| Message ID | 20230504195327.695107-1-stefanha@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | block: remove aio_disable_external() API | expand |
Am 04.05.2023 um 21:53 hat Stefan Hajnoczi geschrieben: > v5: > - Use atomic accesses for in_flight counter in vhost-user-server.c [Kevin] > - Stash SCSIDevice id/lun values for VIRTIO_SCSI_T_TRANSPORT_RESET event > before unrealizing the SCSIDevice [Kevin] > - Keep vhost-user-blk export .detach() callback so ctx is set to NULL [Kevin] > - Narrow BdrvChildClass and BlockDriver drained_{begin/end/poll} callbacks from > IO_OR_GS_CODE() to GLOBAL_STATE_CODE() [Kevin] > - Include Kevin's "block: Fix use after free in blockdev_mark_auto_del()" to > fix a latent bug that was exposed by this series I only just finished reviewing v4 when you had already sent v5, but it hadn't arrived yet. I had a few more comments on what are now patches 17, 18, 19 and 21 in v5. I think they all still apply. Kevin
On Thu, May 04, 2023 at 11:44:42PM +0200, Kevin Wolf wrote: > Am 04.05.2023 um 21:53 hat Stefan Hajnoczi geschrieben: > > v5: > > - Use atomic accesses for in_flight counter in vhost-user-server.c [Kevin] > > - Stash SCSIDevice id/lun values for VIRTIO_SCSI_T_TRANSPORT_RESET event > > before unrealizing the SCSIDevice [Kevin] > > - Keep vhost-user-blk export .detach() callback so ctx is set to NULL [Kevin] > > - Narrow BdrvChildClass and BlockDriver drained_{begin/end/poll} callbacks from > > IO_OR_GS_CODE() to GLOBAL_STATE_CODE() [Kevin] > > - Include Kevin's "block: Fix use after free in blockdev_mark_auto_del()" to > > fix a latent bug that was exposed by this series > > I only just finished reviewing v4 when you had already sent v5, but it > hadn't arrived yet. I had a few more comments on what are now patches > 17, 18, 19 and 21 in v5. I think they all still apply. I'm not sure which comments from v4 still apply. In my email client all your replies were already read when I sent v5. Maybe you can share the Message-Id of something I still need to address? Thanks, Stefan
Am 09.05.2023 um 19:51 hat Stefan Hajnoczi geschrieben: > On Thu, May 04, 2023 at 11:44:42PM +0200, Kevin Wolf wrote: > > Am 04.05.2023 um 21:53 hat Stefan Hajnoczi geschrieben: > > > v5: > > > - Use atomic accesses for in_flight counter in vhost-user-server.c [Kevin] > > > - Stash SCSIDevice id/lun values for VIRTIO_SCSI_T_TRANSPORT_RESET event > > > before unrealizing the SCSIDevice [Kevin] > > > - Keep vhost-user-blk export .detach() callback so ctx is set to NULL [Kevin] > > > - Narrow BdrvChildClass and BlockDriver drained_{begin/end/poll} callbacks from > > > IO_OR_GS_CODE() to GLOBAL_STATE_CODE() [Kevin] > > > - Include Kevin's "block: Fix use after free in blockdev_mark_auto_del()" to > > > fix a latent bug that was exposed by this series > > > > I only just finished reviewing v4 when you had already sent v5, but it > > hadn't arrived yet. I had a few more comments on what are now patches > > 17, 18, 19 and 21 in v5. I think they all still apply. > > I'm not sure which comments from v4 still apply. In my email client all > your replies were already read when I sent v5. Yes, but I added some more replies after you had sent v5 (and before I fetched mail again to actually see v5). > Maybe you can share the Message-Id of something I still need to address? I thought the patch numbers identified them and were easier, but sure: Message-ID: <ZFQc89cFJuoGF+qI@redhat.com> Message-ID: <ZFQgBvWShB4NCymj@redhat.com> Message-ID: <ZFQivbkVPcX3nECA@redhat.com> Message-ID: <ZFQk2TdhZ6DiwM4t@redhat.com> Kevin
