Re: [PATCH v3 0/3] Make target send correct io limits

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 11/14/22 4:24 AM, Anastasia Kovaleva wrote:
> Currently iblock always reports MAXIMUM TRANSFER LENGTH in 512b units
> regardless of the LU block size.
> 
> Target block size:
>   target:~ # fdisk -l /dev/nullb0
>   Disk /dev/nullb0: 250 GiB, 268435456000 bytes, 65536000 sectors
>   Units: sectors of 1 * 4096 = 4096 bytes
>   Sector size (logical/physical): 4096 bytes / 4096 bytes
>   I/O size (minimum/optimal): 4096 bytes / 4096 bytes
> 
> Initiator block size:
>   initiator:~ # fdisk -l /dev/sdc
>   Disk /dev/sdc: 250 GiB, 268435456000 bytes, 65536000 sectors
>   Disk model: nullb0
>   Units: sectors of 1 * 4096 = 4096 bytes
>   Sector size (logical/physical): 4096 bytes / 4096 bytes
>   I/O size (minimum/optimal): 4096 bytes / 131072 bytes
> 
> target max transfer length limit:
>   target:~ # cat /sys/block/nullb0/queue/max_hw_sectors_kb
>   128
> 
> So the maximum transfer length should be 128 * 1024 / 4096 = 32 blocks
> But the target sends MTL in 512b units, so the initiators see 256 blocks
> instead.
> 
>   initiator:~ # sg_inq -p 0xb0 /dev/sdc
>   VPD INQUIRY: Block limits page (SBC)
>     Maximum compare and write length: 1 blocks
>     Optimal transfer length granularity: 1 blocks
>     Maximum transfer length: 256 blocks
>     Optimal transfer length: 32 blocks
>     Maximum prefetch transfer length: 0 blocks [ignored]
> 
> This happens because MAXIMUM TRANSFER LENGTH field in VPD Block Limits
> page is derived from dev->dev_attrib.hw_max_sectors which happens to be
> in 512b units for iblock. This patch series fixes this issue and removes
> some special-casing for other backstores.
> 
> Changes since v1:
> Sinse the v1 patch series, some variables was renamed, the checkpatch
> script was run and issues with debug logs was fixed, some refactoring
> was done.
> 

You forgot the tabbing/spacing issue I mentioned (checkpatch --strict reports
them for example). It's probably not a big enough deal to hold this up though.

Reviewed-by: Mike Christie <michael.christie@xxxxxxxxxx>




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]

  Powered by Linux