Messages in this thread | | | Date | Thu, 5 Oct 2023 16:05:50 +0100 | Subject | Re: [PATCH 21/21] nvme: Support atomic writes | From | John Garry <> |
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On 05/10/2023 14:32, Pankaj Raghav wrote: >>> te_unit_[min| max]_sectors expects sectors (512 bytes unit) >>> as input but no conversion is done here from device logical block size >>> to SECTORs. >> Yeah, you are right. I think that we can just use: >> >> blk_queue_atomic_write_unit_max_sectors(disk->queue, >> atomic_bs >> SECTOR_SHIFT); >> > Makes sense. > I still don't grok the difference between max_bytes and unit_max_sectors here. > (Maybe NVMe spec does not differentiate it?)
I think that max_bytes does not need to be a power-of-2 and could be relaxed.
Having said that, max_bytes comes into play for merging of bios - so if we are in a scenario with no merging, then may a well leave atomic_write_max_bytes == atomic_write_unit_max.
But let us check this proposal to relax.
> > I assume min_sectors should be as follows instead of setting it to 1 (512 bytes)? > > blk_queue_atomic_write_unit_min_sectors(disk->queue, bs >> SECTORS_SHIFT);
Yeah, right, we want unit_min to be the logical block size.
Thanks, John
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