[PATCH RFC v2 04/14] nvme: Add CDQ to xarray and define delete path

[Joel Granados]

Add Controller managed CDQs to a new xarray in nvme_ctrl indexed by the
CDQ id returned by the controller. The new cdqs xarray will house
pointers to the struct cdq_nvme_queue which contains individual CDQ
metadata. Start it off with id and ctrl back pointer; it will grow as
features get added.

Commands on the delete path:
1. Individual -vs- "All" CDQ delete:
  - The individual delete path is taken when there is a specific command
    from user space to "delete" one CDQ
  - The "all" delete is taken on contrller reset
2. Separation between host and controller delete:
  - Controller delete takes care of sending and forwarding the result of
    the nvme CDQ delete command
  - Host delete memory on the host side

The separation between host and controller delete is important in
nvme_disable_ctrl as the host should delete the memory but expect the
controller to follow NVMe protocol and remove the CDQ on its side.

Note that there is no way of adding a CDQ just yet. This commit focuses
on the delete path and leaves room for handling the creation in
subsequent commits.

Signed-off-by: Joel Granados <joel.granados@xxxxxxxxxx>
---
 drivers/nvme/host/Makefile |  2 +-
 drivers/nvme/host/cdq.c    | 62 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/nvme/host/cdq.h    | 20 +++++++++++++++
 drivers/nvme/host/core.c   | 15 ++++++++++-
 drivers/nvme/host/nvme.h   |  1 +
 5 files changed, 98 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/Makefile b/drivers/nvme/host/Makefile
index 6414ec968f99ae69f991cbd61e7ad79554e5041f..cd895082e259a9b0673c7400f6ba62401f95767f 100644
--- a/drivers/nvme/host/Makefile
+++ b/drivers/nvme/host/Makefile
@@ -10,7 +10,7 @@ obj-$(CONFIG_NVME_FC)			+= nvme-fc.o
 obj-$(CONFIG_NVME_TCP)			+= nvme-tcp.o
 obj-$(CONFIG_NVME_APPLE)		+= nvme-apple.o
 
-nvme-core-y				+= core.o ioctl.o sysfs.o pr.o
+nvme-core-y				+= core.o ioctl.o sysfs.o pr.o cdq.o
 nvme-core-$(CONFIG_NVME_VERBOSE_ERRORS)	+= constants.o
 nvme-core-$(CONFIG_TRACING)		+= trace.o
 nvme-core-$(CONFIG_NVME_MULTIPATH)	+= multipath.o
diff --git a/drivers/nvme/host/cdq.c b/drivers/nvme/host/cdq.c
new file mode 100644
index 0000000000000000000000000000000000000000..0e9ac88a054f6630c1eea73ae4140f124b6bb31f
--- /dev/null
+++ b/drivers/nvme/host/cdq.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * NVMe Controller Data Queue (CDQ) support.
+ */
+
+#include "nvme.h"
+#include "cdq.h"
+
+static int nvme_submit_delete_cdq_cmd(const struct cdq_nvme_queue *cdq)
+{
+	struct nvme_command c = {
+		.cdq.opcode = nvme_admin_cdq,
+		.cdq.sel = NVME_CDQ_CMD_MGMT_DELETE,
+		.cdq.dw11.cdqid = cpu_to_le16(cdq->id)
+	};
+
+	return __nvme_submit_sync_cmd(cdq->ctrl->admin_q, &c, NULL, NULL, 0, NVME_QID_ANY, 0);
+}
+
+/* Sends a CDQ delete NVMe cmd */
+static void nvme_delete_cdq_ctrl(struct cdq_nvme_queue *cdq)
+{
+	if (nvme_submit_delete_cdq_cmd(cdq))
+		WARN_ONCE(1, "Failed delete CDQ (id: %d)", cdq->id);
+}
+
+/* Does NOT send a CDQ delete NVMe cmd */
+static void nvme_delete_cdq_host(struct cdq_nvme_queue *cdq)
+{
+	u16 cdq_id = cdq->id;
+	struct nvme_ctrl *ctrl = cdq->ctrl;
+
+	xa_erase(&ctrl->cdqs, cdq_id);
+}
+
+void nvme_delete_cdq(struct cdq_nvme_queue *cdq)
+{
+	nvme_delete_cdq_ctrl(cdq);
+	nvme_delete_cdq_host(cdq);
+}
+EXPORT_SYMBOL_GPL(nvme_delete_cdq);
+
+/* Will NOT send a CDQ delete NVMe cmd. */
+void nvme_delete_cdqs_host(struct nvme_ctrl *ctrl)
+{
+	struct cdq_nvme_queue *cdq;
+	unsigned long i;
+
+	xa_for_each(&ctrl->cdqs, i, cdq)
+		nvme_delete_cdq_host(cdq);
+}
+
+/* Final teardown at device->release: free all CDQs and destroy the xarray. */
+void nvme_free_cdqs(struct nvme_ctrl *ctrl)
+{
+	/*
+	 * Delete host side CDQ only. NOT sending delete cmd as
+	 * Ctrl should delete on disable.
+	 */
+	nvme_delete_cdqs_host(ctrl);
+	xa_destroy(&ctrl->cdqs);
+}
diff --git a/drivers/nvme/host/cdq.h b/drivers/nvme/host/cdq.h
new file mode 100644
index 0000000000000000000000000000000000000000..4378f97553ce2e649d8998eb168f82039dc762b1
--- /dev/null
+++ b/drivers/nvme/host/cdq.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * NVMe Controller Data Queue (CDQ) support.
+ */
+
+#ifndef _NVME_CDQ_H
+#define _NVME_CDQ_H
+
+#include "nvme.h"
+
+struct cdq_nvme_queue {
+	u16 id;
+	struct nvme_ctrl *ctrl;
+};
+
+void nvme_delete_cdq(struct cdq_nvme_queue *cdq);
+void nvme_delete_cdqs_host(struct nvme_ctrl *ctrl);
+void nvme_free_cdqs(struct nvme_ctrl *ctrl);
+
+#endif /* _NVME_CDQ_H */
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index d11858300ad43f3e229eab7f2dd77563075b801e..fbaa2e065ab846e4700cddd7ae9f30a52e8a2cd9 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -25,6 +25,7 @@
 #include <linux/unaligned.h>
 
