[PATCH v16 1/9] nvme-core: Clear any SGL flags in passthru commands

From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org
Cc: Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
	Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	Max Gurtovoy <maxg@mellanox.com>,
	Stephen Bates <sbates@raithlin.com>,
	Logan Gunthorpe <logang@deltatee.com>
Subject: [PATCH v16 1/9] nvme-core: Clear any SGL flags in passthru commands
Date: Fri, 24 Jul 2020 11:25:12 -0600	[thread overview]
Message-ID: <20200724172520.16318-2-logang@deltatee.com> (raw)
In-Reply-To: <20200724172520.16318-1-logang@deltatee.com>

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: Sagi Grimberg <sagi@grimberg.me>
---
 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 1d7c7afb1348..6f80bd78eba6 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -593,6 +593,14 @@ 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)
 {
@@ -758,7 +766,7 @@ 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);
-- 
2.20.1

