Re: [PATCHSET v2 0/6] Allow allocated direct descriptors

[Hao Xu <haoxu.linux@gmail.com>]

在 2022/5/9 下午11:50, Jens Axboe 写道:
> Hi,
> 
> Currently using direct descriptors with open or accept requires the
> application to manage the descriptor space, picking which slot to use
> for any given file. However, there are cases where it's useful to just
> get a direct descriptor and not care about which value it is, instead
> just return it like a normal open or accept would.
> 
> This will also be useful for multishot accept support, where allocated
> direct descriptors are a requirement to make that feature work with
> these kinds of files.
> 
> This adds support for allocating a new fixed descriptor. This is chosen
> by passing in IORING_FILE_INDEX_ALLOC as the fixed slot, which is beyond
> any valid value for the file_index.
> 
> Can also be found here:
> 
> https://git.kernel.dk/cgit/linux-block/log/?h=for-5.19/io_uring-fixed-alloc
> 
>   fs/io_uring.c                 | 113 +++++++++++++++++++++++++++++++---
>   include/uapi/linux/io_uring.h |  17 ++++-
>   2 files changed, 120 insertions(+), 10 deletions(-)
> 
> v2:	- Fix unnecessary clear (Hao)
> 	- Add define for allocating a descriptor rather than use
> 	  UINT_MAX.
> 	- Add patch bumping max file table size to 1M (from 32K)
> 	- Add ability to register a sparse file table upfront rather
> 	  then have the application pass in a big array of -1.
> 

Reviewed-by: Hao Xu <howeyxu@tencent.com>