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| author | Ming Lei <ming.lei@redhat.com> | 2025-05-22 18:20:40 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-05-22 19:03:55 +0300 |
| commit | 914e0dc5082a335ea5e7d905e99e1a1cde001369 (patch) | |
| tree | 9572afb2705e06a4f7387275496753f65ddd3f15 | |
| parent | 3a91f28fab43f093c72312148288d125ae160c2d (diff) | |
| download | linux-914e0dc5082a335ea5e7d905e99e1a1cde001369.tar.xz | |
ublk: run auto buf unregisgering in same io_ring_ctx with registering
UBLK_F_AUTO_BUF_REG requires that the buffer registered automatically
is unregistered in same `io_ring_ctx`, so check it explicitly.
Document this requirement for UBLK_F_AUTO_BUF_REG.
Drop WARN_ON_ONCE() which is triggered from userspace code path.
Fixes: 99c1e4eb6a3f ("ublk: register buffer to local io_uring with provided buf index via UBLK_F_AUTO_BUF_REG")
Reported-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250522152043.399824-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/block/ublk_drv.c | 19 | ||||
| -rw-r--r-- | include/uapi/linux/ublk_cmd.h | 6 |
2 files changed, 21 insertions, 4 deletions
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index f818733901dc..33fadca3ee90 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -84,6 +84,7 @@ struct ublk_rq_data { /* for auto-unregister buffer in case of UBLK_F_AUTO_BUF_REG */ u16 buf_index; + void *buf_ctx_handle; }; struct ublk_uring_cmd_pdu { @@ -1211,6 +1212,8 @@ static bool ublk_auto_buf_reg(struct request *req, struct ublk_io *io, } /* one extra reference is dropped by ublk_io_release */ refcount_set(&data->ref, 2); + + data->buf_ctx_handle = io_uring_cmd_ctx_handle(io->cmd); /* store buffer index in request payload */ data->buf_index = pdu->buf.index; io->flags |= UBLK_IO_FLAG_AUTO_BUF_REG; @@ -2111,12 +2114,22 @@ static int ublk_commit_and_fetch(const struct ublk_queue *ubq, if (ublk_support_auto_buf_reg(ubq)) { int ret; + /* + * `UBLK_F_AUTO_BUF_REG` only works iff `UBLK_IO_FETCH_REQ` + * and `UBLK_IO_COMMIT_AND_FETCH_REQ` are issued from same + * `io_ring_ctx`. + * + * If this uring_cmd's io_ring_ctx isn't same with the + * one for registering the buffer, it is ublk server's + * responsibility for unregistering the buffer, otherwise + * this ublk request gets stuck. + */ if (io->flags & UBLK_IO_FLAG_AUTO_BUF_REG) { struct ublk_rq_data *data = blk_mq_rq_to_pdu(req); - WARN_ON_ONCE(io_buffer_unregister_bvec(cmd, - data->buf_index, - issue_flags)); + if (data->buf_ctx_handle == io_uring_cmd_ctx_handle(cmd)) + io_buffer_unregister_bvec(cmd, data->buf_index, + issue_flags); io->flags &= ~UBLK_IO_FLAG_AUTO_BUF_REG; } diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h index c4b9942697fc..1c40632cb164 100644 --- a/include/uapi/linux/ublk_cmd.h +++ b/include/uapi/linux/ublk_cmd.h @@ -226,7 +226,11 @@ * * For using this feature: * - * - ublk server has to create sparse buffer table + * - ublk server has to create sparse buffer table on the same `io_ring_ctx` + * for issuing `UBLK_IO_FETCH_REQ` and `UBLK_IO_COMMIT_AND_FETCH_REQ`. + * If uring_cmd isn't issued on same `io_ring_ctx`, it is ublk server's + * responsibility to unregister the buffer by issuing `IO_UNREGISTER_IO_BUF` + * manually, otherwise this ublk request won't complete. * * - ublk server passes auto buf register data via uring_cmd's sqe->addr, * `struct ublk_auto_buf_reg` is populated from sqe->addr, please see |