Re: [PATCH V2 0/3] SWIOTLB: Preserve swiotlb map offset when needed.

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Feb 01, 2021 at 10:30:14AM -0800, Jianxiong Gao wrote:
> NVMe driver and other applications may depend on the data offset
> to operate correctly. Currently when unaligned data is mapped via
> SWIOTLB, the data is mapped as slab aligned with the SWIOTLB. This
> patch adds an option to make sure the mapped data preserves its
> offset of the orginal addrss.
> 
> Without the patch when creating xfs formatted disk on NVMe backends,
> with swiotlb=force in kernel boot option, creates the following error:
> meta-data=/dev/nvme2n1   isize=512    agcount=4, agsize=131072 blks
>          =               sectsz=512   attr=2, projid32bit=1
>          =               crc=1        finobt=1, sparse=0, rmapbt=0, refl
> ink=0
> data     =               bsize=4096   blocks=524288, imaxpct=25
>          =               sunit=0      swidth=0 blks
> naming   =version 2      bsize=4096   ascii-ci=0 ftype=1
> log      =internal log   bsize=4096   blocks=2560, version=2
>          =               sectsz=512   sunit=0 blks, lazy-count=1
> realtime =none           extsz=4096   blocks=0, rtextents=0
> mkfs.xfs: pwrite failed: Input/output error
> 
> Jianxiong Gao (3):
>   Adding page_offset_mask to device_dma_parameters
>   Add swiotlb offset preserving mapping when
>     dma_dma_parameters->page_offset_mask is non zero.
>   Adding device_dma_parameters->offset_preserve_mask to NVMe driver.
> 
>  drivers/nvme/host/pci.c     |  4 ++++
>  include/linux/device.h      |  1 +
>  include/linux/dma-mapping.h | 17 +++++++++++++++++
>  kernel/dma/swiotlb.c        | 16 +++++++++++++++-
>  4 files changed, 37 insertions(+), 1 deletion(-)
> 
> -- 
> 2.27.0
> 

You forgot to mention somewhere, what changed from v1 to v2 :(