[PATCH v3] scsi: core: clear driver private data when retry request

Ye Bin
2025-02-17T02:16:39Z

From: Ye Bin <yebin10@huawei.com>

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. 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@huawei.com>
---
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)
--
2.34.1