[PATCH 22/26] block: add BIO_HOLD_PAGES flag
From: Jens Axboe <axboe@kernel.dk>
Date: 2018-12-13 17:57:32
Also in:
linux-fsdevel
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
For user mapped IO, we do get_user_pages() upfront, and then do a put_page() on each page at end_io time to release the page reference. In preparation for having permanently mapped pages, add a BIO_HOLD_PAGES flag that tells us not to release the pages, the caller will do that. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- block/bio.c | 6 ++++-- include/linux/blk_types.h | 1 + 2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 036e3f0cc736..03dde1c03ae6 100644
--- a/block/bio.c
+++ b/block/bio.c@@ -1636,7 +1636,8 @@ static void bio_dirty_fn(struct work_struct *work) next = bio->bi_private; bio_set_pages_dirty(bio); - bio_release_pages(bio); + if (!bio_flagged(bio, BIO_HOLD_PAGES)) + bio_release_pages(bio); bio_put(bio); } }
@@ -1652,7 +1653,8 @@ void bio_check_pages_dirty(struct bio *bio) goto defer; } - bio_release_pages(bio); + if (!bio_flagged(bio, BIO_HOLD_PAGES)) + bio_release_pages(bio); bio_put(bio); return; defer:
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 921d734d6b5d..356a4c89b0d9 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h@@ -228,6 +228,7 @@ struct bio { #define BIO_TRACE_COMPLETION 10 /* bio_endio() should trace the final completion * of this bio. */ #define BIO_QUEUE_ENTERED 11 /* can use blk_queue_enter_live() */ +#define BIO_HOLD_PAGES 12 /* don't put O_DIRECT pages */ /* See BVEC_POOL_OFFSET below before adding new flags */
--
2.17.1