Re: [PATCH v2 0/2] cmd infra for caching iovec/bvec

[Pavel Begunkov <asml.silence@gmail.com>]

On 3/22/25 09:42, Ming Lei wrote:
> On Fri, Mar 21, 2025 at 01:13:23PM -0600, Jens Axboe wrote:
>> On 3/21/25 12:04 PM, Pavel Begunkov wrote:
>>> Add infrastructure that is going to be used by commands for importing
>>> vectored registered buffers. It can also be reused later for iovec
>>> caching.
>>>
>>> v2: clear the vec on first ->async_data allocation
>>>      fix a memory leak
>>>
>>> Pavel Begunkov (2):
>>>    io_uring/cmd: add iovec cache for commands
>>>    io_uring/cmd: introduce io_uring_cmd_import_fixed_vec
>>>
>>>   include/linux/io_uring/cmd.h | 13 ++++++++++++
>>>   io_uring/io_uring.c          |  5 +++--
>>>   io_uring/opdef.c             |  1 +
>>>   io_uring/uring_cmd.c         | 39 +++++++++++++++++++++++++++++++++++-
>>>   io_uring/uring_cmd.h         | 11 ++++++++++
>>>   5 files changed, 66 insertions(+), 3 deletions(-)
>>
>> This version works for me - adding in Ming, so he can test and
>> verify as well.
> 
> With the two patches, all ublk selftest can run to pass, and kernel doesn't
> panic any more.

thanks for testing.

> 
> BTW, I meant vectored fix kernel buffer support for FS read/write, which
> looks not supported yet.

Right, you can't use do a vectored registered buffer read/write/etc.
with a kernel buffer (ala ublk zc provided one). That will likely
need a special version of io_vec_fill_bvec() that would account
for bvec entries not being uniform in size.

-- 
Pavel Begunkov