On 5/12/22 11:28 PM, Hao Xu wrote:
> ? 2022/5/12 ??8:23, Jens Axboe ??:
>> On 5/12/22 2:21 AM, Hao Xu wrote:
>>> ? 2022/5/9 ??11:50, Jens Axboe ??:
>>>> If the application passes in IORING_FILE_INDEX_ALLOC as the file_slot,
>>>> then that's a hint to allocate a fixed file descriptor rather than have
>>>> one be passed in directly.
>>>>
>>>> This can be useful for having io_uring manage the direct descriptor space.
>>>>
>>>> Normal open direct requests will complete with 0 for success, and < 0
>>>> in case of error. If io_uring is asked to allocated the direct descriptor,
>>>> then the direct descriptor is returned in case of success.
>>>>
>>>> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
>>>> ---
>>>> fs/io_uring.c | 32 +++++++++++++++++++++++++++++---
>>>> include/uapi/linux/io_uring.h | 9 +++++++++
>>>> 2 files changed, 38 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>>>> index 8c40411a7e78..ef999d0e09de 100644
>>>> --- a/fs/io_uring.c
>>>> +++ b/fs/io_uring.c
>>>> @@ -4697,7 +4697,7 @@ static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
>>>> return __io_openat_prep(req, sqe);
>>>> }
>>>> -static int __maybe_unused io_file_bitmap_get(struct io_ring_ctx *ctx)
>>>> +static int io_file_bitmap_get(struct io_ring_ctx *ctx)
>>>> {
>>>> struct io_file_table *table = &ctx->file_table;
>>>> unsigned long nr = ctx->nr_user_files;
>>>> @@ -4722,6 +4722,32 @@ static int __maybe_unused io_file_bitmap_get(struct io_ring_ctx *ctx)
>>>> return -ENFILE;
>>>> }
>>>> +static int io_fixed_fd_install(struct io_kiocb *req, unsigned int issue_flags,
>>>> + struct file *file, unsigned int file_slot)
>>>> +{
>>>> + int alloc_slot = file_slot == IORING_FILE_INDEX_ALLOC;
>>>> + struct io_ring_ctx *ctx = req->ctx;
>>>> + int ret;
>>>> +
>>>> + if (alloc_slot) {
>>>> + io_ring_submit_lock(ctx, issue_flags);
>>>> + file_slot = io_file_bitmap_get(ctx);
>>>> + if (unlikely(file_slot < 0)) {
>>>> + io_ring_submit_unlock(ctx, issue_flags);
>>>> + return file_slot;
>>>> + }
>>>> + }
>>>
>>> if (alloc_slot) {
>>> ...
>>> } else {
>>> file_slot -= 1;
>>> }
>>>
>>> Otherwise there is off-by-one error.
>>>
>>> Others looks good,
>>>
>>> Reviewed-by: Hao Xu <howeyxu@xxxxxxxxxxx>
>>
>> Thanks, you are correct, I've folded that in.
>>
>
> Hi Jens,
> I've rebased multishot accept based on your fixed-alloc branch:
>
> https://github.com/HowHsu/linux/commits/for-5.19/io_uring_multishot_accept_v6
>
> Let me know when ixed-alloc is ready, then I'll do the final rebase
> for multishot accept and send it to the list, including the liburing
> change.
Just base it against for-5.19/io_uring, I'm fixing the one-off and
pushing it out.
--
Jens Axboe
