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Subject: [PATCH 0/2] multi-page bvec configuration for integrity payload
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Sender: Jinyoung Choi <j-young.choi@samsung.com>
From:   Jinyoung Choi <j-young.choi@samsung.com>
To:     "hch@lst.de" <hch@lst.de>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        "axboe@kernel.dk" <axboe@kernel.dk>,
        "sagi@grimberg.me" <sagi@grimberg.me>,
        "kbusch@kernel.org" <kbusch@kernel.org>,
        "chaitanya.kulkarni@wdc.com" <chaitanya.kulkarni@wdc.com>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Message-ID: <20230728075537epcms2p194154023a4cdbe37c0346ef1102d1d63@epcms2p1>
Date:   Fri, 28 Jul 2023 16:55:37 +0900
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References: <CGME20230728075537epcms2p194154023a4cdbe37c0346ef1102d1d63@epcms2p1>
Precedence: bulk

In the case of NVMe, it has an integrity payload consisting of one segment.
So, rather than configuring SG_LIST, it was changed by direct DMA mapping.

The page-merge is not performed for the struct bio_vec when creating 
a integrity payload in block.
As a result, when creating an integrity paylaod beyond one page, each 
struct bio_vec is generated, and its bv_len does not exceed the PAGESIZE.

To solve it, bio_integrity_add_page() should just add to the existing 
bvec, similar to bio_add_page() and friends. 
As the bip configuration changed, the code related to sg_list was
also modified.

(ref: https://lore.kernel.org/linux-nvme/yq18rewbmay.fsf@ca-mkp.ca.oracle.com/T/#t)


Tested like this:

- Format (support pi)
$ sudo nvme format /dev/nvme2n1 --force -n 1 -i 1 -p 0 -m 0 -l 1 -r

- Run FIO
[global]
ioengine=libaio
group_reporting

[job]
bs=512k
iodepth=256
rw=write
numjobs=8
direct=1
runtime=10s
filename=/dev/nvme2n1

- Result
...
[   93.496218] nvme2n1: I/O Cmd(0x1) @ LBA 62464, 1024 blocks, I/O Error (sct 0x2 / sc 0x82) MORE
[   93.496227] protection error, dev nvme2n1, sector 62464 op 0x1:(WRITE) flags 0x18800 phys_seg 3 prio class 2
[   93.538788] nvme2n1: I/O Cmd(0x1) @ LBA 6144, 1024 blocks, I/O Error (sct 0x2 / sc 0x82) MORE
[   93.538798] protection error, dev nvme2n1, sector 6144 op 0x1:(WRITE) flags 0x18800 phys_seg 3 prio class 2
[   93.566231] nvme2n1: I/O Cmd(0x1) @ LBA 124928, 1024 blocks, I/O Error (sct 0x0 / sc 0x4)
[   93.566241] I/O error, dev nvme2n1, sector 124928 op 0x1:(WRITE) flags 0x18800 phys_seg 3 prio class 2
[   93.694147] nvme2n1: I/O Cmd(0x1) @ LBA 64512, 1024 blocks, I/O Error (sct 0x2 / sc 0x82) MORE
[   93.694155] protection error, dev nvme2n1, sector 64512 op 0x1:(WRITE) flags 0x18800 phys_seg 3 prio class 2
[   93.694299] nvme2n1: I/O Cmd(0x1) @ LBA 5120, 1024 blocks, I/O Error (sct 0x2 / sc 0x82) MORE
[   93.694305] protection error, dev nvme2n1, sector 5120 op 0x1:(WRITE) flags 0x18800 phys_seg 3 prio class 2
...

Jinyoung Choi (2):
  block: make bvec_try_merge_hw_page() non-static
  bio-integrity: create multi-page bvecs in bio_integrity_add_page()

 block/bio-integrity.c | 50 ++++++++++++++++++++++++-------------------
 block/bio.c           |  2 +-
 block/blk.h           |  4 ++++
 3 files changed, 33 insertions(+), 23 deletions(-)

-- 
2.34.1