ACK.--b.
On Sat, May 27, 2017 at 11:16:53AM +0300, Christoph Hellwig wrote:
> Instead of messing with the address limit to use vfs_read/vfs_writev.
>
> Note that this requires that exported file implement ->read_iter and
> ->write_iter. All currently exportable file systems do this.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/nfsd/vfs.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 2be32955d7f2..37a03c456b38 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -911,13 +911,12 @@ __be32 nfsd_splice_read(struct svc_rqst *rqstp,
> __be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,
> unsigned long *count)
> {
> - mm_segment_t oldfs;
> + struct iov_iter iter;
> int host_err;
>
> - oldfs = get_fs();
> - set_fs(KERNEL_DS);
> - host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset, 0);
> - set_fs(oldfs);
> + iov_iter_kvec(&iter, READ | ITER_KVEC, vec, vlen, *count);
> + host_err = vfs_iter_read(file, &iter, &offset, 0);
> +
> return nfsd_finish_read(file, count, host_err);
> }
>
> @@ -974,7 +973,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
> unsigned long *cnt, int stable)
> {
> struct svc_export *exp;
> - mm_segment_t oldfs;
> + struct iov_iter iter;
> __be32 err = 0;
> int host_err;
> int use_wgather;
> @@ -1000,10 +999,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
> if (stable && !use_wgather)
> flags |= RWF_SYNC;
>
> - /* Write the data. */
> - oldfs = get_fs(); set_fs(KERNEL_DS);
> - host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos, flags);
> - set_fs(oldfs);
> + iov_iter_kvec(&iter, WRITE | ITER_KVEC, vec, vlen, *cnt);
> + host_err = vfs_iter_write(file, &iter, &pos, flags);
> if (host_err < 0)
> goto out_nfserr;
> *cnt = host_err;
> --
> 2.11.0
