Re: [PATCH v2 0/4] scsi: ufs: core: Factor hba->outstanding_reqs helper and fix double completion

[Bean Huo]

On Sat, 2026-10-17 at 16:43 +0800, Stanley Jhu wrote:
> In Single Doorbell (SDB) mode, ufshcd_clear_lu_cmds() clears a transfer
> request slot in the controller and completes the request without
> claiming its bit in hba->outstanding_reqs. A subsequent ufshcd_poll()
> call sees the stale bit with its doorbell bit cleared and completes the
> request a second time, causing a double DMA unmap.
> 
> Patch 1 adds __ufshcd_clear_outstanding_reqs() and
> ufshcd_clear_outstanding_reqs() to share the bit-claim logic across
> ufshcd_poll() and ufshcd_abort() with no functional change. Patch 2 uses
> the new helper in ufshcd_clear_lu_cmds() to fix the SDB double
> completion. Patch 3 uses the new helper in ufshcd_eh_timed_out(). It is
> a follow-on cleanup and is not needed for the fix. Patch 4 removes a
> WARN_ONCE() whose condition is always false.
> 
> This series is based on mkp/for-next (db8b4d2bf2d3).
> 
> Tested on QEMU ARM64 UFS in SDB and MCQ modes across LU reset, polled
> and interrupt I/O, and task abort without double completion or DMA
> unmap warnings.
> 
> Changes since v1:
> - Add a helper for clearing hba->outstanding_reqs and use it in
>   ufshcd_poll(), ufshcd_abort(), and ufshcd_clear_lu_cmds()
>   (Bart Van Assche).
> - Convert ufshcd_eh_timed_out() to use the new helper in patch 3.
> - Remove an always-false WARN_ONCE() in patch 4.
> - Link to v1:
> https://lore.kernel.org/r/20261016085403.1711740-1-stanleyjhu@xxxxxxxxxx
> 
> Stanley Jhu (4):
>   scsi: ufs: core: Add a helper for clearing hba->outstanding_reqs
>   scsi: ufs: core: Fix double completion in ufshcd_clear_lu_cmds()
>   scsi: ufs: core: Use ufshcd_clear_outstanding_reqs() in
>     ufshcd_eh_timed_out()
>   scsi: ufs: core: Remove an always-false WARN_ONCE()
> 

Hi Stanley,

For the whole series:

Reviewed-by: Bean Huo <beanhuo@xxxxxxxxxx>

One more place has the same problem. In ufshcd_abort(), the "cmd was completed,
but without a notifying intr" path completes the request but leaves its bit set
in hba->outstanding_reqs:

if (!hba->mcq_enabled && !(reg & (1 << tag))) {
	...
	 __ufshcd_transfer_req_compl(hba, 1UL << tag);
	...
}


could use the new helper in the same way as patch 2?


 if (ufshcd_clear_outstanding_reqs(hba, BIT(tag)))
	ufshcd_compl_one_cqe(hba, tag, NULL);

Kind regards,
Bean