Re: [PATCH 1/7] block: Init for CBD(CXL Block Device)

Dongsheng Yang <dongsheng.yang@xxxxxxxxxxxx> · Wed, 24 Apr 2024 16:36:36 +0800

在 2024/4/24 星期三 上午 11:58, Chaitanya Kulkarni 写道:
+/*
+ * As shared memory is supported in CXL3.0 spec, we can transfer data via CXL shared memory.
+ * CBD means CXL block device, it use CXL shared memory to transport command and data to
+ * access block device in different host, as shown below:
+ *
+ *    ┌───────────────────────────────┐                               ┌────────────────────────────────────┐
+ *    │          node-1               │                               │              node-2                │
+ *    ├───────────────────────────────┤                               ├────────────────────────────────────┤
+ *    │                               │                               │                                    │
+ *    │                       ┌───────┤                               ├─────────┐                          │
+ *    │                       │ cbd0  │                               │ backend0├──────────────────┐       │
+ *    │                       ├───────┤                               ├─────────┤                  │       │
+ *    │                       │ pmem0 │                               │ pmem0   │                  ▼       │
+ *    │               ┌───────┴───────┤                               ├─────────┴────┐     ┌───────────────┤
+ *    │               │    cxl driver │                               │ cxl driver   │     │  /dev/sda     │
+ *    └───────────────┴────────┬──────┘                               └─────┬────────┴─────┴───────────────┘
+ *                             │                                            │
+ *                             │                                            │
+ *                             │        CXL                         CXL     │
+ *                             └────────────────┐               ┌───────────┘
+ *                                              │               │
+ *                                              │               │
+ *                                              │               │
+ *                                          ┌───┴───────────────┴─────┐
+ *                                          │   shared memory device  │
+ *                                          └─────────────────────────┘
+ *
+ * any read/write to cbd0 on node-1 will be transferred to node-2 /dev/sda. It works similar with
+ * nbd (network block device), but it transfer data via CXL shared memory rather than network.
+ */
+
+/* printk */

I don't think you need above comment ..

Agreed

+#define cbd_err(fmt, ...)							\
+	pr_err("cbd: %s:%u " fmt, __func__, __LINE__, ##__VA_ARGS__)

you can use #define pr_fmt and remove cmd: prefixes in each pr_xxx above ?

pr_fmt was one of my choice, however, it cannot fulfill all my 
requirements, such as adding other prefixes like "transport%u," etc. So, 
in the end, I didn't use pr_fmt, also to maintain consistency with other 
macros.

+#define cbd_info(fmt, ...)							\
+	pr_info("cbd: %s:%u " fmt, __func__, __LINE__, ##__VA_ARGS__)
+#define cbd_debug(fmt, ...)							\
+	pr_debug("cbd: %s:%u " fmt, __func__, __LINE__, ##__VA_ARGS__)
+
+#define cbdt_err(transport, fmt, ...)						\
+	cbd_err("cbd_transport%u: " fmt,					\
+		 transport->id, ##__VA_ARGS__)
+#define cbdt_info(transport, fmt, ...)						\
+	cbd_info("cbd_transport%u: " fmt,					\
+		 transport->id, ##__VA_ARGS__)
+#define cbdt_debug(transport, fmt, ...)						\
+	cbd_debug("cbd_transport%u: " fmt,					\
+		 transport->id, ##__VA_ARGS__)
+
+#define cbd_backend_err(backend, fmt, ...)					\
+	cbdt_err(backend->cbdt, "backend%d: " fmt,				\
+		 backend->backend_id, ##__VA_ARGS__)
+#define cbd_backend_info(backend, fmt, ...)					\
+	cbdt_info(backend->cbdt, "backend%d: " fmt,				\
+		 backend->backend_id, ##__VA_ARGS__)
+#define cbd_backend_debug(backend, fmt, ...)					\
+	cbdt_debug(backend->cbdt, "backend%d: " fmt,				\
+		 backend->backend_id, ##__VA_ARGS__)
+
+#define cbd_handler_err(handler, fmt, ...)					\
+	cbd_backend_err(handler->cbdb, "handler%d: " fmt,			\
+		 handler->channel.channel_id, ##__VA_ARGS__)
+#define cbd_handler_info(handler, fmt, ...)					\
+	cbd_backend_info(handler->cbdb, "handler%d: " fmt,			\
+		 handler->channel.channel_id, ##__VA_ARGS__)
+#define cbd_handler_debug(handler, fmt, ...)					\
+	cbd_backend_debug(handler->cbdb, "handler%d: " fmt,			\
+		 handler->channel.channel_id, ##__VA_ARGS__)
+
+#define cbd_blk_err(dev, fmt, ...)						\
+	cbdt_err(dev->cbdt, "cbd%d: " fmt,					\
+		 dev->mapped_id, ##__VA_ARGS__)
+#define cbd_blk_info(dev, fmt, ...)						\
+	cbdt_info(dev->cbdt, "cbd%d: " fmt,					\
+		 dev->mapped_id, ##__VA_ARGS__)
+#define cbd_blk_debug(dev, fmt, ...)						\
+	cbdt_debug(dev->cbdt, "cbd%d: " fmt,					\
+		 dev->mapped_id, ##__VA_ARGS__)
+
+#define cbd_queue_err(queue, fmt, ...)						\
+	cbd_blk_err(queue->cbd_blkdev, "queue-%d: " fmt,			\
+		     queue->index, ##__VA_ARGS__)
+#define cbd_queue_info(queue, fmt, ...)						\
+	cbd_blk_info(queue->cbd_blkdev, "queue-%d: " fmt,			\
+		     queue->index, ##__VA_ARGS__)
+#define cbd_queue_debug(queue, fmt, ...)					\
+	cbd_blk_debug(queue->cbd_blkdev, "queue-%d: " fmt,			\
+		     queue->index, ##__VA_ARGS__)
+
+#define cbd_channel_err(channel, fmt, ...)					\
+	cbdt_err(channel->cbdt, "channel%d: " fmt,				\
+		 channel->channel_id, ##__VA_ARGS__)
+#define cbd_channel_info(channel, fmt, ...)					\
+	cbdt_info(channel->cbdt, "channel%d: " fmt,				\
+		 channel->channel_id, ##__VA_ARGS__)
+#define cbd_channel_debug(channel, fmt, ...)					\
+	cbdt_debug(channel->cbdt, "channel%d: " fmt,				\
+		 channel->channel_id, ##__VA_ARGS__)
+

[...]

+
+struct cbd_se {
+	struct cbd_se_hdr	header;
+	u64			priv_data;	// pointer to cbd_request

use /**/ instead //

agreed

Thanx

-ck