg->tpg_nexus->tvn_se_sess;
+ stream = uasp_get_stream_by_tag(cmd->fu, cmd->tag);
+
+ /*
+ * There's no guarantee of a matching completion order between
+ * different endpoints. i.e. The device may receive a new (CDB)
+ * command request completion of the command endpoint before it
+ * gets notified of the previous command status completion from
+ * a status endpoint. The driver still needs to detect
+ * misbehaving host and respond with an overlap command tag. To
+ * prevent false overlapped tag failure, give the active and
+ * matching stream id a short time (1ms) to complete before
+ * respond with overlapped command failure.
+ */
+ msleep(1);
+
+ /* If the stream is completed, retry the command. */
+ if (!stream->cmd) {
+ usbg_submit_command(cmd->fu, cmd->req);
+ return;
+ }
+
+ /*
+ * The command isn't submitted to the target core, so we're safe
+ * to remove the bitmap index from the session tag pool.
+ */
+ sbitmap_queue_clear(&se_sess->sess_tag_pool,
+ cmd->se_cmd.map_tag,
+ cmd->se_cmd.map_cpu);
+
+ /*
+ * Overlap command tag detected. Cancel any pending transfer of
+ * the command submitted to target core.
+ */
+ stream->cmd->tmr_rsp = RC_OVERLAPPED_TAG;
+ usbg_aborted_task(&stream->cmd->se_cmd);
+
+ /* Send the response after the transfer is aborted. */
+ return;
+ }
+
uasp_send_tm_response(cmd);
}

@@ -1282,6 +1346,13 @@ static int usbg_submit_command(struct f_uas *fu, struct usb_request *req)
goto skip;
}

+ stream = uasp_get_stream_by_tag(fu, scsi_tag);
+ if (stream->cmd) {
+ pr_err("Command tag %d overlapped\n", scsi_tag);
+ cmd->tmr_rsp = RC_OVERLAPPED_TAG;
+ goto skip;
+ }
+
stream->cmd = cmd;

if (iu->iu_id == IU_ID_TASK_MGMT) {
--
2.28.0