Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Subject: Re: [PATCH v2] ata:libata-eh:Cleanup ata_scsi_cmd_error_handler
To:     Wenchao Hao <haowenchao@huawei.com>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     liuzhiqiang26@huawei.com, linfeilong@huawei.com
References: <20221215105747.1927412-1-haowenchao@huawei.com>
From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Message-ID: <f552f2ab-895a-14dd-d391-a7b1c9930c88@gmail.com>
Date:   Thu, 15 Dec 2022 14:30:38 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.10.1
MIME-Version: 1.0
In-Reply-To: <20221215105747.1927412-1-haowenchao@huawei.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

Hello!

  The subject should really look like "ata: libata-eh: Cleanup
ata_scsi_cmd_error_handler()"...

On 12/15/22 1:57 PM, Wenchao Hao wrote:

> If ap->ops->error_handler is NULL, just return.
> 
> V2:
> - Check ap->ops->error_handler without taking the spin lock

   This normally belongs under ---...

> Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
> ---
>  drivers/ata/libata-eh.c | 96 ++++++++++++++++++++---------------------
>  1 file changed, 48 insertions(+), 48 deletions(-)
> 
> diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
> index 34303ce67c14..c445c272e77f 100644
> --- a/drivers/ata/libata-eh.c
> +++ b/drivers/ata/libata-eh.c
[...]
> @@ -584,62 +589,57 @@ void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
>  	 * timed out iff its associated qc is active and not failed.
>  	 */
>  	spin_lock_irqsave(ap->lock, flags);
> -	if (ap->ops->error_handler) {
> -		struct scsi_cmnd *scmd, *tmp;
> -		int nr_timedout = 0;
> -
> -		/* This must occur under the ap->lock as we don't want
> -		   a polled recovery to race the real interrupt handler
> -
> -		   The lost_interrupt handler checks for any completed but
> -		   non-notified command and completes much like an IRQ handler.
>  
> -		   We then fall into the error recovery code which will treat
> -		   this as if normal completion won the race */
> -
> -		if (ap->ops->lost_interrupt)
> -			ap->ops->lost_interrupt(ap);
> +	/* This must occur under the ap->lock as we don't want

   The multi-line comments should start with /* on its own line...

> +	 * a polled recovery to race the real interrupt handler
> +	 *
> +	 * The lost_interrupt handler checks for any completed but
> +	 * non-notified command and completes much like an IRQ handler.
> +	 *
> +	 * We then fall into the error recovery code which will treat
> +	 * this as if normal completion won the race
> +	 */
> +	if (ap->ops->lost_interrupt)
> +		ap->ops->lost_interrupt(ap);
>  
> -		list_for_each_entry_safe(scmd, tmp, eh_work_q, eh_entry) {
> -			struct ata_queued_cmd *qc;
> +	list_for_each_entry_safe(scmd, tmp, eh_work_q, eh_entry) {
> +		struct ata_queued_cmd *qc;
>  
> -			ata_qc_for_each_raw(ap, qc, i) {
> -				if (qc->flags & ATA_QCFLAG_ACTIVE &&
> -				    qc->scsicmd == scmd)
> -					break;
> -			}
> +		ata_qc_for_each_raw(ap, qc, i) {
> +			if (qc->flags & ATA_QCFLAG_ACTIVE &&
> +			    qc->scsicmd == scmd)
> +				break;
> +		}
>  
> -			if (i < ATA_MAX_QUEUE) {
> -				/* the scmd has an associated qc */
> -				if (!(qc->flags & ATA_QCFLAG_FAILED)) {
> -					/* which hasn't failed yet, timeout */
> -					qc->err_mask |= AC_ERR_TIMEOUT;
> -					qc->flags |= ATA_QCFLAG_FAILED;
> -					nr_timedout++;
> -				}
> -			} else {
> -				/* Normal completion occurred after
> -				 * SCSI timeout but before this point.
> -				 * Successfully complete it.
> -				 */
> -				scmd->retries = scmd->allowed;
> -				scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
> +		if (i < ATA_MAX_QUEUE) {
> +			/* the scmd has an associated qc */
> +			if (!(qc->flags & ATA_QCFLAG_FAILED)) {
> +				/* which hasn't failed yet, timeout */
> +				qc->err_mask |= AC_ERR_TIMEOUT;
> +				qc->flags |= ATA_QCFLAG_FAILED;
> +				nr_timedout++;
>  			}
> +		} else {
> +			/* Normal completion occurred after

   Here as well...

> +			 * SCSI timeout but before this point.
> +			 * Successfully complete it.
> +			 */
> +			scmd->retries = scmd->allowed;
> +			scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
>  		}
> +	}
>  
> -		/* If we have timed out qcs.  They belong to EH from
> -		 * this point but the state of the controller is
> -		 * unknown.  Freeze the port to make sure the IRQ
> -		 * handler doesn't diddle with those qcs.  This must
> -		 * be done atomically w.r.t. setting QCFLAG_FAILED.
> -		 */
> -		if (nr_timedout)
> -			__ata_port_freeze(ap);
> -
> +	/* If we have timed out qcs.  They belong to EH from

   And here...

[...]

MBR, Sergey