Re: [PATCH] ceph: drop special-casing for ITER_PIPE in ceph_sync_read

[John Hubbard <jhubbard@nvidia.com>]

On 8/25/20 1:13 PM, Jeff Layton wrote:
> From: John Hubbard <jhubbard@nvidia.com>
>

I think that's meant to be, "From: Jeff Layton <jlayton@kernel.org>".
This looks much nicer than what I came up with. :)

> This special casing was added in 7ce469a53e71 (ceph: fix splice
> read for no Fc capability case). The confirm callback for ITER_PIPE
> expects that the page is Uptodate or a pagecache page and and returns
> an error otherwise.
> 
> A simpler workaround is just to use the Uptodate bit, which has no
> meaning for anonymous pages. Rip out the special casing for ITER_PIPE
> and just SetPageUptodate before we copy to the iter.
> 
> Cc: "Yan, Zheng" <ukernel@gmail.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>   fs/ceph/file.c | 71 +++++++++++++++++---------------------------------
>   1 file changed, 24 insertions(+), 47 deletions(-)
> 
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index fb3ea715a19d..ed8fbfe3bddc 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -863,6 +863,8 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
>   		size_t page_off;
>   		u64 i_size;
>   		bool more;
> +		int idx;
> +		size_t left;
>   
>   		req = ceph_osdc_new_request(osdc, &ci->i_layout,
>   					ci->i_vino, off, &len, 0, 1,
> @@ -876,29 +878,13 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
>   
>   		more = len < iov_iter_count(to);
>   
> -		if (unlikely(iov_iter_is_pipe(to))) {
> -			ret = iov_iter_get_pages_alloc(to, &pages, len,
> -						       &page_off);


+1 for removing a call to iov_iter_get_pages_alloc()! My list is shorter now.


thanks,
-- 
John Hubbard
NVIDIA