diff options
| author | Caleb Sander Mateos <csander@purestorage.com> | 2026-01-28 13:56:34 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-02-26 15:00:43 -0800 |
| commit | 48eed5f1889d832da1b824c3876f5904f6b5fbe3 (patch) | |
| tree | 6733ced67dc300ca3345b6f87f82dd8beb4191e9 /drivers/block | |
| parent | 025796ccd7f9f2e013e12319de26b6c021a80c1f (diff) | |
ublk: restore auto buf unregister refcount optimization
[ Upstream commit ad5f2e2908c9b79a86529281a48e94d644d43dc7 ]
Commit 1ceeedb59749 ("ublk: optimize UBLK_IO_UNREGISTER_IO_BUF on daemon
task") optimized ublk request buffer unregistration to use a non-atomic
reference count decrement when performed on the ublk_io's daemon task.
The optimization applied to auto buffer unregistration, which happens as
part of handling UBLK_IO_COMMIT_AND_FETCH_REQ on the daemon task.
However, commit b749965edda8 ("ublk: remove ublk_commit_and_fetch()")
reordered the ublk_sub_req_ref() for the completed request before the
io_buffer_unregister_bvec() call. As a result, task_registered_buffers
is already 0 when io_buffer_unregister_bvec() calls ublk_io_release()
and the non-atomic refcount optimization doesn't apply.
Move the io_buffer_unregister_bvec() call back to before
ublk_need_complete_req() to restore the reference counting optimization.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Fixes: b749965edda8 ("ublk: remove ublk_commit_and_fetch()")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/ublk_drv.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index cd1e84653002..6000517645e1 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -2462,11 +2462,11 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd, io->res = result; req = ublk_fill_io_cmd(io, cmd); ret = ublk_config_io_buf(ub, io, cmd, addr, &buf_idx); + if (buf_idx != UBLK_INVALID_BUF_IDX) + io_buffer_unregister_bvec(cmd, buf_idx, issue_flags); compl = ublk_need_complete_req(ub, io); /* can't touch 'ublk_io' any more */ - if (buf_idx != UBLK_INVALID_BUF_IDX) - io_buffer_unregister_bvec(cmd, buf_idx, issue_flags); if (req_op(req) == REQ_OP_ZONE_APPEND) req->__sector = addr; if (compl) |