From: Jens Axboe <axboe@kernel.dk>
To: James Bottomley <James.Bottomley@HansenPartnership.com>,
Bart Van Assche <bvanassche@acm.org>,
Christoph Hellwig <hch@lst.de>,
martin.petersen@oracle.com
Cc: alim.akhtar@samsung.com, avri.altman@wdc.com,
linux-scsi@vger.kernel.org, linux-block@vger.kernel.org
Subject: Re: [PATCH] scsi: ufs: mark HPB support as BROKEN
Date: Tue, 26 Oct 2021 11:25:31 -0600 [thread overview]
Message-ID: <870e986c-08dd-2fa2-a593-0f97e10d6df5@kernel.dk> (raw)
In-Reply-To: <7ed11ee1f8beca9a27c0cb2eb0dcea4dbd557961.camel@HansenPartnership.com>
On 10/26/21 11:19 AM, James Bottomley wrote:
> On Tue, 2021-10-26 at 09:36 -0700, Bart Van Assche wrote:
>> On 10/26/21 12:12 AM, Christoph Hellwig wrote:
>>> The HPB support added this merge window is fundanetally flawed as
>>> it
>> ^^^^^^^^^^^^
>> fundanetally ->
>> fundamentally
>>
>> Since the implementation can be reworked not to use
>> blk_insert_cloned_request() I'm not sure using the word
>> "fundamentally" is appropriate.
>
> I'm not so sure about that. The READ BUFFER implementation runs from a
> work queue and looks fine. The WRITE BUFFER implementation is trying
> to spawn a second command to precede the queued command which is a
> fundamental problem for the block API. It's not clear to me that the
> WRITE BUFFER can be fixed because of the tying to the sent command ...
> but like I said, the standard is proprietary so I can't look at it to
> see if there are alternative ways of achieving the same effect.
Is there a model in which this can actually work? If not, or if we
aren't sure, I think we'd be better off just reverting the parts
involved with that block layer misuse. Simply marking it broken is a
half measure that doesn't really solve anything (except send a message).
IMHO, it should be reverted and the clone usage we currently export be
moved into dm for now. That'll prevent further abuse of this in the
future.
--
Jens Axboe
next prev parent reply other threads:[~2021-10-26 17:25 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-26 7:12 [PATCH] scsi: ufs: mark HPB support as BROKEN Christoph Hellwig
2021-10-26 7:18 ` Hannes Reinecke
2021-10-26 7:24 ` Damien Le Moal
2021-10-26 13:04 ` James Bottomley
2021-10-26 16:36 ` Bart Van Assche
2021-10-26 17:19 ` James Bottomley
2021-10-26 17:25 ` Jens Axboe [this message]
2021-10-26 18:05 ` Bart Van Assche
2021-10-26 18:10 ` Jens Axboe
2021-10-26 18:18 ` James Bottomley
2021-10-26 18:27 ` Martin K. Petersen
2021-10-26 20:10 ` Bart Van Assche
2021-10-27 5:27 ` Christoph Hellwig
2021-10-27 12:20 ` James Bottomley
2021-10-28 20:21 ` Bart Van Assche
2021-10-28 20:33 ` James Bottomley
2021-10-28 20:53 ` Bart Van Assche
[not found] ` <CGME20211028205342epcas2p40838e84438572adf052d106dc82e35ff@epcms2p6>
2021-10-28 21:14 ` Daejun Park
2021-10-27 13:16 ` Bart Van Assche
2021-10-27 14:12 ` Keith Busch
2021-10-27 14:38 ` Jens Axboe
2021-10-27 14:43 ` James Bottomley
2021-10-27 15:03 ` Ming Lei
2021-10-27 15:06 ` Jens Axboe
2021-10-27 15:16 ` Ming Lei
2021-10-27 15:44 ` Martin K. Petersen
2021-10-27 15:58 ` Ming Lei
2021-10-27 16:16 ` Keith Busch
2021-10-27 16:19 ` Jens Axboe
2021-10-28 0:42 ` Ming Lei
[not found] ` <CGME20211028004244epcas2p1f2212bf94ef861dfa6cd082c3cbb1803@epcms2p1>
2021-10-28 1:10 ` Daejun Park
2021-10-28 2:07 ` Ming Lei
2021-10-27 16:59 ` Martin K. Petersen
2021-10-27 15:35 ` Martin K. Petersen
2021-10-27 15:40 ` Jens Axboe
2021-10-27 16:16 ` Martin K. Petersen
2021-10-27 17:01 ` Bart Van Assche
2021-10-28 1:32 ` Ming Lei
[not found] ` <CGME20211026201057epcas2p4174ba542fd5abe7ec8f4469f8c60303a@epcms2p7>
2021-10-26 22:22 ` Daejun Park
2021-10-29 10:53 ` Christoph Hellwig
2021-10-29 11:39 ` James Bottomley
2021-10-29 13:35 ` Avri Altman
2021-10-29 13:44 ` James Bottomley
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=870e986c-08dd-2fa2-a593-0f97e10d6df5@kernel.dk \
--to=axboe@kernel.dk \
--cc=James.Bottomley@HansenPartnership.com \
--cc=alim.akhtar@samsung.com \
--cc=avri.altman@wdc.com \
--cc=bvanassche@acm.org \
--cc=hch@lst.de \
--cc=linux-block@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).