Am 04.05.2023 um 21:53 hat Stefan Hajnoczi geschrieben: > v5: > - Use atomic accesses for in_flight counter in vhost-user-server.c [Kevin] > - Stash SCSIDevice id/lun values for VIRTIO_SCSI_T_TRANSPORT_RESET event > before unrealizing the SCSIDevice [Kevin] > - Keep vhost-user-blk export .detach() callback so ctx is set to NULL [Kevin] > - Narrow BdrvChildClass and BlockDriver drained_{begin/end/poll} callbacks from > IO_OR_GS_CODE() to GLOBAL_STATE_CODE() [Kevin] > - Include Kevin's "block: Fix use after free in blockdev_mark_auto_del()" to > fix a latent bug that was exposed by this series > > v4: > - Remove external_disable_cnt variable [Philippe] > - Add Patch 1 to fix assertion failure in .drained_end() -> blk_get_aio_context() > v3: > - Resend full patch series. v2 was sent in the middle of a git rebase and was > missing patches. [Eric] > - Apply Reviewed-by tags. > v2: > - Do not rely on BlockBackend request queuing, implement .drained_begin/end() > instead in xen-block, virtio-blk, and virtio-scsi [Paolo] > - Add qdev_is_realized() API [Philippe] > - Add patch to avoid AioContext lock around blk_exp_ref/unref() [Paolo] > - Add patch to call .drained_begin/end() from main loop thread to simplify > callback implementations > > The aio_disable_external() API temporarily suspends file descriptor monitoring > in the event loop. The block layer uses this to prevent new I/O requests being > submitted from the guest and elsewhere between bdrv_drained_begin() and > bdrv_drained_end(). > > While the block layer still needs to prevent new I/O requests in drained > sections, the aio_disable_external() API can be replaced with > .drained_begin/end/poll() callbacks that have been added to BdrvChildClass and > BlockDevOps. > > This newer .bdrained_begin/end/poll() approach is attractive because it works > without specifying a specific AioContext. The block layer is moving towards > multi-queue and that means multiple AioContexts may be processing I/O > simultaneously. > > The aio_disable_external() was always somewhat hacky. It suspends all file > descriptors that were registered with is_external=true, even if they have > nothing to do with the BlockDriverState graph nodes that are being drained. > It's better to solve a block layer problem in the block layer than to have an > odd event loop API solution. > > The approach in this patch series is to implement BlockDevOps > .drained_begin/end() callbacks that temporarily stop file descriptor handlers. > This ensures that new I/O requests are not submitted in drained sections. Patches 2-16: Reviewed-by: Kevin Wolf <kwolf@redhat.com>
v5: - Use atomic accesses for in_flight counter in vhost-user-server.c [Kevin] - Stash SCSIDevice id/lun values for VIRTIO_SCSI_T_TRANSPORT_RESET event before unrealizing the SCSIDevice [Kevin] - Keep vhost-user-blk export .detach() callback so ctx is set to NULL [Kevin] - Narrow BdrvChildClass and BlockDriver drained_{begin/end/poll} callbacks from IO_OR_GS_CODE() to GLOBAL_STATE_CODE() [Kevin] - Include Kevin's "block: Fix use after free in blockdev_mark_auto_del()" to fix a latent bug that was exposed by this series v4: - Remove external_disable_cnt variable [Philippe] - Add Patch 1 to fix assertion failure in .drained_end() -> blk_get_aio_context() v3: - Resend full patch series. v2 was sent in the middle of a git rebase and was missing patches. [Eric] - Apply Reviewed-by tags. v2: - Do not rely on BlockBackend request queuing, implement .drained_begin/end() instead in xen-block, virtio-blk, and virtio-scsi [Paolo] - Add qdev_is_realized() API [Philippe] - Add patch to avoid AioContext lock around blk_exp_ref/unref() [Paolo] - Add patch to call .drained_begin/end() from main loop thread to simplify callback implementations The aio_disable_external() API temporarily suspends file descriptor monitoring in the event loop. The block layer uses this to prevent new I/O requests being submitted from the guest and elsewhere between bdrv_drained_begin() and bdrv_drained_end(). While the block layer still needs to prevent new I/O requests in drained sections, the aio_disable_external() API can be replaced with .drained_begin/end/poll() callbacks