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From: Bart Van Assche <bvanassche@acm.org>
To: peter.wang@mediatek.com, linux-scsi@vger.kernel.org,
	martin.petersen@oracle.com, avri.altman@sandisk.com,
	alim.akhtar@samsung.com, jejb@linux.ibm.com
Cc: wsd_upstream@mediatek.com, linux-mediatek@lists.infradead.org,
	chun-hung.wu@mediatek.com, alice.chao@mediatek.com,
	cc.chou@mediatek.com, chaotian.jing@mediatek.com,
	tun-yu.yu@mediatek.com, eddie.huang@mediatek.com,
	naomi.chu@mediatek.com, ed.tsai@mediatek.com,
	quic_cang@guicinc.com, quic_asutoshd@guicinc.com,
	light.hsieh@mediatek.com
Subject: Re: [PATCH v1] ufs: core: decouple CQE processing from spinlock critical section
Date: Thu, 14 May 2026 09:22:54 -0700	[thread overview]
Message-ID: <382f6d79-c877-4dc8-813b-ee91ac5489f9@acm.org> (raw)
In-Reply-To: <20260514082906.58593-1-peter.wang@mediatek.com>

On 5/14/26 1:26 AM, peter.wang@mediatek.com wrote:
> 4. In both ufshcd_mcq_compl_all_cqes_lock() and
>     ufshcd_mcq_poll_cqe_lock(), snapshot the starting CQE pointer before
>     advancing the head slot under the spinlock, then process the collected
>     CQEs after releasing the lock using the new helper.

This can't work reliably. ufshcd_mcq_poll_cqe_lock() may be called
concurrently from different CPU cores, e.g. from a UFS completion
interrupt and from ufshcd_poll(). Processing CQEs without holding
hwq->cq_lock may lead to overwriting of CQEs before these have been
processed.

Thanks,

Bart.


      reply	other threads:[~2026-05-14 16:23 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-14  8:26 [PATCH v1] ufs: core: decouple CQE processing from spinlock critical section peter.wang
2026-05-14 16:22 ` Bart Van Assche [this message]

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