Hi all,
This series clean up the block polling code a bit and changes the interface
to poll for a specific bio instead of a request_queue and cookie pair.
Polling for the bio itself leads to a few advantages:
- the cookie construction can made entirely private in blk-mq.c
- the caller does not need to remember the request_queue and cookie
separately and thus sidesteps their lifetime issues
- keeping the device and the cookie inside the bio allows to trivially
support polling BIOs remapping by stacking drivers
- a lot of code to propagate the cookie back up the submission path can
removed entirely
The one major caveat is that this requires RCU freeing polled BIOs to make
sure the bio that contains the polling information is still alive when
io_uring tries to poll it through the iocb. For synchronous polling all the
callers have a bio reference anyway, so this is not an issue.
Git tree:
git://git.infradead.org/users/hch/block.git bio-poll
Gitweb:
http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/bio-poll
Chances since v3:
- rebased to the latests for-5.14/block tree
- fix the refcount logic in __blkdev_direct_IO
- split up a patch to make it easier to review
- grab a queue reference in bio_poll
- better document the RCU assumptions in bio_poll
Chances since v2:
- remove support for writing to the poll attribute
- better document the block_device life time assumptions in bio_poll
- only set QUEUE_FLAG_POLL on nvme-multipath queues where it makes sense
Chances since v1:
- use SLAB_TYPESAFE_BY_RCU to only free the pages backing the bio
slabs bio RCU
- split the spin argument to bio_poll to avoid sleeping under RCU from
io_uring
- add support for polling nvme multipath devices
Diffstat:
arch/m68k/emu/nfblock.c | 3
arch/xtensa/platforms/iss/simdisk.c | 3
block/bio.c | 4
block/blk-core.c | 129 ++++++++++++++++++++------
block/blk-merge.c | 2
block/blk-mq-debugfs.c | 2
block/blk-mq.c | 173 ++++++++++++++----------------------
block/blk-mq.h | 6 -
block/blk-sysfs.c | 23 ----
drivers/block/brd.c | 12 +-
drivers/block/drbd/drbd_int.h | 2
drivers/block/drbd/drbd_req.c | 3
drivers/block/n64cart.c | 12 +-
drivers/block/null_blk/main.c | 3
drivers/block/pktcdvd.c | 7 -
drivers/block/ps3vram.c | 6 -
drivers/block/rsxx/dev.c | 7 -
drivers/block/zram/zram_drv.c | 10 --
drivers/lightnvm/pblk-init.c | 6 -
drivers/md/bcache/request.c | 13 +-
drivers/md/bcache/request.h | 4
drivers/md/dm.c | 28 ++---
drivers/md/md.c | 10 --
drivers/nvdimm/blk.c | 5 -
drivers/nvdimm/btt.c | 5 -
drivers/nvdimm/pmem.c | 3
drivers/nvme/host/core.c | 4
drivers/nvme/host/multipath.c | 17 ++-
drivers/s390/block/dcssblk.c | 7 -
drivers/s390/block/xpram.c | 5 -
drivers/scsi/scsi_debug.c | 10 +-
fs/block_dev.c | 44 ++-------
fs/btrfs/inode.c | 8 -
fs/direct-io.c | 14 --
fs/ext4/file.c | 2
fs/gfs2/file.c | 4
fs/io_uring.c | 14 +-
fs/iomap/direct-io.c | 56 ++++++-----
fs/xfs/xfs_file.c | 2
fs/zonefs/super.c | 2
include/linux/bio.h | 4
include/linux/blk-mq.h | 15 ---
include/linux/blk_types.h | 34 +------
include/linux/blkdev.h | 12 +-
include/linux/bvec.h | 2
include/linux/fs.h | 8 -
include/linux/iomap.h | 3
mm/page_io.c | 10 --
48 files changed, 350 insertions(+), 408 deletions(-)
