From: Kanchan Joshi <joshi.k@samsung.com>
To: Christoph Hellwig <hch@lst.de>
Cc: axboe@kernel.dk, martin.petersen@oracle.com, kbusch@kernel.org,
brauner@kernel.org, asml.silence@gmail.com, dw@davidwei.uk,
io-uring@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-block@vger.kernel.org, gost.dev@samsung.com,
Anuj Gupta <anuj20.g@samsung.com>
Subject: Re: [PATCH 04/10] block: avoid unpinning/freeing the bio_vec incase of cloned bio
Date: Wed, 1 May 2024 18:32:45 +0530 [thread overview]
Message-ID: <ebeca5f1-8d80-e4d4-cf45-9a14ef1413a5@samsung.com> (raw)
In-Reply-To: <20240429170929.GB31337@lst.de>
On 4/29/2024 10:39 PM, Christoph Hellwig wrote:
> On Mon, Apr 29, 2024 at 05:10:59PM +0530, Kanchan Joshi wrote:
>>> This feels wrong. I suspect the problem is that BIP_COPY_USER is
>>> inherited for clone bios while it shouldn't.
>>>
>>
>> But BIP_COPY_USER flag is really required in the clone bio. So that we
>> can copy the subset of the metadata back (from kernel bounce buffer to
>> user space pinned buffer) in case of read io.
>>
>> Overall, copy-back will happen in installments (for each cloned bio),
>> while the unpin will happen in one shot (for the source bio).
>
> That seems a bit odd compared to the bio data path. If you think this
> is better than the version used in the data path let's convert the
> data path to this scheme first to make sure we don't diverge and get
> the far better testing on the main data map side.
>
Can you please tell what function(s) in bio data path that need this
conversion?
To me data path handling seems similar. Each cloned bio will lead to
some amount of data transfer to pinned user-memory. The same is
happening for meta transfer here.
next prev parent reply other threads:[~2024-05-01 13:02 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20240425184649epcas5p42f6ddbfb1c579f043a919973c70ebd03@epcas5p4.samsung.com>
2024-04-25 18:39 ` [PATCH 00/10] Read/Write with meta/integrity Kanchan Joshi
[not found] ` <CGME20240425184651epcas5p3404f2390d6cf05148eb96e1af093e7bc@epcas5p3.samsung.com>
2024-04-25 18:39 ` [PATCH 01/10] block: set bip_vcnt correctly Kanchan Joshi
2024-04-27 7:02 ` Christoph Hellwig
2024-04-27 14:16 ` Keith Busch
2024-04-29 10:59 ` Kanchan Joshi
2024-05-01 7:45 ` Christoph Hellwig
2024-05-01 8:03 ` Keith Busch
[not found] ` <CGME20240425184653epcas5p28de1473090e0141ae74f8b0a6eb921a7@epcas5p2.samsung.com>
2024-04-25 18:39 ` [PATCH 02/10] block: copy bip_max_vcnt vecs instead of bip_vcnt during clone Kanchan Joshi
2024-04-27 7:03 ` Christoph Hellwig
2024-04-29 11:28 ` Kanchan Joshi
2024-04-29 12:04 ` Keith Busch
2024-04-29 17:07 ` Christoph Hellwig
2024-04-30 8:25 ` Keith Busch
2024-05-01 7:46 ` Christoph Hellwig
2024-05-01 7:50 ` Christoph Hellwig
[not found] ` <CGME20240425184656epcas5p42228cdef753cf20a266d12de5bc130f0@epcas5p4.samsung.com>
2024-04-25 18:39 ` [PATCH 03/10] block: copy result back to user meta buffer correctly in case of split Kanchan Joshi
2024-04-27 7:04 ` Christoph Hellwig
[not found] ` <CGME20240425184658epcas5p2adb6bf01a5c56ffaac3a55ab57afaf8e@epcas5p2.samsung.com>
2024-04-25 18:39 ` [PATCH 04/10] block: avoid unpinning/freeing the bio_vec incase of cloned bio Kanchan Joshi
2024-04-27 7:05 ` Christoph Hellwig
2024-04-29 11:40 ` Kanchan Joshi
2024-04-29 17:09 ` Christoph Hellwig
2024-05-01 13:02 ` Kanchan Joshi [this message]
2024-05-02 7:12 ` Christoph Hellwig
2024-05-03 12:01 ` Kanchan Joshi
[not found] ` <CGME20240425184700epcas5p1687590f7e4a3f3c3620ac27af514f0ca@epcas5p1.samsung.com>
2024-04-25 18:39 ` [PATCH 05/10] block, nvme: modify rq_integrity_vec function Kanchan Joshi
2024-04-27 7:18 ` Christoph Hellwig
2024-04-29 11:34 ` Kanchan Joshi
2024-04-29 17:11 ` Christoph Hellwig
[not found] ` <CGME20240425184702epcas5p1ccb0df41b07845bc252d69007558e3fa@epcas5p1.samsung.com>
2024-04-25 18:39 ` [PATCH 06/10] block: modify bio_integrity_map_user argument Kanchan Joshi
2024-04-27 7:19 ` Christoph Hellwig
[not found] ` <CGME20240425184704epcas5p3b9eb6cce9c9658eb1d0d32937e778a5d@epcas5p3.samsung.com>
2024-04-25 18:39 ` [PATCH 07/10] block: define meta io descriptor Kanchan Joshi
[not found] ` <CGME20240425184706epcas5p1d75c19d1d1458c52fc4009f150c7dc7d@epcas5p1.samsung.com>
2024-04-25 18:39 ` [PATCH 08/10] io_uring/rw: add support to send meta along with read/write Kanchan Joshi
2024-04-26 14:25 ` Jens Axboe
2024-04-29 20:11 ` Kanchan Joshi
[not found] ` <CGME20240425184708epcas5p4f1d95cd8d285614f712868d205a23115@epcas5p4.samsung.com>
2024-04-25 18:39 ` [PATCH 09/10] block: add support to send meta buffer Kanchan Joshi
2024-04-26 15:21 ` Keith Busch
2024-04-29 11:47 ` Kanchan Joshi
[not found] ` <CGME20240425184710epcas5p2968bbc40ed10d1f0184bb511af054fcb@epcas5p2.samsung.com>
2024-04-25 18:39 ` [PATCH 10/10] nvme: add separate handling for user integrity buffer Kanchan Joshi
2024-04-25 19:56 ` Keith Busch
2024-04-26 10:57 ` kernel test robot
2024-04-26 14:19 ` [PATCH 00/10] Read/Write with meta/integrity Jens Axboe
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