that have been added to BdrvChildClass and BlockDevOps. This newer .bdrained_begin/end/poll() approach is attractive because it works without specifying a specific AioContext. The block layer is moving towards multi-queue and that means multiple AioContexts may be processing I/O simultaneously. The aio_disable_external() was always somewhat hacky. It suspends all file descriptors that were registered with is_external=true, even if they have nothing to do with the BlockDriverState graph nodes that are being drained. It's better to solve a block layer problem in the block layer than to have an odd event loop API solution. The approach in this patch series is to implement BlockDevOps .drained_begin/end() callbacks that temporarily stop file descriptor handlers. This ensures that new I/O requests are not submitted in drained sections. Kevin Wolf (1): block: Fix use after free in blockdev_mark_auto_del() Stefan Hajnoczi (20): block-backend: split blk_do_set_aio_context() hw/qdev: introduce qdev_is_realized() helper virtio-scsi: avoid race between unplug and transport event virtio-scsi: stop using aio_disable_external() during unplug util/vhost-user-server: rename refcount to in_flight counter block/export: wait for vhost-user-blk requests when draining block/export: stop using is_external in vhost-user-blk server hw/xen: do not use aio_set_fd_handler(is_external=true) in xen_xenstore block: add blk_in_drain() API block: drain from main loop thread in bdrv_co_yield_to_drain() xen-block: implement BlockDevOps->drained_begin() hw/xen: do not set is_external=true on evtchn fds block/export: rewrite vduse-blk drain code block/export: don't require AioContext lock around blk_exp_ref/unref() block/fuse: do not set is_external=true on FUSE fd virtio: make it possible to detach host notifier from any thread virtio-blk: implement BlockDevOps->drained_begin() virtio-scsi: implement BlockDevOps->drained_begin() virtio: do not set is_external=true on host notifiers aio: remove aio_disable_external() API hw/block/dataplane/xen-block.h | 2 + include/block/aio.h | 57 --------- include/block/block_int-common.h | 90 +++++++------- include/block/export.h | 2 + include/hw/qdev-core.h | 17 ++- include/hw/scsi/scsi.h | 14 +++ include/qemu/vhost-user-server.h | 8 +- include/sysemu/block-backend-common.h | 25 ++-- include/sysemu/block-backend-global-state.h | 1 + util/aio-posix.h | 1 - block.c | 7 -- block/blkio.c | 15 +-- block/block-backend.c | 78 ++++++------ block/curl.c | 10 +- block/export/export.c | 13 +- block/export/fuse.c | 56 ++++++++- block/export/vduse-blk.c | 128 ++++++++++++++------ block/export/vhost-user-blk-server.c | 52 +++++++- block/io.c | 16 ++- block/io_uring.c | 4 +- block/iscsi.c | 3 +- block/linux-aio.c | 4 +- block/nfs.c | 5 +- block/nvme.c | 8 +- block/ssh.c | 4 +- block/win32-aio.c | 6 +- blockdev.c | 18 ++- hw/block/dataplane/virtio-blk.c | 19 ++- hw/block/dataplane/xen-block.c | 42 +++++-- hw/block/virtio-blk.c | 38 +++++- hw/block/xen-block.c | 24 +++- hw/i386/kvm/xen_xenstore.c | 2 +- hw/scsi/scsi-bus.c | 46 ++++++- hw/scsi/scsi-disk.c | 27 ++++- hw/scsi/virtio-scsi-dataplane.c | 31 +++-- hw/scsi/virtio-scsi.c | 127 ++++++++++++++----- hw/virtio/virtio.c | 6 +- hw/xen/xen-bus.c | 11 +- io/channel-command.c | 6 +- io/channel-file.c | 3 +- io/channel-socket.c | 3 +- migration/rdma.c | 16 +-- tests/unit/test-aio.c | 27 +---- tests/unit/test-bdrv-drain.c | 15 +-- tests/unit/test-fdmon-epoll.c | 73 ----------- util/aio-posix.c | 20 +-- util/aio-win32.c | 8 +- util/async.c | 3 +- util/fdmon-epoll.c | 18 +-- util/fdmon-io_uring.c | 8 +- util/fdmon-poll.c | 3 +- util/main-loop.c | 7 +- util/qemu-coroutine-io.c | 7 +- util/vhost-user-server.c | 33 ++--- hw/scsi/trace-events | 2 + tests/unit/meson.build | 3 - 56 files changed, 738 insertions(+), 534 deletions(-) delete mode 100644 tests/unit/test-fdmon-epoll.c