Re: [PATCH] NFS: Allow very small rsize & wsize again

Jeff Layton
2022-12-01T11:44:33Z

On Wed, 2022-11-30 at 15:30 -0500, Anna Schumaker wrote:
> From: Anna Schumaker <Anna.Schumaker@Netapp.com>
>
> 940261a19508 introduced nfs_io_size() to clamp the iosize to a multiple
> of PAGE_SIZE. This had the unintended side effect of no longer allowing
> iosizes less than a page, which could be useful in some situations.
>
> UDP already has an exception that causes it to fall back on the
> power-of-two style sizes instead. This patch adds an additional
> exception for very small iosizes.
>
> Reported-by: Jeff Layton <jlayton@kernel.org>
> Fixes: 940261a19508 ("NFS: Allow setting rsize / wsize to a multiple of PAGE_SIZE")
> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
> ---
> fs/nfs/internal.h | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 647fc3f547cb..ae7d4a8c728c 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -739,12 +739,10 @@ unsigned long nfs_io_size(unsigned long iosize, enum xprt_transports proto)
> iosize = NFS_DEF_FILE_IO_SIZE;
> else if (iosize >= NFS_MAX_FILE_IO_SIZE)
> iosize = NFS_MAX_FILE_IO_SIZE;
> - else
> - iosize = iosize & PAGE_MASK;
>
> - if (proto == XPRT_TRANSPORT_UDP)
> + if (proto == XPRT_TRANSPORT_UDP || iosize < PAGE_SIZE)
> return nfs_block_bits(iosize, NULL);
> - return iosize;
> + return iosize & PAGE_MASK;
> }
>
> /*

Looks good. Thanks, Anna.

Reviewed-by: Jeff Layton <jlayton@kernel.org>