Re: [PATCH V6 00/17] io_uring/ublk: add generic IORING_OP_FUSED_CMD

[Bernd Schubert]

On 3/30/23 13:36, Ming Lei wrote:
[...]
> V6:
> 	- re-design fused command, and make it more generic, moving sharing buffer
> 	as one plugin of fused command, so in future we can implement more plugins
> 	- document potential other use cases of fused command
> 	- drop support for builtin secondary sqe in SQE128, so all secondary
> 	  requests has standalone SQE
> 	- make fused command as one feature
> 	- cleanup & improve naming

Hi Ming, et al.,

I started to wonder if fused SQE could be extended to combine multiple 
syscalls, for example open/read/close.  Which would be another solution 
for the readfile syscall Miklos had proposed some time ago.

https://lore.kernel.org/lkml/CAJfpegusi8BjWFzEi05926d4RsEQvPnRW-w7My=ibBHQ8NgCuw@xxxxxxxxxxxxxx/

If fused SQEs could be extended, I think it would be quite helpful for 
many other patterns. Another similar examples would open/write/close, 
but ideal would be also to allow to have it more complex like 
"open/write/sync_file_range/close" - open/write/close might be the 
fastest and could possibly return before sync_file_range. Use case for 
the latter would be a file server that wants to give notifications to 
client when pages have been written out.


Thanks,
Bernd