[PATCH 9/9] nvme-core: fix nvme_submit_sync_cmd() args

[Sagi Grimberg]

> The __nvme_submit_sync_cmd() function currently has a long list of
> eight arguments, which can make it difficult to read and debug,
> particularly when the function is commonly used from different parts
> of the codebase. This complexity can also increase when extending the
> functionality of the function, resulting in more arguments being added.

I don't think that complexity/difficulty is the issue here, its just
ugly.

> 
> To address this issue, we can create a new structure called
> nvme_submit_cmd_data

Maybe call it nvme_sync_cmd_args.

> and move all the existing arguments into this
> structure. By doing this, we can pass the structure as a single argument
> to the __nvme_submit_sync_cmd() function. This approach simplifies the
> code and makes it more readable, and also provides a way to add future
> arguments to the structure without increasing the number of function
> arguments.

The potential gain here is that on-stack initialized structs you can
implcitly zero-out members so you don't need to explicitly set in all
the call sites. But that is a subjective gain because it can be counter
intuitive at times. Otherwise there is no real coding gain with this
specifically.

But regardless, this looks fine to me.