From 09b92f2ea59cb282de5889d5706507ecac004ce6 Mon Sep 17 00:00:00 2001
From: Maurizio Lombardi <mlombard@redhat.com>
Date: Thu, 3 Aug 2023 14:37:30 +0200
Subject: [PATCH] target support for cancel commands

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
---
 drivers/nvme/target/Makefile        |  2 +-
 drivers/nvme/target/admin-cmd.c     |  4 ++++
 drivers/nvme/target/core.c          | 36 +++++++++++++++++++++++++++++
 drivers/nvme/target/io-cmd-cancel.c | 17 ++++++++++++++
 drivers/nvme/target/nvmet.h         |  4 ++++
 5 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 drivers/nvme/target/io-cmd-cancel.c

diff --git a/drivers/nvme/target/Makefile b/drivers/nvme/target/Makefile
index c66820102493..6541808579ae 100644
--- a/drivers/nvme/target/Makefile
+++ b/drivers/nvme/target/Makefile
@@ -10,7 +10,7 @@ obj-$(CONFIG_NVME_TARGET_FCLOOP)	+= nvme-fcloop.o
 obj-$(CONFIG_NVME_TARGET_TCP)		+= nvmet-tcp.o
 
 nvmet-y		+= core.o configfs.o admin-cmd.o fabrics-cmd.o \
-			discovery.o io-cmd-file.o io-cmd-bdev.o
+			discovery.o io-cmd-file.o io-cmd-bdev.o io-cmd-cancel.o
 nvmet-$(CONFIG_NVME_TARGET_PASSTHRU)	+= passthru.o
 nvmet-$(CONFIG_BLK_DEV_ZONED)		+= zns.o
 nvmet-$(CONFIG_NVME_TARGET_AUTH)	+= fabrics-cmd-auth.o auth.o
diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index f5b7054a4a05..3c2062cf4632 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -177,6 +177,10 @@ static void nvmet_get_cmd_effects_nvm(struct nvme_effects_log *log)
 	log->iocs[nvme_cmd_flush] =
 	log->iocs[nvme_cmd_dsm]	=
 		cpu_to_le32(NVME_CMD_EFFECTS_CSUPP);
+	if (emulate_cancel_cmd) {
+		log->iocs[nvme_cmd_cancel] =
+			cpu_to_le32(NVME_CMD_EFFECTS_CSUPP);
+	}
 	log->iocs[nvme_cmd_write] =
 	log->iocs[nvme_cmd_write_zeroes] =
 		cpu_to_le32(NVME_CMD_EFFECTS_CSUPP | NVME_CMD_EFFECTS_LBCC);
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index e06013c5dace..0d03e9937789 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -26,6 +26,36 @@ static DEFINE_IDA(cntlid_ida);
 struct workqueue_struct *nvmet_wq;
 EXPORT_SYMBOL_GPL(nvmet_wq);
 
+static int param_store_val(const char *str, int *val, int min, int max)
+{
+	int ret, new_val;
+
+	ret = kstrtoint(str, 10, &new_val);
+	if (ret)
+		return -EINVAL;
+
+	if (new_val < min || new_val > max)
+		return -EINVAL;
+
+	*val = new_val;
+	return 0;
+}
+
+static int set_params(const char *str, const struct kernel_param *kp)
+{
+	return param_store_val(str, kp->arg, 0, INT_MAX);
+}
+
+static const struct kernel_param_ops set_param_ops = {
+	.set    = set_params,
+	.get    = param_get_int,
+};
+
+
+int emulate_cancel_cmd;
+device_param_cb(emulate_cancel_cmd, &set_param_ops, &emulate_cancel_cmd, 0644);
+MODULE_PARM_DESC(emulate_cancel_cmd, "Emulate the cancel command. Default = 0");
+
 /*
  * This read/write semaphore is used to synchronize access to configuration
  * information on a target system that will result in discovery log page
@@ -904,6 +934,12 @@ static u16 nvmet_parse_io_cmd(struct nvmet_req *req)
 	if (nvmet_is_passthru_req(req))
 		return nvmet_parse_passthru_io_cmd(req);
 
+	if (emulate_cancel_cmd && req->cmd->common.opcode == nvme_cmd_cancel) {
+		req->execute = nvmet_execute_cancel;
+		if (req->cmd->cancel.nsid == NVME_NSID_ALL)
+			return 0;
+	}
+
 	ret = nvmet_req_find_ns(req);
 	if (unlikely(ret))
 		return ret;
diff --git a/drivers/nvme/target/io-cmd-cancel.c b/drivers/nvme/target/io-cmd-cancel.c
new file mode 100644
index 000000000000..d19a6126c9c8
--- /dev/null
+++ b/drivers/nvme/target/io-cmd-cancel.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe I/O cancel command implementation.
+ * Copyright (c) 2023 Red Hat
+ */
+
+#include "nvmet.h"
+
+void nvmet_execute_cancel(struct nvmet_req *req)
+{
+	if (!nvmet_check_transfer_len(req, 0))
+		return;
+
+	nvmet_set_result(req, (1 << 16));
+	nvmet_req_complete(req, 0);
+}
+
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index c1306de1f4dd..f4fe7956aa43 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -31,6 +31,8 @@
 #define NVMET_SN_MAX_SIZE		20
 #define NVMET_FR_MAX_SIZE		8
 
+extern int emulate_cancel_cmd;
+
 /*
  * Supported optional AENs:
  */
@@ -602,6 +604,8 @@ void nvmet_bdev_execute_zone_mgmt_recv(struct nvmet_req *req);
 void nvmet_bdev_execute_zone_mgmt_send(struct nvmet_req *req);
 void nvmet_bdev_execute_zone_append(struct nvmet_req *req);
 
+void nvmet_execute_cancel(struct nvmet_req *req);
+
 static inline u32 nvmet_rw_data_len(struct nvmet_req *req)
 {
 	return ((u32)le16_to_cpu(req->cmd->rw.length) + 1) <<
-- 
2.43.0