From d74f714896fd6268882789ba28e52c9145951403 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 8 Aug 2023 11:03:28 -0600 Subject: block: get rid of unused plug->nowait flag This was introduced to add a plug based way of signaling nowait issues, but we have since moved on from that. Kill the old dead code, nobody is setting it anymore. Reviewed-by: Chaitanya Kulkarni Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index ed44a997f629..87d94be7825a 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -969,7 +969,6 @@ struct blk_plug { bool multiple_queues; bool has_elevator; - bool nowait; struct list_head cb_list; /* md requires an unplug callback */ }; -- cgit v1.2.3 From 2bc057692599a5b3dc93d75a3dff34f72576355d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 8 Aug 2023 11:06:17 -0600 Subject: block: don't make REQ_POLLED imply REQ_NOWAIT Normally these two flags do go together, as the issuer of polled IO generally cannot wait for resources that will get freed as part of IO completion. This is because that very task is the one that will complete the request and free those resources, hence that would introduce a deadlock. But it is possible to have someone else issue the polled IO, eg via io_uring if the request is punted to io-wq. For that case, it's fine to have the task block on IO submission, as it is not the same task that will be completing the IO. It's completely up to the caller to ask for both polled and nowait IO separately! If we don't allow polled IO where IOCB_NOWAIT isn't set in the kiocb, then we can run into repeated -EAGAIN submissions and not make any progress. Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe --- block/fops.c | 7 ++++--- include/linux/bio.h | 2 +- 2 files changed, 5 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/block/fops.c b/block/fops.c index a286bf3325c5..838ffada5341 100644 --- a/block/fops.c +++ b/block/fops.c @@ -358,13 +358,14 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, task_io_account_write(bio->bi_iter.bi_size); } + if (iocb->ki_flags & IOCB_NOWAIT) + bio->bi_opf |= REQ_NOWAIT; + if (iocb->ki_flags & IOCB_HIPRI) { - bio->bi_opf |= REQ_POLLED | REQ_NOWAIT; + bio->bi_opf |= REQ_POLLED; submit_bio(bio); WRITE_ONCE(iocb->private, bio); } else { - if (iocb->ki_flags & IOCB_NOWAIT) - bio->bi_opf |= REQ_NOWAIT; submit_bio(bio); } return -EIOCBQUEUED; diff --git a/include/linux/bio.h b/include/linux/bio.h index c4f5b5228105..11984ed29cb8 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -791,7 +791,7 @@ static inline int bio_integrity_add_page(struct bio *bio, struct page *page, static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb) { bio->bi_opf |= REQ_POLLED; - if (!is_sync_kiocb(kiocb)) + if (kiocb->ki_flags & IOCB_NOWAIT) bio->bi_opf |= REQ_NOWAIT; } -- cgit v1.2.3