Re: [PATCH 6.14.y v2 2/7] ublk: properly serialize all FETCH_REQs

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: b69b8edfb27dfa563cd53f590ec42b481f9eb174

WARNING: Author mismatch between patch and upstream commit:
Backport author: Jared Holzman<jholzman@nvidia.com>
Commit author: Uday Shankar<ushankar@purestorage.com>

Note: The patch differs from the upstream commit:
---
1:  b69b8edfb27df ! 1:  632ba3dbe853d ublk: properly serialize all FETCH_REQs
    @@ Metadata
      ## Commit message ##
         ublk: properly serialize all FETCH_REQs
     
    +    [ Upstream commit b69b8edfb27dfa563cd53f590ec42b481f9eb174 ]
    +
         Most uring_cmds issued against ublk character devices are serialized
         because each command affects only one queue, and there is an early check
         which only allows a single task (the queue's ubq_daemon) to issue
    @@ drivers/block/ublk_drv.c: static void ublk_mark_io_ready(struct ublk_device *ub,
     -	mutex_unlock(&ub->mutex);
      }
      
    - static void ublk_handle_need_get_data(struct ublk_device *ub, int q_id,
    -@@ drivers/block/ublk_drv.c: static int ublk_unregister_io_buf(struct io_uring_cmd *cmd,
    - 	return io_buffer_unregister_bvec(cmd, index, issue_flags);
    + static inline int ublk_check_cmd_op(u32 cmd_op)
    +@@ drivers/block/ublk_drv.c: static inline void ublk_prep_cancel(struct io_uring_cmd *cmd,
    + 	io_uring_cmd_mark_cancelable(cmd, issue_flags);
      }
      
     +static int ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
    @@ drivers/block/ublk_drv.c: static int ublk_unregister_io_buf(struct io_uring_cmd
      			       unsigned int issue_flags,
      			       const struct ublksrv_io_cmd *ub_cmd)
     @@ drivers/block/ublk_drv.c: static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
    - 	case UBLK_IO_UNREGISTER_IO_BUF:
    - 		return ublk_unregister_io_buf(cmd, ub_cmd->addr, issue_flags);
    + 	ret = -EINVAL;
    + 	switch (_IOC_NR(cmd_op)) {
      	case UBLK_IO_FETCH_REQ:
     -		/* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
     -		if (ublk_queue_ready(ubq)) {
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.4.y        |  Success    |  Success   |