[PATCH 1/2] nvme: retry command if driver control flag given for passthru

[Minwoo Im]

ioctl passthru commands are REQ_FAILFAST_DRIVER requests which are
non-retry requests if failed.  This patch introduced `driver_ctrl` flag
to the ioctl command structure: nvme_passthru_cmd, nvme_passthru_cmd64.
`driver_ctrl` field has not been appended, but replaced existing
reserved field.

Clear the REQ_FAILFASTER_DRIVER flag from the request if `driver_ctrl`
is given with NVME_DRIVER_CTRL_RETRY set to make it retry-able if failed
without DNR.

Signed-off-by: Minwoo Im <minwoo.im.dev at gmail.com>
---
 drivers/nvme/host/core.c        | 12 ++++++++----
 include/uapi/linux/nvme_ioctl.h | 15 +++++++++++----
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index d77f3f26d8d3..20cd4a815944 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1143,7 +1143,7 @@ EXPORT_SYMBOL_NS_GPL(nvme_execute_passthru_rq, NVME_TARGET_PASSTHRU);
 static int nvme_submit_user_cmd(struct request_queue *q,
 		struct nvme_command *cmd, void __user *ubuffer,
 		unsigned bufflen, void __user *meta_buffer, unsigned meta_len,
-		u32 meta_seed, u64 *result, unsigned timeout)
+		u32 meta_seed, u64 *result, unsigned timeout, u16 driver_ctrl)
 {
 	bool write = nvme_is_write(cmd);
 	struct nvme_ns *ns = q->queuedata;
@@ -1157,6 +1157,9 @@ static int nvme_submit_user_cmd(struct request_queue *q,
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
+	if (driver_ctrl & NVME_DRIVER_CTRL_RETRY)
+		req->cmd_flags &= ~REQ_FAILFAST_DRIVER;
+
 	if (timeout)
 		req->timeout = timeout;
 	nvme_req(req)->flags |= NVME_REQ_USERCMD;
@@ -1615,7 +1618,8 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 
 	return nvme_submit_user_cmd(ns->queue, &c,
 			nvme_to_user_ptr(io.addr), length,
-			metadata, meta_len, lower_32_bits(io.slba), NULL, 0);
+			metadata, meta_len, lower_32_bits(io.slba), NULL, 0,
+			io.driver_ctrl);
 }
 
 static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
@@ -1653,7 +1657,7 @@ static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 	status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
 			nvme_to_user_ptr(cmd.addr), cmd.data_len,
 			nvme_to_user_ptr(cmd.metadata), cmd.metadata_len,
-			0, &result, timeout);
+			0, &result, timeout, cmd.driver_ctrl);
 
 	if (status >= 0) {
 		if (put_user(result, &ucmd->result))
@@ -1697,7 +1701,7 @@ static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 	status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
 			nvme_to_user_ptr(cmd.addr), cmd.data_len,
 			nvme_to_user_ptr(cmd.metadata), cmd.metadata_len,
-			0, &cmd.result, timeout);
+			0, &cmd.result, timeout, cmd.driver_ctrl);
 
 	if (status >= 0) {
 		if (put_user(cmd.result, &ucmd->result))
diff --git a/include/uapi/linux/nvme_ioctl.h b/include/uapi/linux/nvme_ioctl.h
index d99b5a772698..b247b3eee2e3 100644
--- a/include/uapi/linux/nvme_ioctl.h
+++ b/include/uapi/linux/nvme_ioctl.h
@@ -14,7 +14,7 @@ struct nvme_user_io {
 	__u8	flags;
 	__u16	control;
 	__u16	nblocks;
-	__u16	rsvd;
+	__u16	driver_ctrl;
 	__u64	metadata;
 	__u64	addr;
 	__u64	slba;
@@ -27,7 +27,7 @@ struct nvme_user_io {
 struct nvme_passthru_cmd {
 	__u8	opcode;
 	__u8	flags;
-	__u16	rsvd1;
+	__u16	driver_ctrl;
 	__u32	nsid;
 	__u32	cdw2;
 	__u32	cdw3;
@@ -48,7 +48,7 @@ struct nvme_passthru_cmd {
 struct nvme_passthru_cmd64 {
 	__u8	opcode;
 	__u8	flags;
-	__u16	rsvd1;
+	__u16	driver_ctrl;
 	__u32	nsid;
 	__u32	cdw2;
 	__u32	cdw3;
@@ -63,7 +63,7 @@ struct nvme_passthru_cmd64 {
 	__u32	cdw14;
 	__u32	cdw15;
 	__u32	timeout_ms;
-	__u32   rsvd2;
+	__u32   rsvd;
 	__u64	result;
 };
 
@@ -79,4 +79,11 @@ struct nvme_passthru_cmd64 {
 #define NVME_IOCTL_ADMIN64_CMD	_IOWR('N', 0x47, struct nvme_passthru_cmd64)
 #define NVME_IOCTL_IO64_CMD	_IOWR('N', 0x48, struct nvme_passthru_cmd64)
 
+enum {
+	/* Retry command if failed with !DNR for <= nvme_max_retries */
+	__NVME_DRIVER_CTRL_RETRY,
+};
+
+#define NVME_DRIVER_CTRL_RETRY  (1 << __NVME_DRIVER_CTRL_RETRY)
+
 #endif /* _UAPI_LINUX_NVME_IOCTL_H */
-- 
2.17.1