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

[Ming Lei <ming.lei@redhat.com>]

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.

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

And it can be useful in the following case:

https://lore.kernel.org/linux-block/20250322093218.431419-9-ming.lei@redhat.com/T/#u


Thanks,
Ming