[RFC PATCH v3 03/11] nvme-tcp-offload: Add device scan implementation

Shai Malin
2021-02-07T18:14:06Z

From: Dean Balandin <dbalandin@marvell.com>

This patch implements the create_ctrl skeleton, specifcially to
demonstrate how the claim_dev op will be used.

The driver scans the registered devices and calls the claim_dev op on
each of them, to find the first devices that matches the connection
params. Once the correct devices is found (claim_dev returns true), we
raise the refcnt of that device and return that device as the device to
be used for ctrl currently being created.

Signed-off-by: Dean Balandin <dbalandin@marvell.com>
Signed-off-by: Michal Kalderon <mkalderon@marvell.com>
Signed-off-by: Ariel Elior <aelior@marvell.com>
Signed-off-by: Shai Malin <smalin@marvell.com>
---
drivers/nvme/host/tcp-offload.c | 82 +++++++++++++++++++++++++++++++++
1 file changed, 82 insertions(+)

diff --git a/drivers/nvme/host/tcp-offload.c b/drivers/nvme/host/tcp-offload.c
index ee3800250e47..49e11638b4fd 100644
--- a/drivers/nvme/host/tcp-offload.c
+++ b/drivers/nvme/host/tcp-offload.c
@@ -13,6 +13,12 @@
static LIST_HEAD(nvme_tcp_ofld_devices);
static DECLARE_RWSEM(nvme_tcp_ofld_devices_rwsem);

+static inline struct nvme_tcp_ofld_ctrl *
+to_tcp_ofld_ctrl(struct nvme_ctrl *nctrl)
+{
+ return container_of(nctrl, struct nvme_tcp_ofld_ctrl, nctrl);
+}
+
/**
* nvme_tcp_ofld_register_dev() - NVMeTCP Offload Library registration
* function.
@@ -96,6 +102,81 @@ nvme_tcp_ofld_req_done(struct nvme_tcp_ofld_req *req,
/* Placeholder - complete request with/without error */
}

+struct nvme_tcp_ofld_dev *
+nvme_tcp_ofld_lookup_dev(struct nvme_tcp_ofld_ctrl *ctrl)
+{
+ struct nvme_tcp_ofld_dev *dev;
+
+ down_read(&nvme_tcp_ofld_devices_rwsem);
+ list_for_each_entry(dev, &nvme_tcp_ofld_devices, entry) {
+ if (dev->ops->claim_dev(dev, &ctrl->conn_params)) {
+ /* Increase driver refcnt */
+ if (!try_module_get(dev->ops->module)) {
+ pr_err("try_module_get failed\n");
+ dev = NULL;
+ }
+
+ goto out;
+ }
+ }
+
+ dev = NULL;
+out:
+ up_read(&nvme_tcp_ofld_devices_rwsem);
+
+ return dev;
+}
+
+static int nvme_tcp_ofld_setup_ctrl(struct nvme_ctrl *nctrl, bool new)
+{
+ /* Placeholder - validates inputs and creates admin and IO queues */
+
+ return 0;
+}
+
+static struct nvme_ctrl *
+nvme_tcp_ofld_create_ctrl(struct device *ndev, struct nvmf_ctrl_options *opts)
+{
+ struct nvme_tcp_ofld_ctrl *ctrl;
+ struct nvme_tcp_ofld_dev *dev;
+ struct nvme_ctrl *nctrl;
+ int rc = 0;
+
+ ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
+ if (!ctrl)
+ return ERR_PTR(-ENOMEM);
+
+ /* Init nvme_tcp_ofld_ctrl and nvme_ctrl params based on received opts */
+
+ /* Find device that can reach the dest addr */
+ dev = nvme_tcp_ofld_lookup_dev(ctrl);
+ if (!dev) {
+ pr_info("no device found for addr %s:%s.\n",
+ opts->traddr, opts->trsvcid);
+ rc = -EINVAL;
+ goto out_free_ctrl;
+ }
+
+ ctrl->dev = dev;
+
+ /* Init queues */
+
+ /* Call nvme_init_ctrl */
+
+ rc = nvme_tcp_ofld_setup_ctrl(nctrl, true);
+ if (rc)
+ goto out_module_put;
+
+ return nctrl;
+
+out_module_put:
+ module_put(dev->ops->module);
+out_free_ctrl:
+ kfree(ctrl);
+
+ return ERR_PTR(rc);
+}
+
static struct nvmf_transport_ops nvme_tcp_ofld_transport = {
.name = "tcp_offload",
.module = THIS_MODULE,
@@ -105,6 +186,7 @@ static struct nvmf_transport_ops nvme_tcp_ofld_transport = {
NVMF_OPT_CTRL_LOSS_TMO | NVMF_OPT_RECONNECT_DELAY |
NVMF_OPT_HDR_DIGEST | NVMF_OPT_DATA_DIGEST |
NVMF_OPT_NR_POLL_QUEUES | NVMF_OPT_TOS,
+ .create_ctrl = nvme_tcp_ofld_create_ctrl,
};

static int __init nvme_tcp_ofld_init_module(void)