From: Logan Gunthorpe <logang@deltatee.com>
Date: Fri, 24 Jul 2020 11:25:12 -0600
Subject: [PATCH] nvme: clear any SGL flags in passthru commands
Git-commit: 2bf5d3bbffad06639db518c8dcf8a14c7dce770e
Patch-mainline: v5.9-rc1
References: jsc#SLE-15608

The host driver should decide whether to use SGLs or PRPs and they
currently assume the flags are cleared after the call to
nvme_setup_cmd(). However, passed-through commands may erroneously
set these bits; so clear them for all cases.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/nvme/host/core.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index c16bfdff2953..2818c17e92ed 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -604,6 +604,14 @@ static void nvme_assign_write_stream(struct nvme_ctrl *ctrl,
 		req->q->write_hints[streamid] += blk_rq_bytes(req) >> 9;
 }
 
+static void nvme_setup_passthrough(struct request *req,
+		struct nvme_command *cmd)
+{
+	memcpy(cmd, nvme_req(req)->cmd, sizeof(*cmd));
+	/* passthru commands should let the driver set the SGL flags */
+	cmd->common.flags &= ~NVME_CMD_SGL_ALL;
+}
+
 static inline void nvme_setup_flush(struct nvme_ns *ns,
 		struct nvme_command *cmnd)
 {
@@ -769,7 +777,7 @@ blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
 	switch (req_op(req)) {
 	case REQ_OP_DRV_IN:
 	case REQ_OP_DRV_OUT:
-		memcpy(cmd, nvme_req(req)->cmd, sizeof(*cmd));
+		nvme_setup_passthrough(req, cmd);
 		break;
 	case REQ_OP_FLUSH:
 		nvme_setup_flush(ns, cmd);
-- 
2.16.4