From: Jens Axboe <axboe@kernel.dk> To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe <axboe@kernel.dk> Subject: [PATCH 03/16] block: add bio_set_polled() helper Date: Mon, 14 Jan 2019 19:55:18 -0700 [thread overview] Message-ID: <20190115025531.13985-4-axboe@kernel.dk> (raw) In-Reply-To: <20190115025531.13985-1-axboe@kernel.dk> For the upcoming async polled IO, we can't sleep allocating requests. If we do, then we introduce a deadlock where the submitter already has async polled IO in-flight, but can't wait for them to complete since polled requests must be active found and reaped. Utilize the helper in the blockdev DIRECT_IO code. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- fs/block_dev.c | 4 ++-- include/linux/bio.h | 14 ++++++++++++++ 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index 5415579f3e14..2ebd2a0d7789 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -233,7 +233,7 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, task_io_account_write(ret); } if (iocb->ki_flags & IOCB_HIPRI) - bio.bi_opf |= REQ_HIPRI; + bio_set_polled(&bio, iocb); qc = submit_bio(&bio); for (;;) { @@ -401,7 +401,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES); if (!nr_pages) { if (iocb->ki_flags & IOCB_HIPRI) - bio->bi_opf |= REQ_HIPRI; + bio_set_polled(bio, iocb); qc = submit_bio(bio); WRITE_ONCE(iocb->ki_cookie, qc); diff --git a/include/linux/bio.h b/include/linux/bio.h index 7380b094dcca..f6f0a2b3cbc8 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -823,5 +823,19 @@ static inline int bio_integrity_add_page(struct bio *bio, struct page *page, #endif /* CONFIG_BLK_DEV_INTEGRITY */ +/* + * Mark a bio as polled. Note that for async polled IO, the caller must + * expect -EWOULDBLOCK if we cannot allocate a request (or other resources). + * We cannot block waiting for requests on polled IO, as those completions + * must be found by the caller. This is different than IRQ driven IO, where + * it's safe to wait for IO to complete. + */ +static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb) +{ + bio->bi_opf |= REQ_HIPRI; + if (!is_sync_kiocb(kiocb)) + bio->bi_opf |= REQ_NOWAIT; +} + #endif /* CONFIG_BLOCK */ #endif /* __LINUX_BIO_H */ -- 2.17.1 -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@kvack.org. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: <a href=mailto:"aart@kvack.org">aart@kvack.org</a>
WARNING: multiple messages have this Message-ID (diff)
From: Jens Axboe <axboe@kernel.dk> To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe <axboe@kernel.dk> Subject: [PATCH 03/16] block: add bio_set_polled() helper Date: Mon, 14 Jan 2019 19:55:18 -0700 [thread overview] Message-ID: <20190115025531.13985-4-axboe@kernel.dk> (raw) Message-ID: <20190115025518.x61iSMNBCbYVIB9dkXvCrVzj3TJ7xQwmUsxK3Q1qnOQ@z> (raw) In-Reply-To: <20190115025531.13985-1-axboe@kernel.dk> For the upcoming async polled IO, we can't sleep allocating requests. If we do, then we introduce a deadlock where the submitter already has async polled IO in-flight, but can't wait for them to complete since polled requests must be active found and reaped. Utilize the helper in the blockdev DIRECT_IO code. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- fs/block_dev.c | 4 ++-- include/linux/bio.h | 14 ++++++++++++++ 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index 5415579f3e14..2ebd2a0d7789 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -233,7 +233,7 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter, task_io_account_write(ret); } if (iocb->ki_flags & IOCB_HIPRI) - bio.bi_opf |= REQ_HIPRI; + bio_set_polled(&bio, iocb); qc = submit_bio(&bio); for (;;) { @@ -401,7 +401,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES); if (!nr_pages) { if (iocb->ki_flags & IOCB_HIPRI) - bio->bi_opf |= REQ_HIPRI; + bio_set_polled(bio, iocb); qc = submit_bio(bio); WRITE_ONCE(iocb->ki_cookie, qc); diff --git a/include/linux/bio.h b/include/linux/bio.h index 7380b094dcca..f6f0a2b3cbc8 