On 2025/2/17 17:44, John Garry wrote:
On 17/02/2025 02:16, Ye Bin wrote:
From: Ye Bin <yebin10@xxxxxxxxxx>
After commit 1bad6c4a57ef
("scsi: zero per-cmd private driver data for each MQ I/O"),
xen-scsifront/virtio_scsi/snic driver remove code that zeroes
driver-private command data. If request do retry will lead to
driver-private command data remains. Before commit 464a00c9e0ad
("scsi: core: Kill DRIVER_SENSE") if virtio_scsi do capacity
expansion, first request may return UA then request will do retry,
as driver-private command data remains, request will return UA
again.
So are there any drivers which expect this sort of behavior, i.e. keep
private data between retries?
No driver that depends on the last state is found. If yes, the driver
should provide the init_cmd_priv function to manage private data. In
this way, the SCSI middle layer ignores the private data of the driver.
As a result, the request keeps retrying, and the request
times out and fails.
So zeroes driver-private command data when request do retry.
Fixes: f7de50da1479 ("scsi: xen-scsifront: Remove code that zeroes
driver-private command data")
Fixes: c2bb87318baa ("scsi: virtio_scsi: Remove code that zeroes
driver-private command data")
Fixes: c3006a926468 ("scsi: snic: Remove code that zeroes
driver-private command data")
Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
---
Ps: in future, please list the changes per version here
Thanks for the heads-up.
drivers/scsi/scsi_lib.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index be0890e4e706..f1cfe0bb89b2 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1669,13 +1669,6 @@ static blk_status_t scsi_prepare_cmd(struct
request *req)
if (in_flight)
__set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
- /*
- * Only clear the driver-private command data if the LLD does not
supply
- * a function to initialize that data.
- */
- if (!shost->hostt->init_cmd_priv)
- memset(cmd + 1, 0, shost->hostt->cmd_size);
-
cmd->prot_op = SCSI_PROT_NORMAL;
if (blk_rq_bytes(req))
cmd->sc_data_direction = rq_dma_dir(req);
@@ -1842,6 +1835,13 @@ static blk_status_t scsi_queue_rq(struct
blk_mq_hw_ctx *hctx,
if (!scsi_host_queue_ready(q, shost, sdev, cmd))
goto out_dec_target_busy;
+ /*
+ * Only clear the driver-private command data if the LLD does not
supply
+ * a function to initialize that data.
+ */
+ if (shost->hostt->cmd_size && !shost->hostt->init_cmd_priv)
+ memset(cmd + 1, 0, shost->hostt->cmd_size);
+
if (!(req->rq_flags & RQF_DONTPREP)) {
ret = scsi_prepare_cmd(req);
if (ret != BLK_STS_OK)
