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Subject: [PATCH 0/2] Fix NVMe metadata mapping size for integrity
Reply-To: j-young.choi@samsung.com
Sender: Jinyoung CHOI <j-young.choi@samsung.com>
From:   Jinyoung CHOI <j-young.choi@samsung.com>
To:     "kbusch@kernel.org" <kbusch@kernel.org>,
        "axboe@fb.com" <axboe@fb.com>, "hch@lst.de" <hch@lst.de>,
        "sagi@grimberg.me" <sagi@grimberg.me>,
        "chaitanya.kulkarni@wdc.com" <chaitanya.kulkarni@wdc.com>,
        "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Message-ID: <20230412051642epcms2p648d91f72aba5647bbccd6d4d6333224e@epcms2p6>
Date:   Wed, 12 Apr 2023 14:16:42 +0900
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References: <CGME20230412051642epcms2p648d91f72aba5647bbccd6d4d6333224e@epcms2p6>
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 this problem, DMA mapping for metadata was modified to use the 
total segment size of the integrity payload.


Tested like this:

- Format (support pi type 1)
$ 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):
  blk-integrity: add rq_integrity_payload_size helper
  nvme-pci: fix metadata mapping length

 drivers/nvme/host/pci.c       | 9 ++++++---
 include/linux/blk-integrity.h | 7 +++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

-- 
2.34.1