Re: [PATCH v1 06/11] io_uring/kbuf: add buffer ring pinning/unpinning

[Jens Axboe <axboe@kernel.dk>]

On 2/10/26 10:57 AM, Caleb Sander Mateos wrote:
> On Mon, Feb 9, 2026 at 5:07?PM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> On 2/9/26 5:28 PM, Joanne Koong wrote:
>>> +int io_uring_buf_ring_pin(struct io_uring_cmd *cmd, unsigned buf_group,
>>> +                       unsigned issue_flags, struct io_buffer_list **bl)
>>> +{
>>> +     struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
>>> +     struct io_buffer_list *buffer_list;
>>> +     int ret = -EINVAL;
>>
>> Probably use the usual struct io_buffer_list *bl here and either use an
>> ERR_PTR return, or rename the passed on **bl to **blret or something.
>>
>>> +int io_uring_buf_ring_unpin(struct io_uring_cmd *cmd, unsigned buf_group,
>>> +                    unsigned issue_flags)
>>> +{
>>> +     struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
>>> +     struct io_buffer_list *bl;
>>> +     int ret = -EINVAL;
>>> +
>>> +     io_ring_submit_lock(ctx, issue_flags);
>>> +
>>> +     bl = io_buffer_get_list(ctx, buf_group);
>>> +     if (bl && (bl->flags & IOBL_BUF_RING) && (bl->flags & IOBL_PINNED)) {
>>
>> Usually done as:
>>
>>         if ((bl->flags & (IOBL_BUF_RING|IOBL_PINNED)) == (IOBL_BUF_RING|IOBL_PINNED))
> 
> FWIW, modern compilers will perform this optimization automatically.
> They'll even optimize it further to !(~bl->flags &
> (IOBL_BUF_RING|IOBL_PINNED)): https://godbolt.org/z/xGoP4TfhP

Sure, it's not about that, it's more about the common way of doing it,
which makes it easier to read for people. FWIW, your example is easier
to read too than the original.

-- 
Jens Axboe