Fix tcmulib get next command on aarch64

[geordieintheshellcode]

Please see See #688 for the problem, repro and rationale behind the fix.

[lxbsz]

This LGTM.
Could you add the comments in the commit and add the singed-off-by at the same time ?
Thanks

[geordieintheshellcode]

@lxbsz thanks. I don't quite follow what you mean when you say:

Could you add the comments in the commit and add the singed-off-by at the same time ?
Thanks

[lxbsz]

@lxbsz thanks. I don't quite follow what you mean when you say:

Could you add the comments in the commit and add the singed-off-by at the same time ?
Thanks

Please see the following commit's format:

commit 245914c1446dddf07d5b58b0a7b2060b50fde4d7
Author: Xiubo Li <[email protected]>
Date:   Tue Sep 14 16:25:23 2021 +0800

    rbd: switch strtok to strtok_r
    
    The strtok is not thread safe, there could be several threads will
    call the tcmu_rbd_open() at the same time.
    
    And sometimes we can randomly hit some errors like:
    
    [ERROR] tcmu_rbd_open:877 datapool/block0: Could not get image name
    
    But when try it again it will succeed.
    
    Signed-off-by: Xiubo Li <[email protected]>

[geordieintheshellcode]

I've done that now @lxbsz. Thanks

[lxbsz]

Use the appropriate atomic load instruction to ensure we synchronize
the read of the command ring head index with any previous stores. Not
doing this causes command ring corruption on aarch64:

[Tue Oct 4 15:45:50 2022] cmd_id 0 not found, ring is broken
[Tue Oct 4 15:45:50 2022] ring broken, not handling completions

See issue open-iscsi#688. PR open-iscsi#693.

Signed-off-by: Xiubo Li [email protected]

NO, this is incorrect.

It should be something likes:

libtcmu: fix tcmulib to get next command on aarch64

Use the appropriate atomic load instruction to ensure we synchronize
the read of the command ring head index with any previous stores. Not
doing this causes command ring corruption on aarch64:

[Tue Oct  4 15:45:50 2022] cmd_id 0 not found, ring is broken
[Tue Oct  4 15:45:50 2022] ring broken, not handling completions

Signed-off-by: ${Your Full Name} <${Your Mail}>

[geordieintheshellcode]

Done! Turns git commit -s is your friend 😄