Re: [PATCH v2 4/4] NFSD: Implement NFSD_IO_DIRECT for NFS READ

[Chuck Lever <cel@kernel.org>]

On 9/18/25 9:29 AM, Mike Snitzer wrote:
>> +	/* Read a properly-aligned region of bytes into rq_bvec */
>> +	dio_start = round_down(offset, nf->nf_dio_read_offset_align);
>> +	dio_end = round_up(offset + *count, nf->nf_dio_read_offset_align);
>> +
>> +	kiocb.ki_pos = dio_start;
>> +
>> +	v = 0;
>> +	total = *count;
> Hi Chuck,
> 
> Looks like you introduced a copy-n-paste bug when updating
> nfsd_direct_read's while loop to follow nfsd_iter_read's lead.
> 
> Should be:
> 	total = dio_end - dio_start;
> 
> [NOTE: this was the reason I saw a crash with my incremental patch
> that handled 'base', see:
> https://lore.kernel.org/linux-nfs/aMwcUdWdey69k2iK@kernel.org/
> ]

Indeed. Fixed in my tree, I will push it in a moment.

I'm traveling this week, so I don't have an opportunity to do more
than compile-test these before posting/pushing.


-- 
Chuck Lever