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From: Bart Van Assche <bvanassche@acm.org>
To: Avri Altman <Avri.Altman@wdc.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/3] scsi: ufs: core: Remove redundant host_lock calls around UTMRLDBR.
Date: Wed, 23 Oct 2024 12:44:22 -0700	[thread overview]
Message-ID: <b43d5e01-cafe-4133-9873-68897439bf5f@acm.org> (raw)
In-Reply-To: <DM6PR04MB65750DBFE520C0DDE075146EFC4D2@DM6PR04MB6575.namprd04.prod.outlook.com>

On 10/22/24 11:47 PM, Avri Altman wrote:
>> On 10/22/24 12:43 AM, Avri Altman wrote:
>>>        for_each_set_bit(tag, &issued, hba->nutmrs) {
>>>                struct request *req = hba->tmf_rqs[tag];
>>>                struct completion *c = req->end_io_data;
>>
>> Would it be sufficient to hold the SCSI host lock around the
>> hba->outstanding_tasks read only? I don't think that the
>> for_each_set_bit() loop needs to be protected with the SCSI host lock.
 >
> That may cause concurrent access to tmf_rqs?

Right, the host_lock serializes hba->tmf_rqs[] accesses. Without having
analyzed whether or not removing locking from around the hba->tmf_rqs[]
accesses, let's keep this locking.

> So better withdraw from changing ufshcd_tmc_handler() and just leave
> the whole function as it is?
That sounds good to me.

Thanks,

Bart.

  reply	other threads:[~2024-10-23 19:44 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-22  7:43 [PATCH v2 0/3] Untie the host lock entanglement - part 1 Avri Altman
2024-10-22  7:43 ` [PATCH v2 1/3] scsi: ufs: core: Remove redundant host_lock calls around UTMRLDBR Avri Altman
2024-10-22 16:51   ` Bart Van Assche
2024-10-23  6:47     ` Avri Altman
2024-10-23 19:44       ` Bart Van Assche [this message]
2024-10-22  7:43 ` [PATCH v2 2/3] scsi: ufs: core: Remove redundant host_lock calls around UTMRLCLR Avri Altman
2024-10-22 16:52   ` Bart Van Assche
2024-10-22  7:43 ` [PATCH v2 3/3] scsi: ufs: core: Remove redundant host_lock calls around UTRLCLR Avri Altman
2024-10-22 16:52   ` Bart Van Assche

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