From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>,
John Garry <john.garry@huawei.com>,
axboe@kernel.dk, jejb@linux.ibm.com, martin.petersen@oracle.com,
brking@us.ibm.com, hch@lst.de, linux-block@vger.kernel.org,
linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org, chenxiang66@hisilicon.com
Subject: Re: [PATCH RFC v2 03/18] scsi: core: Implement reserved command handling
Date: Mon, 20 Jun 2022 08:28:28 +0200 [thread overview]
Message-ID: <20220620062828.GA10753@lst.de> (raw)
In-Reply-To: <88d192b5-741b-7104-7f72-0178aa18bafb@suse.de>
On Mon, Jun 20, 2022 at 08:24:24AM +0200, Hannes Reinecke wrote:
> So my idea for SATA is simply _not_ to use reserved tags.
> Any TMF functions (or the equivalent thereof) should always be sent as
> non-NCQ commands. And when doing so we're back to QD=1 on SATA anyway, so
> there _must_ be tags available. Consequently the main reason for having
> reserved tags (namely to guarantee that tags are available for TMF) doesn't
> apply here.
At least in the non-elevator case (which includes all passthrough I/O)
request have tags assigned as soon as they are allocated. So, we
absolutely can have all tags allocated and then need to do a TMF.
next prev parent reply other threads:[~2022-06-20 6:29 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-09 10:29 [PATCH RFC v2 00/18] blk-mq/libata/scsi: SCSI driver tagging improvements John Garry
2022-06-09 10:29 ` [PATCH RFC v2 01/18] blk-mq: Add a flag for reserved requests John Garry
2022-06-14 6:43 ` Christoph Hellwig
2022-06-14 9:29 ` John Garry
2022-06-14 18:00 ` Bart Van Assche
2022-06-14 18:30 ` John Garry
2022-06-09 10:29 ` [PATCH RFC v2 02/18] scsi: core: Resurrect scsi_{get,free}_host_dev() John Garry
2022-06-14 6:44 ` Christoph Hellwig
2022-06-14 9:33 ` John Garry
2022-06-14 19:33 ` Bart Van Assche
2022-06-15 13:44 ` John Garry
2022-06-09 10:29 ` [PATCH RFC v2 03/18] scsi: core: Implement reserved command handling John Garry
2022-06-13 7:01 ` Damien Le Moal
2022-06-13 8:25 ` John Garry
2022-06-13 9:06 ` Damien Le Moal
2022-06-13 9:34 ` John Garry
2022-06-13 9:43 ` Damien Le Moal
2022-06-13 10:05 ` John Garry
2022-06-20 6:45 ` Hannes Reinecke
2022-06-20 7:06 ` Damien Le Moal
2022-06-14 18:20 ` Bart Van Assche
2022-06-14 23:43 ` Damien Le Moal
2022-06-15 7:35 ` John Garry
2022-06-16 2:47 ` Damien Le Moal
2022-06-16 8:24 ` John Garry
2022-06-16 8:41 ` Damien Le Moal
2022-06-20 8:27 ` Hannes Reinecke
2022-06-20 9:02 ` Damien Le Moal
2022-06-20 9:05 ` Christoph Hellwig
2022-06-20 11:24 ` Damien Le Moal
2022-06-20 11:56 ` Hannes Reinecke
2022-06-20 8:02 ` Hannes Reinecke
2022-06-20 6:24 ` Hannes Reinecke
2022-06-20 6:28 ` Christoph Hellwig [this message]
2022-06-20 7:03 ` Hannes Reinecke
2022-06-20 7:14 ` Damien Le Moal
2022-06-09 10:29 ` [PATCH RFC v2 04/18] scsi: core: Add support to send reserved commands John Garry
2022-06-13 7:03 ` Damien Le Moal
2022-06-13 9:40 ` John Garry
2022-06-13 9:41 ` Damien Le Moal
2022-06-09 10:29 ` [PATCH RFC v2 05/18] scsi: core: Allocate SCSI host sdev when required John Garry
2022-06-09 10:29 ` [PATCH RFC v2 06/18] libata-scsi: Add ata_scsi_queue_internal() John Garry
2022-06-13 7:12 ` Damien Le Moal
2022-06-13 9:41 ` John Garry
2022-06-09 10:29 ` [PATCH RFC v2 07/18] libata-scsi: Add ata_internal_queuecommand() John Garry
2022-06-13 7:16 ` Damien Le Moal
2022-06-13 9:44 ` John Garry
2022-06-09 10:29 ` [PATCH RFC v2 08/18] libata: Queue ATA internal commands as requests John Garry
2022-06-13 7:22 ` Damien Le Moal
2022-06-13 8:13 ` John Garry
2022-06-09 10:29 ` [PATCH RFC v2 09/18] scsi: ipr: Support reserved commands John Garry
2022-06-09 10:29 ` [PATCH RFC v2 10/18] libata/scsi: libsas: Add sas_queuecommand_internal() John Garry
2022-06-09 10:29 ` [PATCH RFC v2 11/18] scsi: libsas: Don't attempt to find scsi host rphy in slave alloc John Garry
2022-06-09 10:29 ` [PATCH RFC v2 12/18] scsi: libsas drivers: Prepare for reserved commands John Garry
2022-06-09 10:29 ` [PATCH RFC v2 13/18] scsi: libsas: Allocate SCSI commands for tasks John Garry
2022-06-09 10:29 ` [PATCH RFC v2 14/18] scsi: libsas: Queue SMP commands as requests John Garry
2022-06-09 10:29 ` [PATCH RFC v2 15/18] scsi: libsas: Queue TMF " John Garry
2022-06-09 10:29 ` [PATCH RFC v2 16/18] scsi: core: Add scsi_alloc_request_hwq() John Garry
2022-06-09 10:29 ` [PATCH RFC v2 17/18] scsi: libsas: Queue internal abort commands as requests John Garry
2022-06-09 10:29 ` [PATCH RFC v2 18/18] scsi: libsas drivers: Remove private tag management John Garry
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