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

[Dongsheng Yang]

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