 #include "nvme.h"
+#include "cdq.h"
 #include "fabrics.h"
 #include <linux/nvme-auth.h>
 
@@ -2665,9 +2666,19 @@ int nvme_disable_ctrl(struct nvme_ctrl *ctrl, bool shutdown)
 	}
 	if (ctrl->quirks & NVME_QUIRK_DELAY_BEFORE_CHK_RDY)
 		msleep(NVME_QUIRK_DELAY_AMOUNT);
-	return nvme_wait_ready(ctrl, NVME_CSTS_RDY, 0,
+	ret =  nvme_wait_ready(ctrl, NVME_CSTS_RDY, 0,
 			       (NVME_CAP_TIMEOUT(ctrl->cap) + 1) / 2, "reset");
+	if (ret)
+		return ret;
+
+	/*
+	 * Delete host side CDQ only. Purposefully NOT sending delete cmd.
+	 * Ctrl should delete on disable.
+	 */
+	nvme_delete_cdqs_host(ctrl);
+	return ret;
 }
+
 EXPORT_SYMBOL_GPL(nvme_disable_ctrl);
 
 int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
@@ -5074,6 +5085,7 @@ static void nvme_free_ctrl(struct device *dev)
 	if (!subsys || ctrl->instance != subsys->instance)
 		ida_free(&nvme_instance_ida, ctrl->instance);
 	nvme_free_cels(ctrl);
+	nvme_free_cdqs(ctrl);
 	nvme_mpath_uninit(ctrl);
 	cleanup_srcu_struct(&ctrl->srcu);
 	nvme_auth_stop(ctrl);
@@ -5120,6 +5132,7 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
 	mutex_init(&ctrl->scan_lock);
 	INIT_LIST_HEAD(&ctrl->namespaces);
 	xa_init(&ctrl->cels);
+	xa_init(&ctrl->cdqs);
 	ctrl->dev = dev;
 	ctrl->ops = ops;
 	ctrl->quirks = quirks;
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 654e5c1b64956c877ff845f0b1f7ee2fa0852b64..7b9d1781816c4bad719584c3d4b4f9fdf7b4e3dc 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -466,6 +466,7 @@ struct nvme_ctrl {
 	enum nvme_dctype dctype;
 
 	u16			awupf; /* 0's based value. */
+	struct xarray cdqs;
 };
 
 static inline enum nvme_ctrl_state nvme_ctrl_state(struct nvme_ctrl *ctrl)

-- 
2.50.1