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -823,5 +823,19 @@ static inline int bio_integrity_add_page(struct bio *bio, struct page *page, #endif /* CONFIG_BLK_DEV_INTEGRITY */ +/* + * Mark a bio as polled. Note that for async polled IO, the caller must + * expect -EWOULDBLOCK if we cannot allocate a request (or other resources). + * We cannot block waiting for requests on polled IO, as those completions + * must be found by the caller. This is different than IRQ driven IO, where + * it's safe to wait for IO to complete. + */ +static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb) +{ + bio->bi_opf |= REQ_HIPRI; + if (!is_sync_kiocb(kiocb)) + bio->bi_opf |= REQ_NOWAIT; +} + #endif /* CONFIG_BLOCK */ #endif /* __LINUX_BIO_H */ -- 2.17.1
next prev parent reply other threads:[~2019-01-15 2:55 UTC|newest] Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-15 2:55 (unknown), Jens Axboe 2019-01-15 2:55 ` [PATCH 01/16] fs: add an iopoll method to struct file_operations Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 02/16] block: wire up block device iopoll method Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` Jens Axboe [this message] 2019-01-15 2:55 ` [PATCH 03/16] block: add bio_set_polled() helper Jens Axboe 2019-01-15 2:55 ` [PATCH 04/16] iomap: wire up the iopoll method Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 05/16] Add io_uring IO interface Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 16:51 ` Jonathan Corbet 2019-01-15 16:51 ` Jonathan Corbet 2019-01-15 16:55 ` Jens Axboe 2019-01-15 16:55 ` Jens Axboe 2019-01-15 17:26 ` Jens Axboe 2019-01-15 17:26 ` Jens Axboe 2019-01-16 10:41 ` Arnd Bergmann 2019-01-16 10:41 ` Arnd Bergmann 2019-01-16 11:00 ` Arnd Bergmann 2019-01-16 11:00 ` Arnd Bergmann 2019-01-16 15:12 ` Jens Axboe 2019-01-16 15:12 ` Jens Axboe 2019-01-16 15:16 ` Arnd Bergmann 2019-01-16 15:16 ` Arnd Bergmann 2019-01-16 15:25 ` Jens Axboe 2019-01-16 15:25 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 06/16] io_uring: add fsync support Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 07/16] io_uring: support for IO polling Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 08/16] io_uring: add submission side request cache Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 09/16] fs: add fget_many() and fput_many() Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 10/16] io_uring: use fget/fput_many() for file references Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 11/16] io_uring: batch io_kiocb allocation Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 12/16] block: implement bio helper to add iter bvec pages to bio Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-16 10:53 ` Arnd Bergmann 2019-01-16 15:14 ` Jens Axboe 2019-01-16 15:14 ` Jens Axboe 2019-01-16 15:32 ` Jens Axboe 2019-01-16 15:32 ` Jens Axboe 2019-01-16 15:41 ` Arnd Bergmann 2019-01-16 15:47 ` Jens Axboe 2019-01-16 15:47 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 14/16] io_uring: add submission polling Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 15/16] io_uring: add file registration Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-16 10:45 ` Arnd Bergmann 2019-01-16 10:45 ` Arnd Bergmann 2019-01-16 15:15 ` Jens Axboe 2019-01-16 15:15 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 16/16] io_uring: add io_uring_event cache hit information Jens Axboe 2019-01-15 2:55 ` Jens Axboe -- strict thread matches above, loose matches on Subject: below -- 2019-01-12 21:29 [PATCHSET v3] io_uring IO interface Jens Axboe 2019-01-12 21:29 ` [PATCH 03/16] block: add bio_set_polled() helper Jens Axboe 2019-01-12 21:29 ` Jens Axboe 2019-01-08 16:56 [PATCHSET v1] io_uring IO interface Jens Axboe 2019-01-08 16:56 ` [PATCH 03/16] block: add bio_set_polled() helper Jens Axboe 2019-01-10 9:43 ` Ming Lei 2019-01-10 9:43 ` Ming Lei 2019-01-10 16:05 ` Jens Axboe 2019-01-10 16:05 ` Jens Axboe
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