Re: [PATCH 4/5] block: kill unused polling bits in __blkdev_direct_IO()

[Jens Axboe <axboe@kernel.dk>]

On Oct 24, 2021, at 12:18 PM, Pavel Begunkov <asml.silence@gmail.com> wrote:
> 
> On 10/24/21 16:09, Jens Axboe wrote:
>>> On 10/23/21 10:46 AM, Pavel Begunkov wrote:
>>> On 10/23/21 17:21, Pavel Begunkov wrote:
>>>> With addition of __blkdev_direct_IO_async(), __blkdev_direct_IO() now
>>>> serves only multio-bio I/O, which we don't poll. Now we can remove
>>>> anything related to I/O polling from it.
>>>> 
>>>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
>>>> ---
>>>>   block/fops.c | 20 +++-----------------
>>>>   1 file changed, 3 insertions(+), 17 deletions(-)
>>>> 
>>>> diff --git a/block/fops.c b/block/fops.c
>>>> index 8800b0ad5c29..997904963a9d 100644
>>>> --- a/block/fops.c
>>>> +++ b/block/fops.c
>>>> @@ -190,7 +190,6 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
>>>>       struct blk_plug plug;
>>>>       struct blkdev_dio *dio;
>>>>       struct bio *bio;
>>>> -    bool do_poll = (iocb->ki_flags & IOCB_HIPRI);
>>>>       bool is_read = (iov_iter_rw(iter) == READ), is_sync;
>>>>       loff_t pos = iocb->ki_pos;
>>>>       int ret = 0;
>>>> @@ -216,12 +215,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
>>>>       if (is_read && iter_is_iovec(iter))
>>>>           dio->flags |= DIO_SHOULD_DIRTY;
>>>>   -    /*
>>>> -     * Don't plug for HIPRI/polled IO, as those should go straight
>>>> -     * to issue
>>>> -     */
>>>> -    if (!(iocb->ki_flags & IOCB_HIPRI))
>>>> -        blk_start_plug(&plug);
>>> 
>>> I'm not sure, do we want to leave it conditional here?
>> For async polled there's only one user and that user plug already...
> 
> It's __blkdev_direct_IO() though, covers both sync and async

Pointless to plug for sync, though.